Extremely high temperatures resulting from climate change have become a major challenge for increasing rice production.Therefore,our objective was to develop heat-tolerant aromatic rice varieties using the pedigree me...Extremely high temperatures resulting from climate change have become a major challenge for increasing rice production.Therefore,our objective was to develop heat-tolerant aromatic rice varieties using the pedigree method,focusing on selecting for seed-setting ability under extremely high temperatures along with the use of single nucleotide polymorphism/insertion and deletion(SNP/InDel)markers to improve aromatic properties and grain quality.Furthermore,the QTL-seq approach was utilized to identify QTLs for seed-setting rate in an F2 population subjected to heat stress.The candidate QTL regions were then aligned to confirm SNPs/InDels in synonymous F7 candidate heat-tolerant lines.The results revealed that four promising lines,namely 84-7-1-9,84-7-1-10,159-3-3-1,and 159-3-3-10,were classified as heat-tolerant with low amylose content.In addition,lines 84-7-1-9 and 84-7-1-10 were identified as aromatic rice encompassing the aroma gene(badh2).Regarding the QTL-seq results,the qSF2.1 region ranged from 311051 to 3929422 bp on chromosome 2,was identified based on the highest contrasting SNP index between the heat-susceptible and tolerant bulks.The candidate genes within this region include two genes related to heat shock proteins,three genes associated with pollen fertility,and four genes involved in heat stress and other abiotic stress responses.These genes are proposed as potential candidates for heat tolerance and could serve as targets in rice breeding programs aimed at enhancing heat tolerance.展开更多
Seedling emergence and seedling establishment are two important phases for the good crop stand and final maize crop harvest. A field study was conducted to explore the effects of different tillage practices and poultr...Seedling emergence and seedling establishment are two important phases for the good crop stand and final maize crop harvest. A field study was conducted to explore the effects of different tillage practices and poultry manure levels on the seedling emergence, growth, development, yield, and economics of the spring planted maize during 2010 and 2011. Experimental treatments include four tillage treatments (zero, minimum, conventional and deep tillage) and three poultry manure amendments (control (no manure), 5 Mg·ha-1 and 10 Mg·ha-1). Seedling emergence was linearly affected as the tillage intensity was increased. Significant relationship of tillage with leaf area index, leaf area duration, crop growth rate, net assimilation rate and total dry matter was recorded during the both years. Poultry manure at the rate of 10 Mg·ha-1 produced the higher leaf area index, leaf area duration, crop growth rate, total dry matter and grain yield as compared to 5 Mg·ha-1 and control. Moreover, experimental results concluded that the deep tillage practice has taken less time to start emergence. Similarly, higher values trend of leaf area index, leaf area duration, crop growth rate, total dry matter accumulation and grain yield was shifted from deep tillage to conventional, minimum and zero tillage practices during both years. Economically, the minimum tillage with poultry manure at rate of 10 Mg·ha-1 gave the better benefit to cost ratio and crop productivity as compared to conventional, deep and zero tillage. The experiment suggested the minimum tillage with poultry manure at the rate of 10 Mg·ha-1 may ensure the maize grain yield sustainability.展开更多
Humic acid （HA）, a fairly stable product of decomposed organic matter that consequently accumulates in ecological systems, enhances plant growth by chelating unavailable nutrients and buffering pH. We examined the e...Humic acid （HA）, a fairly stable product of decomposed organic matter that consequently accumulates in ecological systems, enhances plant growth by chelating unavailable nutrients and buffering pH. We examined the effect of HA derived from lignite on growth and macronutrient uptake of wheat （Triticum acstivum L.） grown in earthen pots under greenhouse conditions. The soils used in the pot experiment were a calcareous Haplustalf and a non-calcareous Haplustalf collected from Raisalpur and Guliana, respectively, in Punjab Province, Pakistan. The experiment consisted of four treatments with HA levels of 0 （control without HA）, 30, 60, and 90 mg kg^-1 soil designated as HA0, HA1, HA2, and HA3, respectively. In the treatment without HA （HA0）, nitrogen （N）, phosphorus （P）, and potassium （K） were applied at 200, 100, and 125 mg kg^-1 soil, respectively. Significant differences among HA levels were recorded for wheat growth （plant height and shoot weight） and N uptake. On an average of both soils, the largest increases in plant height and shoot fresh and dry weights were found with HA2 （60 mg kg^-1 soil）, being 10%, 25%, and 18%, respectively, as compared to the control without HA （HA0）. Both soils responded positively towards HA application. The wheat growth and N uptake in the non-calcareous soil were higher than those of the calcareous soil. The HA application significantly improved K concentration of the non-calcareous soil and P and NO3-N of the calcareous soil. The highest rate of HA （90 mg kg^-1 soil） had a negative effect on growth and nutrient uptake of wheat as well as nutrient accumulation in soil, whereas the medium dose of HA （60 mg kg^-1 soil） was more efficient in promoting wheat growth.展开更多
Low germination and vigor of rice seed associated with dry-seed broadcasting are common problems encountered by rice growers.The objectives of this study were to evaluate the role of potassium nitrate（KNO3）on the pa...Low germination and vigor of rice seed associated with dry-seed broadcasting are common problems encountered by rice growers.The objectives of this study were to evaluate the role of potassium nitrate（KNO3）on the pattern of seed imbibition and to determine the effect of seed priming with KNO3 on the germination percentage,speed and uniformity of germination in rice seed.Experiment 1 compared the patterns of seed imbibition of six concentrations of KNO3（0,0.25,0.50,1.00,1.50,and 2.00%）in two rice cultivars-KDML105 and RD15.The results showed that soaking rice seed in KNO3 at higher concentrations could delay the imbibition time.The higher concentrations of KNO3 delayed the imbibition time of rice seed and took a longer time to reach the end of phases 1 and 2 compared to the lower concentrations.The patterns of seed imbibition using distilled water of both rice cultivars（KDML105 and RD15）were quite similar,but with different concentrations of KNO3,the imbibition time taken to reach the end of phases 1 and 2 was slightly postponed in KDML105 suggesting that different rice cultivars may need different imbibition times for soaking seed in the priming process.Experiment 2 evaluated the effects of seed priming with 1.0 and 2.0%KNO3 at different imbibition times.It was found that priming with 1.0%KNO3 showed better seed germination than priming with 2.0%KNO3 and seed priming with 1.0%KNO3 at the imbibition time of early phase 2（or 28 h for KDML105）improved seed germination and increased both the speed and uniformity of seed germination.The results of this study show promise for the use of priming with 1.0%KNO3 soaked until early phase 2 of seed imbibition for improving the seed germination and vigor of rice in dry seed broadcasting.展开更多
The effects of bispyribac sodium 10% SC and butachlor 50% SC on soil physico-chemical properties and microflora in transplanted kharifrice were investigated over two seasons （2010 and 2011 ） Effects of the herbicide...The effects of bispyribac sodium 10% SC and butachlor 50% SC on soil physico-chemical properties and microflora in transplanted kharifrice were investigated over two seasons （2010 and 2011 ） Effects of the herbicide on bulk density, water holding capacity, moisture content, soil pH, organic matter content, electrical conductivity, as well as total nitrogen, available phosphorus and available potassium contents were analyzed along with microflora population （total bacteria, actinomycetes and fungi）. No significant changes in soil physico-chemical properties were observed. Herbicide treatments resulted in decreases in microbial counts initially. With the degradation of applied herbicides within a considerable time, the microflora populations even exceeded the initial count at 60 d after application of the herbicide.展开更多
With decreasing availability of water for agriculture and increasing demand for rice production, an optimum use of irrigation water and phosphorus may guarantee sustainable rice production. Field experiments were cond...With decreasing availability of water for agriculture and increasing demand for rice production, an optimum use of irrigation water and phosphorus may guarantee sustainable rice production. Field experiments were conducted in 2003 and 2004 to investigate the effect of phosphorus and irrigation levels on yield, water productivity （WP）, phosphorus use efficiency （PUE） and income of low land rice. The experiment was laid out in randomized complete block design with split plot arrangements replicated four times. Main plot consisted of five phosphorus levels, viz. 0 （P0）, 50 （P50）, 100 （P100）, 150 （P15o）, and 200 （P200） kg/hm2, while subplots contained of irrigation times, i.e. 8 （I8）, 10 （I10）, 12 （I12）, and 14 （I14） irrigation levels, each with a water depth of 7.5 cm. Mean values revealed that P150 in combination with I10 produced the highest paddy yield （9.8 t/hm2） and net benefit （1 231.8 US$/hm2） among all the treatments. Phosphorus enhanced WP when applied in appropriate combination with irrigation level. The highest mean WP [13.3 kg/（hm2-mm）] could be achieved at Plso with 18 and decreased with increase in irrigation level, while the highest mean PUE （20.1 kg/kg） could be achieved at P100 with I10 and diminished with higher P levels. The overall results indicate that P150 along with I10 was the best combination for sustainable rice cultivation in silty clay soil.展开更多
Seed-setting rate, yield components and grain quality traits of 169 accessions from an exotic rice germplasm were tested under high temperatures from 40 oC to 45 oC for 6 h during the daytime at the vegetative and rep...Seed-setting rate, yield components and grain quality traits of 169 accessions from an exotic rice germplasm were tested under high temperatures from 40 oC to 45 oC for 6 h during the daytime at the vegetative and reproductive stages, respectively. The results showed that heat stress significantly decreased the seed-setting rate of all the accessions, but the heat stress effects varied among accessions. Based on the decreases in seed-setting rate at high temperatures, N22 was the most tolerant, followed by AUS17, M9962, SONALEE and AUS16. Moreover, the reductions in seed-setting rate and yield under heat stress were more serious at the vegetative stage （45 d before heading） than at the booting stage （15 d before heading）. In addition, heat stress also affected grain quality, especially by conferring chalkiness to most of the accessions, but SONALEE did not change much. The heat-tolerant accessions identified here and the phenotype protocols developed could be used in future genetic studies and breeding programmes focused on heat tolerance.展开更多
Zero tillage with residues retention and optimizing nitrogen fertilization are important strategies to improve soil quality and wheat （Triticum aestivum L.） yield in rice （Oryza sativa L.）-wheat system. Field expe...Zero tillage with residues retention and optimizing nitrogen fertilization are important strategies to improve soil quality and wheat （Triticum aestivum L.） yield in rice （Oryza sativa L.）-wheat system. Field experiments were conducted on silty clay soil （Hyperthermic, and Typic Torrilfuvents） in D. I. Khan, Pakistan, to explore the impact of six tillage methods （zero tillage straw retained （ZTsr）, ZT straw burnt （ZTsb）, reduced tillage straw incorporated （RTsi, including tiller and rotavator）, RT straw burnt （RTsb）, conventional tillage straw incorporated （CTsi, including disc plow, tiller, rotavator, and leveling operations）, CT straw burnt （CTsb）） and ifve nitrogen rates, i.e., 0, 100, 150, 200, and 250 kg ha-1 on wheat yield. Mean values for N revealed that spikes m-2, grains/spike, 1 000-grain weight （g）, and grain yield （kg ha-1） were signiifcantly higher at 200 kg N ha-1 in both the years as well as mean over years than all other treatments. Mean values for tillage revealed that ZTsr produced highest number of spikes m-2 among tillage methods. However, grains/spike, 1 000-grain weight, and grain yield were higher in tillage methods with either straw retained/incorporated than tillage methods with straw burnt. Interaction effects were signiifcant in year 1 and in mean over years regarding spikes m-2, 1 000-grain weight, total soil organic matter （SOM）, and total soil N （TSN）. ZTsr produced the most spikes m-2 and 1 000-grain weight at 200 kg N ha-1. ZTsr also produced higher SOM and TSN at 200-250 kg N ha-1 at the end of 2 yr cropping. Thus ZTsr with 200 kg N ha-1 may be an optimum and sustainable approach to enhance wheat yield and soil quality in rice-wheat system.展开更多
A total of 10 000 M4 individuals in Jao Hom Nil (JHN) mutant population was treated with high temperature (40 ℃ to 45 ℃) during the day time (6 h) from the booting to the harvesting stages, and ambient temperature (...A total of 10 000 M4 individuals in Jao Hom Nil (JHN) mutant population was treated with high temperature (40 ℃ to 45 ℃) during the day time (6 h) from the booting to the harvesting stages, and ambient temperature (33 ℃ to 35℃) was used as the control. The results of screening and yield trials found that the mutant line M9962 had a high spikelet fertility of 78% under heat stress. In addition, the other mutant lines, including M3181 and M7988, had a spikelet fertility of approximately 70%. However, the JHN wild type, Sin Lek, RD15 and RD33 had very low spikelet fertility of 34%, 14%, 9% and 4%, respectively. The lower spikelet fertility at an elevated temperature resulted in a dramatic decrease of filled grain and contributed to a loss in 100-grain weight. M9962 is a potential genetic stock for use in a heat tolerance breeding programme. In addition, spikelet fertility at high temperature was representative of heat tolerance and can be used as a screening trait for heat tolerance during the reproductive phase on a large scale.展开更多
The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated with arsenic （above 0.01 mg/L） in the Indian subcontinent. The study was conducted with organi...The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated with arsenic （above 0.01 mg/L） in the Indian subcontinent. The study was conducted with organic matter to find out the reducing effect on arsenic load to rice （cv. Khitish）. It was observed that intermittent ponding reduced arsenic uptake （23.33% in root, 13.84% in shoot and 19.84% in leaf） at panicle initiation stage, instead of continuous ponding. A decreasing trend of arsenic accumulation （root straw husk whole grain milled grain） was observed in different plant parts at harvest. Combined applications of lathyrus ＋ vermicompost ＋ poultry manure reduced arsenic transport in plant parts （root, straw, husk, whole grains and milled grain） which was significantly at par （p 0.05） with chopped rice straw （5 tons/ha ） ＋ lathyrus green manuring （5 tons/ha） in comparison to control and corresponding soils. A significant negative correlation of arsenic with phosphorus （grain P with arsenic in different parts R 2 = 0.627–0.726 at p 0.01） was observed. Similarly, soil arsenic had a negative correlation with soil available phosphorus （R 2 = 0.822 at p 0.001） followed by soil nitrogen （R 2 = 0.762 at p 0.01） and soil potassium （R 2 = 0.626 at p 0.01）. Hence, effective management of contaminated irrigation water along with organic matter could reduce the arsenic build up to plants and soil.展开更多
Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill^-l on the productivity of rice in Dera Ismail Khan district of North West Frontier Province （NWFP）,...Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill^-l on the productivity of rice in Dera Ismail Khan district of North West Frontier Province （NWFP）, Pakistan. The experiment was laid out in a randomized complete block design with split plot arrangements. Main plots consisted of four transplanting dates viz. 20th and 27th of June and 4th and 1 lth of July while sub-plots contained 1, 2, 3 or 4 seedlings hill^-1. Among transplanting dates, June 20th planted crop gave highest paddy yield and net return with I seedling hill^-1. It explains that the use of more seedlings hill^-1 not only adds to cost but is also a mere wastage of natural resources. Based on research findings, we conclude that the use of I seedling hill^-1 is most appropriate for timely sowing otherwise 4 seedlings hill^-1 should be used to compensate for the yield gap in late transplanted rice.展开更多
Winged bean[Psophocarpus tetragonolobus(L.)DC.]is a vegetable legume crop.The center of origin,diversity and domestication of this crop are not known.In this study,we assessed the genetic diversity and population stru...Winged bean[Psophocarpus tetragonolobus(L.)DC.]is a vegetable legume crop.The center of origin,diversity and domestication of this crop are not known.In this study,we assessed the genetic diversity and population structure of 457 accessions of winged bean collected from six geographical regions(North,Northeast,East,West,and central,and South)in Thailand using 14 simple sequence repeat(SSR)markers.In total,the SSR markers detected only 55 alleles with an average of 3.9 alleles per locus.Observed heterozygosity was relatively high(0.15)and overall gene diversity was moderate(0.487).Gene diversity,allelic richness and observed heterozygosity in the six regions were comparable,while the estimated out-crossing rate was relatively high(16.4%).STRUCTURE analysis grouped the 457 winged bean accessions into three subpopulations.Neighbor-joining(NJ)analysis grouped all the accessions into two major clusters.Genetic groups identified by both STRUCTURE analysis and NJ analysis were unrelated to geographical origins.Principal coordinate analysis revealed no clear clustering of the winged bean accessions.Although genetic groups were not unrelated to geographical origins,most of the winged bean accessions with long pods(30 cm or higher in length)or having purple seed coats or purple young pods were grouped together.This suggested that the winged beans with long pods or with purple seed or purple young pods may have a single origin.Altogether,these results demonstrated that the genetic diversity of winged bean in Thailand was moderate with high genetic admixture.We argue that the high genetic admixture of the winged bean in Thailand is due to seed migration and relatively high outcrossing rate.展开更多
Wheat straw burial has great potential to sustain rice production under alternate wetting and drying(AWD)irrigation.A field experiment was conducted with three wheat straw burial treatments,including without straw bur...Wheat straw burial has great potential to sustain rice production under alternate wetting and drying(AWD)irrigation.A field experiment was conducted with three wheat straw burial treatments,including without straw burial(NSB),with light straw burial of 300 kg/hm^(2)(LSB)and dense straw burial of 800 kg/hm^(2)(DSB),as well as three AWD regimes:alternate wetting/moderate drying(AWMD),alternate wetting/severe drying(AWSD)and alternate wetting/critical drying(AWCD).The rice growth and grain quality were higher in LSB and NSB than those in NSB under the same AWD regime.The AWMD×DSB treatment resulted in the highest yield,brown rice rate,milled rice rate,amylose content and protein content.Conversely,the AWCD×NSB treatment led to the lowest yield,brown rice rate,milled rice rate,amylose content and protein content.The active absorption area and nitrate reductase activity of roots were higher in the AWMD×DSB treatment than those in the AWCD×NSB treatment,as the former increased organic carbon and nitrogen contents in the rhizosphere,whereas the latter reduced their availability.Total soluble protein content and glutamine synthetase activity were greater in the AWMD×DSB treatment than those in the AWCD×NSB treatment.The activities of superoxide dismutase and catalase were higher in the AWMD×DSB treatment compared with the AWCD×NSB treatment,leading to the amelioration of oxidative cell injury,as shown by a lower malonaldehyde level.This study suggested that farmers should implement AWMD irrigation after leaving the straw residues in the field,followed by deep tillage to improve soil quality and mitigate the drought stress cycles of AWD.This approach can improve rice growth and grain quality and alleviate the problems of disposal of straw residues and water scarcity for sustainable rice production.展开更多
Studies were carried out for two years to evaluate the effect of methods of sowing and weed control practices on the productivity of transplanted and direct wet-seeded rice in Dera Ismail Khan, NWFP, Pakistan. The exp...Studies were carried out for two years to evaluate the effect of methods of sowing and weed control practices on the productivity of transplanted and direct wet-seeded rice in Dera Ismail Khan, NWFP, Pakistan. The experiment was laid out in a randomized complete block design with a split plot arrangement. The planting techniques viz. transplanting and direct seeding were maintained in main plots while weed control practices included the use of granular herbicide Sunstar 15WG （ethoxy sulfuron）, Machete 60EC （butachlor）, conventional hand weeding, and the weedy check （control） were assigned to the sub-plots. Data were recorded on weed parameters like weed density and dry weed biomass 60 and 90 days after sowing （DAS）; agronomic parameters including plant population, number of panicles and paddy yield and physiological parameters like leaf area index and net assimilation rate 45 and 90 DAS. The planting methods and weed management significantly influenced most of the parameters studied. The data revealed that the paddy yield and its components were significantly higher in the transplanted method than that in direct-seeded method, while the weed density and biomass were lower in the transplanted plots than the direct-seeded plots. Among weed management tools, the maximum paddy yield was obtained in hand weeding, closely followed by herbicide application Machete 60EC during both cropping seasons.展开更多
A ifeld experiment was conducted to study the impact of tillage, crop residue management and nitrogen （N） splitting on spring wheat （Triticum aestivum L.） yield over 2 yr （2010-2012） in a rice （Oryza sativa L....A ifeld experiment was conducted to study the impact of tillage, crop residue management and nitrogen （N） splitting on spring wheat （Triticum aestivum L.） yield over 2 yr （2010-2012） in a rice （Oryza sativa L.）-wheat system in northwestern Pakistan. The experiment was conducted as split plot arranged in randomized complete blocks design with three replications. Treatments comprised six tillage and residue managements：zero tillage straw retained （ZTsr）, zero tillage straw burnt （ZTsb）, reduced tillage straw incorporated （RTsi）, reduced tillage straw burnt （RTsb）, conventional tillage straw incorporated （CTsi）, and conventional tillage straw burnt （CTsb） as main plots and N （200 kg ha-1） was applied as split form viz., control （no nitrogen＆no splitting, N0S0）;2 splits of total N, half at sowing and half at the 1st irrigation （i.e., 20 d after sowing （DAS）） （NS1）;3 splits of total N, 1/3 at sowing, 1/3 at the 1st irrigation, and 1/3 at the 2nd irrigation （NS2）;4 splits of total N, 1/4 at sowing, 1/4 at the 1st irrigation, 1/4 at the 2nd irrigation （45 DAS）, and 1/4 at the 3rd irrigation （70 DAS） （NS3）;and 4 splits of total N, 1/4 at the 1st irrigation, 1/4 at the 2nd irrigation, 1/4 at the 3rd irrigation, and 1/4 at the 4th irrigation （95DAS） （NS4） as sub plots. The results showed that the most pikes m-2, grains/spike, 1 000-grain weight, grain yield, and N use efifciency （NUE） were obtained at zero tillage, straw retained and 4 splits application of total N （i.e., at sowing 20, 45 and 70 d after sowing）. The results indicated that ZTsr with application of 200 kg N ha-1 in 4 equal splits viz. at sowing 20, 45 and 70 d after sowing is an appropriate strategy that enhanced wheat yield （7 436-7 634 kg ha-1） and N efifciency （28.6-29.5 kg kg-1） in rice-wheat system.展开更多
Conservation tillage and nitrogen may improve soil fertility, yield and income on sustainable basis. The aim of this study was to evaluate the impact of three tillage systems viz. zero (ZT), reduced (RT), and conventi...Conservation tillage and nitrogen may improve soil fertility, yield and income on sustainable basis. The aim of this study was to evaluate the impact of three tillage systems viz. zero (ZT), reduced (RT), and conventional tillage (CT) and five N rates (0, 80, 120, 160, and 200 kg·N·ha-1) on yield and yield components, soil organic matter (SOM), total soil N (TSN), and income of wheat (Triticum aestivum L.) grown after rice (Oryza sativa L.). Nitrogen rates significantly affected yield and yield attributing characters with highest values recorded at200 kg·N·ha-1. Mean maximum grain yield (6390 -6845 kg·ha-1), net benefit (1359 - 1460 US$ ha-1), and benefit cost ratio (5.6 - 5.7) could be achieved at 160 to200 kg·N·ha-1. The tillage systems produced similar yield and yield components except spikes m-2. The SOM and TSN were highest in ZT compared to other tillage systems. Though tillage × N interactions were not significant for most of the parameters under study, the overall effect of ZT with200 kg·N·ha-1 appeared to be most favorable compared to RT and CT. Zero tillage resulted in highest number of spikes m-2 (304.4), SOM (9.6 g·kg-1) and TSN (0.5 g·kg-1) with200 kg·N·ha-1. The results suggest that ZT with200 kg·N·ha-1 was optimum and sustainable strategy to achieve higher yield and income and also to improve SOM and TSN on silty clay soil.展开更多
The process of ripening involves physiological and biochemical events that become a concern during postharvest storage.We have documented different approaches for the preservation and maintenance of fruit quality duri...The process of ripening involves physiological and biochemical events that become a concern during postharvest storage.We have documented different approaches for the preservation and maintenance of fruit quality during the postharvest period that are biocompatible and fully safe for consumption.Chemical residues that sustain sensory characteristics,such as color,flavor,aroma,and texture,are considered.In fruit ripening,both physical and chemical elicitors are described that regulate ethylene biosynthesis or its signaling for gene expression.The key regulatory enzymes,such as ACC synthase and ACC oxidase,for ethylene biosynthesis,are important for both climacteric and non-climacteric fruits.Anti-oxidizing genes that retain sensory characteristics are concerns in this respect.Chemical elicitors,including chitosan,polyamine,phenolics,lipopolysaccharide,silver derivatives,and nanocomposites,are described.Gas pressure,light wavelengths,relative humidity,cooling,and other environmental factors are important for improved postharvest storage.These elicitors maintain redox status by inhibiting the generation of reactive oxygen species(ROS)or their lysis.Growth regulators,including abscisic acid,auxin,brassinosteroids,jasmonic acid,and salicylic acid,are important for the regulation of ripening.Mechanical injuries,ionic imbalances,temperature variations,and tissue dehydration can occur irrespective of ripening cate-gories.The use of synthetic physiochemically active compounds is discussed in terms of physiological,metabolic,cellular,and molecular functions.Ethylene-induced autocatalytic processes,antioxidant cascades,epigenetic regulation,and homeodomain gene expression are discussed.Sugar–acid metabolism,dissolution of the cell wall,and direct or indirect production of secondary metabolites related to postharvest storage are mentioned regarding chilling storage.Elicitors and agrochemicals that trigger plant defense to increase secondary metabolite production are discussed for reducing fruit senescence during postharvest storage.展开更多
The response of seed germination to environmental factors can be estimated by nonlinear regression. The present study was performed to compare four nonlinear regression models(segmented, beta, beta modified, and dent-...The response of seed germination to environmental factors can be estimated by nonlinear regression. The present study was performed to compare four nonlinear regression models(segmented, beta, beta modified, and dent-like) to describe the germination rate–temperature relationships of milk thistle(Silybum marianum L.) at six constant temperatures, with the aim of identifying the cardinal temperatures and thermal times required to reach different germination percentiles. Models and statistical indices were calibrated using an iterative optimization method and their performance was compared by root mean square error(RMSE), coefficient of determination(R2) and Akaike information criterion correction(AICc). The beta model was found to be the best model for predicting the required time to reach 50% germination(D50),(R2= 0.99;RMSE = 0.004; AICc =-276.97). Based on the model outputs, the base, optimum, and maximum temperatures of seed germination were 5.19 ± 0.79, 24.01 ± 0.11, and 34.32 ± 0.36 °C,respectively. The thermal times required for 50% and 90% germination were 4.99 and7.38 degree-days, respectively.展开更多
Coconut(Cocos nucifera L.)is an important economic crop in tropical countries.However,the lack of a complete reference genome and the limitations of usable DNA markers hinder genomic studies and the molecular breeding...Coconut(Cocos nucifera L.)is an important economic crop in tropical countries.However,the lack of a complete reference genome and the limitations of usable DNA markers hinder genomic studies and the molecular breeding of coconut.Here,we present the results of simple sequence repeat(SSR)mining from a high-throughput genotyping-bysequencing(GBS)study of a collection of 38 coconut accessions.A total of 22,748 SSRs with di-,tri-,tetra-,penta-and hexanucleotide repeats of five or more were identified,2451 of which were defined as polymorphic loci based on locus clustering in 38 coconut accessions,and 315 loci were suitable for the development of SSR markers.One hundred loci were selected,and primer pairs for each SSR locus were designed and validated in 40 coconut accessions.The analysis of 74 polymorphic markers identified between 2 and 9 alleles per locus,with an average of 3.01 alleles.The assessment of the genetic diversity and genetic relationships among the 40 coconut varieties based on the analysis of population structure,principal coordinate analysis(PCoA),and phylogenetic tree analysis using the 74 polymorphic SSR markers revealed three main groups of coconuts in Thailand.The identified SSR loci and SSR markers developed in this study will be useful for the study of coconut diversity and molecular breeding.The SSR mining approach used in this study could be applied to other plant species with a complex genome regardless of the availability of reference genome.展开更多
The main objective of the research is to assess the role of foliar application of silicon(Si)for enhancing the survival ability of wheat under drought stress through improving its morphology,physicochemical and antiox...The main objective of the research is to assess the role of foliar application of silicon(Si)for enhancing the survival ability of wheat under drought stress through improving its morphology,physicochemical and antioxidants activities.Treatments were five doses of Si at the rate of 2,4,6 and 8 mM and a control.After completion of seeds germination,pots were divided into four distinct groups at various field capacity(FC)levels,such as 100%FC(well-irrigated condition),75%FC(slight water deficit),50%FC(modest water deficit)and 25%FC(severe water deficit stress condition).Foliar application of Si at the rate of 2,4,6 and 8 mM and a control were given after 30 days of sowing at the tillering stage of wheat.Findings of the present investigation indicated that increasing the level of water deficit stress reduced the morphological parameters(such as root and shoot fresh and dry-biomass weight)and physico-biochemical events((such as chlorophyll contents by estimating SPAD value),total free amino acid(TFAA),total soluble sugar(TSS),total soluble protein(TSP),total proline(TP),CAT(catalase),POD(peroxidase),SOD(superoxide dismutase)and APX(ascorbate peroxidase))of wheat;while foliar application of Si at 6 mM at tillering stage enhanced the drought tolerance in wheat by increasing morphology and physiochemical characters under all levels of drought stress.Similarly,antioxidants activities in wheat also enhanced by the application of Si at 6 mM under normal as well as all drought stress levels.There-fore,it may be concluded that foliar application of Si at 6 mM at the tillering stage of wheat is an important indication for increasing the drought tolerance by improving the morphology,physico-biochemical and antioxidants activities in plants under deficit water(drought)conditions.展开更多
基金Agricultural Research Development Agency in Thailand for financing the study and the provision of this research.
文摘Extremely high temperatures resulting from climate change have become a major challenge for increasing rice production.Therefore,our objective was to develop heat-tolerant aromatic rice varieties using the pedigree method,focusing on selecting for seed-setting ability under extremely high temperatures along with the use of single nucleotide polymorphism/insertion and deletion(SNP/InDel)markers to improve aromatic properties and grain quality.Furthermore,the QTL-seq approach was utilized to identify QTLs for seed-setting rate in an F2 population subjected to heat stress.The candidate QTL regions were then aligned to confirm SNPs/InDels in synonymous F7 candidate heat-tolerant lines.The results revealed that four promising lines,namely 84-7-1-9,84-7-1-10,159-3-3-1,and 159-3-3-10,were classified as heat-tolerant with low amylose content.In addition,lines 84-7-1-9 and 84-7-1-10 were identified as aromatic rice encompassing the aroma gene(badh2).Regarding the QTL-seq results,the qSF2.1 region ranged from 311051 to 3929422 bp on chromosome 2,was identified based on the highest contrasting SNP index between the heat-susceptible and tolerant bulks.The candidate genes within this region include two genes related to heat shock proteins,three genes associated with pollen fertility,and four genes involved in heat stress and other abiotic stress responses.These genes are proposed as potential candidates for heat tolerance and could serve as targets in rice breeding programs aimed at enhancing heat tolerance.
文摘Seedling emergence and seedling establishment are two important phases for the good crop stand and final maize crop harvest. A field study was conducted to explore the effects of different tillage practices and poultry manure levels on the seedling emergence, growth, development, yield, and economics of the spring planted maize during 2010 and 2011. Experimental treatments include four tillage treatments (zero, minimum, conventional and deep tillage) and three poultry manure amendments (control (no manure), 5 Mg·ha-1 and 10 Mg·ha-1). Seedling emergence was linearly affected as the tillage intensity was increased. Significant relationship of tillage with leaf area index, leaf area duration, crop growth rate, net assimilation rate and total dry matter was recorded during the both years. Poultry manure at the rate of 10 Mg·ha-1 produced the higher leaf area index, leaf area duration, crop growth rate, total dry matter and grain yield as compared to 5 Mg·ha-1 and control. Moreover, experimental results concluded that the deep tillage practice has taken less time to start emergence. Similarly, higher values trend of leaf area index, leaf area duration, crop growth rate, total dry matter accumulation and grain yield was shifted from deep tillage to conventional, minimum and zero tillage practices during both years. Economically, the minimum tillage with poultry manure at rate of 10 Mg·ha-1 gave the better benefit to cost ratio and crop productivity as compared to conventional, deep and zero tillage. The experiment suggested the minimum tillage with poultry manure at the rate of 10 Mg·ha-1 may ensure the maize grain yield sustainability.
基金Supported by the University of Azad Jammu and Kashmir,Muzaffarabad,Pakistan
文摘Humic acid （HA）, a fairly stable product of decomposed organic matter that consequently accumulates in ecological systems, enhances plant growth by chelating unavailable nutrients and buffering pH. We examined the effect of HA derived from lignite on growth and macronutrient uptake of wheat （Triticum acstivum L.） grown in earthen pots under greenhouse conditions. The soils used in the pot experiment were a calcareous Haplustalf and a non-calcareous Haplustalf collected from Raisalpur and Guliana, respectively, in Punjab Province, Pakistan. The experiment consisted of four treatments with HA levels of 0 （control without HA）, 30, 60, and 90 mg kg^-1 soil designated as HA0, HA1, HA2, and HA3, respectively. In the treatment without HA （HA0）, nitrogen （N）, phosphorus （P）, and potassium （K） were applied at 200, 100, and 125 mg kg^-1 soil, respectively. Significant differences among HA levels were recorded for wheat growth （plant height and shoot weight） and N uptake. On an average of both soils, the largest increases in plant height and shoot fresh and dry weights were found with HA2 （60 mg kg^-1 soil）, being 10%, 25%, and 18%, respectively, as compared to the control without HA （HA0）. Both soils responded positively towards HA application. The wheat growth and N uptake in the non-calcareous soil were higher than those of the calcareous soil. The HA application significantly improved K concentration of the non-calcareous soil and P and NO3-N of the calcareous soil. The highest rate of HA （90 mg kg^-1 soil） had a negative effect on growth and nutrient uptake of wheat as well as nutrient accumulation in soil, whereas the medium dose of HA （60 mg kg^-1 soil） was more efficient in promoting wheat growth.
基金financially supported by a Kasetsart University 72 Year Anniversary Graduate Scholarship, from the Graduate School, Kasetsart University, Thailand
文摘Low germination and vigor of rice seed associated with dry-seed broadcasting are common problems encountered by rice growers.The objectives of this study were to evaluate the role of potassium nitrate（KNO3）on the pattern of seed imbibition and to determine the effect of seed priming with KNO3 on the germination percentage,speed and uniformity of germination in rice seed.Experiment 1 compared the patterns of seed imbibition of six concentrations of KNO3（0,0.25,0.50,1.00,1.50,and 2.00%）in two rice cultivars-KDML105 and RD15.The results showed that soaking rice seed in KNO3 at higher concentrations could delay the imbibition time.The higher concentrations of KNO3 delayed the imbibition time of rice seed and took a longer time to reach the end of phases 1 and 2 compared to the lower concentrations.The patterns of seed imbibition using distilled water of both rice cultivars（KDML105 and RD15）were quite similar,but with different concentrations of KNO3,the imbibition time taken to reach the end of phases 1 and 2 was slightly postponed in KDML105 suggesting that different rice cultivars may need different imbibition times for soaking seed in the priming process.Experiment 2 evaluated the effects of seed priming with 1.0 and 2.0%KNO3 at different imbibition times.It was found that priming with 1.0%KNO3 showed better seed germination than priming with 2.0%KNO3 and seed priming with 1.0%KNO3 at the imbibition time of early phase 2（or 28 h for KDML105）improved seed germination and increased both the speed and uniformity of seed germination.The results of this study show promise for the use of priming with 1.0%KNO3 soaked until early phase 2 of seed imbibition for improving the seed germination and vigor of rice in dry seed broadcasting.
基金supported by M/S Crystal Crop Protection Pvt.Ltd.,Corp.Office:G I/17,GT Karnal Road,Industrial Area,Azadpur(Near Azadpur Metro Station),Delhi 110033,India
文摘The effects of bispyribac sodium 10% SC and butachlor 50% SC on soil physico-chemical properties and microflora in transplanted kharifrice were investigated over two seasons （2010 and 2011 ） Effects of the herbicide on bulk density, water holding capacity, moisture content, soil pH, organic matter content, electrical conductivity, as well as total nitrogen, available phosphorus and available potassium contents were analyzed along with microflora population （total bacteria, actinomycetes and fungi）. No significant changes in soil physico-chemical properties were observed. Herbicide treatments resulted in decreases in microbial counts initially. With the degradation of applied herbicides within a considerable time, the microflora populations even exceeded the initial count at 60 d after application of the herbicide.
基金Gomal University, Dera IsmailKhan, Pakistan for partial support
文摘With decreasing availability of water for agriculture and increasing demand for rice production, an optimum use of irrigation water and phosphorus may guarantee sustainable rice production. Field experiments were conducted in 2003 and 2004 to investigate the effect of phosphorus and irrigation levels on yield, water productivity （WP）, phosphorus use efficiency （PUE） and income of low land rice. The experiment was laid out in randomized complete block design with split plot arrangements replicated four times. Main plot consisted of five phosphorus levels, viz. 0 （P0）, 50 （P50）, 100 （P100）, 150 （P15o）, and 200 （P200） kg/hm2, while subplots contained of irrigation times, i.e. 8 （I8）, 10 （I10）, 12 （I12）, and 14 （I14） irrigation levels, each with a water depth of 7.5 cm. Mean values revealed that P150 in combination with I10 produced the highest paddy yield （9.8 t/hm2） and net benefit （1 231.8 US$/hm2） among all the treatments. Phosphorus enhanced WP when applied in appropriate combination with irrigation level. The highest mean WP [13.3 kg/（hm2-mm）] could be achieved at Plso with 18 and decreased with increase in irrigation level, while the highest mean PUE （20.1 kg/kg） could be achieved at P100 with I10 and diminished with higher P levels. The overall results indicate that P150 along with I10 was the best combination for sustainable rice cultivation in silty clay soil.
基金supported by the Agriculture Research Development Agency of Thailandthe Office of the Higher Education Commission of Thailand for the Strategic Scholarships Fellowships Frontier Research Networks for financially supporting
文摘Seed-setting rate, yield components and grain quality traits of 169 accessions from an exotic rice germplasm were tested under high temperatures from 40 oC to 45 oC for 6 h during the daytime at the vegetative and reproductive stages, respectively. The results showed that heat stress significantly decreased the seed-setting rate of all the accessions, but the heat stress effects varied among accessions. Based on the decreases in seed-setting rate at high temperatures, N22 was the most tolerant, followed by AUS17, M9962, SONALEE and AUS16. Moreover, the reductions in seed-setting rate and yield under heat stress were more serious at the vegetative stage （45 d before heading） than at the booting stage （15 d before heading）. In addition, heat stress also affected grain quality, especially by conferring chalkiness to most of the accessions, but SONALEE did not change much. The heat-tolerant accessions identified here and the phenotype protocols developed could be used in future genetic studies and breeding programmes focused on heat tolerance.
文摘Zero tillage with residues retention and optimizing nitrogen fertilization are important strategies to improve soil quality and wheat （Triticum aestivum L.） yield in rice （Oryza sativa L.）-wheat system. Field experiments were conducted on silty clay soil （Hyperthermic, and Typic Torrilfuvents） in D. I. Khan, Pakistan, to explore the impact of six tillage methods （zero tillage straw retained （ZTsr）, ZT straw burnt （ZTsb）, reduced tillage straw incorporated （RTsi, including tiller and rotavator）, RT straw burnt （RTsb）, conventional tillage straw incorporated （CTsi, including disc plow, tiller, rotavator, and leveling operations）, CT straw burnt （CTsb）） and ifve nitrogen rates, i.e., 0, 100, 150, 200, and 250 kg ha-1 on wheat yield. Mean values for N revealed that spikes m-2, grains/spike, 1 000-grain weight （g）, and grain yield （kg ha-1） were signiifcantly higher at 200 kg N ha-1 in both the years as well as mean over years than all other treatments. Mean values for tillage revealed that ZTsr produced highest number of spikes m-2 among tillage methods. However, grains/spike, 1 000-grain weight, and grain yield were higher in tillage methods with either straw retained/incorporated than tillage methods with straw burnt. Interaction effects were signiifcant in year 1 and in mean over years regarding spikes m-2, 1 000-grain weight, total soil organic matter （SOM）, and total soil N （TSN）. ZTsr produced the most spikes m-2 and 1 000-grain weight at 200 kg N ha-1. ZTsr also produced higher SOM and TSN at 200-250 kg N ha-1 at the end of 2 yr cropping. Thus ZTsr with 200 kg N ha-1 may be an optimum and sustainable approach to enhance wheat yield and soil quality in rice-wheat system.
基金supported by the Agriculture Research Development Agency and the Office of the Higher Education Commission for the Strategic Scholarships Fellowships Frontier Research Networks of Thailand
文摘A total of 10 000 M4 individuals in Jao Hom Nil (JHN) mutant population was treated with high temperature (40 ℃ to 45 ℃) during the day time (6 h) from the booting to the harvesting stages, and ambient temperature (33 ℃ to 35℃) was used as the control. The results of screening and yield trials found that the mutant line M9962 had a high spikelet fertility of 78% under heat stress. In addition, the other mutant lines, including M3181 and M7988, had a spikelet fertility of approximately 70%. However, the JHN wild type, Sin Lek, RD15 and RD33 had very low spikelet fertility of 34%, 14%, 9% and 4%, respectively. The lower spikelet fertility at an elevated temperature resulted in a dramatic decrease of filled grain and contributed to a loss in 100-grain weight. M9962 is a potential genetic stock for use in a heat tolerance breeding programme. In addition, spikelet fertility at high temperature was representative of heat tolerance and can be used as a screening trait for heat tolerance during the reproductive phase on a large scale.
基金supported by the National Agricultural Innovation Project Component-IV(NAIP/C4/C1005/2006-07),Indian Council of Agricultural Research,Pusa,New Delhi,India
文摘The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated with arsenic （above 0.01 mg/L） in the Indian subcontinent. The study was conducted with organic matter to find out the reducing effect on arsenic load to rice （cv. Khitish）. It was observed that intermittent ponding reduced arsenic uptake （23.33% in root, 13.84% in shoot and 19.84% in leaf） at panicle initiation stage, instead of continuous ponding. A decreasing trend of arsenic accumulation （root straw husk whole grain milled grain） was observed in different plant parts at harvest. Combined applications of lathyrus ＋ vermicompost ＋ poultry manure reduced arsenic transport in plant parts （root, straw, husk, whole grains and milled grain） which was significantly at par （p 0.05） with chopped rice straw （5 tons/ha ） ＋ lathyrus green manuring （5 tons/ha） in comparison to control and corresponding soils. A significant negative correlation of arsenic with phosphorus （grain P with arsenic in different parts R 2 = 0.627–0.726 at p 0.01） was observed. Similarly, soil arsenic had a negative correlation with soil available phosphorus （R 2 = 0.822 at p 0.001） followed by soil nitrogen （R 2 = 0.762 at p 0.01） and soil potassium （R 2 = 0.626 at p 0.01）. Hence, effective management of contaminated irrigation water along with organic matter could reduce the arsenic build up to plants and soil.
文摘Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill^-l on the productivity of rice in Dera Ismail Khan district of North West Frontier Province （NWFP）, Pakistan. The experiment was laid out in a randomized complete block design with split plot arrangements. Main plots consisted of four transplanting dates viz. 20th and 27th of June and 4th and 1 lth of July while sub-plots contained 1, 2, 3 or 4 seedlings hill^-1. Among transplanting dates, June 20th planted crop gave highest paddy yield and net return with I seedling hill^-1. It explains that the use of more seedlings hill^-1 not only adds to cost but is also a mere wastage of natural resources. Based on research findings, we conclude that the use of I seedling hill^-1 is most appropriate for timely sowing otherwise 4 seedlings hill^-1 should be used to compensate for the yield gap in late transplanted rice.
基金supported by Kasetsart University Research and Development Institute,Kasetsart University,Thailandfunded by the Thailand Research Fund through the Senior Research Scholar Project(Grant No.RTA6180002)。
文摘Winged bean[Psophocarpus tetragonolobus(L.)DC.]is a vegetable legume crop.The center of origin,diversity and domestication of this crop are not known.In this study,we assessed the genetic diversity and population structure of 457 accessions of winged bean collected from six geographical regions(North,Northeast,East,West,and central,and South)in Thailand using 14 simple sequence repeat(SSR)markers.In total,the SSR markers detected only 55 alleles with an average of 3.9 alleles per locus.Observed heterozygosity was relatively high(0.15)and overall gene diversity was moderate(0.487).Gene diversity,allelic richness and observed heterozygosity in the six regions were comparable,while the estimated out-crossing rate was relatively high(16.4%).STRUCTURE analysis grouped the 457 winged bean accessions into three subpopulations.Neighbor-joining(NJ)analysis grouped all the accessions into two major clusters.Genetic groups identified by both STRUCTURE analysis and NJ analysis were unrelated to geographical origins.Principal coordinate analysis revealed no clear clustering of the winged bean accessions.Although genetic groups were not unrelated to geographical origins,most of the winged bean accessions with long pods(30 cm or higher in length)or having purple seed coats or purple young pods were grouped together.This suggested that the winged beans with long pods or with purple seed or purple young pods may have a single origin.Altogether,these results demonstrated that the genetic diversity of winged bean in Thailand was moderate with high genetic admixture.We argue that the high genetic admixture of the winged bean in Thailand is due to seed migration and relatively high outcrossing rate.
基金supported by the Water Conservancy Science and Technology Project of Jiangsu Province,China(Grant Nos.2020049 and 2021055).
文摘Wheat straw burial has great potential to sustain rice production under alternate wetting and drying(AWD)irrigation.A field experiment was conducted with three wheat straw burial treatments,including without straw burial(NSB),with light straw burial of 300 kg/hm^(2)(LSB)and dense straw burial of 800 kg/hm^(2)(DSB),as well as three AWD regimes:alternate wetting/moderate drying(AWMD),alternate wetting/severe drying(AWSD)and alternate wetting/critical drying(AWCD).The rice growth and grain quality were higher in LSB and NSB than those in NSB under the same AWD regime.The AWMD×DSB treatment resulted in the highest yield,brown rice rate,milled rice rate,amylose content and protein content.Conversely,the AWCD×NSB treatment led to the lowest yield,brown rice rate,milled rice rate,amylose content and protein content.The active absorption area and nitrate reductase activity of roots were higher in the AWMD×DSB treatment than those in the AWCD×NSB treatment,as the former increased organic carbon and nitrogen contents in the rhizosphere,whereas the latter reduced their availability.Total soluble protein content and glutamine synthetase activity were greater in the AWMD×DSB treatment than those in the AWCD×NSB treatment.The activities of superoxide dismutase and catalase were higher in the AWMD×DSB treatment compared with the AWCD×NSB treatment,leading to the amelioration of oxidative cell injury,as shown by a lower malonaldehyde level.This study suggested that farmers should implement AWMD irrigation after leaving the straw residues in the field,followed by deep tillage to improve soil quality and mitigate the drought stress cycles of AWD.This approach can improve rice growth and grain quality and alleviate the problems of disposal of straw residues and water scarcity for sustainable rice production.
文摘Studies were carried out for two years to evaluate the effect of methods of sowing and weed control practices on the productivity of transplanted and direct wet-seeded rice in Dera Ismail Khan, NWFP, Pakistan. The experiment was laid out in a randomized complete block design with a split plot arrangement. The planting techniques viz. transplanting and direct seeding were maintained in main plots while weed control practices included the use of granular herbicide Sunstar 15WG （ethoxy sulfuron）, Machete 60EC （butachlor）, conventional hand weeding, and the weedy check （control） were assigned to the sub-plots. Data were recorded on weed parameters like weed density and dry weed biomass 60 and 90 days after sowing （DAS）; agronomic parameters including plant population, number of panicles and paddy yield and physiological parameters like leaf area index and net assimilation rate 45 and 90 DAS. The planting methods and weed management significantly influenced most of the parameters studied. The data revealed that the paddy yield and its components were significantly higher in the transplanted method than that in direct-seeded method, while the weed density and biomass were lower in the transplanted plots than the direct-seeded plots. Among weed management tools, the maximum paddy yield was obtained in hand weeding, closely followed by herbicide application Machete 60EC during both cropping seasons.
文摘A ifeld experiment was conducted to study the impact of tillage, crop residue management and nitrogen （N） splitting on spring wheat （Triticum aestivum L.） yield over 2 yr （2010-2012） in a rice （Oryza sativa L.）-wheat system in northwestern Pakistan. The experiment was conducted as split plot arranged in randomized complete blocks design with three replications. Treatments comprised six tillage and residue managements：zero tillage straw retained （ZTsr）, zero tillage straw burnt （ZTsb）, reduced tillage straw incorporated （RTsi）, reduced tillage straw burnt （RTsb）, conventional tillage straw incorporated （CTsi）, and conventional tillage straw burnt （CTsb） as main plots and N （200 kg ha-1） was applied as split form viz., control （no nitrogen＆no splitting, N0S0）;2 splits of total N, half at sowing and half at the 1st irrigation （i.e., 20 d after sowing （DAS）） （NS1）;3 splits of total N, 1/3 at sowing, 1/3 at the 1st irrigation, and 1/3 at the 2nd irrigation （NS2）;4 splits of total N, 1/4 at sowing, 1/4 at the 1st irrigation, 1/4 at the 2nd irrigation （45 DAS）, and 1/4 at the 3rd irrigation （70 DAS） （NS3）;and 4 splits of total N, 1/4 at the 1st irrigation, 1/4 at the 2nd irrigation, 1/4 at the 3rd irrigation, and 1/4 at the 4th irrigation （95DAS） （NS4） as sub plots. The results showed that the most pikes m-2, grains/spike, 1 000-grain weight, grain yield, and N use efifciency （NUE） were obtained at zero tillage, straw retained and 4 splits application of total N （i.e., at sowing 20, 45 and 70 d after sowing）. The results indicated that ZTsr with application of 200 kg N ha-1 in 4 equal splits viz. at sowing 20, 45 and 70 d after sowing is an appropriate strategy that enhanced wheat yield （7 436-7 634 kg ha-1） and N efifciency （28.6-29.5 kg kg-1） in rice-wheat system.
文摘Conservation tillage and nitrogen may improve soil fertility, yield and income on sustainable basis. The aim of this study was to evaluate the impact of three tillage systems viz. zero (ZT), reduced (RT), and conventional tillage (CT) and five N rates (0, 80, 120, 160, and 200 kg·N·ha-1) on yield and yield components, soil organic matter (SOM), total soil N (TSN), and income of wheat (Triticum aestivum L.) grown after rice (Oryza sativa L.). Nitrogen rates significantly affected yield and yield attributing characters with highest values recorded at200 kg·N·ha-1. Mean maximum grain yield (6390 -6845 kg·ha-1), net benefit (1359 - 1460 US$ ha-1), and benefit cost ratio (5.6 - 5.7) could be achieved at 160 to200 kg·N·ha-1. The tillage systems produced similar yield and yield components except spikes m-2. The SOM and TSN were highest in ZT compared to other tillage systems. Though tillage × N interactions were not significant for most of the parameters under study, the overall effect of ZT with200 kg·N·ha-1 appeared to be most favorable compared to RT and CT. Zero tillage resulted in highest number of spikes m-2 (304.4), SOM (9.6 g·kg-1) and TSN (0.5 g·kg-1) with200 kg·N·ha-1. The results suggest that ZT with200 kg·N·ha-1 was optimum and sustainable strategy to achieve higher yield and income and also to improve SOM and TSN on silty clay soil.
文摘The process of ripening involves physiological and biochemical events that become a concern during postharvest storage.We have documented different approaches for the preservation and maintenance of fruit quality during the postharvest period that are biocompatible and fully safe for consumption.Chemical residues that sustain sensory characteristics,such as color,flavor,aroma,and texture,are considered.In fruit ripening,both physical and chemical elicitors are described that regulate ethylene biosynthesis or its signaling for gene expression.The key regulatory enzymes,such as ACC synthase and ACC oxidase,for ethylene biosynthesis,are important for both climacteric and non-climacteric fruits.Anti-oxidizing genes that retain sensory characteristics are concerns in this respect.Chemical elicitors,including chitosan,polyamine,phenolics,lipopolysaccharide,silver derivatives,and nanocomposites,are described.Gas pressure,light wavelengths,relative humidity,cooling,and other environmental factors are important for improved postharvest storage.These elicitors maintain redox status by inhibiting the generation of reactive oxygen species(ROS)or their lysis.Growth regulators,including abscisic acid,auxin,brassinosteroids,jasmonic acid,and salicylic acid,are important for the regulation of ripening.Mechanical injuries,ionic imbalances,temperature variations,and tissue dehydration can occur irrespective of ripening cate-gories.The use of synthetic physiochemically active compounds is discussed in terms of physiological,metabolic,cellular,and molecular functions.Ethylene-induced autocatalytic processes,antioxidant cascades,epigenetic regulation,and homeodomain gene expression are discussed.Sugar–acid metabolism,dissolution of the cell wall,and direct or indirect production of secondary metabolites related to postharvest storage are mentioned regarding chilling storage.Elicitors and agrochemicals that trigger plant defense to increase secondary metabolite production are discussed for reducing fruit senescence during postharvest storage.
文摘The response of seed germination to environmental factors can be estimated by nonlinear regression. The present study was performed to compare four nonlinear regression models(segmented, beta, beta modified, and dent-like) to describe the germination rate–temperature relationships of milk thistle(Silybum marianum L.) at six constant temperatures, with the aim of identifying the cardinal temperatures and thermal times required to reach different germination percentiles. Models and statistical indices were calibrated using an iterative optimization method and their performance was compared by root mean square error(RMSE), coefficient of determination(R2) and Akaike information criterion correction(AICc). The beta model was found to be the best model for predicting the required time to reach 50% germination(D50),(R2= 0.99;RMSE = 0.004; AICc =-276.97). Based on the model outputs, the base, optimum, and maximum temperatures of seed germination were 5.19 ± 0.79, 24.01 ± 0.11, and 34.32 ± 0.36 °C,respectively. The thermal times required for 50% and 90% germination were 4.99 and7.38 degree-days, respectively.
基金supported by Biodiversity-based Economy Development Office(Public Organization)and National Research Council of Thailand,grant number BEDO-NRCT 48/2562.
文摘Coconut(Cocos nucifera L.)is an important economic crop in tropical countries.However,the lack of a complete reference genome and the limitations of usable DNA markers hinder genomic studies and the molecular breeding of coconut.Here,we present the results of simple sequence repeat(SSR)mining from a high-throughput genotyping-bysequencing(GBS)study of a collection of 38 coconut accessions.A total of 22,748 SSRs with di-,tri-,tetra-,penta-and hexanucleotide repeats of five or more were identified,2451 of which were defined as polymorphic loci based on locus clustering in 38 coconut accessions,and 315 loci were suitable for the development of SSR markers.One hundred loci were selected,and primer pairs for each SSR locus were designed and validated in 40 coconut accessions.The analysis of 74 polymorphic markers identified between 2 and 9 alleles per locus,with an average of 3.01 alleles.The assessment of the genetic diversity and genetic relationships among the 40 coconut varieties based on the analysis of population structure,principal coordinate analysis(PCoA),and phylogenetic tree analysis using the 74 polymorphic SSR markers revealed three main groups of coconuts in Thailand.The identified SSR loci and SSR markers developed in this study will be useful for the study of coconut diversity and molecular breeding.The SSR mining approach used in this study could be applied to other plant species with a complex genome regardless of the availability of reference genome.
文摘The main objective of the research is to assess the role of foliar application of silicon(Si)for enhancing the survival ability of wheat under drought stress through improving its morphology,physicochemical and antioxidants activities.Treatments were five doses of Si at the rate of 2,4,6 and 8 mM and a control.After completion of seeds germination,pots were divided into four distinct groups at various field capacity(FC)levels,such as 100%FC(well-irrigated condition),75%FC(slight water deficit),50%FC(modest water deficit)and 25%FC(severe water deficit stress condition).Foliar application of Si at the rate of 2,4,6 and 8 mM and a control were given after 30 days of sowing at the tillering stage of wheat.Findings of the present investigation indicated that increasing the level of water deficit stress reduced the morphological parameters(such as root and shoot fresh and dry-biomass weight)and physico-biochemical events((such as chlorophyll contents by estimating SPAD value),total free amino acid(TFAA),total soluble sugar(TSS),total soluble protein(TSP),total proline(TP),CAT(catalase),POD(peroxidase),SOD(superoxide dismutase)and APX(ascorbate peroxidase))of wheat;while foliar application of Si at 6 mM at tillering stage enhanced the drought tolerance in wheat by increasing morphology and physiochemical characters under all levels of drought stress.Similarly,antioxidants activities in wheat also enhanced by the application of Si at 6 mM under normal as well as all drought stress levels.There-fore,it may be concluded that foliar application of Si at 6 mM at the tillering stage of wheat is an important indication for increasing the drought tolerance by improving the morphology,physico-biochemical and antioxidants activities in plants under deficit water(drought)conditions.
