The genetic diversity among 15 NIFOR breeding parents was assessed using 10 microsatellite markers. A high genetic diversity was observed with a total of 64 alleles including 23 rare alleles or alleles at frequencies ...The genetic diversity among 15 NIFOR breeding parents was assessed using 10 microsatellite markers. A high genetic diversity was observed with a total of 64 alleles including 23 rare alleles or alleles at frequencies less than 0.05. The NIFOR tenera parents recorded the highest number of rare alleles. The average observed heterozygosity and mean gene diversity across all parental groups were 0.6889 and 0.7029, respectively. Higher genetic diversity was detected among the NIFOR dura and tenera parents compared to that of the Deli dura parents in absolute terms. Analysis of molecular variance (AMOVA) showed that 87% of the total variation (p < 0.001) observed was due to differences among parents. Rogers’ genetic distance ranged from 0.2988 to 0.8000 (mean = 0.5570). The dendrogram constructed on the basis of Rogers’ genetic distance clustered the parents in three groups. They generally clustered in heterotic manner rather than by geographic origins. The groupings obtained through PCoA confirmed the results obtained by cluster analysis. The results obtained are strong assets for NIFOR breeding programme.展开更多
Twenty short-statured maize inbred lines were collected from CIMMYT India and Mexico through the Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipur. The experiment was conducted from N...Twenty short-statured maize inbred lines were collected from CIMMYT India and Mexico through the Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipur. The experiment was conducted from November 2020 to April 2021 in three different agroecological regions such as BARI, Gazipur, RARS Barisal and RARS Rangpur. Seven inbred lines were selected on the basis of genetic diversity and per se performance and they were crossed separately in a 7 × 7 half diallel fashion, producing 21F1 hybrids in 2019 which were evaluated at three locations. However, variances due to GCA were much higher in magnitude than SCA for all the characters indicating preponderance of additive gene effects on the inheritance of these characters. Two parents viz., P3 (CML33) and P4 (CML41) were good general combiners and two crosses viz., P4 × P5 (CML41 × CML31) and P5 × P7 (CML31 × CML124) expressed significant positive SCA effects coupled with significant positive heterosis for grain yield and for most of the yield contributing characters over the two commercial check varieties BHM 9 and NK40. Four crosses: P1 × P5 (CML116 × CML31), P1 × P6 (CML116 × CML32), P2 × P6 (CML72 × CML32) and P3 × P4 (CML33 × CML41), exhibited significant and negative SCA effects for both plant and ear height which were desirable for short stature. Genotypes x location interaction was also significant for maximum characters, suggesting that genotypes interacted significantly in different environments.展开更多
The chromosomes of Chlamys farreri were analyzed by means of silver staining and fluorescence in situ hybridization （FISH） with 18S-28S rDNA probe. Probe was made by PCR amplification of a DNA fragment containing in...The chromosomes of Chlamys farreri were analyzed by means of silver staining and fluorescence in situ hybridization （FISH） with 18S-28S rDNA probe. Probe was made by PCR amplification of a DNA fragment containing internal transcribed spacers ITS1 between 18S and 5.8S ribosomal RNA gene, ITS2 between 5.8S and 28S ribosomal RNA gene and 5.8S rRNA gene, and labeled by PCR incorporation of bio-16-dUTP. FISH signals were located on the short arm of subtelocentrie chromosome 10. After silverstaining, nucleolus organizer regions （NORs） could be observed on the telomere of the short arm of chromosome 10. However, one metaphase spread displayed an additional silver spot on the short arm of subtelocentrie chromosome 12.展开更多
Common carp expressed sequence tags （ESTs） were analyzed for the existence of microsatellites, or simple sequence repeats （SSRs）. In the NCBI dbEST database, a total of 10612 sequences were registered before Decem...Common carp expressed sequence tags （ESTs） were analyzed for the existence of microsatellites, or simple sequence repeats （SSRs）. In the NCBI dbEST database, a total of 10612 sequences were registered before December 31, 2004. A complete search of 2-6 nucleotide microsatellites resulted in the identification of 513 SSR-containing ESTs, accounting for 4.8% of the total. Cluster analysis indicated that 73 sequences of SSR-containing ESTs fell into 27 groups and the remaining 440 ESTs were independent. A total of 467 unique SSR-containing ESTs were identified. These EST-SSRs contained a vari- ety of simple sequence types, and di- and tri-nucleotide repeats were the most abundant, accounting for 42.1% and 27.9% of the whole, respectively. Of the dinucleotide repeats, CA/TG was the most abundant, followed by GA/TC. BLASTx search showed that 38.1% of the SSR loci could be associated with genes or proteins of known or unknown function. BLASTx searches of SSR-containing ESTs also showed high frequencies （98/179） of hits on zebrafish sequences.展开更多
Azadirachta indica seed samples were collected from four different agro-ecological regions（AERs） viz.,AER-2,AER-4,AER-5A and AER-5B of Gujarat state,India during 2000 to 2002 with an aim to assess variability in aza...Azadirachta indica seed samples were collected from four different agro-ecological regions（AERs） viz.,AER-2,AER-4,AER-5A and AER-5B of Gujarat state,India during 2000 to 2002 with an aim to assess variability in azadirachtin,oil and fatty acids content of the seeds and assess correlation of these parameters with morphological characters.Azadirachtin,oil and fatty acids content indicated significant（p0.01） variations between years and AERs in Gujarat.The azadirachtin ranged from 142 to 9 527 μg·g-1 seed kernel with an average of 2 426 μg·g-1 for the state.AER-5B recorded highest azadirachtin and oil content.Fatty acid composition was found to be affected by environmental factors particularly varying degree of annual rainfall and temperature during fruit ripening period.Conclusively trees growing in AER-5B performed better in term of azadirachtin,oil and stearic acid content.Tree girth at breast height showed no significant relation with these biochemicals.展开更多
Identification of quantitative trait loci （QTLs） for grain mineral elements can assist in faster and more precise development of micronutrient dense rice varieties through marker-assisted breeding. In the present st...Identification of quantitative trait loci （QTLs） for grain mineral elements can assist in faster and more precise development of micronutrient dense rice varieties through marker-assisted breeding. In the present study, QTLs were mapped for Fe and Zn concentrations in two BC2F3 mapping populations derived from the crosses of O. sativa cv Swarna with two different accessions of O. nivara. In all, 10 and 8 QTLs were identified for grain Fe and Zn concentrations in population 1, and 7 and 5 QTLs were identified in population 2, respectively. Eighty percent of the QTLs detected in both populations were derived from O. nivara. Five QTLs for Fe and three QTLs for Zn explained more than 15% phenotypic variance either in interval or composite interval mapping. The locations of O. nivara derived QTLs such as qFe2.1, qFe3.1, qFe8.2 and qZn12.1 were consistently identified in both the populations. Epistatic interaction was observed only between RM106 and RM6 on chromosome 2 and between RM22 and RM7 on chromosome 3 for Fe concentration in population 1. Sixteen candidate genes for metal homeostasis were found to co-locate with 10 QTLs for Fe and Zn concentrations in both the populations. Most of the Fe and Zn QTLs were found to co-locate with QTLs for grain yield and grain quality traits. Some of the major effect QTLs identified can be used to improve rice grain Fe and Zn concentrations.展开更多
Waterlogging is an illustrious abiotic stress and the constrictions it enforces on plant roots have negative effects on growth and development.This study was undertaken to investigate waterlogging stress tolerant pote...Waterlogging is an illustrious abiotic stress and the constrictions it enforces on plant roots have negative effects on growth and development.This study was undertaken to investigate waterlogging stress tolerant potential in chilli(Capsicum annum L.)genotypes through evaluating morphological,physiological,biochemical and anatomical parameters.Thirty-five days old seedlings of 10 chilli genotypes were exposed to waterlogging stress maintaining water height 3–5 cm over the soil surface artificially for three days.This duration(36–38 DAE)was termed as waterlogging period,and subsequent withdrawal of waterlogging condition(39–45 DAE)was regarded as a recovery phase.Based on their survival performance,two tolerant genotypes viz.,SRC-517 and BARI morich-2 and two susceptible genotypes viz.,AHM-206 and RI-1(6)were selected for studying stress tolerance mechanism.Under waterlogging,however,both genotypes(tolerant and susceptible)exhibited reduced root shoot length,dry weight ratio,petiole weight and leaf area,and noticeable reduction regarding these parameters was observed in susceptible genotypes.Moreover,tolerant genotypes displayed a higher recovery than susceptible genotypes after removal of waterlogging stress.Lower reduction of leaf area and photosynthetic pigments as well as higher reduction of relative water content(RWC)were noticed in susceptible genotypes.Higher accumulation of proline and total antioxidant capacity(TAC)during waterlogging condition in tolerant genotypes suggested lower oxidative damage.Although both genotypes lost total soluble sugar(TSS)relative to control at waterlogging stress,better performance was recorded in tolerant genotypes.During the period after the removal of extra water,a similar genotypic response in terms of TSS gain was seen.Undoubtedly,under flooding conditions,the development of aerenchyma cells in tolerant genotypes is a means of tolerance mechanism for long-term survival.Thus,the morpho-physiological and biochemical changes help to understand the tolerance mechanism in chilli under waterlogging stress.展开更多
Drought is envisaged as the greatest demolishing natural impacts throughout the world since it has observed extensive place of agronomical land sterile almost the world. It’s the significant crop output-limiting prod...Drought is envisaged as the greatest demolishing natural impacts throughout the world since it has observed extensive place of agronomical land sterile almost the world. It’s the significant crop output-limiting producer, and elaborated learning of its result on plant enhancement dictation is diametrical. At present, drought tolerant hybrid maize has been trying to induce Bangladesh especially drought affected zone to identify the drought endurance maize genotypes. Consequently, a feasible pot study of 49 hybrid maize genotypes were directed to determine an adequate drought level to promote aliment and promotion of maize plant below the water stress conditions with treatment (control and drought) and three replications. The data were received after 35 days of sowing using appropriate procedures. Specially, the stomata were collected by the white transparent nail polish from the lower part of leaves. Descriptive statistic of the all traits like percentage of SPAD, leaf rolling (LR), maximum root length (MRL), maximum shoot length (MSL), root dry matter (RDM), shoot dry matter (SDM), length of stomata (LS), width of stomata (WS), thickness of stomata (TS), total dry matter (TDM) and ANOVA for control and drought condition individually showed significant (P < 0.05) variations among the germplasm for their genotypes, treatment and interaction. The first fourth principal components (PCs) narrated about 82.0% of the total variation. Cluster analysis placed the 49 hybrid into 6 main groups among those cluster;groups five showed the maximum number mean value of traits. The highest positive relationship was obtained from TS, WS, RDM, SDM and TDM traits by forming genotype-traits bi-plot of 11traits of 49 genotypes. After analyzing, it is explicit that G18 (CML-80 × IPB911-16) and G22 (CZI-04 × IPB911-16) were the most tolerant hybrids maize genotypes and very susceptible hybrids maize genotypes were G16 (P-12 × CML487), G34 (CML-32 × PB911-16) and G37 (P-33 × CML487). It is expected that the higher expression of considered traits might be obligate for better yield under drought stress.展开更多
The quantitative resistance gene pi21 from Sensho was introgressed to an indica breeding line IR63307-4B-13-2,a pyramiding line IRBB4/5/13/21,and a tropical japonica line Kinandang Patong by marker-assisted backcrossi...The quantitative resistance gene pi21 from Sensho was introgressed to an indica breeding line IR63307-4B-13-2,a pyramiding line IRBB4/5/13/21,and a tropical japonica line Kinandang Patong by marker-assisted backcrossing.A total of 192 improved lines at the BC4F3 and BC4F4 generations were developed and confirmed to have the gene introgression via genotyping using a pi21-specific InDel marker.Thirteen randomly selected improved lines,representing all the three genetic backgrounds,demonstrated resistance against leaf blast composites in the field and a broader spectrum resistance against individual isolates compared to the recurrent parents in the glasshouse.Specifically,the tested lines exhibited pi21-acquired resistance against 11 leaf blast isolates that elicited susceptible reactions from the recurrent parents.All the tested lines maintained a comparative heading date,and similar or improved panicle length,number of primary branches per panicle and number of total grains per panicle relative to the recurrent parents.The physical grain characteristics of the recurrent parents were also maintained in the 13 lines tested,although variability in the amylose content and chalkiness degree was observed.The successful marker-assisted introgression of pi21 in diverse genetic backgrounds and the resulting broader spectrum resistance of improved lines against leaf blast indicate the potential of pi21 for deployment in cultivars grown across other rice growing regions in Asia.展开更多
The current study investigated the comparative oxidative damage in twomaize seedlings induced by saline,drought,and combined stress and the ameliorative role of two different doses(20 and 80μM)of 5-aminolevulinic aci...The current study investigated the comparative oxidative damage in twomaize seedlings induced by saline,drought,and combined stress and the ameliorative role of two different doses(20 and 80μM)of 5-aminolevulinic acid(ALA)against the above-mentioned stresses.Hydroponically grown 10-day-old maize(Zea mays,var.BARI Hybrid Maize-7(BHM-7)and BARI Hybrid Maize-9(BHM-9))seedlings were exposed to 12 dS/m of saline solution,200 mM mannitol-induced drought stress alone and their combined stress for 7 days.Result revealed that individual stresses retard the plant growth to some degrees,however,their combined stress has more detrimental effects,which might be correlated with lipid peroxidation(MDA)-induced oxidative stress in seedlings,enhanced Na+/K+ratio,and augmented generation of superoxide(O_(2)•^(−))and hydrogen peroxide(H_(2)O_(2)).In contrast,exogenous ALA supplementation at 20μM concentration markedly recovered from chlorosis and growth inhibition,substantially scavenged reactive oxygen species(ROS)and MDA by preserving ionhomeostasis and relaxing oxidative stress,also,by boosting catalase(CAT)and glutathione S-transferase(GST),and exclusively via depressing the activity of lipoxygenase(LOX)antioxidant enzyme.On the contrary,80μM ALA made things worse,nevertheless,higher activities shown by other antioxidant enzymes,like,superoxide dismutase(SOD),ascorbate peroxidase(APX),peroxidase(POD),and glutathione peroxidase(GPX),which were related to lessen the oxidative damage by highly produced O_(2)•^(−)and H_(2)O_(2) under combined stress.Non-denaturing gel electrophoresis was done for further confirmation.However,ALA importantly increased the photosynthetic pigment contents in both genotypes irrespective of doses.Nevertheless,GST might have assisted the plants to escape from the herbicidal effect by detoxification.However,in the combined stress condition,high ALA concentration may have some positive role to play.Our findings also showed that BHM-9 performed better than BHM-7.Therefore,ALA at lower concentration was effective for single stress of saline and drought,while higher concentration can improve plant survival under combined stress.展开更多
Biological control through habitat management leads to sustainable insect pest control. Different types of land composition such as multiple landscapes, patchiness of landscapes enhance the natural enemies which ultim...Biological control through habitat management leads to sustainable insect pest control. Different types of land composition such as multiple landscapes, patchiness of landscapes enhance the natural enemies which ultimately lead to control of insect pest. Plant characteristics such as flower shape, flower color and blooming period ensures excess food for natural enemies like nectar and pollen. Moreover, some agricultural practices such as tillage, crop rotation, and intercropping influence the natural enemies especially parasitoid and preda-tors. Consequently, they increase longevity and fecundity of parasitoid and predator that help to control insect pest. One of the most important recently used methods is push-pull which consists of semiochemicals called Herbi-vore-Induced Plant Volatiles (HIPVs). This compound has been used to pre-vent pest and attract natural enemies.展开更多
Eighteen isolates of Rhizoctonia solani collected from infected rice plants in four different locations of Bangladesh were studied by using morphological characters and molecular markers. Anastomosis study with a refe...Eighteen isolates of Rhizoctonia solani collected from infected rice plants in four different locations of Bangladesh were studied by using morphological characters and molecular markers. Anastomosis study with a reference isolate confirmed that all the isolates belonged to R. solani. Significant variation was observed in sclerotial size, shape and distribution. Un-weighted pair group method with arithmetic mean dendrogram constructed based on the Gower＇s general similarity coefficient showed that these isolates were grouped into four clusters at the 0.68 similarity coefficent according to morphological characters. Cluster I was a major cluster consisting of 13 isolates, while clusters Ⅱ to Ⅳ consisted of 1 or 2 isolates. Analyses by variable number of tandem repeat and amplified fragment length polymorphism markers showed that the isolates were grouped into five and three clusters at a similarity coefficient of 0.64 and 0.69, respectively. Although most of the variability was found between isolates from different regions as expected, significant variation was observed within the isolates collected from similar agro-ecological regions. Our results suggest the presence of different races of R. solani within the same local geographic regions.展开更多
Genetic diversity is one of the useful tools to select appropriate lines for hybridization. Twenty short</span><span style="font-family:Verdana;">-</span><span style="font-family:Ve...Genetic diversity is one of the useful tools to select appropriate lines for hybridization. Twenty short</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize inbred lines were taken for present study</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">which</span><span style="font-family:""><span style="font-family:Verdana;"> were collected from CIMMYT India and Mexico through Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipu</span><span style="font-family:Verdana;">r. This experiment was conducted </span></span><span style="font-family:Verdana;">from</span><span style="font-family:Verdana;"> November 2015 to April 2016 t</span><span style="font-family:Verdana;">o identify parental lines to produce single cross short statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize hyb</span><span style="font-family:""><span style="font-family:Verdana;">rids. </span><span style="font-family:Verdana;">From th</span></span><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;"> genetic diversity studies</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">importance of both additive and non-additive</span><span style="font-family:Verdana;"> gene actions for the expression of yield and yield contributing characters were found. Values of vector I and II revealed that both the vectors had positive values for date of silking, plant height, rows/cob, grains/row and yield. These results indicated that these five characters had highest contribution towards divergence. Based on </span><span style="font-family:Verdana;">the </span><span style="font-family:""><span style="font-family:Verdana;">relative magnitude of D</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> values;20 inbred lines were grouped into five clusters. Seven inbred lines were selected on the basis of genetic diversity and per se performance which will be crossed separately in a half</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">diallel fashion to develop hybrids.展开更多
The research was conducted to investigate comparative oxidative damage including probable protective roles of antioxidant and glyoxalase systems in rice(Oryza sativa L.)seedlings under salinity stress.Seedlings of two...The research was conducted to investigate comparative oxidative damage including probable protective roles of antioxidant and glyoxalase systems in rice(Oryza sativa L.)seedlings under salinity stress.Seedlings of two rice genotypes:Pokkali(tolerant)and BRRI dhan28(sensitive)were subjected to 8 dSm^(−1) salinity stress for seven days in a hydroponic system.We observed significant variation between Pokkali and BRRI dhan28 in phenotypic,biochemical and mole-cular level under salinity stress.Carotenoid content,ion homeostasis,antioxidant enzymes,ascorbate and glutathione redox system and proline accumulation may help Pokkali to develop defense system during salinity stress.However,the activity antioxidant enzymes particularly superoxide dismutase(SOD),catalase(CAT)and non-chloroplastic peroxidase(POD)were observed significantly higher in Pokkali compared to salt-sensitive BRRI dhan28.Higher glyoxalase(Gly-I)and glyoxalase(Gly-II)activity might have also accompanied Pokkali genotype to reduce potential cytotoxic MG through non-toxic hydroxy acids conversion.However,the efficient antioxidants and glyoxalase system together increased adaptability in Pokkali during salinity stress.展开更多
Texture is a complex trait and a major component of fruit quality in apple.While the major effect of MdPG1,a gene controlling firmness,has already been exploited in elite cultivars,the genetic basis of crispness remai...Texture is a complex trait and a major component of fruit quality in apple.While the major effect of MdPG1,a gene controlling firmness,has already been exploited in elite cultivars,the genetic basis of crispness remains poorly understood.To further improve fruit texture,harnessing loci with minor effects via genomic selection is therefore necessary.In this study,we measured acoustic and mechanical features in 537 genotypes to dissect the firmness and crispness components of fruit texture.Predictions of across-year phenotypic values for these components were calculated using a model calibrated with 8,294 SNP markers.The best prediction accuracies following cross-validations within the training set of 259 genotypes were obtained for the acoustic linear distance(0.64).Predictions for biparental families using the entire training set varied from low to high accuracy,depending on the family considered.While adding siblings or half-siblings into the training set did not clearly improve predictions,we performed an optimization of the training set size and composition for each validation set.This allowed us to increase prediction accuracies by 0.17 on average,with a maximal accuracy of 0.81 when predicting firmness in the‘Gala’בPink Lady’family.Our results therefore identified key genetic parameters to consider when deploying genomic selection for texture in apple.In particular,we advise to rely on a large training population,with high phenotypic variability from which a‘tailored training population’can be extracted using a priori information on genetic relatedness,in order to predict a specific target population.展开更多
Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize...Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize linkage drag by BC2F2 generation. Without recombinant selection, the introgression size in the backcross recombinant lines （BRLs） was approximately 15 Mb on the carrier chromosome. The BRLs were found submergence tolerance compared to the check varieties under complete submergence for two weeks at Bangladesh Rice Research Institute, and produced higher yield compared to the isogenic Subl-line under controlled submerged condition. The BRL IR85260-66-654-Gaz2 was released as BRRI dhan52 in 2010, which was the first high yielding submergence tolerant variety in Bangladesh. BRRI dhan52 produced grain yield ranging from 4.2 to 5.2 t/hm2 under different flash flood prone areas of Bangladesh in three consecutive seasons. The study demonstrated the efficiency of recombinant selection and better adaptability of the newly released submergence tolerant high yielding variety in flash flood prone different areas of the country with respect to submergence tolerance and yield potential.展开更多
Single nucleotide polymorphisms and restriction digestion-based haplotype variations among 160 flood prone rice varieties were analyzed with enzymes Alu I and Cac8 I to generate polymorphisms at Sub1A and Sub1C loci ...Single nucleotide polymorphisms and restriction digestion-based haplotype variations among 160 flood prone rice varieties were analyzed with enzymes Alu I and Cac8 I to generate polymorphisms at Sub1A and Sub1C loci （conferring submergence tolerance）, respectively. Haplotype associated with phenotype was used to study the haplotype variations at Sub1A and Sub1C loci and to determine their functional influence on submergence tolerance and stem elongation. Three patterns at Sub1A locus, Sub1A0 （null allele）, Sub1A1 （does not cut） and Sub1A2 （one SNP）, and four patterns at Sub1C locus, Sub1C1, Sub1C2, Sub1C3 and Sub1C4, were generated. Both tolerant Sub1A1 and intolerant Sub1A2 had the same length, but the difference was presence of a restriction site in the Sub1A2, but absent at the Sub1A1. Further, two types of polymorphism were detected at the Sub1C, one included major length polymorphisms （165, 170 and 175 bp） and the other was a single restriction site at different position. Eight haplotypes （different combinations of the two loci）, A1C1, A1C2, A1C4, A2C2, A2C4, A0C2, A0C3 and A0C4, were detected among 160 varieties. Haplotype A1C1 was comparatively more related to haplotypes A1C2 and A1C4, having the same Sub1A allele, and these haplotypes were found only in Bangladeshi, Sri Lankan and Indian varieties. Most tolerant varieties in A1C1 haplotype showed slow elongation, having tolerant specific Sub1A1 and Sub1C1 alleles. Further, the varieties Madabaru and Kottamali （A2C2） also showed moderate level of tolerance without Sub1A1 allele. These varieties were different with FR13A and also suspected to carry different novel tolerant genes at other loci. These materials could be used for hybridization with Sub1 varieties for pyramiding additional tolerant specific alleles into a single genotype for improving submergence tolerance in rice.展开更多
Rice (Oryza sativa L.) is the most important economic activity on earth as it is second largest single use of the land for food production and also consumed by the half of the world's population. Salinity is the o...Rice (Oryza sativa L.) is the most important economic activity on earth as it is second largest single use of the land for food production and also consumed by the half of the world's population. Salinity is the one of the展开更多
Salinity stress is a major factor limiting plant growth and productivity of many crops including oilseed.The present study investigated the identification of salt tolerant mustard genotypes and better understanding th...Salinity stress is a major factor limiting plant growth and productivity of many crops including oilseed.The present study investigated the identification of salt tolerant mustard genotypes and better understanding the mechanism of salinity tolerance.Salt stresses significantly reduced relative water content(RWC),chlorophyll(Chl)content,K^(+) and K^(+)/Na^(+) ratio,photosynthetic rate(P N),tran-spiration rate(Tr),stomatal conductance(gs),intercellular CO_(2) concentration(Ci)and increased the levels of proline(Pro)and lipid peroxidation(MDA)contents,Na+,superoxide(O_(2)^(•−))and hydrogen peroxide(H_(2)O_(2))in both tolerant and sensitive mustard genotypes.The tolerant genotypes maintained higher Pro and lower MDA content than the salt sensitive genotypes under stress condition.The activities of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),glutathione peroxidase(GPX),monodehydroascorbate reductase(MDHAR)and dehydroascorbate reductase(DHAR)were increased with increasing salinity in salt tolerant genotypes,BJ-1603,BARI Sarisha-11 and BARI Sarisha-16,but the activities were unchanged in salt sensitive genotype,BARI Sarisha-14.Besides,the increment of ascorbate peroxidase(APX)activity was higher in salt sensitive genotype as compared to tolerant ones.However,the activ-ities of glutathione reductase(GR)and glutathione S-transferase(GST)were increased sharply at stress conditions in tolerant genotypes as compared to sensi-tive genotype.Higher accumulation of Pro along with improved physiological and biochemical parameters as well as reduced oxidative damage by up-regulation of antioxidant defense system are the mechanisms of salt tolerance in selected mustard genotypes,BJ-1603 and BARI Sarisha-16.展开更多
This study was undertaken to investigate oxidative stress tolerant mechanisms in chilli(Capsicum annuum L.)under drought genotypes through evaluating morphological,physiological,biochemical and stomatal parameters.Twe...This study was undertaken to investigate oxidative stress tolerant mechanisms in chilli(Capsicum annuum L.)under drought genotypes through evaluating morphological,physiological,biochemical and stomatal parameters.Twenty genotypes were evaluated for their genetic potential to drought stress tolerant at seedling stage.Thirty days old seedlings were exposed to drought stress induced by stop watering for the following 10 days and rewatering for the following one week as recovery.Based on their survival performance,two tolerant genotypes viz.BD-10906 and BD-109012 and two susceptible genotypes viz.BD-10902 and RT-20 were selected for studying the oxidative stress tolerance mechanism.Drought reduced root and shoot length,dry weight,ratio,petiole weight and leaf area in both tolerant and susceptible genotypes,and a higher reduction was observed in susceptible genotypes.Lower reduction of leaf area and photosynthetic pigments were also found in tolerant genotypes.Moreover,tolerant genotypes showed higher recovery than susceptible genotypes after the removal of stress.A higher reduction of relative water content(RWC)may cause an imbalance between absorbed and transpirated water in susceptible genotypes.Higher accumulation of proline in tolerant genotypes might be helpful to for better osmotic maintenance than that in susceptible genotypes.Tolerant genotypes showed higher antioxidant activity as they showed DPPH radical scavenging percentage than the susceptible genotypes.Moreover,closer stomata in tolerant genotypes than susceptible ones helped to avoid dehydration in tolerant genotypes.Thus,the above morphological,physiological,biochemical and stomatal parameters helped to show better tolerance in chilli under drought stress.展开更多
文摘The genetic diversity among 15 NIFOR breeding parents was assessed using 10 microsatellite markers. A high genetic diversity was observed with a total of 64 alleles including 23 rare alleles or alleles at frequencies less than 0.05. The NIFOR tenera parents recorded the highest number of rare alleles. The average observed heterozygosity and mean gene diversity across all parental groups were 0.6889 and 0.7029, respectively. Higher genetic diversity was detected among the NIFOR dura and tenera parents compared to that of the Deli dura parents in absolute terms. Analysis of molecular variance (AMOVA) showed that 87% of the total variation (p < 0.001) observed was due to differences among parents. Rogers’ genetic distance ranged from 0.2988 to 0.8000 (mean = 0.5570). The dendrogram constructed on the basis of Rogers’ genetic distance clustered the parents in three groups. They generally clustered in heterotic manner rather than by geographic origins. The groupings obtained through PCoA confirmed the results obtained by cluster analysis. The results obtained are strong assets for NIFOR breeding programme.
文摘Twenty short-statured maize inbred lines were collected from CIMMYT India and Mexico through the Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipur. The experiment was conducted from November 2020 to April 2021 in three different agroecological regions such as BARI, Gazipur, RARS Barisal and RARS Rangpur. Seven inbred lines were selected on the basis of genetic diversity and per se performance and they were crossed separately in a 7 × 7 half diallel fashion, producing 21F1 hybrids in 2019 which were evaluated at three locations. However, variances due to GCA were much higher in magnitude than SCA for all the characters indicating preponderance of additive gene effects on the inheritance of these characters. Two parents viz., P3 (CML33) and P4 (CML41) were good general combiners and two crosses viz., P4 × P5 (CML41 × CML31) and P5 × P7 (CML31 × CML124) expressed significant positive SCA effects coupled with significant positive heterosis for grain yield and for most of the yield contributing characters over the two commercial check varieties BHM 9 and NK40. Four crosses: P1 × P5 (CML116 × CML31), P1 × P6 (CML116 × CML32), P2 × P6 (CML72 × CML32) and P3 × P4 (CML33 × CML41), exhibited significant and negative SCA effects for both plant and ear height which were desirable for short stature. Genotypes x location interaction was also significant for maximum characters, suggesting that genotypes interacted significantly in different environments.
基金work was mainly supported by the ＂863＂ Hi-Tech Research and Development Program of China under contract No. 2005AA603220the National Natural Science Foundation of China under contract No. 30300268.
文摘The chromosomes of Chlamys farreri were analyzed by means of silver staining and fluorescence in situ hybridization （FISH） with 18S-28S rDNA probe. Probe was made by PCR amplification of a DNA fragment containing internal transcribed spacers ITS1 between 18S and 5.8S ribosomal RNA gene, ITS2 between 5.8S and 28S ribosomal RNA gene and 5.8S rRNA gene, and labeled by PCR incorporation of bio-16-dUTP. FISH signals were located on the short arm of subtelocentrie chromosome 10. After silverstaining, nucleolus organizer regions （NORs） could be observed on the telomere of the short arm of chromosome 10. However, one metaphase spread displayed an additional silver spot on the short arm of subtelocentrie chromosome 12.
文摘Common carp expressed sequence tags （ESTs） were analyzed for the existence of microsatellites, or simple sequence repeats （SSRs）. In the NCBI dbEST database, a total of 10612 sequences were registered before December 31, 2004. A complete search of 2-6 nucleotide microsatellites resulted in the identification of 513 SSR-containing ESTs, accounting for 4.8% of the total. Cluster analysis indicated that 73 sequences of SSR-containing ESTs fell into 27 groups and the remaining 440 ESTs were independent. A total of 467 unique SSR-containing ESTs were identified. These EST-SSRs contained a vari- ety of simple sequence types, and di- and tri-nucleotide repeats were the most abundant, accounting for 42.1% and 27.9% of the whole, respectively. Of the dinucleotide repeats, CA/TG was the most abundant, followed by GA/TC. BLASTx search showed that 38.1% of the SSR loci could be associated with genes or proteins of known or unknown function. BLASTx searches of SSR-containing ESTs also showed high frequencies （98/179） of hits on zebrafish sequences.
基金supported by the NOVOD Board, Ministry of Agriculture, Government of India
文摘Azadirachta indica seed samples were collected from four different agro-ecological regions（AERs） viz.,AER-2,AER-4,AER-5A and AER-5B of Gujarat state,India during 2000 to 2002 with an aim to assess variability in azadirachtin,oil and fatty acids content of the seeds and assess correlation of these parameters with morphological characters.Azadirachtin,oil and fatty acids content indicated significant（p0.01） variations between years and AERs in Gujarat.The azadirachtin ranged from 142 to 9 527 μg·g-1 seed kernel with an average of 2 426 μg·g-1 for the state.AER-5B recorded highest azadirachtin and oil content.Fatty acid composition was found to be affected by environmental factors particularly varying degree of annual rainfall and temperature during fruit ripening period.Conclusively trees growing in AER-5B performed better in term of azadirachtin,oil and stearic acid content.Tree girth at breast height showed no significant relation with these biochemicals.
基金financially supported by Network Project on Transgenics and Functional Genomics of Crops-Project 3019 of the Indian Council for Agricultural Research,India(NPTC/FG/05/2672/33)
文摘Identification of quantitative trait loci （QTLs） for grain mineral elements can assist in faster and more precise development of micronutrient dense rice varieties through marker-assisted breeding. In the present study, QTLs were mapped for Fe and Zn concentrations in two BC2F3 mapping populations derived from the crosses of O. sativa cv Swarna with two different accessions of O. nivara. In all, 10 and 8 QTLs were identified for grain Fe and Zn concentrations in population 1, and 7 and 5 QTLs were identified in population 2, respectively. Eighty percent of the QTLs detected in both populations were derived from O. nivara. Five QTLs for Fe and three QTLs for Zn explained more than 15% phenotypic variance either in interval or composite interval mapping. The locations of O. nivara derived QTLs such as qFe2.1, qFe3.1, qFe8.2 and qZn12.1 were consistently identified in both the populations. Epistatic interaction was observed only between RM106 and RM6 on chromosome 2 and between RM22 and RM7 on chromosome 3 for Fe concentration in population 1. Sixteen candidate genes for metal homeostasis were found to co-locate with 10 QTLs for Fe and Zn concentrations in both the populations. Most of the Fe and Zn QTLs were found to co-locate with QTLs for grain yield and grain quality traits. Some of the major effect QTLs identified can be used to improve rice grain Fe and Zn concentrations.
基金This work was supported by the R&D Projects of Ministry of Science and Technology,Government of the People’s Republic of Bangladesh.
文摘Waterlogging is an illustrious abiotic stress and the constrictions it enforces on plant roots have negative effects on growth and development.This study was undertaken to investigate waterlogging stress tolerant potential in chilli(Capsicum annum L.)genotypes through evaluating morphological,physiological,biochemical and anatomical parameters.Thirty-five days old seedlings of 10 chilli genotypes were exposed to waterlogging stress maintaining water height 3–5 cm over the soil surface artificially for three days.This duration(36–38 DAE)was termed as waterlogging period,and subsequent withdrawal of waterlogging condition(39–45 DAE)was regarded as a recovery phase.Based on their survival performance,two tolerant genotypes viz.,SRC-517 and BARI morich-2 and two susceptible genotypes viz.,AHM-206 and RI-1(6)were selected for studying stress tolerance mechanism.Under waterlogging,however,both genotypes(tolerant and susceptible)exhibited reduced root shoot length,dry weight ratio,petiole weight and leaf area,and noticeable reduction regarding these parameters was observed in susceptible genotypes.Moreover,tolerant genotypes displayed a higher recovery than susceptible genotypes after removal of waterlogging stress.Lower reduction of leaf area and photosynthetic pigments as well as higher reduction of relative water content(RWC)were noticed in susceptible genotypes.Higher accumulation of proline and total antioxidant capacity(TAC)during waterlogging condition in tolerant genotypes suggested lower oxidative damage.Although both genotypes lost total soluble sugar(TSS)relative to control at waterlogging stress,better performance was recorded in tolerant genotypes.During the period after the removal of extra water,a similar genotypic response in terms of TSS gain was seen.Undoubtedly,under flooding conditions,the development of aerenchyma cells in tolerant genotypes is a means of tolerance mechanism for long-term survival.Thus,the morpho-physiological and biochemical changes help to understand the tolerance mechanism in chilli under waterlogging stress.
文摘Drought is envisaged as the greatest demolishing natural impacts throughout the world since it has observed extensive place of agronomical land sterile almost the world. It’s the significant crop output-limiting producer, and elaborated learning of its result on plant enhancement dictation is diametrical. At present, drought tolerant hybrid maize has been trying to induce Bangladesh especially drought affected zone to identify the drought endurance maize genotypes. Consequently, a feasible pot study of 49 hybrid maize genotypes were directed to determine an adequate drought level to promote aliment and promotion of maize plant below the water stress conditions with treatment (control and drought) and three replications. The data were received after 35 days of sowing using appropriate procedures. Specially, the stomata were collected by the white transparent nail polish from the lower part of leaves. Descriptive statistic of the all traits like percentage of SPAD, leaf rolling (LR), maximum root length (MRL), maximum shoot length (MSL), root dry matter (RDM), shoot dry matter (SDM), length of stomata (LS), width of stomata (WS), thickness of stomata (TS), total dry matter (TDM) and ANOVA for control and drought condition individually showed significant (P < 0.05) variations among the germplasm for their genotypes, treatment and interaction. The first fourth principal components (PCs) narrated about 82.0% of the total variation. Cluster analysis placed the 49 hybrid into 6 main groups among those cluster;groups five showed the maximum number mean value of traits. The highest positive relationship was obtained from TS, WS, RDM, SDM and TDM traits by forming genotype-traits bi-plot of 11traits of 49 genotypes. After analyzing, it is explicit that G18 (CML-80 × IPB911-16) and G22 (CZI-04 × IPB911-16) were the most tolerant hybrids maize genotypes and very susceptible hybrids maize genotypes were G16 (P-12 × CML487), G34 (CML-32 × PB911-16) and G37 (P-33 × CML487). It is expected that the higher expression of considered traits might be obligate for better yield under drought stress.
基金supported by the Japan International Cooperation Agency as part of the Wonder Rice Initiative for Food Security and Health (WISH) Projectin part by the Canon Foundation and the SATREPS project entitled ‘Improvement in Productivity and Yield Stability of Rice under Kenya’s Biotic and Abiotic Stress Conditions Through Tailor-made Breeding and Development of Cultivation Methods’.
文摘The quantitative resistance gene pi21 from Sensho was introgressed to an indica breeding line IR63307-4B-13-2,a pyramiding line IRBB4/5/13/21,and a tropical japonica line Kinandang Patong by marker-assisted backcrossing.A total of 192 improved lines at the BC4F3 and BC4F4 generations were developed and confirmed to have the gene introgression via genotyping using a pi21-specific InDel marker.Thirteen randomly selected improved lines,representing all the three genetic backgrounds,demonstrated resistance against leaf blast composites in the field and a broader spectrum resistance against individual isolates compared to the recurrent parents in the glasshouse.Specifically,the tested lines exhibited pi21-acquired resistance against 11 leaf blast isolates that elicited susceptible reactions from the recurrent parents.All the tested lines maintained a comparative heading date,and similar or improved panicle length,number of primary branches per panicle and number of total grains per panicle relative to the recurrent parents.The physical grain characteristics of the recurrent parents were also maintained in the 13 lines tested,although variability in the amylose content and chalkiness degree was observed.The successful marker-assisted introgression of pi21 in diverse genetic backgrounds and the resulting broader spectrum resistance of improved lines against leaf blast indicate the potential of pi21 for deployment in cultivars grown across other rice growing regions in Asia.
文摘The current study investigated the comparative oxidative damage in twomaize seedlings induced by saline,drought,and combined stress and the ameliorative role of two different doses(20 and 80μM)of 5-aminolevulinic acid(ALA)against the above-mentioned stresses.Hydroponically grown 10-day-old maize(Zea mays,var.BARI Hybrid Maize-7(BHM-7)and BARI Hybrid Maize-9(BHM-9))seedlings were exposed to 12 dS/m of saline solution,200 mM mannitol-induced drought stress alone and their combined stress for 7 days.Result revealed that individual stresses retard the plant growth to some degrees,however,their combined stress has more detrimental effects,which might be correlated with lipid peroxidation(MDA)-induced oxidative stress in seedlings,enhanced Na+/K+ratio,and augmented generation of superoxide(O_(2)•^(−))and hydrogen peroxide(H_(2)O_(2)).In contrast,exogenous ALA supplementation at 20μM concentration markedly recovered from chlorosis and growth inhibition,substantially scavenged reactive oxygen species(ROS)and MDA by preserving ionhomeostasis and relaxing oxidative stress,also,by boosting catalase(CAT)and glutathione S-transferase(GST),and exclusively via depressing the activity of lipoxygenase(LOX)antioxidant enzyme.On the contrary,80μM ALA made things worse,nevertheless,higher activities shown by other antioxidant enzymes,like,superoxide dismutase(SOD),ascorbate peroxidase(APX),peroxidase(POD),and glutathione peroxidase(GPX),which were related to lessen the oxidative damage by highly produced O_(2)•^(−)and H_(2)O_(2) under combined stress.Non-denaturing gel electrophoresis was done for further confirmation.However,ALA importantly increased the photosynthetic pigment contents in both genotypes irrespective of doses.Nevertheless,GST might have assisted the plants to escape from the herbicidal effect by detoxification.However,in the combined stress condition,high ALA concentration may have some positive role to play.Our findings also showed that BHM-9 performed better than BHM-7.Therefore,ALA at lower concentration was effective for single stress of saline and drought,while higher concentration can improve plant survival under combined stress.
文摘Biological control through habitat management leads to sustainable insect pest control. Different types of land composition such as multiple landscapes, patchiness of landscapes enhance the natural enemies which ultimately lead to control of insect pest. Plant characteristics such as flower shape, flower color and blooming period ensures excess food for natural enemies like nectar and pollen. Moreover, some agricultural practices such as tillage, crop rotation, and intercropping influence the natural enemies especially parasitoid and preda-tors. Consequently, they increase longevity and fecundity of parasitoid and predator that help to control insect pest. One of the most important recently used methods is push-pull which consists of semiochemicals called Herbi-vore-Induced Plant Volatiles (HIPVs). This compound has been used to pre-vent pest and attract natural enemies.
基金funded by the National Science and Information and Communication Technology fellowship and research grant of Ministry of Science,Information and Communication Technology,Bangladesh
文摘Eighteen isolates of Rhizoctonia solani collected from infected rice plants in four different locations of Bangladesh were studied by using morphological characters and molecular markers. Anastomosis study with a reference isolate confirmed that all the isolates belonged to R. solani. Significant variation was observed in sclerotial size, shape and distribution. Un-weighted pair group method with arithmetic mean dendrogram constructed based on the Gower＇s general similarity coefficient showed that these isolates were grouped into four clusters at the 0.68 similarity coefficent according to morphological characters. Cluster I was a major cluster consisting of 13 isolates, while clusters Ⅱ to Ⅳ consisted of 1 or 2 isolates. Analyses by variable number of tandem repeat and amplified fragment length polymorphism markers showed that the isolates were grouped into five and three clusters at a similarity coefficient of 0.64 and 0.69, respectively. Although most of the variability was found between isolates from different regions as expected, significant variation was observed within the isolates collected from similar agro-ecological regions. Our results suggest the presence of different races of R. solani within the same local geographic regions.
文摘Genetic diversity is one of the useful tools to select appropriate lines for hybridization. Twenty short</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize inbred lines were taken for present study</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">which</span><span style="font-family:""><span style="font-family:Verdana;"> were collected from CIMMYT India and Mexico through Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipu</span><span style="font-family:Verdana;">r. This experiment was conducted </span></span><span style="font-family:Verdana;">from</span><span style="font-family:Verdana;"> November 2015 to April 2016 t</span><span style="font-family:Verdana;">o identify parental lines to produce single cross short statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize hyb</span><span style="font-family:""><span style="font-family:Verdana;">rids. </span><span style="font-family:Verdana;">From th</span></span><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;"> genetic diversity studies</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">importance of both additive and non-additive</span><span style="font-family:Verdana;"> gene actions for the expression of yield and yield contributing characters were found. Values of vector I and II revealed that both the vectors had positive values for date of silking, plant height, rows/cob, grains/row and yield. These results indicated that these five characters had highest contribution towards divergence. Based on </span><span style="font-family:Verdana;">the </span><span style="font-family:""><span style="font-family:Verdana;">relative magnitude of D</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> values;20 inbred lines were grouped into five clusters. Seven inbred lines were selected on the basis of genetic diversity and per se performance which will be crossed separately in a half</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">diallel fashion to develop hybrids.
文摘The research was conducted to investigate comparative oxidative damage including probable protective roles of antioxidant and glyoxalase systems in rice(Oryza sativa L.)seedlings under salinity stress.Seedlings of two rice genotypes:Pokkali(tolerant)and BRRI dhan28(sensitive)were subjected to 8 dSm^(−1) salinity stress for seven days in a hydroponic system.We observed significant variation between Pokkali and BRRI dhan28 in phenotypic,biochemical and mole-cular level under salinity stress.Carotenoid content,ion homeostasis,antioxidant enzymes,ascorbate and glutathione redox system and proline accumulation may help Pokkali to develop defense system during salinity stress.However,the activity antioxidant enzymes particularly superoxide dismutase(SOD),catalase(CAT)and non-chloroplastic peroxidase(POD)were observed significantly higher in Pokkali compared to salt-sensitive BRRI dhan28.Higher glyoxalase(Gly-I)and glyoxalase(Gly-II)activity might have also accompanied Pokkali genotype to reduce potential cytotoxic MG through non-toxic hydroxy acids conversion.However,the efficient antioxidants and glyoxalase system together increased adaptability in Pokkali during salinity stress.
基金funded by the EU seventh Framework Programme by the FruitBreedomics Project No.265582。
文摘Texture is a complex trait and a major component of fruit quality in apple.While the major effect of MdPG1,a gene controlling firmness,has already been exploited in elite cultivars,the genetic basis of crispness remains poorly understood.To further improve fruit texture,harnessing loci with minor effects via genomic selection is therefore necessary.In this study,we measured acoustic and mechanical features in 537 genotypes to dissect the firmness and crispness components of fruit texture.Predictions of across-year phenotypic values for these components were calculated using a model calibrated with 8,294 SNP markers.The best prediction accuracies following cross-validations within the training set of 259 genotypes were obtained for the acoustic linear distance(0.64).Predictions for biparental families using the entire training set varied from low to high accuracy,depending on the family considered.While adding siblings or half-siblings into the training set did not clearly improve predictions,we performed an optimization of the training set size and composition for each validation set.This allowed us to increase prediction accuracies by 0.17 on average,with a maximal accuracy of 0.81 when predicting firmness in the‘Gala’בPink Lady’family.Our results therefore identified key genetic parameters to consider when deploying genomic selection for texture in apple.In particular,we advise to rely on a large training population,with high phenotypic variability from which a‘tailored training population’can be extracted using a priori information on genetic relatedness,in order to predict a specific target population.
基金supported in part by a grant from the German Federal Ministry for Economic Cooperation and Development and Bill and Melinda Gates Foundation
文摘Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize linkage drag by BC2F2 generation. Without recombinant selection, the introgression size in the backcross recombinant lines （BRLs） was approximately 15 Mb on the carrier chromosome. The BRLs were found submergence tolerance compared to the check varieties under complete submergence for two weeks at Bangladesh Rice Research Institute, and produced higher yield compared to the isogenic Subl-line under controlled submerged condition. The BRL IR85260-66-654-Gaz2 was released as BRRI dhan52 in 2010, which was the first high yielding submergence tolerant variety in Bangladesh. BRRI dhan52 produced grain yield ranging from 4.2 to 5.2 t/hm2 under different flash flood prone areas of Bangladesh in three consecutive seasons. The study demonstrated the efficiency of recombinant selection and better adaptability of the newly released submergence tolerant high yielding variety in flash flood prone different areas of the country with respect to submergence tolerance and yield potential.
文摘Single nucleotide polymorphisms and restriction digestion-based haplotype variations among 160 flood prone rice varieties were analyzed with enzymes Alu I and Cac8 I to generate polymorphisms at Sub1A and Sub1C loci （conferring submergence tolerance）, respectively. Haplotype associated with phenotype was used to study the haplotype variations at Sub1A and Sub1C loci and to determine their functional influence on submergence tolerance and stem elongation. Three patterns at Sub1A locus, Sub1A0 （null allele）, Sub1A1 （does not cut） and Sub1A2 （one SNP）, and four patterns at Sub1C locus, Sub1C1, Sub1C2, Sub1C3 and Sub1C4, were generated. Both tolerant Sub1A1 and intolerant Sub1A2 had the same length, but the difference was presence of a restriction site in the Sub1A2, but absent at the Sub1A1. Further, two types of polymorphism were detected at the Sub1C, one included major length polymorphisms （165, 170 and 175 bp） and the other was a single restriction site at different position. Eight haplotypes （different combinations of the two loci）, A1C1, A1C2, A1C4, A2C2, A2C4, A0C2, A0C3 and A0C4, were detected among 160 varieties. Haplotype A1C1 was comparatively more related to haplotypes A1C2 and A1C4, having the same Sub1A allele, and these haplotypes were found only in Bangladeshi, Sri Lankan and Indian varieties. Most tolerant varieties in A1C1 haplotype showed slow elongation, having tolerant specific Sub1A1 and Sub1C1 alleles. Further, the varieties Madabaru and Kottamali （A2C2） also showed moderate level of tolerance without Sub1A1 allele. These varieties were different with FR13A and also suspected to carry different novel tolerant genes at other loci. These materials could be used for hybridization with Sub1 varieties for pyramiding additional tolerant specific alleles into a single genotype for improving submergence tolerance in rice.
文摘Rice (Oryza sativa L.) is the most important economic activity on earth as it is second largest single use of the land for food production and also consumed by the half of the world's population. Salinity is the one of the
基金This research cost supported by National Agricultural Technology Program-Phase II(NATP-II)Project,Bangladesh Agricultural Research Council,Dhaka,Bangladesh is greatly acknowledge.
文摘Salinity stress is a major factor limiting plant growth and productivity of many crops including oilseed.The present study investigated the identification of salt tolerant mustard genotypes and better understanding the mechanism of salinity tolerance.Salt stresses significantly reduced relative water content(RWC),chlorophyll(Chl)content,K^(+) and K^(+)/Na^(+) ratio,photosynthetic rate(P N),tran-spiration rate(Tr),stomatal conductance(gs),intercellular CO_(2) concentration(Ci)and increased the levels of proline(Pro)and lipid peroxidation(MDA)contents,Na+,superoxide(O_(2)^(•−))and hydrogen peroxide(H_(2)O_(2))in both tolerant and sensitive mustard genotypes.The tolerant genotypes maintained higher Pro and lower MDA content than the salt sensitive genotypes under stress condition.The activities of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),glutathione peroxidase(GPX),monodehydroascorbate reductase(MDHAR)and dehydroascorbate reductase(DHAR)were increased with increasing salinity in salt tolerant genotypes,BJ-1603,BARI Sarisha-11 and BARI Sarisha-16,but the activities were unchanged in salt sensitive genotype,BARI Sarisha-14.Besides,the increment of ascorbate peroxidase(APX)activity was higher in salt sensitive genotype as compared to tolerant ones.However,the activ-ities of glutathione reductase(GR)and glutathione S-transferase(GST)were increased sharply at stress conditions in tolerant genotypes as compared to sensi-tive genotype.Higher accumulation of Pro along with improved physiological and biochemical parameters as well as reduced oxidative damage by up-regulation of antioxidant defense system are the mechanisms of salt tolerance in selected mustard genotypes,BJ-1603 and BARI Sarisha-16.
基金supported by the R&D projects of Ministry of Science and Technology,Government of the Bangladesh.
文摘This study was undertaken to investigate oxidative stress tolerant mechanisms in chilli(Capsicum annuum L.)under drought genotypes through evaluating morphological,physiological,biochemical and stomatal parameters.Twenty genotypes were evaluated for their genetic potential to drought stress tolerant at seedling stage.Thirty days old seedlings were exposed to drought stress induced by stop watering for the following 10 days and rewatering for the following one week as recovery.Based on their survival performance,two tolerant genotypes viz.BD-10906 and BD-109012 and two susceptible genotypes viz.BD-10902 and RT-20 were selected for studying the oxidative stress tolerance mechanism.Drought reduced root and shoot length,dry weight,ratio,petiole weight and leaf area in both tolerant and susceptible genotypes,and a higher reduction was observed in susceptible genotypes.Lower reduction of leaf area and photosynthetic pigments were also found in tolerant genotypes.Moreover,tolerant genotypes showed higher recovery than susceptible genotypes after the removal of stress.A higher reduction of relative water content(RWC)may cause an imbalance between absorbed and transpirated water in susceptible genotypes.Higher accumulation of proline in tolerant genotypes might be helpful to for better osmotic maintenance than that in susceptible genotypes.Tolerant genotypes showed higher antioxidant activity as they showed DPPH radical scavenging percentage than the susceptible genotypes.Moreover,closer stomata in tolerant genotypes than susceptible ones helped to avoid dehydration in tolerant genotypes.Thus,the above morphological,physiological,biochemical and stomatal parameters helped to show better tolerance in chilli under drought stress.
