[ Objective] The aim is to research the relationship between bending property and density of wheat stem. [ Method ] The bending properties such as elastic modulus, bending strength, flexural rigidity, moment of inerti...[ Objective] The aim is to research the relationship between bending property and density of wheat stem. [ Method ] The bending properties such as elastic modulus, bending strength, flexural rigidity, moment of inertia, density and water content of the second base internodes of Zhengmai 9023 and Yumai 25 were determined. [ Result] The results show that during filling stage, there are significant differences in the elastic modulus, moment of inertia, flexural rigidity and density among wheat varieties, while there are no significant differences in the bending strength and water content among wheat varieties. The moment of inertia, flexural strength and flexural rigidity have positive relationship to density but negative relationship to water content. [ Conclusion] The study results provide some references for the research on high yield cultivation and lodging resistance of wheat.展开更多
[Objectives]This study was conducted to improve the quality of straw returning to the field,enhance wheat disease resistance and ensure high and stable yield of wheat.[Methods]The effects of four returning modes on wh...[Objectives]This study was conducted to improve the quality of straw returning to the field,enhance wheat disease resistance and ensure high and stable yield of wheat.[Methods]The effects of four returning modes on wheat stem rot and yield were studied by observation and experiments.[Results]The incidence rate and disease index of stem rot and white head rate of wheat were significantly reduced and the yield was significantly increased by adopting the method of straw returning to the field with the separation of"returning and seeding".The incidence rate and disease index of stem rot and white head rate of wheat were higher than those of the CK and the yield was significantly reduced when adopting the straw returning method of direct sowing.Treatment T_(1)(after maize was harvested,fertilizers,a nutrient-loaded microbial agent and a soil conditioner were evenly spread on the surface of straw,which was then returned to the field using a straw returning machine twice,and then ploughing,soil preparation and wheat sowing were carried out)showed an incidence rate of wheat crown rot 54.8%lower than that of the CK and a white head rate 87.5%lower than that of the CK,and the yield was 2305 kg/hm^(2) higher than that of the CK.[Conclusions]Straw returning can increase soil organic matter content,reduce soil bulk density,enhance soil respiration,and improve wheat disease resistance and yield.展开更多
Stem strength affects directly the resistance of wheat plant to lodging. Unfortunately, the determination of the stem strength is not perfect for wheat breeding and genetics up to now. In this study a prostrate tester...Stem strength affects directly the resistance of wheat plant to lodging. Unfortunately, the determination of the stem strength is not perfect for wheat breeding and genetics up to now. In this study a prostrate tester was engaged for testing the stem strength of 661 wheat varieties and of 1183 single plants from a F2 population. The results showed that the suitable time to determine the stem strength should be from milk stage to dough ripe stage. The stem strength at the maturity would decrease and it was not easy to distinguish the difference among the varieties. The single plant with a strong stem could be judged using the prostrate tester from the F2 population. By testing the stem strength and anatomic characters of 30 varieties, a significant negative relationship between the pith diameter of the upper internodes and the stem strength was observed. On the other hand, there was a significant positive relationship between the stem diameter of the lower internodes and stem strength. It was suggested that a wheat breeder should breed the cultivar with a strong stem, because the spike weight and biomass yield were significantly related to the stem strength.展开更多
Wheat is the second most important cereal in Kenya. However, production is severely constrained by both abiotic and biotic stresses. Of the biotic stresses a devastating pest (Russian wheat aphid (RWA)) and a serious ...Wheat is the second most important cereal in Kenya. However, production is severely constrained by both abiotic and biotic stresses. Of the biotic stresses a devastating pest (Russian wheat aphid (RWA)) and a serious disease (stem rust race TTKS (“Ug99”)) are currently the biggest problem for wheat producers in Kenya. Severe infestations by RWA may result in yield losses of up to 90% while “Ug99” infected fields may suffer 100% crop loss. The two pests combined are seriously affecting wheat farmers’ incomes because of the heavy reliance on pesticides that increase the cost of production. This study attempted to develop and characterize wheat lines that are resistant to both RWA and “Ug99” by pyramiding two major resistance genes. Three wheat varieties: “Kwale”, a Kenyan high yielding variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line with resistance to RWA but of poor agronomic attributes were used. A double cross F1 (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99” resistance. Surviving DC F1 progenies were left to self pollinate to obtain the F2 of the double cross (DC F2). The DC F2 progenies were sequentially screened against RWA and “Ug99” to yield a population that was resistant to both RWA and “Ug99”. Genotyping of the DC F2:3 families were conducted to select homozygous resistant plants. Data indicated that the RWA and “Ug99” resistance genes were successfully pyramided. Though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99” and can still be effectively used as a component for “Ug99” resistance breeding together with other Sr genes.展开更多
InKenya, Russian wheat aphid (RWA) and stem rust race TTKS (“Ug99”) are the most devastating pests of wheat. Severe infestations by RWA result in yield losses of up to 90% while epidemics of “Ug99”can cause up to ...InKenya, Russian wheat aphid (RWA) and stem rust race TTKS (“Ug99”) are the most devastating pests of wheat. Severe infestations by RWA result in yield losses of up to 90% while epidemics of “Ug99”can cause up to 100% loss. The two pests combined have seriously affected farmer incomes forcing them to rely heavily on pesticides and increasing the cost of production. This study sought to evaluate a wheat line that has been developed to be resistant to both RWA and “Ug99”by pyramiding two major resistance genes. Three varieties were used in this study: “Kwale”, a Kenyan high yielding commercial variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line resistant to RWA but with poor agronomic attributes. The F1 of the double cross (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99”resistance. The surviving DC F1 progenies were left to self pollinate in the field to obtain the DC F2. The DC F2 progenies were sequentially screened against RWA and “Ug99”to obtain a resistant population to both RWA and “Ug99”. The yield and yield components of the new resistant line were compared with the three parents. Results showed that the DC F2:3 had higher yields than the three parents based on 1000 kernel weight, weight of kernel per spike, and the actual yield in tons/ha, indicating that the genes were successfully introgressed. It is concluded that though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99”and can be used as a component for “Ug99”resistance breeding together with other Sr genes.展开更多
Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wh...Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ)of China during the period of 1964–2015 were evaluated for several lodging-related traits in three cropping seasons.Plant height,height at center of gravity,length of the basal second internode,and lodging index decreased significantly in this period,and the average annual genetic gains for these traits were–0.50 cm or–0.62%,–0.27 cm or–0.60%,–0.06 cm or–0.63%,and–0.01 or–0.94%,respectively.Different from other traits,stem strength showed a significant increasing trend with the breeding period,and the annual genetic gains were 0.03 N or 0.05%.Correlation analysis showed that lodging index was positively correlated with plant height,height at center of gravity,and length of the basal second internode,but negatively correlated with stem strength.Meanwhile,significantly positive correlations were observed between plant height,height at center of gravity,and length of the basal first and second internodes.By comparison with the wild types,dwarfing genes had significant effects on all lodging-related traits studied except for length of the basal first internode and stem strength.Principle component analysis demonstrated that plant height and stem strength were the most important factors influencing lodging resistance.Clustering analysis based on the first two principle components further indicated the targets of wheat lodging-resistant breeding have changed from reducing plant height to strengthening stem strength over the breeding periods.This study indicates that the increase of stem strength is vital to improve lodging resistance in this region under the high-yielding condition when plant height is in an optimal range.展开更多
Wheat stem rust, caused by Puccinia graminis f. sp. tritici(Pgt), is a potentially devastating fungal disease of wheat worldwide. The present study was to evaluate the resistance of 42 wheat monogenic lines with known...Wheat stem rust, caused by Puccinia graminis f. sp. tritici(Pgt), is a potentially devastating fungal disease of wheat worldwide. The present study was to evaluate the resistance of 42 wheat monogenic lines with known stem rust resistance(Sr) genes and 69 wheat cultivars to three new Pgt races(34C0MRGQM, 34C3MKGQM, and 34C6MTGSM)identified from aeciospores at the seedling and adult-plant stages. The phenotyping results revealed that monogenic lines harboring resistance genes Sr9e, Sr17, Sr21, Sr22, Sr26, Sr30, Sr31, Sr33, Sr35, Sr36, Sr37, Sr38, Sr47, SrTmp,and SrTt3 were effectively resistant to all three Pgt races at the seedling and adult-plant stages. In contrast, monogenic lines containing Sr5, Sr6, Sr7b, Sr9a, Sr9d, Sr9f, Sr9g, Sr9b, Sr16, Sr24, Sr28, and Sr39 were highly susceptible to these races at both seedling and adult-plant stages. The other lines with Sr8a, Sr10, Sr11, Sr13, Sr14, Sr15, Sr18, Sr20,Sr19, Sr23, Sr25, Sr27, Sr29, Sr32, and Sr34, displayed variable levels of resistance to one or two of the tested races.Seedling infection types(ITs) and adult-plant infection responses(IRs) indicated that 41(59.4%) of the wheat cultivars showed high resistance to all the three races. Molecular marker analysis showed that four wheat culitvars likely carried Sr2, 20 wheat culitvars likely carried Sr31, 9 wheat culitvars likely carried Sr38, and none of the cultivars carried Sr24,Sr25, and Sr26. Our results provide a scientific basis for rational utilization of the tested Sr genes and wheat cultivars against these novel Pgt races.展开更多
Anatomical and chemical characteristics of stems affect lodging in wheat(Triticum aestivum L.) cultivars. Traits associated with lodging resistance, such as plant height, stem strength, culm wall thickness, pith diame...Anatomical and chemical characteristics of stems affect lodging in wheat(Triticum aestivum L.) cultivars. Traits associated with lodging resistance, such as plant height, stem strength, culm wall thickness, pith diameter, and stem diameter, were extensively investigated in earlier studies. However, the solid stem trait was rarely considered. In this study, we measured a range of anatomical and chemical characteristics on solid and hollow stemmed wheat cultivars. Significant correlations were detected between resistance to lodging and several anatomical features, including width of mechanical tissue, weight of low internodes, and width of stem walls. Morphological features that gave the best indication of improved lodging resistance were increased stem width, width of mechanical tissue layer, and stem density. Multiple linear regression analysis showed that 99% of the variation in lodging resistance could be explained by the width of the mechanical tissue layer, suggesting that solid stemmed wheat has several anatomical features for increasing resistance to lodging. In addition, microsatellite markers GWM247 and GWM340 were linked to a single solid stem QTL on chromosome 3BL in a population derived from the cross Xinongshixin(solid stem)/Line 3159(hollow stem). These markers should be valuable in breeding wheat for solid stem.展开更多
Wheat along with rice and maize is fulfilling half of the calories demands of the world. Global Wheat production has increased tremendously since green revolution in 1960’s and helped in minimizing hunger and malnutr...Wheat along with rice and maize is fulfilling half of the calories demands of the world. Global Wheat production has increased tremendously since green revolution in 1960’s and helped in minimizing hunger and malnutrition. Developing countries, which consume 60% of the global wheat production, have shown a higher yield increase than the developed countries in the past [1]. It was driven by the hunger prevalence in these countries and was attributable to the introduction of high yielding and rusted resistant semi dwarf varieties developed under the collaborative efforts of International and National research systems during the last 50 years. Whereas, climate change and the emergence of new pests and diseases are threatening the food sustainability. The evolution of new races of disease pathogens like stem rust (Ug 99) is of serious concern. In order to feed the ever increasing population we have to increase wheat production at the rate 1.6% which can be achieved by developing high yielding varieties having a good tolerance level for biotic and abiotic stresses.展开更多
基金Supported by Natural Foundation Program of Henan Province(2009B210016)~~
文摘[ Objective] The aim is to research the relationship between bending property and density of wheat stem. [ Method ] The bending properties such as elastic modulus, bending strength, flexural rigidity, moment of inertia, density and water content of the second base internodes of Zhengmai 9023 and Yumai 25 were determined. [ Result] The results show that during filling stage, there are significant differences in the elastic modulus, moment of inertia, flexural rigidity and density among wheat varieties, while there are no significant differences in the bending strength and water content among wheat varieties. The moment of inertia, flexural strength and flexural rigidity have positive relationship to density but negative relationship to water content. [ Conclusion] The study results provide some references for the research on high yield cultivation and lodging resistance of wheat.
基金Supported by Shaanxi Provincial Innovation Capability Support Program(2019XY-03)Shaanxi Provincial Key R&D Program(2019ZDLNY01-05-02)+3 种基金Key R&D Project of Guangxi Zhuang Autonomous Region(GK AB19259016)Scientific and Technological Innovation Program of Shaanxi Academy of Forestry(SXLK2020-0218)Xi’an Science and Technology Program(20193051YF039N039)Xianyang Key R&D Program(2021DYF-GY-0008)。
文摘[Objectives]This study was conducted to improve the quality of straw returning to the field,enhance wheat disease resistance and ensure high and stable yield of wheat.[Methods]The effects of four returning modes on wheat stem rot and yield were studied by observation and experiments.[Results]The incidence rate and disease index of stem rot and white head rate of wheat were significantly reduced and the yield was significantly increased by adopting the method of straw returning to the field with the separation of"returning and seeding".The incidence rate and disease index of stem rot and white head rate of wheat were higher than those of the CK and the yield was significantly reduced when adopting the straw returning method of direct sowing.Treatment T_(1)(after maize was harvested,fertilizers,a nutrient-loaded microbial agent and a soil conditioner were evenly spread on the surface of straw,which was then returned to the field using a straw returning machine twice,and then ploughing,soil preparation and wheat sowing were carried out)showed an incidence rate of wheat crown rot 54.8%lower than that of the CK and a white head rate 87.5%lower than that of the CK,and the yield was 2305 kg/hm^(2) higher than that of the CK.[Conclusions]Straw returning can increase soil organic matter content,reduce soil bulk density,enhance soil respiration,and improve wheat disease resistance and yield.
文摘Stem strength affects directly the resistance of wheat plant to lodging. Unfortunately, the determination of the stem strength is not perfect for wheat breeding and genetics up to now. In this study a prostrate tester was engaged for testing the stem strength of 661 wheat varieties and of 1183 single plants from a F2 population. The results showed that the suitable time to determine the stem strength should be from milk stage to dough ripe stage. The stem strength at the maturity would decrease and it was not easy to distinguish the difference among the varieties. The single plant with a strong stem could be judged using the prostrate tester from the F2 population. By testing the stem strength and anatomic characters of 30 varieties, a significant negative relationship between the pith diameter of the upper internodes and the stem strength was observed. On the other hand, there was a significant positive relationship between the stem diameter of the lower internodes and stem strength. It was suggested that a wheat breeder should breed the cultivar with a strong stem, because the spike weight and biomass yield were significantly related to the stem strength.
文摘Wheat is the second most important cereal in Kenya. However, production is severely constrained by both abiotic and biotic stresses. Of the biotic stresses a devastating pest (Russian wheat aphid (RWA)) and a serious disease (stem rust race TTKS (“Ug99”)) are currently the biggest problem for wheat producers in Kenya. Severe infestations by RWA may result in yield losses of up to 90% while “Ug99” infected fields may suffer 100% crop loss. The two pests combined are seriously affecting wheat farmers’ incomes because of the heavy reliance on pesticides that increase the cost of production. This study attempted to develop and characterize wheat lines that are resistant to both RWA and “Ug99” by pyramiding two major resistance genes. Three wheat varieties: “Kwale”, a Kenyan high yielding variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line with resistance to RWA but of poor agronomic attributes were used. A double cross F1 (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99” resistance. Surviving DC F1 progenies were left to self pollinate to obtain the F2 of the double cross (DC F2). The DC F2 progenies were sequentially screened against RWA and “Ug99” to yield a population that was resistant to both RWA and “Ug99”. Genotyping of the DC F2:3 families were conducted to select homozygous resistant plants. Data indicated that the RWA and “Ug99” resistance genes were successfully pyramided. Though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99” and can still be effectively used as a component for “Ug99” resistance breeding together with other Sr genes.
文摘InKenya, Russian wheat aphid (RWA) and stem rust race TTKS (“Ug99”) are the most devastating pests of wheat. Severe infestations by RWA result in yield losses of up to 90% while epidemics of “Ug99”can cause up to 100% loss. The two pests combined have seriously affected farmer incomes forcing them to rely heavily on pesticides and increasing the cost of production. This study sought to evaluate a wheat line that has been developed to be resistant to both RWA and “Ug99”by pyramiding two major resistance genes. Three varieties were used in this study: “Kwale”, a Kenyan high yielding commercial variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line resistant to RWA but with poor agronomic attributes. The F1 of the double cross (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99”resistance. The surviving DC F1 progenies were left to self pollinate in the field to obtain the DC F2. The DC F2 progenies were sequentially screened against RWA and “Ug99”to obtain a resistant population to both RWA and “Ug99”. The yield and yield components of the new resistant line were compared with the three parents. Results showed that the DC F2:3 had higher yields than the three parents based on 1000 kernel weight, weight of kernel per spike, and the actual yield in tons/ha, indicating that the genes were successfully introgressed. It is concluded that though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99”and can be used as a component for “Ug99”resistance breeding together with other Sr genes.
基金supported by the National Key Research and Development Program of China (2016YFD0101600 and 2016YFD0100102)the National Natural Science Foundation of China (31401468 and 31771881)the Innovation Team and the National Engineering Laboratory of Crop Molecular Breeding of Chinese Academy of Agricultural Sciences
文摘Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ)of China during the period of 1964–2015 were evaluated for several lodging-related traits in three cropping seasons.Plant height,height at center of gravity,length of the basal second internode,and lodging index decreased significantly in this period,and the average annual genetic gains for these traits were–0.50 cm or–0.62%,–0.27 cm or–0.60%,–0.06 cm or–0.63%,and–0.01 or–0.94%,respectively.Different from other traits,stem strength showed a significant increasing trend with the breeding period,and the annual genetic gains were 0.03 N or 0.05%.Correlation analysis showed that lodging index was positively correlated with plant height,height at center of gravity,and length of the basal second internode,but negatively correlated with stem strength.Meanwhile,significantly positive correlations were observed between plant height,height at center of gravity,and length of the basal first and second internodes.By comparison with the wild types,dwarfing genes had significant effects on all lodging-related traits studied except for length of the basal first internode and stem strength.Principle component analysis demonstrated that plant height and stem strength were the most important factors influencing lodging resistance.Clustering analysis based on the first two principle components further indicated the targets of wheat lodging-resistant breeding have changed from reducing plant height to strengthening stem strength over the breeding periods.This study indicates that the increase of stem strength is vital to improve lodging resistance in this region under the high-yielding condition when plant height is in an optimal range.
文摘Wheat stem rust, caused by Puccinia graminis f. sp. tritici(Pgt), is a potentially devastating fungal disease of wheat worldwide. The present study was to evaluate the resistance of 42 wheat monogenic lines with known stem rust resistance(Sr) genes and 69 wheat cultivars to three new Pgt races(34C0MRGQM, 34C3MKGQM, and 34C6MTGSM)identified from aeciospores at the seedling and adult-plant stages. The phenotyping results revealed that monogenic lines harboring resistance genes Sr9e, Sr17, Sr21, Sr22, Sr26, Sr30, Sr31, Sr33, Sr35, Sr36, Sr37, Sr38, Sr47, SrTmp,and SrTt3 were effectively resistant to all three Pgt races at the seedling and adult-plant stages. In contrast, monogenic lines containing Sr5, Sr6, Sr7b, Sr9a, Sr9d, Sr9f, Sr9g, Sr9b, Sr16, Sr24, Sr28, and Sr39 were highly susceptible to these races at both seedling and adult-plant stages. The other lines with Sr8a, Sr10, Sr11, Sr13, Sr14, Sr15, Sr18, Sr20,Sr19, Sr23, Sr25, Sr27, Sr29, Sr32, and Sr34, displayed variable levels of resistance to one or two of the tested races.Seedling infection types(ITs) and adult-plant infection responses(IRs) indicated that 41(59.4%) of the wheat cultivars showed high resistance to all the three races. Molecular marker analysis showed that four wheat culitvars likely carried Sr2, 20 wheat culitvars likely carried Sr31, 9 wheat culitvars likely carried Sr38, and none of the cultivars carried Sr24,Sr25, and Sr26. Our results provide a scientific basis for rational utilization of the tested Sr genes and wheat cultivars against these novel Pgt races.
基金supported by the National Basic Research Program of China (2011CB100302)the Knowledge Innovation Program of CAS (KSCX2-EW-N-02)
文摘Anatomical and chemical characteristics of stems affect lodging in wheat(Triticum aestivum L.) cultivars. Traits associated with lodging resistance, such as plant height, stem strength, culm wall thickness, pith diameter, and stem diameter, were extensively investigated in earlier studies. However, the solid stem trait was rarely considered. In this study, we measured a range of anatomical and chemical characteristics on solid and hollow stemmed wheat cultivars. Significant correlations were detected between resistance to lodging and several anatomical features, including width of mechanical tissue, weight of low internodes, and width of stem walls. Morphological features that gave the best indication of improved lodging resistance were increased stem width, width of mechanical tissue layer, and stem density. Multiple linear regression analysis showed that 99% of the variation in lodging resistance could be explained by the width of the mechanical tissue layer, suggesting that solid stemmed wheat has several anatomical features for increasing resistance to lodging. In addition, microsatellite markers GWM247 and GWM340 were linked to a single solid stem QTL on chromosome 3BL in a population derived from the cross Xinongshixin(solid stem)/Line 3159(hollow stem). These markers should be valuable in breeding wheat for solid stem.
文摘Wheat along with rice and maize is fulfilling half of the calories demands of the world. Global Wheat production has increased tremendously since green revolution in 1960’s and helped in minimizing hunger and malnutrition. Developing countries, which consume 60% of the global wheat production, have shown a higher yield increase than the developed countries in the past [1]. It was driven by the hunger prevalence in these countries and was attributable to the introduction of high yielding and rusted resistant semi dwarf varieties developed under the collaborative efforts of International and National research systems during the last 50 years. Whereas, climate change and the emergence of new pests and diseases are threatening the food sustainability. The evolution of new races of disease pathogens like stem rust (Ug 99) is of serious concern. In order to feed the ever increasing population we have to increase wheat production at the rate 1.6% which can be achieved by developing high yielding varieties having a good tolerance level for biotic and abiotic stresses.
