| Wheat is one of the three major food crops in the world.With the increasing demand for crop production,the decrease of arable land and the impact of climate change,wheat production safety has become an important guarantee for food security.In order to further enrich the genetic background of wheat breeding materials and improved varieties,and explore excellent drought-resistant wheat germplasm resources,the collected wheat germplasm resources were identified and evaluated for drought resistance,and analyzed in combination with the detection of vernalization,photoperiod,dwarf and other functional genes.The results of this study are as follows:1.Using 244 wheat germplasm resources from different regions or organizations(domestic,foreign,CIMMYT)as test materials,normal treatment and drought treatment were conducted by water control and drought treatment at seedling stage to determine the correlation indexes of drought resistance at seedling stage.The drought resistance coefficients of coleoptile length,underground dry weight,root/shoot ratio of fresh weight and root/shoot ratio of dry weight under drought treatment were higher than those under normal level,and the other characters were lower than those under control treatment.The comprehensive drought resistance coefficient D was obtained by principal component analysis and membership function method,and the drought resistance of wheat was evaluated comprehensively.The wheat materials were divided into five drought-resistant groups by cluster analysis,and 22 drought-resistant were selected.The drought-resistance coefficients of first leaf morphology,dry weight of above ground,shape of below ground and root/shoot ratio of fresh weight of drought-resistant and drought-resistant materials were significantly different from those of sensitive and highly sensitive materials.There was no significant correlation between field agronomic traits at maturity stage and comprehensive drought resistance coefficient D value at seedling stage,but there was a certain correlation with seedling stage indexes.The drought-resistance ability of wheat varieties was measured by relevant indexes at seedling stage,and the related agronomic traits and yield traits at maturity stage were predicted.2.A total of 241 germplasm materials were labeled to detect vernalization,photoperiod,dwarf and other important functional genes in wheat.The highest frequency of vernalization gene Vrn-B1 was 46.9%,and that of Ppd-D1 a was 87.6%.Materials containing Vrn-1dominant allelic variation had no significant effect on grain characters at maturity.Materials containing Ppd-D1 a allelic variation decreased flag leaf length,plant height,ear length and spikelet number,but increased grain number per spike and 1000-grain weight.The gene frequencies of dwarf rods were 47.7% for Rht-B1,14.1% for Rht-D1,58.5% for Rht-8 and51.9% for Rht-24.The distribution frequency of related genes was different in different regions,and the correlation between the genes and agronomic traits at field maturity stage was different in different environments.The flag leaf length,plant height,ear length and spikelet containing Rht-D1 gene materials were significantly lower than those of other materials,while the number of grains per spike and thousand grain weight were significantly higher than those of other materials.The flag leaf length,plant height and ear length of Rht-8 gene materials were significantly higher than those of other materials in dry land environment.The number of spikelet and grains per spike decreased compared with other materials,but the thousand grain weight increased relatively,even higher than that in water land environment.Previous studies showed that Rht-8 gene had a certain tolerance to drought.Stripe rust resistance genes were detected,including Yr5,Yr26,Yr29,Yr30,Yr75,Yr78,Yr80,Yr82,etc.The distribution frequency of Yr29 was 96.7%.At the same time,the resistance level of wheat materials at seedling stage was identified,and 33 varieties of stripe rust resistance materials were selected,including Chuanmai 35,Chuanmai 90,Chuannong23,Mianyang 27,Nanmai 618,Liangmai 2,Zhongkemai 47,etc.Leaf rust resistance genes were Lr21,Lr34,Lr37,Lr46,Lr67,Lr68 and Lr80.The distribution frequency of Lr67 was98.5%.Ta Sdr-A1,Ta Sdr-B1,Ta MFT-3A and Ta Ph S1 were the anti-sprouting genes,with the highest distribution frequency of Ta Ph S1 being 85.5%.Ta Cwi-A1、Tabas1,Ta GS5-A1,Ta GW2-6A,Ta Sus2-2A and Ta Sus2-2B were associated with grain yield.The highest allelic variation frequency of Tabas1 was 59.8%.For further exploration of important functional genes in wheat and cultivation of excellent varieties.In summary,22 germplasm resources with high drought resistance were selected by identification of drought resistance at seedling stage,and correlated traits at seedling stage were identified by analysis of traits at field maturity stage.The distribution frequency of different vernalization,photoperiod and dwarf genes in wheat and their effects on agronomic characters and grain characters at maturity stage were analyzed.Thirty-three germplasm resources of resistance to stripe rust(R)were identified at seedling stage,and the distribution of other functional genes,such as resistance to leaf rust,resistance to ear germination and grain yield related genes,were described. |
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