| Drought is one of the limiting factors affecting wheat yield in north China.It is of great importance,therefore,to identify drought-resistant accessions from newly released wheat varieties to ensure stability of wheat production in this area.In this study,PEG-6000 was used to evaluate the drought resistance of 56 wheat varieties.At the same time,the drought resistance evaluation and index selection were carried out for 51 wheat varieties planted in Heilonggang and North Hebei.In addition,through the transcriptome sequencing of drought resistant wheat varieties,to find the different genes responding to drought stress in different periods,through the analysis of go and KEGG of the different genes,in order to lay a good foundation for the research of drought resistance genes in wheat.The main results are as follows.1.The germination rate,seedling height and coleoptile length of 56 wheat varieties under simulated drought stress were analyzed.When relative germination rate,could be used to evaluate the drought resistance of varieties,a total of nine varieties can be chosen as varieties with drought resistance.The relative germination rate and the seedling height under stress showed strongly related with drought resistance,and the seedling height can be used for indicators for drought evaluation.2.The yield,agronomic and physiological characters of 13 wheat varieties were analyzed under field conditions.The results showed that,compared to normal watering regime,under serious stress,plant height,thousand kernel weight,kernels per spike,spikes per mu,grain yield,chlorophyll content and leaf water loss rate in vitro of wheat decreased significantly,and differed significantly under limited water regimes.When evaluated based on drought resistance index(DI),weighed drought resistance index(WDI)and drought resistance comprehensive evaluation value(D)respectively,the resistance level of each wheat varieties was different slightly.Nevertheless,two varieties can be screened as drought-resistant varieties.When water saving evaluation of varieties with water-saving index,three varieties can be identified as water-saving varieties.Among the agronomic and physiological traits tested,chlorophyll content,spikelet per spike,plant height,leaf water loss rate in vitro,flag leaf length and kernels per spike showed strongly related with drought resistance,and chlorophyll content,spikelet per spike can be used for indicators for drought evaluation.3.The test of drought resistant and water-saving varieties under field conditions was carried out at experimental stations of Cheng'an and Xinji counties during 2017-2018 and 2018-2019 seasons,respectively.The results showed that,when the drought index(DI)based on yield combined with high stability coefficient(HSC),could be used to evaluate the drought resistance of varieties in field production,a total of seven varieties can be chosen as varieties with drought resistance and highly stability.What's more,a total of four varieties can be chosen as varieties with drought resistance but medium stability.When evaluated based on water saving index(WSI)and HSC,two varieties can be chosen as varieties with high water-saving potential and highly stability.Additionally,four varieties can be chosen as ones with high water-saving potential e but medium stability varieties.4.The three varieties were analyzed by transcriptome sequencing in three periods.A total of 482.38gb clean reads were obtained.The results showed that each sample obtained more than 7.52G bases,and the percentage of Q30 bases in each sample was more than 93.67%.What's more,GC content was about 55%.About 90.25%-93.04%of the spliced sequences can be successfully matched to the genome sequence of wheat spring China.Seven databases were used to annotate gene functions,with a total of 130312 genes and 20149 new genes. |
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