| Wheat is one of the staple food in our country and even in the world.The healthy and high yield of wheat is of great significance to ensure our country’s food security.At present,the relatively narrow genetic background of parental materials in wheat breeding has become an important factor restricting the improvement of wheat varieties in our country.Based on the preliminary identification and evaluation,combined with genome-wide association analysis,we hope to screen out excellent stress-resistant varieties and stressresistant genes.The main results of this study are as follows:1.Using 325 wheat materials from 4 wheat areas in China and CIMMTY,the drought resistance-related morphological indicators of wheat were determined at the seedling stage by controlling the water content to simulate drought and normal water treatment.Under the drought treatment,the coleoptile length,fresh weight root-shoot ratio and dry weight rootshoot ratio were all higher than those under the normal level,and the rest of the characters were lower than the normal values.There is a very significant positive correlation between the D value of the comprehensive drought resistance coefficient and the drought resistance coefficient of each measured index,indicating that most morphological indicators of wheat are affected under drought stress and the drought resistance mechanism of wheat has a certain complexity;combined with the membership function The drought resistance of the test materials was comprehensively evaluated by means of value,principal component analysis and comprehensive drought resistance ability coefficient,and 87 strong drought resistance and drought resistance varieties were screened out.Among them,220 materials were identified by repeated drought method for drought resistance at seedling stage,and 26 strong drought-resistant and drought-resistant wheat varieties were identified according to the average survival rate of two drought treatments.Among them,4 wheat varieties were identified as drought-resistant varieties under the two drought-resistance identification methods at seedling stage.The wheat materials from different wheat areas were comprehensively evaluated by the comprehensive drought resistance coefficient D value,and the drought resistance of wheat materials from the northern spring wheat area and Huanghuai wheat area was significantly better than that of other wheat areas.The correlation analysis between the field agronomic traits at the adult stage and the D value of the comprehensive drought resistance coefficient at the seedling stage showed that there was no significant correlation between the field agronomic traits at the adult stage and the drought resistance at the seedling stage.2.Lead stress at seedling stage was carried out on 102 wheat materials,and the tolerance to lead of wheat was comprehensively evaluated by the lead tolerance coefficient of the index and the weighted membership function value D value composed of each lead tolerance coefficient under normal and lead stress conditions.According to the tolerance D value,7 wheat materials with strong lead tolerance were selected from the population,namely Xinong 794,Zimai 603,Hanyou 98,Luohan 7,Shannong 24,Zhongxin 78,Chang6878 can provide resources for lead-tolerant wheat germplasm innovation.The lead tolerance of the tested materials was subjected to genome-wide association analysis,and 20 genetic loci significantly associated with lead tolerance in wheat were obtained through the Q+K mixed linear model,and 8 significantly associated with lead tolerance in wheat were detected through the Farm CPU model.The associated QTL,the analysis results of the two models have good consistency in physical location.Finally,13 candidate genes directly or indirectly related to lead tolerance in wheat were obtained,encoding different transporters,peroxidase,transmembrane proteins,and ubiquitin and deubiquitination,which may be involved in oxidative stress response,protein Modification and other pathways to modulate lead tolerance in wheat.Finally,87 varieties with strong drought resistance and drought resistance were identified by controlling the water content at the seedling stage to simulate drought,and 26 varieties with strong drought resistance and 4 varieties were identified by the two drought method;7 wheat materials with strong lead tolerance were selected from the population through the lead stress test at the seedling stage,and 13 wheat materials with direct or Indirectly related candidate genes.These results will help deepen the understanding of wheat drought resistance and lead tolerance,provide resources for wheat varieties innovation,and help accelerate the process of wheat stress resistance breeding. |
PDF Full Text Request