Evaluation Of Salt Tolerance And Their Association Analysis With SSR Markers In Barley Wild Relatives And Cultivated Qingke (Hulless Barley) Of China

In this study, the salinity tolerance from75accessions of barley wild relatives in Tibet of China, including21accessions of two-rowed wild barley (Hordeum vulgare L. ssp. spontaneum) and54six-rowed wild barley (H. agriocrithon), and148entries of cultivated qingke (hulless barley, H. hexastichon var. nudum Hsu) cultivars (lines) from different regions of China, was evaluated, and also genetic diversity and association analysis were performed using SSR markers-related salinity tolerance. The main results were as follows:1. The significant differences for salinity tolerance were existed among wild relatives of barley and cultivated qingke (hulless barely) cultivars (lines).2entries of wild barley and51qingke cultivars (lines) with the high tolerance to salt were selected out based on the relative salt injury index in germination stage. Among hulless barley accessions, Ailiumi and XQ0674respectively from Ganzi region of Sichuan and Tibetan region of China indicated the most tolerant to salt with relative salt injury index of1.67%. While86236and86791, respectively from Ali region and Shannan region of Tibet in China had the highest salinity tolerance among wild barley accessions with relative salt injury indices of13.79%and16.67%, respectively. From the results in this study, hulless barley accessions had higher salt tolerance than wild barley in germination stage, and were more important for digging salt tolerance gene.2. The salt tolerance of wild barley in seedling stage and their relationships to Na+ content, K+content and the ration of Na+/K+in shoot According to relative shoot dry biomass under salinity stress,86671from Shannan Prefecture of Tibet of China, showed the highest salinity tolerance with relative shoot dry biomass of77.85%. It was found that salt tolerance was significantly negatively correlated with Na+content and the ratio of Na+/K+in shoot, while significantly positively correlated with K+content in shoot. The results indicated that the compartmentalized Na+ion distribution on the organ level and regulated dynamic equilibrium of Na+, K+ion concentration inside the cell is one of the most important salt-tolerant mechanism for barley.3. The correlation between germination and seedling stage of wild barley. Based on correlation analysis between germination and seedling stage of wild barley, there is no significantly correlation between the two stage in wild barley.4. The genetic diversity analysis of wild barley and hulless barley accesions using SSR markers-related to QTL for salt tolerance. PCR amplification for experimental materials were carried out using32specific SSR markers from7chromosomes of barley which closely linked with salt tolerance QTL.27primer pairs were screened to analyze the genetic diversity of Qingke (hulless barley) and wild barley.87alleles,90alleles with the range of1-6were detected in wild barley and qingke(hulless barley), respectively. The average alleles are3.000and3.103, respectively. For all the sites which PIC is not equal to zero, the range of PIC is0.096-0.742with the average of0.387for wild barley,while0.014-0.778with the average is0.309for qingke (hulless barley).5. The genotypic analysis was made for both the population of148Qingke (hulless barley) and75wild barley using SSR markers The population of148Qingke (hulless barley) and75wild barley was genotyped using SSR markers. The best subpopulation was divided by EVANNO method. When K=2, the content of AK is the biggest according to the InP(D), three subpopulations was divided for wild barley, and two subpopulations for qingke (hulless barley).6.10SSR loci with a total of14loci (times) significantly associated (p<0.05)with12phenotypic traits were screened out from the population. Three loci associated with more than one trait were consistently detected. Bmag0125marker from the chromosome2H was significantly associated with relative sodium ion content in shoot and relative sodium/ potassium ion ratio in seedling stage of wild barley, respectively. HVM62from the chromosome3H was significantly associated with relative coleoptile length and relative lateral root number in germination stage of wild barley. EBmag0757from the chromosome7H was significantly associated with relative shoot dry weight and plant dry weight in seedling stage of allied wild barley.