Genetic Diversity Analysis and Comprehensive Evaluation of Phenotypic Traits in Hulless Barley Germplasm Resources

【Objective】The genetic diversity in the hulless barley (Hordeum vulgare L. var. nudum Hook. f.) germplasm resources can be screened to improve phenotypic appearance traits. 【Method】Shannon-Wiener diversity index was used to analyze the genetic diversity of 15 phenotypic traits in 205 hulless barley accessions. The distribution frequency of all phenotypic traits in test germplasm resources were analyzed, which contained the data of Xining and Haibei experiment point. Correlation analysis was used to identify the relationship among all traits; cluster analysis was carried out to clarify its classification of the tested germplasm. Principal component analysis was used to construct a comprehensive evaluation system of hulless barley germplasm resources, and the system was verified by linear regression analysis. Screening excellent hulless barley germplasm resources based on the results of comprehensive evaluation and high yield and stability analysis. Correlation analysis, principal component analysis, cluster analysis and high yield and stability analysis were used to evaluate the germplasms. 【Result】The genetic variation level of lodging rate was the richest, the genetic variation level of the center of gravity is the most deficient, the genetic variation of the Haibei test plot showed higher than that of Xining point. The genetic diversity of panicle weight was the most abundant, the genetic uniformity of lodging rate was the highest. Except for the lodging rate, the additional traits showed normal or skewed distribution, and the distribution frequency showed the trend of higher middle and lower sides. The spike length and spike weight showed normally distributed in each genotype. Spike length and panicle weight have normal distributions among the hulless barley accessions. The phenotypic traits showed highly significant differences related to environmental, genotypes, and years factors. Genotype and environment (G×E) factors, genotype and year (G×Y) factors and genotype × environment× year (G×E×Y) interactions produced highly significant differences in the phenotypic traits. There was a significant correlation between the indicators among the roots, stems and panicles of the hulless barley, and there was also a significant correlation between the agronomic traits among the tissues. Well-developed root system, greater stem bending resistance, and stronger mechanical retention, reduced the lodging. Susceptibility to lodging of hulless barley limits the growth and development of spikes and reduce spike length, grain number per ear, grain size, and ear weight. This greatly reduces hulless barley yield. The clustering results demonstrated that the germplasm could be divided into three categories. Category one had a high center of gravity and was susceptible to lodging, but the remaining traits were intermediate. Category two contained germplasm with good agronomic qualities such as dwarf, stalk with a low center of gravity and other useful traits. Category three contained germplasm with high plant height, underdeveloped roots, easily to folded stems, and poor panicle performance. The F value results and yield stability analysis identified five types of barley hull germplasms with excellent overall traits, high yield and stability. 【Conclusion】 High genetic diversity exists in the barley germplasm resources. The spike length and spike weight were normally distributed within each genotype. With the exception of the lodging rate, 12 other traits had skewed distributed within the genotypes. Eight traits including root dry weight, center of gravity, stem wall thickness, main stem diameter, stem strength, spike length, kernels per spike and yield are useful indicators for evaluating barley germplasms.