Assessment And Association Analysis Of Part Of Traits With Molecular Markers In Stylosanthes Varieties

Stylosanthes is one of the most important sources of leguminous forage and pasture in tropical and subtropical regions. While high yield, high qulity, strong resistance of new varieties as the main goal of Stylosanthes breeding in the field. In this study, Stylosanthes were used as experimental materials and their main agronomic traits, quality characters, disease resistance were analysed to be used to comprehensively evaluate excellent lines; genetic diversity of these germplasm analysis by using SSR markers and SRAP markers to explore genetic relationship at the same time, based on the analysis of the population genetic structure and likage disequilibrium analysis, Finally the association analysis between SSR, SRAP and agronomic traits, quality characters, The results provide the theoretic and practical scientific data for identifing germplasm, molecular breeding and crossing breeding sequentially. The results were summarized as follow:(1) Compare the five times dradle total production.12of them is higher than the average (8.49t/hm2);6of them is higher than the control cultival (Ryan no.20), the production of Stylo540(3008), TPRC2001-84, Stylo541(3009), Nina and other four cultivals is significantly higher than other makers, but no obvious difference between each other; Oxley is lowest.(2) Variance analysis of crude protein, crude fat, crude fiber, ash, non-N extract, P, K and Ca content of20selected accessions of Stylosanthes indicated that8nutrient content (crude protein, crude fat, crude fiber, ash, non-N extract, P, K and Ca) had significant correlation.The concent of Ryan no.21is significantly higher than others, no significantly differences between18of them and control cultival (Ryan no.20). The nutritional quality of the highest value is Ryan no.21; the lowest is TPRC2001-5with the crude protein, crude fat, crude fiber and nitrogen free extract as the indicators for nutritional quality evaluation.(3) Comprehensive evaluation has been done through a gray model of decision-making by using dry matter yield, nutritional quality, survival rate, resistance index as the indicators. The eight germplasm in turn: Stylo540(3008), TPRC2001-84, Nina, Stylo541(3009), Temprano, TPRC2001-81, TPRC2001-80and Ryan no.20. Stylo540(3008), TPRC2001-84is expected to be new varieties with high yield, high quality and disease-resistant.(4) The genomic regions with selection sweep were detected through scanning20Stylosanthes cultivars by using SSR markers and SRAP markers and SSR marker have generated176polymorphic alleles, SRAP generated1084polymorphic alleles, with the polymorphic alleles ratio of76.86%and77.99%.(5) Combining to SSR markers and SRAP markers, and cluster analysis20Stylosanthes varieties divided into three groups at the genetic similarity coefficient is equal to0.79. TPRC2001-1and TPRC2001-5, TPRC2001-7, TPRC2001-9, TPRC2001-15, TPRC2001-55, Ryan no.21, TPRC2001-79, TPRC2001-80, TPRC2001-81, TPRC2001-84, TPR2001-85, Ryan no.20, Nina, Temprano, Stylo540(3008), Stylo541(3009) belonged to the I group; Tardio belonged to the II group; S.hippocampoides Fine stem and S.guianensiscv.Oxley belonged to the III group.(6) The markers associated with traits including dry weight, fresh weight, stem diameter, leave width, plant height, gross ash content and gross protein content and so on, were performed using the association analysis of TASSEL, in which10SSR markers associated with the dry weight,1SSR and15SRAP markers associated with the fresh weight,12SSR and1SRAP marker involved in diameter of plant height,12SSR and1SRAP marker with stem diameter, and1SSR marker related with leave width,1SSR marker with gross ash content,11SRAP marker with gross protein content.