Genetic Model Analysis And Preliminary QTL Mapping Of Main Agronomic Characters Of Sweet Sorghum Hybrid Population

Sorghum is an important crop cultivated worldwide, sweet sorghum is a variant of grain sorghum, with tall plants, high light efficiency, short growth period, high biomass, strong resistance, higher sugar content in stalk, can be planted on marginal land, these made sorghum a great energy crops. The stalk of sweet sorghum can be used to produce biofuels, and the seed also used to make sugar, wine and feed. So sweet sorghum is not only a source of energy, but also a excellent sugar and forage crops, with high economic value.In this study, grain sorghum male sterile line(BT x 623A) and sweet sorghum sterile line (Shi28A) hybrid to three different sweet sorghum to obtain 4 hybrid respectively. The plant height, fresh weight, diameter, brix and number of sections were conducted genetic model analysis, selected Shi28A-S148 F2 population with significant hybrid advantages, analyzed the SSR molecular marker, constructed sorghum SSR marker genetic linkage map and number of sections, diameter and brix three important agronomic traits QTL initial mapping, in order to provide basis for the subsequent genetic breeding design and precise mapping of QTL. We obtained the following results:1. With sorghum varieties BT x 623A, Shi28A as female parent, sweet sorghum varieties S148, S184 and sweet night as male parent, for six groups of four different hybrid combinations(BT × 623A-sweet night, BT × 623A-S184, Shi28A-S148, Shi28A-S184), the plant height, fresh weight, diameter, brix and number of sections five traits were conducted genetic model analysis and drew sweet sorghum genetic model more generation joint analysis summary graph. The study found the same trait in different hybrid combinations, there are some differences in the major genes and genetic model, different traits of the same hybrid combinations have particular main effect genes and genetic model, the genetic model analysis of the important agronomic traits of sorghum, reveal genetic factors in different combinations and different environments, and can provide a theoretical basis for genetic improvement;2. Male sterile lines Shi28A and sweet sorghum varieties S148 hybrid, heterosis significantly, the traits distribution of F2 population are typical, take advantage of this group to analysis SSR molecular marker and constructed sorghum SSR marker genetic linkage map containing a total of 75 marker loci, covering sorghum genome 1459.5 cM, the average distance between markers is 19.46 cM, a total of 19 linkage groups;3. On the basis of molecular marker linkage map of sorghum, number of sections, diameter and brix three important agronomic traits were constructed QTL mapping analysis. A total of 10 QTL were detected, the number of QTL number of sections, diameter and brix was 4,2 and 4, the number of the corresponding main effect QTL were 2,1 and 2. Two number of sections main effect QTL located at SBI-03 and SBI-06 respectively, diameter main effect QTL located on SBI-06, two brix main effect QTL are all located on the SBI-06. Most of the main effect QTL distribution in SBI-06, regional between the three markers s253, s54 and s9 may be gene cluster where multiple traits QTL expression.