| Sorghum [Sorghum bicolor (L.) Moench] is the fifth most important cereal crop, after wheat,rice,maize,and barley.Sorghum and sweet sorghum have a great development potential facing theclimate change and the increasing population in the world for its excellent characteristics likedrought-tolerant,water-logging tolerant,saline tolerant and etc.Sorghum has received increasingattention from the world as a model of renewable bioenergy plant and how to use it to utilize themarginal land.The development of molecular biology on sorghum is getting to a fast period after itswhole genome was released from2009.Association mapping analysis is a method using linkage disequilibrium to detect the gene loci andallele variation in a natural population,now is widely used for detecting QTLs in human medicine andhigher plants. In the present study a synthetic sorghum population containing119representativesamples, including43sweet and76grain sorghum accessions originating mainly from China,USA andIndia, were genotyped using51simple sequence repeat (SSR) markers. Linkage disequilibrium(LD) ofpair-wise loci and population structure were analyzed, followed by association analysis of SSR loci and3sugar yield related traits using the TASSEL general linear model program. Results showed that:(1)different degrees of LD occurred among syntenic markers and also among nonsyntenic markers,indicating historical recombination among sorghum linkage groups; significant LD extended up to7.31cM.(2)the collection of accessions was composed of three subgroups based on ssr data analysis.(3)four marker loci were associated with stalk sugar concentration, fresh stalk weight and stalkjuice weight measured in different growing environments and could be used,therefore, in future markerassisted breeding programs.Several loci were also associated with two or more traits simultaneously,which might be due to tight linkage between different genes affecting these traits. In addition, someassociated markers were located close to QTLs previously mapped in family-based linkage mappinganalyses. |
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