Germplasm Evaluation And Genome-Wide Association Study On Target Traits Of Wild Castor In South China

Castor is an important cash crop and industrial oil crop.Due to the narrow genetic basis and the relatively lagging genetic research,the improvement of breeding level is limited,resulting in the lack of high-yield,disease-resistant varieties in production.In this experiment,the genetic diversity analysis and genome-wide association study were performed with a natural population composed of 171 wild castor accessions collected from South China on 35 target traits based on SSR markers.The main results are as follows:1.Wild castor in southern China could be devided in 3 main categorys according to 15 qualitative traits,the most common type with spherical capsule with dense spines,shallow leaf crack,short inflorescences and cyan leaves green,the type with deep leaf cracks just as the shape of papaya leaf and the type with purple stems,leaves and fruits.The coefficient of variation of the 20 quantitative traits ranged from 0.16-0.97 with an average value of 0.50.The maximum coefficient of variation reached 0.97 with a range of 1-85.The Shannon's information index of 35 target traits ranged from 3.76 to 4.71 and the average value was 4.39.A total of 266 alleles were identified in the population by 71 pairs of polymorphic SSR primers selected out from 1600 SSR markers,2-10 on each SSR locus,with an average of 3.705.The average Shannon's information index was 0.980,and the average polymorphic information content the value was 0.480.Both phenotypic data analysis and molecular data analysis results show that the genetic diversity of the wild castor population in South China is higher than previous studies on other castor population.2.The population was devided into 3 sub-populations by population structure analysis,consistent with the the result of NJ cluster analysis.3.Using the Q + K MLM model,27 loci was identified which were significantly or extremely significantly associated with target traits,among which 4,12,7 and 4 associated with photoperiod,yield traits,plant type traits and kernel traits respectively.The above results are expected to facilitate the research,application of wild castor in south China and molecular marker asistanted selection.