Identification,Evaluation And Genetic Diversity Study Of Coix Germplasm Resource

In this study,through systematic investigations on the agronomic traits of coix germplasm resources at the heading stage and the maturity stage and the determination of forage nutritional quality,high-yield and high-quality germplasm resources for edible and forage use were screened out.Correlation analysis,principal component analysis and systematic cluster analysis were used to analyze the genetic diversity of each coix germplasm.The SRAP molecular markers were used to correlate with the coix Agronomic traits and other traits,and the sites significantly associated with the coix Agronomic traits and other traits were obtained.The specific results are as follows:(1)Through the evaluations of the whole plant forage,seed stem agronomic characters and whole plant feed nutritional quality of 51 Coix germplasm resources in Liuyang experimental base for two years,the germplasms with excellent performance was selected.Among them,Longhui coix,YY17-33,Xiao hei ke and YY17-15 had high and stable fresh grass yield in two years at heading stage.The average fresh grass yields of the whole plant in two years were 3704.2 kg/667m~2,3324.04 kg/667m~2,3262.24 kg/667m~2,3247.95 kg/667m~2,respectively.The straw yields of Longhui coix,YY17-33,YY17-15 and YY-21 were high and stable in the two years of maturity,and the average straw yields in the two years were4547.77 kg/667m~2,4133.81 kg/667m~2,4052.54 kg/667m~2,4040.41 kg/667m~2,respectively.The grain yields of YY-14,YY17-33 and Longhui coix were high and stable in two years,and the average grain yields in two years were 308.40 kg/667m~2,286.70 kg/667m~2,269.62kg/667m~2,respectively.The crude protein content of YY-07 was the highest at heading stage,with an average crude protein content of 12.60%in two years.The crude protein content of YY17-30 was the highest in mature stage,with an average crude protein content of 7.86%in two years.Through the evaluations of the whole plant forage and seed stem agronomic characters of 82 Coix germplasm resources in Liuyang,Yunyuan,Taoyuan and other experimental bases,the excellent germplasms were selected.Among them,the whole plant fresh grass yields of Longhui coix,YY-21,YY17-15 and YY17-33 were high and stable at heading stage,and the average fresh grass yields of the three experimental sites were 3749.36 kg/667m~2,3484.82 kg/667m~2,3233.59 kg/667m~2,3184.53 kg/667m~2,respectively.The straw yields of Longhui coix,YY-21,YY17-15 and YY17-33 were high and stable at the mature stage,and the average straw yields of the three sites were 4758.93 kg/667m~2,4239.10 kg/667m~2,4073.16 kg/667m~2,3958.27 kg/667m~2,respectively.The grain yields of YY-14,Longhui Coix and YY17-33 were high and stable,and the average grain yields of the three sites were298.00 kg/667m~2,290.56 kg/667m~2,269.58 kg/667m~2,respectively.(2)The genetic diversity of 82 Coix germplasm resources was studied.The principal component analysis showed that the cumulative contribution rate of the first four principal components was 76.17%,the first principal component mainly included grain width,grain length,thousand-grain weight and grain yield.The second principal component included plant height,main stem node number,main stem diameter,leaf number and stem-leaf ratio.And the third principal component mainly included grain number per plant,grain yield and tiller number.The fourth principal component included tiller number,grain length and thousand-grain weight.Through systematic clustering,using Euclidean distance as genetic distance,82 Coix germplasm resources could be divided into 4 groups at chi-square distance of 114.1.The first group was mainly characterized by large grains,more grains per plant and high grain yield,while the second group was mainly characterized by small grains,more tillers and more grains per plant.The third group was mainly characterized by medium grain number per plant and medium grain yield,while the fourth group was mainly characterized by slender and small grains,few tillers and low grain yield.In the analysis of population structure,it was divided into three subgroups Q1,Q2 and Q3 and a mixed group MP.Most of the germplasm in Q1 came from the central and northern part of Hunan,Q2 mainly came from the central and southern part of Hunan Province,and Q3 mainly came from the central and northern part of Hunan.(3)Through the association analysis of 7 agronomic character data and SRAP molecular markers of 82 Coix germplasm resources from three locations,it was found that 15 pairs of primers were significantly associated with 7 Coix agronomic traits,and their variation interpretation rates ranged from 6.75%to 18.64%.Primer me8/em8 was extremely significantly correlated with the coix thousand-grain weights of the three experimental bases;primer me2/em6 was significantly correlated with the coix traits and the diameters of the main stem of the two experimental bases;primer me1/em7 was significantly correlated with the thousand-seed weights of the coix traits in two experimental bases.