Waxy Corn Inbred Lines Of Genetic Diversity And Yield, Agronomic Traits And Ssr Molecular Markers In Association Studies

Maize is one of the most important cereal crops worldwide. In 1998, maize yield surpassed that of rice and wheat, ranking first in the world. Waxy corn originated in China is a precious maize germplasm. Waxy maize, characteristics of sweet taste, wax and fragrance, is widely used in foodstuffs and industry. Evidently, investigation of the genetic diversity of waxy maize will provide valuable information for waxy corn breeding programme. In this study, a total of 84 waxy corn inbred lines were used as experimental materials. Seventy one SSR markers in maize 10 chromosomes were adopted to explore the genetic diversity of waxy maize. Moreover, association analysis of 11 agronomic and yield traits of waxy corn were conducted in this study. The results were described in detail as followings.(1) A total of 150 SSR primers were used to detect the polymorphism of experimental materials. Finally, seventy one SSR primers could obtain polymorphic bands among waxy corn inbred lines. The percent of polymorphic SSR primers was 47%. Seventy one pairs of primers in maize 10 chromosomes detected 342 alleles. The number of detected alleles was with a range of 2 to 11. The average allele number was 4.75. Polymorphism information content (PIC) value ranged from 0.249 to 0.876, with an average of 0.479. Primer umc1019 was with the highest PIC value. Contrarily, primer umc1474 was with the lowest PIC value.(2) Similarity coefficient of waxy maize inbred lines ranged from 0.68 to 0.98, with an average of 0.83. Eighty four waxy maize could be divided into eight groups with the threshold value 0.69. Based on custering results presented in this study, redundant bybrid crosses can be avoid and thus improve the breeding efficiency. Additionally, waxy maize inbred lines with large genetic differences should be selected to explore the potential use of heterosis. (3) To some extent, 2557 combinations of two loci among 71 SSR primers were in linkage disequilibrium state, regardless of linear or non-linear combination. The proportion of unbalanced pairs of sites supported by statistical probability (P <0.01) was 12.9%. However, the percent of combinations with D '>0.5 was only 6.5%.(4) Twenty one SSR markers associated with 10 agronomic and yield traits were identified in this study. Of all, the number of SSR loci associated with plant height, tassel branch number, tassel length, early tasseling stage, end tasseling stage, shedding period, silking, ear weight, ear diameter,100-kernel weight was 5, 2, 1, 3, 2, 2, 2, 15, 2, 4, respectively.