The Genetic Diversity Among 27 Maize Populations Based On SSR

The narrower genetic background is the first constraint restricting the maize (Zea mays L.) breeding efforts in China. The complete approach to solve this problem is to enhance and improve the germplasm with concrete objectives based on heterotic group and pattern studies. However, Genetic diversity research had emphasized on inbred lines for years but not yet on populations and synthetics , which have wide genetic background. Therefore, it limits the improvement and enhancement of the com germplasm and thus limits the deveiopvug of the commercial breeding in China at present. By using 71 pair of SSR primers, the genetic diversity among 27 populations, including 13 domestic and 14 CIMMYT populations, has been analyzed based on SSR analysis from 4 bulk DNA each from 10 random individual plants leaves equally. The main results are summarized as follows:(1) It reduced the genetic information after mixed sampling method was used. But it could reflect allele numbers and SSR difference of a maize population. Because of consumedly reducing the experiment workload, it can be applied to the comparison for genetic difference in the more maize population.(2) A total of 389 alleles had been detected On 71 SSR loci in these populations. Wheras, 2 to 19 alleles could be detected at one locus,, with an average of 5.48. Mean polymorphism information content was 0.66, varied from 0.27 to 0.92.(3) No dramatic difference of the proportion of polymorphic sites between domestic and CIMMYT populations had been found, where Chinese populations is 0 compared with 92.2% for CIMMYT populations. The number of polymorphic sites differed in domestic and CIMMY populations, which are 329-for-domestic populations and 370 for CIMMYT populations.(4) Cluster analysis was based on the genetic similarity coefficient. Two heterotic groups were determined among the 27 populations: group 1 was of CIMMYT populations including: Pob21, Pob32, StayGreen, Pob43, Pob49, Pooll9, Pob28, Pob45, Pob46, Pob501, Pob502, Suwanl.Group 2 was of domestic populations including: Jilin Syn A, Liaolv Syn, CSyn 5, Csyn3, Csyn4, Yu Syn5, Golden Queen, Sh,aan Synl, Shaan Syn3, Dongnong Pop C5, WBM-C4, CPopl3, CPopl4, Pob69, Pob70. The results basically were agreeable with the available pedigree data.