Genetic diversity in a collection of Chinese maize inbred lines for resistance to head smut caused by Sporisorium reiliana.

摘要

Head smut caused by Sporisorium reiliana (S. reiliana) is one of the most important diseases in many maize-growing countries including China. In this study, we characterized the genetic diversity in 60 maize inbred lines related to S. reiliana. Sixty inbred lines were evaluated for reaction to S. reiliana under field conditions with artificial inoculation in 2003 and 2004 at Harbin, Heilongjiang province, China. After disease evaluation, we identified 8, 11 and 5 lines from high, moderate and low resistance to S. reiliana, respectively. 70 SSR markers were used to investigate the DNA diversity. The average number of alleles was 3-94 with a range from 2 to 7 alleles per locus. A mean polymorphism information content of 0.58, with a range of 0.237 to 0.811, was observed. About 30% of the alleles in the inbreds had frequencies of 0.10 or less, and only 2% had frequencies of 0.80 or more. Some of the high-frequency alleles were in chromosomal regions associated with disease resistance. The UPGMA analysis showed these 60 inbreds could be classified into 6 groups (Sipingtou, Luda Red Cob, PA, PB, BSSS and Lancaster), which were generally consistent to their known pedigree information. Differences were observed for the mean of S. reiliana disease incidence among the six groups with the highest level of 56.4% for Sipingtou and 21.3%, 19-3%, 12.9%, 14.7% and 1.8% for PA, Luda Red Cob, BSSS, PB and Lancaster, respectively. The Lancaster group was identified as the important source of resistance to S. reiliana.