Genetic diversity of maize inbred lines in relation to downy mildew

George, M L and et al, . (2004) Genetic diversity of maize inbred lines in relation to downy mildew. Euphytica, 135 (2). pp. 145-155. ISSN 1573-5060

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A major emphasis in maize breeding in Asian countries has been the improvement for resistance to downy mildew, a serious disease that causes significant yield losses. A total of 102 inbred lines, including lines from Asian breeding programs, Mexico, USA and Germany, were analyzed with 76 SSR markers to measure diversity and investigate the effect of selection for downy mildew resistance. A mean polymorphism information content of 0.59, with a range of 0.14 to 0.83, was observed. Diversity at the gene level showed an average of 5.4 alleles per locus and a range of two to 16 alleles per locus, with a total of 409 alleles. About half of the alleles in the Asian lines had frequencies of 0.10 or less, and only 2% had frequencies > 0.80, indicating the presence of many alleles, and thus a high level of diversity. Some of the high-frequency alleles were in chromosomal regions associated with disease resistance. However, the frequencies of alleles in three SSR loci that are linked to a QTL for resistance to downy mildews in Asia were not significantly different in the subtropical/tropical Asian lines as compared to all the lines in the study. Lines from the US, Germany, and China, comprised three clusters of temperate maize (GS = 0.31), while those from India, Indonesia, Philippines, Thailand, Vietnam and CIMMYT comprised seven indistinct clusters of subtropical and subtropical maize (GS = 0.29). We conclu

Item Type: Article
Subjects: Others > Genetics and Genomics
Others > Maize
Depositing User: Mr Sanat Kumar Behera
Date Deposited: 15 Mar 2012 07:45
Last Modified: 15 Mar 2012 07:45
Official URL:
Funders: Asian Development Bank, International Maize and Wheat Improvement Center (CIMMYT)
Acknowledgement: D. A. Hoisington is presently with ICRISAT (Patancheru)
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