Molecular marker diversity among current and historical maize inbreds

Lu, H. and Bernardo, R. (2001) Molecular marker diversity among current and historical maize inbreds. Theoretical and Applied Genetics, 103 (4). pp. 613-617.

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Advanced-cycle pedigree breeding has caused maize (Zea mays) inbreds to become more-elite but more-narrow genetically. Our objectives were to evaluate the genetic distance among current and historical maize inbreds, and to estimate how much genetic diversity has been lost among current inbreds. We selected eight maize inbreds (B14, B37, B73, B84, Mo17, C103, Oh43 and H99) that largely represented the genetic background of current elite inbreds in the USA seed industry. A total of 32 other inbreds represented historical inbreds that were once important in maize breeding. Cluster analysis of the inbreds, using data for 83 SSR marker loci, agreed well with pedigree information. Inbreds from Iowa Stiff Stalk Synthetic (BSSS), Reid Yellow Dent, and Lancaster clustered into separate groups with only few exceptions. The average number of alleles per locus was 4.9 among all 40 inbreds and 3.2 among the eight current inbreds. The reduction in the number of alleles per locus was not solely due to sample size. The average genetic distance (Dij) was 0.65 among the eight current inbreds, 0.67 among the 32 historical inbreds, and 0.67 among all 40 inbreds. These differences were statistically insignificant. We conclude that genetic diversity among current inbreds has been reduced at the gene level but not at the population level. Hybrid breeding in maize maintained, rather than decreased, genetic diversity, at least during the initial subdivision of inbreds into BSSS and non-BSSS heterotic groups. We speculate, however, that exploiting other germplasm sources is necessary for sustaining long-term breeding progress in maize.

Item Type: Article
Author Affiliation: Department of Agronomy, Purdue University, West Lafayette, IN 47907-1150, USA
Subjects: Crop Improvement > Genetics/Genomics
Crop Improvement > Plant Breeding
Crop Improvement > Biotechnology
Divisions: Maize
Depositing User: Sandhya Gir
Date Deposited: 15 Oct 2010 05:38
Last Modified: 15 Oct 2010 05:38
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