ISSN:
1432-2242
Keywords:
Key words Genetic mapping
;
Restriction fragment length polymorphism
;
Soybean
;
Seed size
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The objectives of this study were to use molecular markers to: (1) identify quantitative trait loci (QTL) controlling seed-weight in soybean, (2) characterize the genetic basis of seed-weight expression, and (3) determine whether soybean shares orthologous seed-weight genes with cowpea and/or mung bean. An F2 population was developed between a large-seeded Glycine max breeding line and a small-seeded G. soja plant introduction. DNA samples from 150 F2 individuals were analyzed with 91 polymorphic genetic markers, including RFLPs, RAPDs and SSRs. Seed-weight was analyzed by randomly sampling 100 seeds from each of 150 greenhouse-grown F2 individuals, and their 150 F2:3 lines, from a replicated field trial. Markers associated with seed-weight were identified using the computer program MapMaker-QTL and a one-way analysis of variance. Three and five markers were significantly associated with seed-weight variation (P〈0.01) in the F2 and F2:3 generations, respectively. Tests for digenic epistasis revealed three significant interactions in both generations. In a combined analysis, these markers and interactions explained 50 and 60% of the phenotypic variation for seed-weight in the F2 and F2:3 generations, respectively. Comparison of our results in soybean (Glycine) with those previously reported in cowpea and mung bean (Vigna) indicated that soybean and cowpea share an orthologous seed-weight gene. In both species, a genomic region significantly associated with seed-weight spanned the same RFLP markers in the same linkage order. A significant digenic interaction involving this genomic region was conserved in all three species. These results suggest that the exploitation of ``comparative QTL mapping'' is an invaluable tool for quantitative geneticists working with poorly characterized plant systems.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s001220050317
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