ISSN:
1573-5109
Keywords:
cowpea
;
crop evolution/domestication
;
genetic diversity
;
isozyme
;
Vigna unguiculata
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Isozyme analyses of genetic diversity in Vigna unguiculata were performed to determine genetic relationships and level of genetic diversity between wild and cultivated cowpea. Thirty-four cultivated accessions of V. unguiculata, 56 wild accessions of V. unguiculata, and six accessions representing five related wild Vigna species were analyzed. Ten enzyme systems were polymorphic within Vigna unguiculata: AAT, ACO, G6PDH, DIAP, LAP, MUE, ME MDH, PRX, and SOD. Fourteen of 24 putative loci (58%) were polymorphic within wild V. unguiculata, but only one locus (4%) was polymorphic within cultivated cowpea; when five related Vigna species were examined, 21 of the 24 bands of activity showed polymorphisms (88%) adding 33 alleles to the 48 identified within V. unguiculata. In one F2 population of 68 plants (UCDVg 36 × UCDVg 21) a loose linkage was indicated between Diap-2 and G6pd-1 (χ2 = 15.39; p = 0.004) with an estimated distance of 36.0 cM ± 5.02 (recombination (r) = 0.31). Also in another F2 population of 38 plants (CB 88 × UCDVg 21) a loose linkage was indicated between Lap-1 and Prx (\gC2 = 9.62; p = 0.047) with an estimated distance of 39.8 cM ± 7.0 (r = 0.33). Total genetic diversity (HT) was 0.085 over all of the accessions including the one classified as V. nervosa. Within accession diversity (Hs) approached zero and between accession diversity (Dsi) was responsible for all of the genetic diversity present. Therefore the coefficient of gene differentiation (GST = DSTIIT) approached 1. Absolute gene differentiation (Dm) was 0.087. Two of the nine segregations in this study were skewed. In general, results of this study concurred with the taxonomic classification within V. unguiculata and provided a strong indication that a severe genetic bottleneck occurred during the domestication process of cowpea.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00051226
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