ISSN:
1439-0523
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Previous genetic studies on resistance to aflatoxin production in maize (Zea mays L.) only used a limited amount of germplasm. The objective of this study was to determine general (GCA) and specific combining abilities (SCA) for resistance to prehar-vest aflatoxin accumulation in grain, utilizing A619 Lfy syn, A632 Lfy syn, B73 Lfy syn, Hy Lfy syn, Mol7 Lfy syn, Wf9 Lfy syn, and 914 Lfy syn. We evaluated 21 F1 crosses (diallel) for aflatoxin accumulation in grain in three environments. Twenty-one days after mid-silk, ears were slash-inoculated with Aspergillus parasiticus (Speare). Samples were analyzed for aflatoxins Bl B2, G1 and G2. Significant differences for aflatoxin accumulation were detected among environments, with the environment that experienced drought stress showing the highest concentration for all four aflatoxins. The GCA and crosses mean squares were not significant for any aflatoxin and the SCA mean square was significant (P = 0.1) only for aflatoxin G2. Relatively small quantities of aflatoxin accumulation on, and nonsignificant differences among the 21 F1 crosses might be indicative of their inherently high resistance levels. The SCA sums of squares constituted two thirds or more of crosses sums of squares, which indicated a preponderance of dominance and/or epistatic effects for aflatoxin accumulation. The Hy Lfy syn GCA effect tended to increase aflatoxin Bl and Wf9 Lfy syn tended to reduce aflatoxin accumulation as it showed a significant (P = 0.1), negative GCA effect for aflatoxin G1. The F1 cross Wf9 Lfy syn × 914 Lfysyn showed significant, negative SCA effect for af-latoxins B1 and G1, whereas A619 Lfy syn × 914 Lfy syn and Mo17 Lfy syn × Wf9 Lfy syn tended to increase one or more aflatoxins. For aflatoxin Br, a significant environments (E) × crosses (C) interaction was largely due to E × GCA interaction, which, in turn, was due to an interaction of the B73 Lfy syn GCA effect with E. This interaction effect tended to reduce aflatoxin BS. The E × C interaction for aflatoxin G2 was due to both E × GCA and E × SCA interactions. B73 Lfy syn GCA × E tended to reduce aflatoxin G, and Mo17 Lfy syn GCA × E tended to increase aflatoxin G. Additive genetic correlations based on GCA effects among the four aflatoxins were significant (0.76 to 0.96), except the correlation between aflatoxins B, and G2 (0.43), suggesting that, in general, increasing resistance to one toxin may lead to resistance to the other three toxins.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1439-0523.1992.tb00188.x
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