The effect of water stress on genetic recombination in maize

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Date
2001
Authors
Verde, Luis Abel
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Lee, Michael
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Abstract
Plant genomes have the capacity to change in response to abiotic stress and other environmental signals. Increased recombination has been proposed as a response mechanism in several species (e.g., Drosophila, Neurospora, Mus and Lycopersicon). In maize, effects on recombination have been documented for sex, genotype, environment, chromosome rearrangements and supernumerary chromosomes. The effects of water stress have not been reported. In this study, we compare male recombination observed in stress and non-stress plants. In the greenhouse, two treatments were applied to F1 plants (B73xMo17), stress (25% field capacity), and non-stress (field capacity). The treatments were applied before and during male meiosis. Backcross populations (93 individuals each) were created by crossing each F1 as male to B73. Two backcross populations (i.e., two F1 plants) from each treatment were analyzed with 16 SSR loci from chromosome one to create genetic maps. Comparisons of recombination were made within and between treatments. No significant differences were observed between maps within a treatment; therefore, maps from the same treatment were combined. However, differences were observed between treatments: the total genetic map length was greater for stressed plants (170.7cM vs. 156.4cM). The long arm of the chromosome one was the region of additional recombination in the stressed plants. A significant excess of Mol7 alleles was observed in the same genetic region of all populations. Analyses of an additional backcross population for chromosome one and the study of another chromosome are being conducted.
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