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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #86577
Title: RECOMBINATION AND LINKAGE ESTIMATION BETWEEN THE K2 AND MDH1-N Y20 LOCI IN SOYBEAN

Author
item CHEN, XIAN - IOWA STATE UNIVERSITY
item PALMER, REID

Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Recombination of genes controlling plant traits is the major method breeders use to improve the quality and productivity of crops. Plant breeders utilize the predictability of recombination rates of genes to maximize efficiency of effort. This paper reports an unusual recombination phenomenon in soybean. In some cross-combinations between certain mutant soybeans, expected recombination rates were observed. In other cross- combinations among the same soybean types, no recombination was observed and new genetic mutations arose. These unexpected observations are indicative of an instability in this part of the soybean genetic material. The mechanism of this instability is important because it generates mutations and could be used by breeders to direct mutations resulting in novel desirable traits.

Technical Abstract: Tan saddle seed coat (k2), mitochondrial malate dehydrogenase 1 null (Mdhl- nd yellow foliage (y20) are three mutant phenotypes in soybean. In this report, genetic recombination were examined among the k2, Mdhl-n, and y20 loci. Recombination rates of approximately 55-60% between the k2 and Mdhl-n y20 loci were estimated in repulsion recombination phase in F2 plants derived from crossing the mutants, T323 (Mdhl-n y20), T324 (Mdhl-n y20), and T325 (Mdhl-n y20), with the mutants, T239 (k2) and L67-3483 (k2). However, no recombination among the k2, Mdhl-n, and y20 loci was detected in coupling recombination phase in the estimated total of 13,187 F2 plants. The excess of the recombinants in repulsion phase in F2 plants was considered to be the result of breakage at the k2 Mdhl-n y20 chromosomal region in the mutants, T239 and L67-3483, when the Mdhl-n y20 loci were introduced into the T239 and L67-3483 genetic backgrounds. In contrast, no orecombinants were identified in repulsion phase in 455 F2 yellow plants derived from the crosses of T317 (Mdhl-n y20) recombination rate was estimated between the k2 and Mdhl-n y20 loci in a total of 677 F2:3 families with tan saddle seed coat derived from crossing T317 (Mdhl-n y20) with T239 (k2) and L67-3483 (k2). Our data suggests that the mutation in T317 is different from that in T323, and T325.