Genetics with the k2 Mdhl-n y20 chromosomal region in soybean [Glycine max (L) Merr

Abstract

Twenty-two new mutants have been isolated at the k2 (tan saddle seed coat), Mdhl-n (mitochondrial malate dehydrogenase 1 null), and >'20 (yellow foliage) chromosomal region, were the focus of this dissertation research. Cultivar'Mandell', USDA PI 567.391, and PI 567. 630A are green foliage Mdhl nulls. Genetic Type T261 is a green foliage, Mdhl null, and tan saddle seed coat mutant. T234 and CD-9 are yellow foliage and Mdhl null mutants. Additional 16 new mutants have been isolated with tan saddle seed coat, Mdhl null and yellow foliage phenotypes in this dissertation research. All tan saddle seed coat mutants, the 22 Mdhl null mutants, and the 18 yellow foliage mutants were allelic at the k2, Mdhl-n, and >'20 loci, respectively. k2, Mdhl-n, and>'20 alleles were inherited as single nuclear recessive alleles. Approximately 1 ± 1.36% recombination rate between the k2 and the Mdhl-n loci was detected in coupling phase in F2 plants from crosses of T261 (ifc2 Mdhl-ri) with wild type plants; and approximately 3.04 ± 0.48% recombination rate was estimated between the k2 mi Mdhl-n y20 loci in F2:3 families with tan saddle seed coat from the crosses T317 (Mdhl-ny20) with T239 (k2) and L67-3483 (k2). Approximately 55-60% recombination rates between the k2 and Mdhl-n y20 loci were detected in repulsion phase in F2 plants derived from crossing T323 (Mdhl-ny20), T324 (Mdhl-ny20 ), and T325 (Mdhl-ny20 ) with T239 (k2) and L67-3483 (k2). The excess of the recombinants in repulsion phase in F2 plants was considered to be due to chromosomal breakage at the k2 Mdhl Y20 region in T239 and L67-3483. However, no recombinants were identified in F2 plants in repulsion phase in the crosses of T317 (Mdhl-n y20) with