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Abstract
Two new mutants for the reclining foliage (RF) character were induced by treating seed of dry bean (Phaseolus vulgaris L.) breeding lines B-351 and 182-1 with 20 krad of γ-radiation. These two mutants were shown to be monogenic and recessive. Allelism tests between the common RF gene rf and the two new mimic mutants for RF indicated that each of the three mutants has an independent locus. The symbols rf2 and rf3 were given to the new mutants. F2 data from the allelism tests showed that the rf2 stock carries a recessive epistatic gene i that does not affect rf2 but suppresses expression of rf and rf3. The rf locus was shown to be independent of the Sur locus for RF in linkage group VII.
Abstract
Linkage detection and estimation procedures based on deviation from expected F2 segregation ratios in common bean (Phaseolus vulgaris L.) were used to localize two genes. The product ratio method of estimation was used with four-class segregations, and the maximum likelihood method was used with three-class segregations and for combining multiple sets of data. A tight linkage of 1.6 ± 1.5 map units (m.u.) was found between dwarf seed (ds) and dark green savoy leaf (dgs), two genes in linkage group VII. A third gene in linkage group VII, stipelless lanceolate leaf (sl), was found to be 18.7 ± 1.6 m.u. from ds. The distance between dgs and sl was found to be 21.2 ± 1.0 m.u., thus establishing that ds is located between dgs and sl. This location of ds supports the contention that ds and tenuis (te), a gene described by Lamprecht, are the same gene. In linkage group IX, an estimate of 4.6 ± 1.5 m.u. was obtained for the linkage between diamond leaf (dia) and progressive chlorosis (prc). Spindly branch (sb) was found to be 15.4 ± 0.7 m.u. from prc and 11.4 ± 1.1 m.u. from dia. Thus, dia is located between sb and prc. The independence of linkage groups VII and IX is demonstrated by the independence of representatives of the two groups.
Abstract
Linkage tests in common bean (Phaseolus vulgaris L.) were made between black-seeded lines carrying the marker genes round leaf (rnd) and stipelless lanceolate leaf (sl) and the white-seeded lines ‘Miami’ and ‘Inepuisable’ and an induced mutant for white seed, 3-254. The crosses ‘Miami’ × ‘Inepuisable’ and ‘Miami’ × 3-254 were made to test for allelism of the white seed genes in these lines. ‘Miami’ was found to be allelic to ‘Inepuisable’ and 3-254 at the white seed locus (presumed to be P). Furthermore, there was no indication of linkage between the white seed locus and the markers rnd and sl. These results contradict expectations of linkage of P with rnd and sl based on previously published linkage maps and indicate that the present map position of P is incorrect.