A new allele, tcf, at the T locus for partly colored seedcoats in common bean

摘要

Common bean (Phaseolus vulgaris) plants with partly coloured seeds and coloured flowers were derived from PI507984 in two genetic tester stocks: 2-points tcf BC1 5-593 and 2-points tcf BC2 5-593. These stocks were produced by backcrossing to the recurrent parent, Florida dry bean breeding line 5-593, which has black self-coloured seeds and purple flowers due to the genotype T P V. The crosses 2-points tcf BC1 5-593 X 5-593 and 2-points tcf)> BC2 5-593 X 5-593 produced F2 populations in which all plants had coloured flowers. Those results, when considered with previously published work, do not support the previously reported hypothesis that genes t Fcr Fcr-2 produce partly coloured seedcoats and flower colour restoration with t. The crosses 2-points tcf BC1 5-593 X self-coloured t BC2 5-593 and 2-points tcf BC2 5-593 X minimus t BC3 5-593 produced F2 populations that segregated 3:1 for coloured:white flowers, respectively. Those results are consistent with the revised hypothesis that tcf can produce partly coloured seed coats without affecting flower colour. The RAPD marker OM19400, which is linked in repulsion to T, was used with F2 populations from the crosses 2-points tcf BC2 5-593 X 5-593 and 2-points tcf BC2 5-593 X minimus t BC3 5-593, andestablished that the tcf gene from PI507984 is either an allele at T or tightly linked to T. F3 data from the cross 2-points tcf BC2 5-593 X 5-593 also support the tcf hypothesis. On the basis of the above experiments, the gene symbol tcf is proposed foran allele at T that pleiotropically produces partly coloured seeds and coloured flowers.