A New Allele, tcf, at the T Locus for Partly Colored Seedcoats in Common Bean

Abstract

Common bean (Phaseolus vulgaris L.) plants with partly colored seeds and colored flowers were derived from PI 507984 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-colored seeds and purple flowers due to the genotype T P V. The crosses `2-points tcf BC1 5-593' × 5-593 and `2-points tcf BC2 5-593' × 5-593 produced F2 populations in which all plants had colored flowers. Those results, when considered with previously published work, do not support the previously reported hypothesis that the genes t Fcr Fcr-2 produce partly colored seedcoats and flower color restoration with t. The crosses `2-points tcf BC1 5-593' × `self-colored t BC2 5-593' and `2-points tcf BC2 5-593' × `minimus t BC3 5-593' produced F2 populations that segregated 3:1 for colored:white flowers, respectively. Those results are consistent with the revised hypothesis that tcf can produce partly colored seedcoats without affecting flower color. The RAPD marker OM19400, which is linked in repulsion to T, was used with the F2 populations from the crosses `2-points tcf BC2 5-593' × 5-593 and `2-points tcf BC2 5-593' × `minimus t BC3 5-593' and established that the tcf gene from PI 507984 is either an allele at T or tightly linked to T. F3 data from the cross `2-points tcf BC2 5-593 × 5-593 also support the tcf hypothesis. On the basis of the above experiments, the gene symbol tcf is proposed for an allele at T that pleiotropically produces partly colored seeds and colored flowers.