Interaction of Two Genes, Fcr and Fcr2, with the t Allele in Common Bean that Restores Color to Flowers

Abstract

Plant Introduction (PI) accession 507984 of common bean (Phaseolus vulgaris L.) has partly colored seed coats and either pure white flowers or light laelia flowers. Crosses were made with white-flowered plants of PI 507984: white-flowered plant #1 × the genetic stock t ers ers2 BC2 5-593 and white-flowered plant #2 × recurrent parent dry bean breeding line 5-593. Inheritance was studied in the F1, F2, and F3 of the former cross and the F1 and F2 of the latter cross. PI 507984 (white flower, plant #1) × t ers ers2 BC2 5-593 gave F1 plants with colored flowers and partly colored seeds. The F2 gave a 9:7 segregation ratio (colored flowers to white flowers), and the genetic model proposed is that flower color is restored in the presence of t/t by two complementary genes, Fcr and Fcr-2. That model was confirmed by F3 progeny tests of 21 F2 parents with colored flowers. The cross PI 507984 (white flower, plant #2) × 5-593 gave an F2 segregation ratio of 9:3:4 (bishops-violet: light laelia: white flowers), indicating that the white-flowered PI 507984 has vlae masked by t. Analysis of all the data suggests that PI 507984 is heterogeneous at Fcr and Fcr-2, having all three possible homozygous genotypes, viz., either light laelia flowers from vlae t Fcr Fcr-2 or white flowers from vlae t Fcr fcr-2 or vlae t fcr Fcr-2. The flower color restoration gene in 5-593 is arbitrarily assigned the symbol Fcr. Great variability occurs in partly colored seeds of PI 507984 due to the environment in which the seed was produced.