Classical and Molecular Genetic Studies of the Strong Greenish Yellow Seedcoat Color in `Wagenaar' and `Enola' Common Bean

Abstract

Inheritance of the strong greenish-yellow (SGY) seedcoat color in `Wagenaar' common bean ( Phaseolus vulgaris L.) was investigated. Line 5-593 is a determinate, Florida dry bean breeding line (with small black seeds) used as the recurrent parent in the development of many genetic stocks, e.g., g b v BC 3 5-593. Through crosses with genetic tester stocks, the seedcoat genotype of `Wagenaar' was confirmed to be C J g b v lae Rk . Three randomly amplified polymorphic DNA markers (OAP7 850 , OAP3 1400 , and OU14 950 ) that cosegregated with the G seedcoat color locus were developed from the F 2 population derived from the cross g b v BC 2 5-593 × G b v BC 3 5-593. From the cross `Wagenaar' × g b v BC 3 5-593, 80 F 2 plants were classified into 54 non-SGY and 16 SGY seedcoat color plants. When the OAP7 850 marker was applied to that population, linkage was not observed with the non-SGY and SGY phenotypes. Conversely, a molecular marker (OAP12 400 , that was developed from the F 2 from the cross `Wagenaar' × g b v BC 3 5-593) linked to the locus controlling the SGY phenotype segregated independently of the G locus. Therefore, SGY phenotype is not controlled by the G locus. An F 3 progeny test of 76 F 2 plants from the cross `Wagenaar' × g b v BC 3 5-593 confirmed the hypothesis that a single recessive gene (for which we propose the symbol gy ) controls the seedcoat color change from pale greenish yellow (PGY) to SGY. Through crosses with genetic tester stocks, the seedcoat genotype of `Enola' was determined to be C J g b v lae Rk . The test cross `Enola' × `Wagenaar' demonstrated that `Enola' also carries the gy gene. The relationship of `Enola' to the `Mayocoba' market class of common bean and to `Azufrado Peruano 87' is discussed.