A New Gene (Prpi-2) for Intensified Anthocyanin Expression (IAE) Syndrome in Common Bean and a Reconciliation of Gene Symbols Used by Early Investigators for Purple Pod and IAE Syndrome

Abstract

The inheritance of intensified anthocyanin expression (IAE) in a syndrome of plant organs of common bean (Phaseolus vulgaris L.) was investigated. A selection from accession line G07262, having white flowers with blue veins on the wing petals and a long, white micropyle stripe on black seedcoats, was used as the source of IAE syndrome. G07262 was crossed with three genetic tester stocks based on Florida dry bean line 5-593, which has the flower and seedcoat genotype T P [C r] Z J G B V Rk. The tester stocks were 5-593 (black seed and bishops violet flowers), t z bip bipunctata BC1 5-593 (a partly colored seedcoat), and v BC2 5-593 (mineral brown seedcoat and white flowers). Analysis of the F1 and F2 data from the test cross G07262 × t z bip bipunctata BC1 5-593 demonstrated that 1) G07262 has genotype t pmic V; 2) genotype t/t prevents expression of IAE syndrome by a dominant gene (Prpi-2) carried cryptically by G07262, i.e., T/-is required for expression of the gene; and 3) Prpi-2 may (preliminary data) express blue veins on white flowers with t V. From the cross with v BC2 5-593, an F4 selection for white flowers with red banner back and mineral brown seedcoats (due to v) was made. When the F4 selection was crossed with 5-593, analysis of the F2 progeny demonstrated that G07262 carries a dominant gene for IAE syndrome, which expresses with V/- but not with v/v. From the test cross 5-593 × G07262, a series of additional cycles of selection and test crosses (including the dark red kidney tester cu b v rkd BC1 5-593) were made, and two new two-colored seedcoat patterns were developed that have never been previously reported. In a test cross with one of them, F2 data demonstrated that the dominant gene for IAE syndrome from G07262 is independent of the C locus, and the gene symbol Prpi-2 is proposed for this IAE syndrome gene to distinguish it from the previously reported IAE syndrome gene [cu Prpi]. A gene symbol reconciliation was made for all previous work with inheritance of IAE syndrome and purple pod genes without the syndrome.