A genetic analysis of red seed-coat color inPhaseolus vulgaris

Abstract

does not appear. First page follows. Introduction Several varieties of red beans are grown commercially in California. The market grades of these beans are determined largely by variations of the red color. The red changes to brownish red and brown after a year or two of storage. The occurrence of brown beans in these red varieties is considered by the trade to indicate old beans. Some varieties, especially Red Kidney, are easily discolored by the sun during the harvest so that occasionally newly threshed beans appear to be a year old. The present study is a genetic analysis of red seed-coat color in the common bean (Phaseolus vulgaris L.) preliminary to a breeding program that might result in the introduction of factors that would stabilize the color of the Red Kidney variety. Commercial conditions are adverse to the introduction of varieties with new colors. The breeding problem, then, resolves itself into making more fast the red color without altering it. The ideal may be visualized as a color between the normal red and a darker red, and it was hoped that such an intermediate type could be developed. Crosses were made between red beans of several varieties. This paper reports the results obtained from these experiments. Review of Literature The common bean is world-wide in distribution and is represented by hundreds of horticultural varieties with scores of seed-coat colors and a number of patterns of distribution of color. The species hybridizes easily. Therefore there is little wonder that the literature on the genetics of this species is voluminous and polylingual. Since different workers used different varieties and described the colors by various standards there is little wonder that the results, too, are variable and often apparently contradictory. There is no standard usage of symbols for the genes which have been analyzed; the same symbol has been used to mean a number of different characters.