Genetics of a virescent foliage mutant in beans

ABSTRACT: A foliage color mutant In a dry edible bean breeding line was controlled by one reces-sive gene. The mutant exhibited a virescent characteristic under some environmental condi-tions. Segregation in F2 and backcross populations from crosses of the virescent and a previously described pale-foliage mutant clearty indicate that the two genes are Independent The gene symbol vlr, Is proposed for the virescent foliage mutant, which may be useful In genetic or physiological studies In beans. GENETIC MARKERS of bean seedlings (Phase-olus vulgaris L.) are useful in breeding programs and genetic studies. Smith6 described a dry bean phenotype with pale-green foliage that developed normal green color in the greenhouse when the plants were 10 to 15 centimeters tall. This vir-escent characteristic was controlled by a single, recessive gene. Virescent chlorophyll mutants also have been observed in several other crops, such as muskmelon2, cotton4, and maize5. Dale and Heyes1 studied a recessive mutant with pale-green coloration due to low rates of chlo-rophyll production and rapid breakdown of chlorophyll when subjected to high light intensity conditions. Wyatt8 reported a naturally occurring pale-green foliage mutant in snap beans con-trolled by the recessive gene pa/. The objective of the present study was to determine the inher-itance of another chlorophyll deficient mutant observed in a dry edible bean breeding line and the genetic relationship of this mutant to that studied by Wyatt8