Biology Group, Bhabha Atomic Research Centre, Bombay-85
1This manuscript was prepared during the generous award of the International Atomic Energy Agency's Fellowship to the author in 1967–68.
Critical understanding of genetic behaviour is better accomplished by studying a variety of cross-combinations (Hammons, 1964). Accordingly, the v mutant of groundnut was crossed to four distinct genotypes. The results indicated its monogenic relationship with the Spanish parent and dr and imp mutants, and a digenic relationship with the Lp mutant. Based on the segre-gant types in F2 the following genotypic composition of parents and F1s may be suggested.
Parental types F1 Spanish Improved (V1V1) × Virescent (v1v1) (V1v1) Darker green Virescent (V1V1dr1dr1dr2dr2) × (v1v1Dr1Dr1Dr2Dr2) (V1v1Dr1dr1Dr2dr2) Impairpinnate Virescent (V1V1imp imp) × (v1v1Imp Imp) (V1v1 Imp imp) Large pod Virescent (V1V1V2V2W1W1w2w2) × (v1 v1- V2V2W1w1W2W2) (VIvIV2v2w1W2w2) While epistatic effects apparently controlled the darker green expression in the dr mutant, additive action accomplished the same in large pod mutant.
The genetic behaviour of imp character appeared to be simple and was independent of v. In spite of the low frequency of imp type plants in the heterozygous progenies, the segregation pattern was consistent. Therefore, this mutant character in addition to virescent can be utilized as genetic marker in breeding experiments.
