Enhanced cross pollination to widen the scope of breeding in groundnut (Arachis hypogaea L.)

Six groundnut genotypes belonging to the Virginia and Valencia sub-groups were irradiated with gamma rays at doses of 5, 10, 15 and 20 kR, much below LD50, and grown surrounded by a pollen parent in a split-plot design. The succeeding two generations were checked for the occurrence of hybrids by examining the segregation for pod and seed characteristics and the two quantitative characters, pod and seed yield. Cross-pollination up to 20.8% was observed in 'M13', a Virginia cultivar. There was a genotype-dose interaction for the extent of cross-pollination. Cross-pollination was higher in Virginia than Valencia genotypes and more frequent under 15 and 20 kR than under other doses, in general. The observed substantial enhancement of cross-pollination encourages the use of seed irradiation at proper doses as a method for increasing recombination in plant breeding programmes.