FREQUENCY OF NATURAL OUT-CROSSING IN PARTIALLY CLEISTOGAMOUS PIGEONPEA LINES IN DIVERSE ENVIRONMENTS

Natural out-crossing is the major cause of loss of varietal purity in pigeonpea [Cajanus cajan (L.) Millsp.]. The frequency of natural out-c rossing of partially cleistogamous mutant lines, characterized by a mo dified keel and filamentous anthers, was studied at two locations in S ri Lanka and three locations in India. Indeterminate growth habit and normal floral morphology were used as dominant markers and the frequen cy of natural out-crossing was estimated as percentage of the observed hybrid plants. Natural out-crossing in the mutant lines in Sri Lanka ranged from 0.14 to 1.33%, in comparison to 6.34 to 19.64% in the cont rols. In the Indian environments, natural outcrossing ranged from 0.16 to 2.67%. The mutant was highly stable over diverse environments, and may be of considerable economic importance in pigeonpea improvement a nd seed-production programs.