FLOWERING IN PISUM - A FURTHER GENE CONTROLLING RESPONSE TO PHOTOPERIOD

Two early-flowering mutants, M2/137 and M2/176, induced in the garden pea (Pisum sativum L.) cultivar Borek were characterized and identifie d. Borek was found to have a late-flowering, quantitative long-day hab it while both mutants were early-flowering, day-neutral types. The mut ants showed monogenic recessive (M2/176) or partially recessive (M2/13 7) inheritance. Mutant M2/137 complemented with the two previously ide ntified day-neutral mutants, sn and dne, and was assigned to a new loc us controlling response to photoperiod, designated ppd. Mutant M2/176 proved to be allelic with sn. The ability to respond to photoperiod in pea is therefore conferred by the joint presence of the complementary genes Sn, Dne, and Ppd. Significant evidence (P <.002) was obtained f or linkage (32 +/- 5 cM) between ppd and chromosome 1 marker a.