Flowering in <italic>Pisum</italic>: A Further Gene Controlling Response to Photoperiod

Abstract

Two early-flowering mutants, M2/137 and M2/176, induced in the garden pea (Pisum sativum L.) cultivar Borek were characterized and identified. Borek was found to have a late-flowering, quantitaive long-day habit while both mutants were early-flowering, day-neutral types. The mutants showed monogenic recessive (M2/176) or partially recessive (M2/137) inheritance. Mutant M2/137 complemented with the two previously identified day-neutral mutants, sn and dne, and was assigned to a new locus contolling 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, One, and Ppd. Significant evidence (P < .002) was obtained for linkage (32 ±5 cM) between ppd and chromosome 1 marker a.