PATTERN OF FLOWER AND POD DEVELOPMENT IN RAPESEED

Abstract

Bud, flower, and pod production, and pod abortion were recorded at daily intervals for individual inflorescences on early- and late-seeded Brassica campestris (L.) ’Torch’ and B. napus (L.) ’Tower’. Flowering on plants of both cultivars, and both seeding dates, was initiated progressively later on each of the developing inflorescences. While late-developing inflorescences of Torch terminated flowering later than early-developing inflorescences, all inflorescences on Tower terminated flowering at about the same time. All flower initials that gave rise to open flowers were clearly visible on individual inflorescences soon after flowering commenced. Abortion, the failure of pods to elongate, increase in girth and become seed-bearing, was substantial for both varieties and both seedings. Abortion occurred predominantly towards the end of the flowering period or after, and was most prevalent on the later-developing inflorescences. The pattern of flower and pod development in rapeseed indicates a potential for recovery from hail or other injuries early in flowering. This recovery may occur by development of additional flowers or retention of flowers or pods which otherwise would have been lost through natural abortion.