EFFECT OF PLANT DENSITY ON DEVELOPMENT AND YIELD OF RAPESEED AND ITS SIGNIFICANCE TO RECOVERY FROM HAIL INJURY

Abstract

The ability of rapeseed crops (Brassica campestris L. ’Torch’ and B. napus L. ’Tower’) to recover from, and compensate for, loss of plants at the early vegetative stage of development was investigated by hand thinning plant populations established at commercial seeding rates with commercial seeding equipment. Plant density was reduced from 100-200 plants m −2 to 40 plants m −2 with less than a 20% loss in seed yield. Seeds per pod and seed weight in some instances increased with reduced plant density. However, compensation was attributed predominantly to an increased number of pods on the remaining plants, which increased from 20-90 to as many as 600. Branching increased from as few as 3 to, in some instances, almost 40. With reduced plant population there was a tendency for increased and prolonged accumulation of dry matter by the plants following flowering.Key words: Brassica campestris L., Brassica napus L., rapeseed, development, seed yield, hail.