The effect of time of planting on yield attributes of varieties of safflower

Abstract

At Kimberley Research Station in the 1961 d y season, two varieties of safflower, Gila and 4(1), were sown at monthly intervals in May, June, July and August. The crops were grown under irrigation with adequate fertilizer. There was no significant interaction in seed or oil yield between varieties and dates of planting. Seed and oil yield were significantly reduced in plantings made after June 5 (mean of varieties). Gila outyielded 4(1) in seed and oil yield by 32 and 44 per cent respectively (mean of plantings). There appeared to be two major factors contributing to the decline in final yield of plantings made after June : a reduction in vegetative vigour and a shortening of the reproductive phase. These changes were associated with increasing temperatures and day length.