CROPPHYSIOLOGICAL STUDIES ON GROWTH AND YIELDS OF SUNFLOWER

Abstract

A investigation in to the comparative productivity of three hybrids of sunflower, namely Hysun 33, HV 772 and AS 502 at three spacings, 25 x 50 cm, 50 x 50 cm and 100 x 50 cm, was carried out at the Fac. of Agriculture, Chiang Mai University during November 1986-March 1987. The experimental design was a split-plot. The hybrids were used as main-plot and plant spacings as sub-plot.

There was no significant difference in seed yields due to the hybrids. The seed yields from all hybrids significantly increased as plart density increased. The dry seed yields of 1944-2510 kg / ha (variation due to plant densities) were observed from Hysun 33, while HV 772 and AS 502 yielded 1998-2563 kg / ha and 1593-2325 kg / ha respectively. Increasing plant densities caused a decrease in head diameter, the number of seed per head and seed weight. There was no significant difference in these yield components among the hybrids, except that the cultivar AS 502 gave a smaller seed than the other two. The highest seed oil content 49.0% was observed from Hysun 33 compared to 43.1% and 39.5% from HV 772 and AS 502 respectively. However AS 502 gave the highest seed protein content of 23.3% compared to 21.1% for HV 772 and 20.6% for Hysun 33. The relationship between LAI and growth are recorded in this report.