ALLOMETRY, AGRONOMIC TRAITS AND YIELD OF AUTUMN PLANTED SUNFLOWER HYBRIDS UNDER VARYING ROW SPACING

Studies were conducted to assess the agronomic kg ha^-1and physiological basis of variation in yield among three sunflower hybrids of varying maturity groups, sow at row spacing of 45, 60 and 75 cm during the autumn seasons of 2006 and 2007. in both years of experimentation, the hybrid hysun-33, a long season hybrid, stood out not only for maximum leaf area index, but also for its crop growth rate, plant height, number of achenes and achene yield. hysun-33 produced significantly higher achene yield (3033 kg/ha), planted at the 60 cm apart rows, followed by sf-187 (2783 kg/ha), when sown at 45 cm apart rows. the minimum yield was recorded, when fh- 331 was sown at 75 cm apart rows. although, head diameter, number of achenes per head, 1000 achene weight increased with increasing row spacing from 45-75 cm, but the increase in yield with narrow rows was largely related to increased achene number, higher leaf area index and maximum crop growth rate.