Field experiments have been conducted to quantify the growth and development of sunflower in response to seasonal variation over two seasons, i.e., Spring and Fall. Five sunflower hybrids were sown in a randomized complete block design. Growth and development parameters like stem girth, plant height and dry matter accumulation m-2 were recorded at the time of maturity. The hybrid Suncross-42 produced the maximum stem girth in Spring which was significantly different from that of XF-263 which was the lowest in both seasons. Plant height followed a pattern similar to stem girth. The hybrid Suncross- 42 produced the tallest plants in both seasons. Stem girth and plant height are considered major contributors to total dry matter production. Dry matter accumulation m-2 followed a pattern similar to those of stem girth and plant height. The hybrid Suncross-42 produced the maximum dry matter in both seasons. Similarly, it produced maximum seed yields in both seasons. Overall superiority of the Spring crop over the Fall crop, in terms of stem girth plant height, dry matter and seed yield production, may be related to the duration of crop in the field and environmental factors prevailing during the crop life cycle.

dry matter; life cycle; growth; development; seasonal variations