Growth Analysis in Sunflower (Helianthus annus L.) under Semi-Controlled Conditions@@@تحليل النمو في زهرة الشمس تحت ظروف بيئة شبه محكمة

Five sunflowes cultivars, viz.. Hemus, Armata, DKS-37l, Aia and Yimimilk were evaluated for growth and dry mailer accumulation in a plastic house in Al-Bahaarea in the winter of 1988. Data taken on total (TOW). culm (COW), leaf (LOW) and head (HOW) dry weights and on LAI al seven sam­ pling dates extending from 25 to 115 days from planting (dfp) revealed high significant differences (P:S; 0.01) among sampling dates. Differences among cultivars were significant for TOW and LOW at 85 dfp and for COW at both 85 and 100 dfp. Differencesin HOW and LAI at each sampling date were non­ significant. On the average, estimates of 864.6.315.3.245.5 and 273.7 g m- 2 and of 3.108 m 2 m- 2 , for the respective traits, were recorded for the five culti­ vars at the final harvesting dale (115 dfp)..Contributions of LDW and CDW and HOW to TOWduring the growing season ranged from 28.3-76.1. 18.3-50.7. and 3.2-31.7%, respectively. Estimates in the ranges of 2.25-17.05 g m-2 day·I, 20.5-80.0 mg g-I day-I, 4.16-7.63 g m-2 day-I. 42.7-200 cm2 s:'. 140.3-272.9 cm2 g-I and 0.315-0.744 g g-I, among the cultivars, indicating high significant differences among sampling dates, were recorded, respective­ Iy, for CGR, RGR, NAR, LAR, SLA and LWR during the growing season.