Growth analysis in sunflower (Helianthus annus l.)‎ under semi-controlled conditions

الملخص EN

Five sunflowep cultivars, viz..

Hemus, Amiata, DKS-371, Aia and Vimimilk were evaluated for growth and dry matter accumulation in a plastic house in Al-Baha area in the winter of 1988.

Data taken on total (TDW), culm (CDW), leaf (LDW) and head (HDW) dry weights and on LAI at seven sam- pling dates extending from 25 to 115 days from planting (dfp) revealed high significant differences (PS0.01) among sampling dates.

Differences among cultivars were significant for TDW and LDW at 85 dfp and for CDW at both 85 and 100 dfp.

Differences in HDW 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 m2 nrr2, for the respective traits, were recorded for the five culti- vars at the final harvesting date (115 dfp).

Contributions of LDW and CDW and HDW to TDW during 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 nr2 day-1, 20.5-80.0 mg g_I day-1, 4.16-7.63 g m-2 day'1, 42.7-200 cm2 g'1, 140.3-272.9 cm2 g~‘ and 0.315-0.744 g g_1, among the cultivars, indicating high significant differences among sampling dates, were recorded, respective- ly, for CGR, RGR, NAR, LAR, SLA and LWR during the growing season.