تاثير تاريخ كاشت بر مراحل رشد ونمو برخي ويژگي هاي زراعي و فيزيولوژيكي پنجح رقم سويا در كشت دوم

Effects of Planting Dates on Growth and Development Stages and Some Agronomic and Physiological Characteristic in Five Soybean Cultivars

The effect of different planting dates on yield and yield components of five soybean cultivars, as the second crop, was evaluated at Research Station of Chahar Mahal and Bakhteyari Agricultural center in 1997. For this purpose, live soybean cultivars, namely Williams, Zane, Harcure, Elgin and Karaj - 18 were evaluated at mid and late June and mid July planting dates in a split plot design with randomized complete block layout. Planting dates and cultivars were considered as main and sub - plot, respectively. Vegetative and reproductive growth durations, plant dry weight at flowering, pod - set, maturity, vegetative growth related trails, yield components, seed weight per plant and grain yield were evaluated. Delay in planting reduced the number of days from planting to flowering and necessary growing degree days for all the cultivars, but the duration from germination and flowering to physiological maturity increased and growing degree days from flowering to maturity decreased. Harcure, Williams cvs. and Karaj - 18 reached maturity after 101, 1[7 and 117 days from planting respectively. The effect of planting date on growth and development lenght period were significant at 1% probability level. Delay in planting date reduced plant height, height of first pod from soil surface, number of secondary stem, harvest index and yield. Mean comparisons show that duration of growth and development reduced with delay in planting date. The first planting date (16 June) was better than other dates and had the highest yield (2942.2 kg/ha).