GROWTH DURATIONS AND SOME GROWTH TRAITS OF RAPESEED AS AFFECTED BY PLANTING DATE

N.O.Sarkees,; A. Ali, A.; R.H.Baker,

	GROWTH DURATIONS AND SOME GROWTH TRAITS OF RAPESEED AS AFFECTED BY PLANTING DATE
The Iraqi Journal of Agricultural Science
Article 1, Volume 38, Issue 1, 2007, Pages 101-112
Authors
; A. A. Ali;
Abstract
A field study was conducted at the experimental farm of the College of Agriculture, University of Baghdad, Abu-Ghraib, during three winter seasons (2002/2005). This was to study the effect of sowing dates on crop growth cycle and some growth traits of rapesecd (Brassica napus L). A split-plot arrangement in a randomized complete block design with three replicates was used. Sowing dates were assigned in the main plots, and genotypes in the sub-plots. Delay of sowing dates led to extended some growth stages and shortened others. The period from sowing to emergence and from emergence to rosette was extended whereas period from sowing to flowering (90.5,85.7 and 90.8 days) for three seasons respectively, from flowering to physiological maturity (55.1 and 46.4 days) and from sowing to physiological maturity (141.6 and 137.0 days) for the last two seasons respectively were shortened. The adverse conditions which prevailed at later sowing date (17/12) had a great impact on the life cycle of the crop. The higher temperature and longer photopcriod had hastened the physiological processes of most of the development stages and consequently the optimum period of the life cycle of the crop was shortened and therefore leaves plant'1 (10.8,11.9 and 9.2 leaves), leaf area index (1.8,2.2 and 2.4), dry matter production (6.8,8.8 and 5.21 ha"1), crop growth rate (7.5, 10.1 and 5.7 g m2 d'1), thermal (555,564 and 566) and photothcrmal units (5759, 5979 and 6073) were reduced for three seasons respectively. There were significant differences among genotypes in seed emergence and flowering time. Seed emergence of Topscore, Pluto and Star was delayed in all seasons. Pioneer had an early flowering for the same three seasons which resulted in a fewer number of leaves (8,8 and 9 leaves), least leaf area (247.9,323.6 and 364.9 cm2 plant'1) and leaf area index (1.5,2.0 and 2.3) and accordingly produced least dry' matter (6.3,5.7 and 6.11 ha"1) for three seasons respectively, a positive significant relationship was found between dry matter production at flowering stage and number of leaves, leaf area and leaf area index. A positive correlation was also found between these traits and the periods from elongation to flowering buds, flowering buds to flowering and from sowing to flowering. However, negative correlation between time from sowing to emergence, flowering buds to flowering and sowing to flowering were obtained, which significantly and negatively correlated with flowering to physiological maturity.

Statistics Article View: 46 PDF Download: 8