Path Coefficient Analysis in Rape seed as Affected by Planting Date

Abstract

Field trial was carried out at the experimental farm of the Agricultural College, Abu-Ghraib during the growing season of 2003-2004 and 2004-2005 to study the effect of sowing dates on seed yield and yield components of eight rape seed varieties. A split plot arrangement in randomized complete block design with three replicates was used. Planting dates (Sep. 28th , Oct. 18th , Nov. 7th and 27th) were assigned at the main plots, where as the varieties were assigned in the sub plots. Data collected on seed yield and yield components and some other characters for each planting date and season. Genotypic correlation coefficients among seed yield and other characters were determined, for partition it to direct and indirect effects by using path coefficient analysis to determine which one was the most effect character in seed yield. Results of the path analysis in first season showed the plant height and harvest index had the highly positive direct effect on the seed yield (12.32 and 6.51) respectively at the planting date Sep. 28th. Number of branches and pods per plant, number of seeds per pod and average of seed weight gave highly positive direct effect on the seed yield (1.66 , 0.737 , 1.39 and 3.34) respectively at the planting date Nov. 27th. In the second season, results of the analysis showed that the number of pods per plant, number of seeds per pod, average of seed weight and harvest index had the highly positive direct effect on the seed yield (13.18 , 8.40 , 3.85 and 1.56) respectively at the planting date Sep. 28th , where as plant height gave highly positive direct effect on the seed yield (1.29) at the planting date 27th. Also these characters appeared highly positive indirect effects on the seed yield through the others characters. It was concluded that it should be considered that planting date and growing season, where we could be depended these characters that had direct and indirect effects in the seed yield used as criteria to improve seed yield of rape seed by selection in next generations at irrigated central region of Iraq.