Evaluation of genetic variation and indirect selection criteria for improvement of oil yield in canola cultivars (Brassica napus L.)

摘要

A randomized complete block design with three replications was conducted in order to evaluate the genetic variation and determination of the best indirect selection criteria for genetic improvement of oil yield in canola cultivars. Correlation analysis for oil yield showed positive and significant relationship among this trait with all the traits except days to flowering initiation, flowering duration and no.pod/plant. Step-wise regression of oil yield as dependent variable and the other traits as independent variables revealed that 99.1% of total variation exists in oil yield accounted for by the traits seed yield, oil percent, plant height and days to physiological maturity. Path analysis for oil yield designed high efficiency of the traits plant height and days to physiological maturity as indirect selection criteria for genetic improvement of this trait in canola cultivars especially in early generations of breeding programs. For seed yield and oil percent, positive indirect effects of these traits on oil yield via the traits plant height and days to physiological maturity must be considered. Cluster analysis revealed considerable genetic variation and efficacy of selection among canola cultivars as well as progenies to be obtained from crosses between them to improve oil yield.