Evaluation of factors affecting rape (swede type) yield using the projection pursuit model

The relative contributions of factors that affect rapeseed production were determined. A field experiment was conducted in Jianyang, Sichuan using 12 early-maturing and 38 late-maturing newly recombinant rapeseed varieties. Contributions were evaluated using the projection pursuit model based on real code deaccelerating genetic algorithm. The evaluation was compared with gray correlation analysis and principal component analysis. Effective pods in main inflorescence, effective branching position, and second effective branch number were the major contributors for early-maturing varieties, accounting for 36.79%, 24.02%, and 11.33% of the yield variation, respectively. For late-maturing varieties, seeds per silique, 1000-grain weight, and effective branching position were the most influential factors, accounting for 29.81%, 17.52%, and 14.75% of the yield variation, respectively. Interestingly, effective branching position was a significant contributor for both early- and late-maturing varieties. In addition, yield appeared to be influenced mostly by the number of effective branches and the number of effective pods, both formed during early growing stages, for early-maturing rape plants, and by seeds per silique and 1000-grain weight, formed during late growing stages, for late-maturing varieties. Predicted yields by the projection pursuit model were consistent with observed yields. Rapeseed yield was affected mostly by branching and pod formation for early-maturing varieties and by seed development for late-maturing varieties, and the yield potential was accurately predicted by the projection pursuit model.