Evaluation of the Effect of Crop Rotations on Yield and Yield Components of Bread Wheat (Triticum aestivum L. cv. Darya)

Grain yield in wheat is influenced directly and indirectly by other plant characteristics. One of the main goals in wheat breeding programs is increase of grain yield. Considering the role of crop rotation in increasing grain yield, and in order to study the difference between crop rotations for wheat yield and yield components (Darya cultivar), an experiment was conducted with six rotation treatments (wheat-chickpea-wheat, wheat-cotton-wheat, wheat-watermelon-wheat, wheat-wheat-wheat, wheat-canola-wheat and wheat-sunflower-wheat), as a randomized complete blocks design with six replications, at Research Farm of Agricultural Research Station of Gonbad Kavous, Iran, during 2004 to 2008. Results showed that number of spikes per m-2, number of kernels per spike and mean kernel weight were important traits in all rotations. Also, selection of different traits could be changed depending on the experiment’s conditions, as in the wheat-wheat-wheat, wheat-watermelon-wheat and wheat-sunflower-wheat rotations the kernel weight, grain filling period and vegetative growth period are useful for indirect selection of breeding strategy; while in wheat-canola-wheat and wheat-chickpea-wheat rotations the number of kernels per spike, number of spikes per m2, grain filling period and vegetative growth period are more important.