The genetic gain obtained with the selection in segregating generations depends on the cross, experimental conditions and the target trait selected. The objective of this work was to determine the genetic gain with selection in spaced plants, in the F2 generation for the character number of tillers, using different selection criteria. In addition it aimed at to verify the effectiveness of these selections by looking at next generations of plants selected by the spaced plant and full row methods. The segregating generations were conducted in the years 2006 (F2) and 2007 (F2 and F3), being the F3 generation evaluated as spaced plant and full row. Three selection criteria were used: i) high tiller number and grain production; ii) low tiller number with high grain production and iii) a bulk of 15 parental genotypes with different tillering potential. The results pointed out that heritability estimates were efficient for the prediction of next generation means when the generations used were under the same environmental and management conditions. The efficiency of the selection for high or low tillering ability and the bulk selection were dependent of the crop management system used. The selection for high tiller number was associated to a higher genetic gain for grain production. However, the efficiency of the selection was different when spaced and competing plants are compared. The best performance for grain yield was achieved selecting for low tiller number in competing plants, resulted in higher total grain weight.
Triticum aestivum L.; seeding scheme; heritability and genetic gain
