This study was designed to assess the effects of six cycles of recurrent selection (RS) on eleven spike characters. Eighty four S-derived families (twelve per cycle) and twelve commercial varieties were evaluated (2001 and 2002) in the central semiarid region of Argentina. A spike random sample per family was divided in thirds for seed number and weight per spikelet determination. Also spikelet and seed number per spike; thousand seed weight and spike index were estimated. Significant differences between cycles of RS mean values were observed in four of the eleven analyzed characters. With respect to the spikelet number per spike a 7; 8% increase was denoted after six cycles of RS. Of the two physical grain yield components; seed number and weight; the weight increased 11% at the 3'^'* cycle; and not significant difference was observed between it and the 6* cycle mean value one. The higher spikelet number per spike of the sixth cycle of RS did not generate more seeds per spike. A tendency to diminish the spikelet fertility with respect to the initial cycle was observed. Taking into account the invariable fertile flower number per spikelet; the diminution of the spikelet fertility could be related to the environmental condition of evaluation.
展开▼
