The genetic variability is importam for lhe development of new genotypes in breeding programs. This variability is obtained through genetic recombination in plants originated from crosses involving contrating genotypes. However, artificial cresses in wheat is a difficult task because of its selfpolinization. The induction of male-sterility may be na altemative for the production of hybrid seeds. The present work had the following objectives: evaluate the efficiency of the gametocide 2-chloroethilphosphonic (Ethrel) in the induction of maleterility in wheat, estimate the frequency of crosspoilination in wheat genotypes cultivated in the field, and verify the effect of Ethrel in the production o f wheat hybrid seeds in the field. The product was appiied in five wheat varieties in three different doses in the pre-booting development stage, and the variety BR 43 was used as tester to verify the frequency of crossing. The evaluated traits were: percentage of viable pollen, number of grains produced in protected ears, percentage of artificial and natural cross-poilination. The results indicated that the product Ethrel was efficient in the induction of male-sterility in ali tested genotypes; however, the ovules were aiso affected, evidenced by the reduction in the number of seeds produced in piots treated with the gametocide. The doses of 10l/ha and 20l/ha caused accentuated pollen sterility; on the other hand, na increment in the production of hybrid seeds was not observed. As a consequence, it is necessary to adjust the technique of appiication of Ethrel for the production of hybrid seeds in wheat.
gametocide; wheat; cross-poilination
