Field experiments with ten winter and facultative wheat varieties distributed commerciaHy between 1968 and 1993 were carried out to assess genetic gain in yield and related variables. The genotypes tested were developed in the Quilamapu Regional Investigation Center's Wheat Improvement Programo Lilifén was the first variety ofthis group and was used as the reference variety. The experiments were carried out at the Instituto de Investigaciones Agropecuarias, Chillán, Chile, from 1995 to 1998. Two experiments were carried out each year, with and without foliar fungus disease control, to evaluated genetic gains and foliar disease damage, respectively. Only the 1996 experiment demonstrated a larger grain yield associated with a genetic gain. In this year the genetic gain was 75 kg ha-1 year-1, with an annual relative genetic gain of 0.72%. An increase in biomass production was not detected. In the harvest index, a genetic gain of 0.26% was observed in 1996 and 0.22% in 1997, with annual relative genetic gains of 0.82% and 0.72%, respectively. The weight ofa hectoliter showed genetic gains of 0.20; 0.11; 0.21 and 0.18 kg hL-1 yearl during 1995, 1996, 1997 and 1998, respectively. Number ofgrains per spike and kernel weight did not show genetic gains. In conclusion, increases in grain yield, due to genetic gains, in the varieties distributed between 1969 and 1993 were not very evident. The average yields (t ha-1) of all varieties tested with and without fungicides were: 8.01 vs. 8.05 in 1995; 10.44 vs. 8.42 in 1996; 8.81 vS. 7.02 in 1997, and 9.89 vS. 9.21 in 1998. |
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