The effect of a high selection intensity on the change of maize yield components' additive variance

A set of 31 SSD lines from ZP-Syn-1 Co and 37 from ZP-Syn-1 C3 maize population was studied in this paper. After line selection and seed multiplication in 2000, the trials were carried out in 2001-2002. at Kruševac and Zemun Polje, in RCB design. After three cycles of recurrent selection we observed a significant decrease of homozygous progenies' means of root and stalk lodged plants percent, plant and ear height, but also of row number per ear. The means of grain number per ear and 1000 grain mass were increased, and the differences in ear length and grain yield were not significant. After three cycles, a significant narrowing of additive variance happened for root and stalk lodged plant percent, ear length, and row number per ear, but this narrowing was not significant for the other traits. We also found significant values of narrow-sense heretability