Comparison of Progeny‐Testing Methods in Lolium perenne L.: I. Polycross vs. Topcross Progenies Using cms‐Tester Lines

From 28 genotypes, half‐sib families were generated by polycross (PX) and 2 topcrosses (TC). TC‐testers were partially inbred cms‐lines. Progenies were tested for annual dry matter yield in 3 successive years. The three year average was 80.7, 76.6 and 74.0 dt/ha for TC 1, PX and TC 2, respectively. TC 1 had the highest yielding families and the largest mean in all years. TC 2 revealed the largest range among its families. Genetic variance was highest for TC 2 with 14.02, followed by TC 1 and PX with 12.05 and 10.92. However, genotype × year interaction variance was about 2 and 4 times greater for TC 1 and TC 2 as compared to PX. Genetic correlation between testcross progenies was tightest for PX vs. TC 1 (rg = 0.644++), while between the two TC's only rg = 0.307+ was observed. Predicted response to selection yielded very similar results for all test‐crosses.