Comparison of Progeny-Testing Methods in <em>Lolium perenne</em> L.

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 &#215; 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&#39;s only rg = 0.307+ was observed. Predicted response to selection yielded very similar results for all test-crosses. [ABSTRACT FROM AUTHOR]