Realized Heritability Estimates during a Cyclical Process of Selection and Intercrossing in Bread Wheat and Hexaploid Triticale

This study was designed to compare realized heritability estimates for several traits of a selection index applied in rain fed bread wheat (Triticum aestivum L.) and hexaploid triticale (x Triticosecale Wittmack) recurrent selection programs. The experimental material consisted in C-4-C-5 triticale and C-7-C-8 bread wheat S-0 progenies selected disruptively and evaluated as S-1 derived families. The selection differential (SD) and the response to selection (RS) were estimated from the S-0 progenies and the S-1 derived families, respectively, as the differences (in percent) between high and low (= 100) selection index group mean values. In bread wheat, significant differences between groups of S-1 derived families were observed in the 7(th) cycle for all the studied traits; while only significant differences for harvest index were observed in the 8(th) cycle. Taking into account only the statistically significant differences between high and low selection index group mean values, the realized heritability estimates for grain yield, biomass yield and grain number were lower (7.0% to 11.2%) than those obtained for 1000-grain weight and harvest index (12.3% to 20.5%). The narrow germplasm base in triticale generated insignificant response to selection results.