PURE LINE SELECTION FROM BREAD WHEAT FOR BIOLOGICAL YIELD UNDER DIFFERENT SEEDING RATES

Abstract

Field experiments were conducted over three growing seasons, during 2009-2012, at the experimental farm of Field Crop Sciences - College of Agriculture - University of Baghdad. This study aimed to application pure line selection in fifteen F4 segregating populations of bread wheat produced from half diallel crossing among 6 parents.The selection was applied in the first season by using 10% selection intensity, further screening was conducted and selected 12 plants from each population .The grains of individual selected plants were planted in the following year in plant to row method and the best 15 progeny lines were selected depending on yield performance. Varietal trail was conducted in the third season as RCBD with four replications using a split plot arrangement, where three seed rates (120, 160, and 200 kg.ha-1) randomized in the main plots and 21 genotypes in the sub-plots. The genotypes included fifteen F6 progeny lines plus six parents: Al-fatah, A3103, M.2, IPA99, A4.10, and Abu-Ghraib3. The results showed significant differences among genotypes, seeding rates and interaction between them for all the traits. It was revealed the superiority of progeny lines S123, S102, S52, S130, S148 and S83 over the best cultivars, they yielded 6.64, 6.41, 6.34, 6.16, 6.11 and 6.11t.ha-1 respectively.The progeny S123 superior significantly to other best progenies in grain yield and biological yield. The highest harvest index produced from using 160 kg.ha-1 seeding rate. Response of grain yield to seeding rates was quadratic relation. Highly significant differences were found among the genotypes under the three seed rates for all traits, indicating relatively high magnitude of genetic variability in these genotypes.