GENETIC VARIABILITY, HERITABILITY AND TRAIT ASSOCIATIONS IN BREAD WHEAT GENOTYPES

A set of 15 F-6 advanced wheat lines along with six check varieties were evaluated under three seeding rates (120, 160 and 200 kg/ha) as independent experiments at the field of Crop Science Dept., Coll. of Agric. University of Baghdad, during the winter season of 2011-2012 in order to estimate genetic variability parameters and relationship among 14 agro-physiological traits. There was highly genetic variability among the genotypes for all studied traits. Furthermore, high estimates of genotypic and phenotypic coefficients of variation and broad sense heritability were observed in the most of the studied traits. Correlation results revealed that grain filling duration, crop growth rate, flag leaf area, spike length, spike density, grain per spike, grain per square meter, grain weight, biological yield and harvest index had positive correlation with grain yield at both genotypic and phenotypic levels, whereas days to anthesis and plant height showed negative association with grain yield at both levels under the three seeding rates. It is concluded that more grain per spike or by depending more spikes or grains per square meter are major yield contributing factors in selecting high yielding wheat varieties.