الفهرس 
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Abstract
The present work aims to study the efficiency of pedigree and ICL selection in improving heading date and grain yield and estimate the correlated response of the other studied traits. Two selection procedures were used; pedigree selection for grain yield/plant, days to heading and the independent culling levels (ICL) of two traits (days to heading and grain yield/plant). The experiments were carried out at Sids and Arab Al-Awamer Agric. Res. Station Agric. Res. Center, Egypt, during 2009/10, 2010/11 and 2011/12 successive seasons. Two cycles of selection were completed on the F4 and F5-generations.
The base population was the F3 generation of Bani Sweif 1/3/STJ3//Bani Sweif 1/3/LK54. The 80 F3-families as well as the F3 bulk sample and the original parents were grown in a randomized complete block design of three replications.
The results could be summarized in four main topics:
I- Description of the base population, season 2009/2010:
1.1- The analyses of variance indicated that the significant differences among F3 families for heading date, plant height, spikes/plant, 100-kernel weight and grain yield/plant.
The average number of days to heading of P1 was 100.0 compared to 91.6 days for P2 with F3-families mean of 105.98 days. Days to heading showed over-dominance towards lateness. The phenotypic (PCV%) and genotypic (GCV%) coefficients of variation for days to heading were 6.23 and 4.71%, respectively. Such magnitude of variability could be considered sufficient for selection for early heading.
The average no. of spikes/plant of P1 was 4.67 compared to 6.00 for P2 with F3-families mean of 6.03. Number of spikes/plant of the F3-families, tended to show complete dominance towards higher parent. The phenotypic (PCV%) and genotypic (GCV%) coefficients of variation for this trait were 33.99 and 30.21%, respectively.
The average of plant height of P1 was 90.0 compared to 88.3 cm for P2 with F3-population average of 98.45 cm. Plant height showed over dominance towards tallness. The genetic coefficient of variation (GCV%) in plant height reached 7.72%.
The average number of grains/spike was higher for P2 than P1. Number of grains/spike of P1 was 73.3 compared to 81.6 for P2. This could be due to the difference in spike length. The phenotypic (PCV%) and genotypic (GCV%) coefficient of variations for number of grains/spike were 18.55 and 18.09%, respectively.
The average grain yield/plant was larger for P1 than P2. Grain yield/plant of P1 was 32.35 compared to 30.53 g for P2, with F3-families average of 34.14 g tended to show over dominance towards the highest grain yield parent. The phenotypic (PCV%) and genotypic (GCV%) coefficient of variations for grain yield/plant were 26.12 and 25.74%, respectively. This indicates that selection of grain yield may increase grain yield/plant.
1.2- Results of phenotypic correlation coefficient indicated negative between heading date and each of no. of spikes/plant (-0.32), no. of kernels/spike (-0.01), 100-kernel weight (-0.06) and grain yield/plant (-0.43). While genotypic correlation values were -0.41, -0.08, -0.12 and -0.34 between heading date and each of the above mentioned traits, respectively, indicating that selection for earliness may decrease any of these traits in these materials.
The results of genotypic correlation indicated low and positive values between no. of spikes/plant and each of no. of kernels/spike (0.04) and 100-kernel weight (0.21), but it was high and positive with grain yield/plant (0.81). This indicates that selection for no. of spikes/plant.