This study was carried out at the Agricultural Experimental Farm of Faculty
of Agriculture Kafr EI-Sheikh. Tanta University. through the period from 1998/1999 to
200012001. The main objectives of the study were: to determining heterosis, genetic
effects, heritability, and expected genetic advance; for yield, and yield components,
plant height and heading date in wheat. Two crosses (Sakha 61 x Dobri) in cross I
and (Gemmeiza x Rigstan) in cross II were used for applying Gamble Model (1962).
Data from parents, F" F₂, BC, and BC2 were used in the analysis. The results could be summarized as follows: Significant positive heterotic effects relative to mid parent were found for most
traits in both crosses, except for heading date in both crosses and spike ler)gth as
well as spike weight in cross 1. Significant negative heterotic effects relative to high parent were found for most
traits in both crosses, except for heading date and 1000 kernels weight in cross 1
and plant height in cross II. Positive values of inbreeding depression were obtained for all traits in both
crosses except for heading date which showed negative value. Additive gene effects were significantly exhibited in all traits in the two crosses,
except spike weight in cross I. Also, dominance effects were significant for all
studied traits in the two crosses except for spike length and spike weight in the
first cross. Epistatic effects were found to be responsible and significant for most
of the studied traits in the two crosses. Heritability estimates in broad sense were high to moderate in magnitudes with
values ranged between 52.34% for spike length to 93.07% for plant height. Heritability estimates in narrow sense for all studied characters ranged between
relatively high for plant height and number of kemels/spike in both crOSSH, with
moderate estimates for spike length, spike weight and 1000-kemels weight and
with low estimates for heading date and grain yield/plant in the two crosses. The predicted genetic advance was rather moderate for spike weight in the two
crosses, and low for the remaining traits.