Two field experiments were carried out during two successive seasons
on six wheat genotypes at the experimental farm, Faculty of Agriculture, ElFayoum Univ. In 2005/2006 season, the six parental genotypes were planted
and all possible crosses excluding reciprocals were hand made to produce
15 F1 hybrids. In the second season (2006/2007), the parents and hybrids
were planted using the randomized complete block design with five
replications. The correlation coefficients and path analysis were calculated
between grain yield and yield components of the 21 wheat genotypes. The
tested genotypes exhibited significant differences due to the presence of
sufficient genetic variability, and standard error values were in the range of
0.5 for spike length to 2.54 for number of grains/spike. Consequently the
latter trait showed the highest values of phenotypic, genotypic and
environmental variances followed by those of grain yield/ plant. Heritability
and genetic advance values were high for days to heading, days to maturity,
number of grains /spike and grain yield /plant. Grain yield /plant was
positively correlated phenotypically and genotypically with days to heading
and days to maturity and negatively with number of grains /spike.
Phenotypic path coefficient revealed that the direct effect of days to
maturity on grain yield was the highest (0.57) with relative importance of
18.8% followed by those of spike length. Concerning genotypic path
coefficient, both traits, respectively, ranked as the first and second traits
affecting grain yield /plant. The indirect phenotypic effects on grain yield
exhibited by days to heading, days to maturity, plant height and spike length
were 0.39, -0.11, 0.22 and 0.028, respectively. The relative importance of
indirect genotypic effects on grain yield showed by plant height, days to
maturity and spike length were 27.6, 21.1, and 11.8, respectively.