HALF diallel set of crosses comprising two local and four intro
duced barley varieties was used to estimate the neterosis and combin
ing ability for grain yield per plant, plant height, peduncle length, stem
diaveter, number of nodes, flag leaf area and lodging.
Variances associated with general combining ability were found
to be significant for all traits studied Significant SCA variences were
detected for grain yielcL’plant, plant height, peduncle length and lodg
ing degree. The parental cultivar Giza 117 seemed to be the best com
biner for grain yield and plant height. Gheng Tung expressed its su
periority in GCA for peduncle length and lodging resistance. Biatori
and Giza 119 were almost the best in GCA for stem diameter and
number of nodes, respectively
The most desirable hybrids were (Giza 117 X Baitori) for grain
yield, (Gizall9 X Baicori) for plant height, and (Giza 119 X Gheng
Tung ) for peduncle length.
Significant positive corrrelation coefficients were obtained be
tween mid-parent and F1 hybrid means for; number of nodes, flag leaf
area and lodging degree. Low positive cosrelation values were detect
ed for grain yield, plant height, pedtmcle length and stem diameter.
Heterosis in grain yield varied from 31% above the better parent to
59% below the mid parent.
Several methods are available to study the inheritance of quantitative traits. The
diallel cross is of common usage in this respect for its power and versatility. Dif
ferent approaches to the dialiel analysis for estimating certain genetic parameters
in ternis of gene models have been developed. Total genetic variation is parti
tioned into the effects of general and specific combining ability. In this context,
Sprague and Tatum (1942) defined general combining ability as the average per
formance of a line in hybrid combinations, and as such, general combining