ABSTRACT
This research was conducted with the aim of estimating the
effects of general and specific ability and some other genetic parameters
for the characteristic of the crop and its components and some
agricultural characteristics of some durum wheat hybrids. To achieve this
purpose, a half-diallel crosses set among six durum wheat (Triticum
turgidum var. durum L.) genotypes namely; P1 (line1), P2 (line 2) , P3
(Sohag 1), P4 (Sohag 3), P5 (Bani Sweef 5) and P6 (Bani Sweef 6( was
carried out in 2017-2018 growing seasons. The fifteen crosses and their
respective six parents were grown in 2018-2019 season in experimental
field at Sids agricultural Research Station. A Randomized complete
block design (RCBD) with three replications was used in this
Experimental field. From the results of crosses and their parents, mean
square of general combining ability (GCA) and specific combining
ability (SCA) were for all studied traits. The ratio between GCA and
SCA exceeded than unity for most studied traits revealing that additive
and additive x additive type gene actions are more important than nonadditive
gene action in controlling these traits. General and specific
combining ability effects were estimated by the method II of the
Griffing''s model I. P1 (line 1) and P6 (Bani Sweef 6) were negative and
significant GCA effects for days to heading and P5 (Bani sweef 5) for
days to maturity as well as positive and significant in P2 ( line 2) and P6
(Bani Sweef 6) for grain yield/plant, so these two parents were good
combiners for grain yield/plant. Cross combination P1xP2 give desirable
heterotic effects for days to heading The most desirable crosses for SCA
in earliness were P1xP2 for days to heading and P5xP6 for days to
maturity. Furthermore, seven crosses were excellent in grain yield/plant.
Concerning grain yield/plant, eight and six crosses showed significant
positive heterotic effect relative to mid and better parent values,
respectively. Based on the Hayman method, the results indicated that
Egypt. J. of Appl. Sci., 35 (7) 2020 116-131
additive and non-additive gene effects were involved in the control of
most studied traits. The additive component of genetic variance effect
(D) was significant for all characters except days to heading and spike
length whereas dominance genetic components (H1 and H2) were
significant for all traits. The average degree of dominance (H1/D)0.5
indicated that all studied traits might be controlled by over dominance
effects. . Broad sense heritability ranged from 18.019 % for 100-kernel
weight to 97.025 % for grain yield/plant On the other hand, heritability in
narrow sense was moderate (30 - < 50%) for plant height, days to
heading, no. of kernels/spike and grain yield/plant and low (< 30%) for
the remaining characters. These results agree with those obtained by El-
Sayed et al. (2000), Awaad (2002), El-Sayed and Moshref