Mehdi Al-Atrat
General Commission for Scientific Agric. Research-
Administration of Field Crops Research
Faculty of Agriculture, Damascus University,
2010

Abstract

This study was carried out jointly with Faculty of Agriculture, Damascus University and General Commission for Scientific Agricultural Research at Karahta Field Cops Research Station during 2007/2008 -2008/2009.Tine durum wheat genotypes were crossed using half diallel cross method. The crosses were grown along with their parents in randomized complete block design with three replications to estimate general combining ability, specific combining ability, and both mid and high parent heterosis and to study the path coefficient analysis and the phenotypic correlation between grain yield and its components.
As for number of days to heading,  number of days to maturity, grain filling period, plant height, spike length, peduncle spike length, number of tillers per plant, thousand kernel weight, number of grains per spike, weight of grains per spike, biological yield per plant, grain yield per plant,  harvest index, lodging resistance, protein content, gluten content, sodium dodousl sulphate, sedimentation test firmness, virtuousness , and yellow pigment.
The genotypes used have good variation to be used as important parents in wheat hybridization program. The results showed that both additive and non-additive types of gene action were included in the inheritance of traits under study with preponderance of additive gene effects for: number of days to heading, plant height, spike length, and yellow pigment.
While non-additive gene effects were included number of days to maturity, grain filling period, peduncle spike length, number of tillers per plant, thousand kernel weight, number of grains per spike, weight of grains per spike, biological yield per plant, grain yield per plant,  harvest index lodging resistance, protein content, gluten content, sodium dodousl sulphate, sedimentation test firmness, and virtuousness.
High general combiners for grain yield and its components were obtained and the most important parents were Bohouth9 , Horani, Sawade, Hamary and Cham7, suggesting that these lines to be used as important parents in wheat hybridization program because of their ability to inherit their characteristics to their progenies.
Many positive specific combiners having both mid and high parent heterosis and derived from positive general combiners were obtained such like Cham1 x Q88, Sawade x Cham7, Cham1 x Hamary, Hamary x Q130, Bohouth9 x Hamary, Cham1 x Q130, Cham1 x Bohouth9, Sawade x Q131, Cham1 x Sawade.
Grain yield showed positive significant correlation with weight of grains per  spike (r=0.70**), harvest index(r=0.47**), biological yield per plant(r=0.46**), and  number of tillers per plant(r=0.30**).
The results of path coefficient analysis showed that the percentage of traits: weight of grains per spike, biological yield per plant, plant height, harvest index, number of tillers per plant was (66.41%) i.e. grain yield improvement can be achieved by increasing weight of grains per spike, thousand kernel weight, and number of grains per plant.