Abstract
The parent seeds of Six durum wheat (Triticum durum Desf), (1-Azul-5, 2-Yousef-1, 3-Omgenil-3, 4-Syrian-4, 5-Mrb3/mna-1 and 6-Um-Rabee) and their half diallel crosses were planted in the field of College of Agricultural and Forestry at Hammam AL-Alil during the season 2001 – 2002 using randomized complete block design (R.C.B.D.) with three replications to study the effects of general and specific combining abilities for number of days to 50 % flowering, plant hight, number of grains/spike, number of spikes/plant, Biological yield, grain yield, harvest index, 1000-grain weight and protein percentage. The genotype mean variance (parents and F1) was significant at probability level of 1% for all the traits. General combining ability variance was significant at 1% probability level for all the traits except for 1000-grain weight where as specific combining ability variance was significant at 1% of probability level for all the traits except for number of days to 50% flowering which was significant at 5% of probability level. The ratio of the general combining ability to specific combining ability components was more than one for all the traits except for number of spikes / plant, 1000-grain weight and protein percentage. General combining ability effects for Syrian-4 and Um-Rabee parents were in desirable direction for most traits. The cross Azil-5 × Um-Rabee exhibited desirable effects for general and specific combining ability for all the traits except for the harvest index and protein percentage.