Agri. Eng. Ghroud Abd Alnbee Alaswd
General Commission of Scientific Agricutural Research-
GCSAR.
Faculty of Agriculture Damascus University,
2010

Abstract

This study was carried out within the cooperation between Faculty of Agricultural Damascus University and General Commission of Agricultural Scientific Researches in 1May Station in General
Commission for Scientific Agricultural Research,  during (2008, 2009).
Six soybean genotypes were crossed using half diallel cross method. The crosses were grown along with their parents in Randomized Complete Block Design (RCBD) with four replications to estimate general and specific combining ability, and heterosis For: number of days to flowering, number of days to the initiation of first pod, physilogical maturity, number of days to maturity, height of first pod, plant height, number of branches, number of pods /plant, number of seeds /pod, one hundred seeds weight, seed yield, oil and protein content in seed.
also to study the path coefficient analysis and the phynotypic correlation between seed yield and its component.
The genotypes which we used have good variation to be used as important parents in soybean hybridization program.
The results indicated 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 flowering, number of days to the initiation of first pod, physilogical maturity, number of days to maturity, height of first pod, plant height, oil content, protein content, non- additive gene effects participated in the control of number of pods per plant, number of seeds / pod.
Both additive gene effects and non- additive gene effects participated equally in the control of these traits which included number of branches, one hundred seeds weight, seed yield.
High GCA genotypes for seed yield and its components were obtained and the most important parents were Sb181, Sb239, Sb235, Sb298 which suggests these lines to be used as important parents in soyabean hybridization program because of their ability to inherit their characteristics to their progenies.
Many positive SCA genotypes having both mid and high parent heterosis derived from positive GCA parents were obtained such as (Sb181—Sb305), (Sb181—Sb235), (Sb235—Sb308), (Sb239—Sb308), (Sb235—Sb239).
Seed yield showed positive significant correlation with number of pods / plant (0.513 ­), less positive significant correlation with number of days to maturity (0.425­), and number of seeds/ pod(0.383­).
Results of path coefficient analysis showed that the percentage of three traits: / number of pods /plant, number of seeds /pod, 100 seeds weight / was (50.33%). Wich means that seed yield improvement can be achieved by increasing number of pods /plant, number of seed /pod, 100 seed weight.