IBRAHIM M. SEIFELDIN1, MOHAMED OSMAN KHIDIR2
1University of Bonn, Department of Crop Science and Plant Breeding, Germany
2Faculty of Agriculture, University of Khartoum, Department of Agronomy,
Two hundreds and twenty F5 families derived from ten sesame crosses and advanced by the single seed descent (SSD) method were evaluated at the Demonstration Farm, University of Khartoum, Shambat, Sudan, for two consecutive seasons (1998/99 and 1999/00), using nested design with three replications. Data were collected on 10 characters in 10 randomly selected plants. Genotypic associations between 10 characters and direct and indirect effects of plant height, number of capsules/plant, number of primary branches, number of seeds/capsule, 1000-seed weight and on seed yield/plant were estimated.
Highly significant positive genotypic associations were detected for seed yield/plant with seed yield/ha and for each of them with plant height, number of capsules/plant, number of primary branches, height to first capsule, days to 50% flowering and days to maturity as well as number of capsules/plant with number of primary branches, days to 50% flowering and days to maturity; plant height with height to first capsule and days to maturity; and height to first capsule with number of capsules/plant, number of primary branches and days to 50% flowering. On the other hand, significant negative genotypic associations were recorded for 1000-seed weight with number of capsules/plant and number of primary branches. However, significant negative genotypic associations were detected for number of seeds/capsule with number of capsules/plant; number of primary branches with plant height and number of seeds/capsule. For the rest of character combinations, there were different patterns of associations within and over seasons.
Path analysis revealed that number of capsules/plant had the highest positive direct effect (0.804) on seed yield/plant, followed by the 1000-seed weight (0.314) and then the number of seeds/capsule (0.284). On the other hand, the number of primary branches via the number of capsules/plant gave the highest positive indirect effect (0.555) on seed yield/plant, followed by plant height also via the number of capsules/plant. However, the highest negative indirect effect (-0.199) on seed yield/plant was exhibited by the 1000-seed weight through number of capsules/plant.
Keywords: Crosses, direct and indirect effects, F5 families, genotypic association, sesamum indicum L., single seed descent (SSD) method