HETEROSIS AND COMBINING ABILITY FOR SUGAR CONTENT AND GRAIN YIELD IN SWEET AND GRAIN SORGHUM (SORGHUM BICOLOR L. MOENCH) HYBRIDS
This research was conducted to study heterosis and inheritance of sugar, grain yield and other agronomic traits in sweet sorghum. The parental materials used in this study comprised ten parents (seven males and three females) selected based on their high sugar level. Seven sweet sorghum genotypes were used as male parent which were crossed with three IAR improved grain sorghum as female parents.
The parents were mated in a North Carolina mating design II Model I in IAR Samaru field, generating 21 F1s. The 10 parents and their 21 F1 progenies were evaluated at Institute for Agricultural Research (IAR) Samaru, Ahmadu Bello University Zaria irrigation field during the 2015/2016 dry season. The experiment was laid out in a randomized, 4 x 8 alpha lattice design with two replications. Data were collected on some agronomic traits along with brix content and sugar yield. . Data were analyzed using SAS (2002) following alpha lattice and NCII design model I. Significant genetic variations were observed for most of the characters studied indicating the presence of variability among the genotypes which is a pre-requisite for any crop improvement programme. High heritability was observed in days to 50% flowering, plant height and brix content while panicle exertion recorded the lowest heritability, indicating that the expression of most of the trait is not easily affected by environment. Baker‟s ratio value revealed the preponderance of additive gene action for the inheritance of sugar concentration, brix content, plant height and 1000-grain weight. Hybrids Samsorg 40 x F5.3ssm10-31/2-3 (3938.64 kg/ha, 11.38 g/l), Samsorg
- x F5.3ssm10-31/5-1 (3086.4 kg/ha, 13.18 g/l), Samsorg 40 x F5.3ssm10-1/1-8 (3000.16 kg/ha, 12.53 g/l) had resulted in higher grain yields and sugar content when compared to the original grain-type parents. They also had negative heterosis for days
to flowering making them early materials. IESV92028DL and F5.3ssm10-31/2-3 were