Abstract
The genetic potentials of resistance to turcicum leaf blight (TLB), grey leaf spot (GLS), and common rust (CR) disease, grain yield and selected agronomic trait were studied in 45 F1 hybrids from a half diallel following Griffing’s Model 1, Method 4. The 45 hybrids excluding parents were evaluated in 5 × 9 alpha lattice designs with three replications. The study was carried out at Jimma Agricultural Research Center during 2015 cropping season with the objective to evaluate combining ability for turcicum leaf blight, grey leaf spot, common rust disease, grain yield and selected agronomic trait in maize inbred lines. For analysis of variance, days to 50% anthesis, days to 50% silking, turcicum leaf blight, grey leaf spot, common rust disease severity index, days to maturity and grain yield data were collected. Mean square due to general combining ability (GCA) was highly significant (P ≤ 0.01) for all traits, while specific combining ability (SCA) mean square was non-significant except for grain yield, days to 50% tasseling, days to 50% of silking, and days to maturity. This study showed the importance of additive types of gene action in controlling the inheritance of the traits. Among ten inbred lines, L7 and L10 were best combiners for GLS tolerance with the highest negative value of GCA effects and inbred line L7 was the best combiner for TLB and CR tolerance with the highest negative value of GCA effect. Inbred lines L2 and L9 were best combiner for grain yield with the highest positive GCA effect value. Therefore, maize breeding program can engage in hybridization and synthetic variety formation based on the information of inbred lines with high negative value GCA effect for diseases tolerant and high GCA for grain yield. Key words: Combining ability, general combining ability (GCA), inbred lines, specific combining ability (SCA).
Highlights
Maize (Zea mays) is the third most important cereal crop in the world after rice and wheat in production and it is stable food crop in Ethiopia
analysis of variance (ANOVA) showed significant difference among genotypes for all character. It showed highly significant (P ≤ 0.01) and significant (P ≤ 0.05) mean squares due to general combining ability (GCA) for all traits, while mean square due to specific combining ability (SCA) was nonsignificant except for days to tessiling, days to silking, maturity date and grain yield traits (Table 2). This suggests that significant difference exists among the materials with respect to combining ability and both additive and non-additive gene actions were important for the expression of the traits
The ratio of GCA/SCA was greater than unity for the trait, indicating that this trait is pre-dominantly controlled by additive type of gene action
Summary
Maize (Zea mays) is the third most important cereal crop in the world after rice and wheat in production and it is stable food crop in Ethiopia. It is believed to have originated in Mexico and to have been introduced to Ethiopia in the 1600s to 1700s (McCann, 2005). It is cultivated in a wider range of environments than wheat and rice, because of its greater adaptability (KoutsikaSotiriou, 1999). The mid-altitude sub-humid agroecology is the most important maize producing environment in Ethiopia (Kebede et al, 1993). Maize production in Ethiopia is constrained by a number of abiotic and biotic stress factors, including pests and diseases (northern leaf blight, gray leaf spot, maize streak virus, rust and downy mildew) (Dagne et al, 2004)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
