HETEROTIC EFFECTS FOR YIELD AND PROTEIN CONTENT INWHITE QUALITY PROTEIN MAIZE

The present study was performed to determine the magnitude of genetic variability and to identify heterotic populations for maturity, yield, and grain protein content. High genetic variability among the inbred lines and resultant F1 hybrid populations was observed for all traits as indicated by high level of heterosis over the mid and high parent. For this purpose, four S5 quality protein maize inbred lines (NC1QW1, NC1QW3, NC1QW5 and NC1QW13) were crossed in diallel fashion during 2006. The four inbred lines and twelve crosses were evaluated at two locations; Agricultural University, Peshawar (AUP) and Cereal crops Research Institute (CCRI), Pirsabak, Nowshera, Khyber Pakhtunkhwa Province, Pakistan during 2007. Randomized complete block design with three replications was used at each location. Grain yield of white QPM lines and their resultant F1 hybrids was generally higher at CCRI than AUP. However, mid and best-parent heterotic effects for grain yield were greater in magnitude at AUP than CCRI. Grain yield of parental lines ranged from 1951 to 3934 kg ha^-1 at AUP vs. 3645 to 4435 kg ha^-1 at CCRI. Similarly, grain yield of white QPM F1 hybrids ranged from 4214 to 5758 and 5093 to 6597 kg ha^-1 at AUP and CCRI, respectively. Among F1 hybrids, NC1QW5×NC1QW13 was the high yielding at AUP (5758 kg ha-^1), while its reciprocal cross (NC1QW13×NC1QW5) ranked first for grain yield at CCRI (6908 kg ha^-1). For protein content, F1 hybrid NC1QW5×NC1QW3 at AUP displayed highest values of mid-parent (8.72%) and best-parent (7.48%) heterosis. On the basis of F1 yield and protein content, NC1QW3, NC1QW5, NC1QW13 and their F1 hybrid populations are suggested for further exploitation in maize breeding programmes for varied purposes.