Sultan Mahmood1, Saad Imran Malik1* and Mozamil Hussain2

1Department of Plant Breeding and Genetics, PMAS Arid Agriculture University Rawalpindi.

2Maize, Sorghum and Millet Programme, NARC, Park Road, Islamabad.

ABSTRACT

To increase maize yields, exploitation of heterosis has been proven as highly effective and is widely used over the world to produce new and improved hybrids. Present study was undertaken to estimate combining ability and heterosis in maize hybrid combinations for ear traits, plant height and leaf area. Five inbred parents were crossed in a diallel fashion excluding reciprocals and fifteen genotypes including 10 hybrid combinations and 5 parents were tested during summer 2013. Statistical analysis revealed significant difference for kernel rows ear-1 (P≤0.05), and highly significant difference (P≤0.01) for days to silking, plant height, leaf area, kernels row-1, 1000-kernel weight and grain yield. Hybrid P3×P5 and P3×P4 was marked as suitable for breeding early maturing hybrids due to negative heterosis values. High heterosis for plant height was recorded for P2×P3 with significant SCA effects. P2 in combination with P3, P4 and P5 showed significant SCA for greater leaf area, however, a significant positive heterosis was obtained only for P2×P3. Maximum numbers of kernel rows ear-1 were counted in hybrid P3×P4; nevertheless, hybrid P1×P3 exhibited the highest MPH while P3×P4 was the only combination to have significant BPH. On the other hand P1×P4 had the highest number of kernels row-1. The highest 1000-kernel weight was obtained for the hybrid P2×P3 with highly significant heterosis and SCA. The grain yield remained highest in P2×P3 (4719 kg/ha) followed by P4×P5 (4616 kg/ha) and P3×P4 (4532 kg/ha). Hence the hybrid combination P2×P3 was marked as superior for the development of high yielding hybrids among 10 hybrids tested considering its significant and positive SCA for yield related traits and highest grain yield.

Keywords: Maize, Zea mays, heterosis, combining ability, diallel.