HETEROSIS STUDIES IN DIALLEL CROSSES OF MAIZE

A study was undertaken to estimate the heterotic and heterobeltiotic effects in maize during 2004 and 2005 at Agricultural Research Institute, Dera Ismail Khan, to identify combinations expressing high hybrid vigour. The crosses were made in 2004 and F1 hybrids along with parents were studied in 2005. Thirty F1 crosses including reciprocals were developed and planted along with their 6 parents. Data were recorded on days to maturity, plant height, ear height, kernels ear^-1, 1000-grain weight and grain yield kg ha^-1. The analysis of variance (Table I) revealed that mean squares due to progenies and parents were highly significant for all the traits. Twenty one crosses had positive heterosis for grain yield kg ha^-1 and ranged from +0.39 % (Kisan x Jalal) to +16.86 % (Jalal x Azam) and two hybrids having heterobeltiosis i.e Kisan x Azam (+3.99 %) and Sarhad white x Kisan (+5.44 %). For days to maturity 16 F1 hybrids shown heterosis, while only one hybrid (Sadaf x Azam) enunciated heterobeltiosis ranged from +0.14 % (Sarhad White x Azam) to +5.39 % (Kisan x Jalal). The 19 hybrids revealed positive heterosis and 5 hybrids showed heterobeltiosis for plant height and ranged from +0.33 % (Sarhad White x Jalal) and (Sarhad yellow x Azam) to +7.60 (Azam x Kisan) and heterobeltiosis ranged from +0.38 (Sarhad x Azam) and (Sadaf x Sarhad white) hybrids to 2.21 % (Azam x Kisan). For ear height 13 hybrids showed positive heterosis and one hybrid showed heterobeltiosis and ranged from +0.80% (Jalal x Azam) to +14.69 % (Jalal x Kisan) and from +4.83% (Sarhad white x Sadaf). Heterotic and heterobeltiotic ranged from +0.06% (Sarhad White x Jalal) to +19.92% (Azam x Sadaf) and +0.29% (Sarhad yellow x Jalal) to +7.38% (Azam x Sadaf) for kernels ear^-1 respectively. The heterosis and heterobeltiosis for 1000 seed weight was 12.92% (Azam x Sarhad white) and 4.57 % (Sarhad white x Sarhad Yellow).