Unveiling superior cross combination in maize (Zea mays L.)
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Abstract
An experiment was conducted to find out the heterotic and heterobeliotic in maize during 2013-14 at Agricultural Research Institute, Dera Ismail Khan to get the superior cross combination expressing high hybrid vigour. The crosses were made in 2013 and F1 hybrids along with their parents were studied in 2014. Six maize inbred lines viz; Islamabad-white, Buffa Selection I, Sahiwal-2002, Sadaf, Islamabad Gold and Azam were used and full diallel approach was adopted to get the superior cross combination and to unveil best cross combination. Data were recorded on days to 50% pollen shed, days to 50% silking, plant height, number of ears plant-1 , ear length, number of kernel rows ear-1 , number of kernel row-1, 1000 kernel weight and grain yield kg ha-1. The analysis of variance revealed that means squares due to progenies and their parents were highly significant for all the traits except number of kernels ear-1 and 1000 kernel weight which showed significant differences. Only number of kernels row ear-1 depicted non-significant variation. The analysis of variance (Table 1) showed that mean squares due progenies and parents were highly significant for all the traits. Twenty two crosses had positive heterosis ranged from +0.84% (BS-1 x Sadaf) to 51.3 % (Islamabad-white x Sadaf) for grain yield kg ha-1. For days to 50% pollen shed, heterosis ranged from (-10.8 to +0.6%). The twenty seven hybrids showed negative heterosis, while the two hybrids showed positive heterosis for days to 50% silking. For plant height twenty seven crosses showed positive heterosis ranged from (0.0% to 15.5%). The heterosis and heterobeltiosis for number of ears palnt-1 ranged from (-11.5% to 16.0 %), (-14.6 to +13.8 %) respectively. For ear length heterosis ranged from +0.12% (Islamabad-white x BS-1) to +26 % (BS-1 x Islamabad gold). Heterosis and heterobeltiosis ranged from +2.5 % (BS-1 x Islamabad-white) to 9.1 % (Sahiwal-2002 x Islamabad white) and 4.7 % (BS-1 x Azam) to 7.6 % (Sahiwal-2002 x Islamabad-white) for number of kernel rows ear-1. 1000 kernel weight showed heterosis and heterobeltiosis ranged from +1.5 (BS-1 x Azam) to +19.5 % (Islamabad white x Sadaf) and +0.2 % (Azam x Islamabad white) to 19.2 % (Islamabad white x Sadaf). Hence it is suggested that 3 parents viz; Islamabad Gold, Sahiwal 2002 and Sadaf can give promising yield if included in breeding experiments to unzip genetic configuration.
Keyword: Maize; Inbred lines; Heterosis and heterobeltiosis