Assessment of Heterosis for Grain Yield and Yield-attributing Traits in Maize (Zea mays L.) Hybrids

Abstract

The present investigation assessed standard heterosis for grain yield and yield-attributing traits in maize hybrids. Twenty maize inbred lines were used as female parents, and two broad-based testers, LM-13 and LM-14, were used as male parents. These parents were crossed in a line × tester mating design during Rabi 2022–23 to generate 40 hybrids. The hybrids, along with the standard checks Karimnagar Makka and Kaveri Ekka, were evaluated during Kharif 2023 at the Agricultural Research Station, Karimnagar, Telangana, using a randomised block design with two replications. Observations were recorded for 12 morpho-physiological traits, namely days to 50% anthesis, days to 50% silking, days to maturity, plant height, ear height, ear length, ear diameter, number of kernel rows per ear, number of kernels per row, test weight, shelling percentage and grain yield. Standard heterosis was estimated over both checks. Negative heterosis for flowering and maturity traits was considered desirable for earliness, whereas positive heterosis was considered desirable for grain yield and most yield-attributing traits. Several hybrids showed desirable heterosis for earliness and selected agronomic traits. For grain yield, KML-132 × LM-14 recorded the highest standard heterosis, with 18.48% over Karimnagar Makka and 11.48% over Kaveri Ekka. KML-132 × LM-13 and KML-127 × LM-13 also showed positive standard heterosis for grain yield over both checks. Further multilocation and multi-season evaluation is required to confirm the stability and breeding value of these hybrids.