Genetic variability, heritability, and grain yield performance of tropical maize (Zea mays L.) hybrid lines in lowland Central Java, Indonesia

Abstract

Abstract Hybrid maize production in tropical Indonesia faces persistent challenges related to narrow genetic bases and limited locally adapted cultivars. A field experiment was carried out in the lowland agroecological zone of Central Java, Indonesia, to assess genetic variability, heritability, and agronomic performance of nine experimental hybrid maize lines alongside two commercial check varieties. The trial followed a randomized complete block design with three replications. Eight quantitative traits were recorded: plant height, ear height, days to 50% silking, ear length, ear diameter, grain yield per plot, grain moisture at harvest, and number of ears harvested per plot. Analysis of variance detected highly significant (p < 0.01) genotypic differences for plant height, ear height, days to silking, ear diameter, yield, and grain moisture, alongside significant (p < 0.05) differences for ear length and ear number. Broad-sense heritability ranged from 0.34 (ear number) to 0.88 (grain moisture). The genotypic coefficient of variation was highest for yield per plot (47.29%), ear height (12.09%), and ear number (10.08%). Genetic advance as percentage of the mean exceeded 20% for ear height and yield. Line GSI-96 recorded the top yield at 31.74 kg per plot (21.16 t ha−1 on a 15 m2 plot basis), surpassing both check varieties by 14% (P-21) and 86% (Bisi-2), while L-263 was the earliest to flower at 49 days. High heritability paired with substantial GCV and genetic advance for yield components suggests favorable prospects for selection-based improvement. These findings reinforce the breeding value of locally evaluated hybrid lines for tropical lowland maize systems. By strengthening the genetic foundation for higher-yielding, locally adapted maize, this work contributes directly to SDG 2 (Zero Hunger) through improved food security and productivity, and supports SDG 8 (Decent Work and Economic Growth) by enhancing smallholder productivity and the maize value chain in tropical Indonesia.