Zinc deficiency prevails in one-third of the world’s population, which is mainly due to the intake of cereals grown on zinc-deficient soils. Biofortification is a top priority among different solutions to this condition and is an agricultural intervention suitable for farmers and consumers due to accessibility and cost-effectiveness. Maize (Zea mays L.) is a short-duration and high-yielding crop that can grow in two seasons per annum and is the most suitable cereal for biofortification. The present study investigated 150 genetically diverse maize inbred lines for grain-zinc contents, yield, and yield-contributing traits, employing an augmented field design. Significant genotypic diversity was prominent for the studied traits. The first four components of the principal component analysis (PCA) depicted an Eigen value of more than one, which explained 73.5% of the total variability. Among inbred lines, E102, E38, E92, E52, E91, E1, E93, E54, E28, E25, E72, E30, and E90 showed higher grain-zinc contents and average grain yields per plant in the PCA-based study. The grain-zinc contents were less than the desired level (33 mg kg-1) notified by HarvestPlus. Creating significant genetic diversity and exploiting its existing level for heterotic performance is a prerequisite to achieve the desired level of grain-zinc contents and yield. Correlation studies revealed a significant positive association of average grain yield per plant with the ear length, the number of grains per row, the number of rows per cob, and 1000-grain weight. Selection of inbred lines based on the standards of positive association with grain yield per plant could improve total yield.

Keywords: Maize, augmented design, biofortification, correlation coefficients, genetic variability, PCA

Key findings: Improving grain-zinc contents can succeed by selecting early maturing genotypes with less anthesis-silking interval (ASI). Lesser days to silking and days to tasseling cause early mobilization of available zinc from tassel to cob; hence, more zinc is available for grain under long grain-filling periods. High-kernel zinc contents improve grain weight due to enhanced carbohydrate supply for grain filling. Indirect selection to develop zinc biofortified maize genotypes should require high mean values for plant height, total grain weight, ear length, and grain yield and lower mean values for days to silking and days to tasseling.