Genetic diversity analysis and heterotic grouping of Indian white maize inbred lines using combining ability and SNP markers

Abstract

Maize (Zea mays L.) is a versatile crop with high genetic yield potential and various uses. While yellow maize is primarily used for animal feed, white maize is preferred as a food by rural and tribal populations in India. However, white maize landraces suffer immensely in terms of low yield. Heterotic grouping is an excellent method to develop hybrids with increased yield potential in maize. The heterotic grouping of 78 white maize inbred lines was performed using combining ability and molecular diversity analysis. The lines were crossed with two testers, and the resulting hybrids were evaluated for grain yield at three locations representing different agroecological zones in India. The combining ability analysis based on specific combining ability effects on mean grain yield was used to classify the inbred lines into heterotic groups (HG-A: 18 inbreds; HG-B: 33 inbreds). Additionally, marker-based clustering using 62,470 single nucleotide polymorphisms (SNPs) generated through genotyping by sequencing was also employed to determine the genetic relationships among these lines. The combining ability information was superimposed on marker-based clustering data to obtain the heterotic grouping information, and two distinct HGs with 7 (HG-1) and 18 inbred lines (HG-2) were developed. The results of this study will contribute to the development of high-performing white maize hybrids through the efficient utilization of clear-cut and well-defined HGs. Hence, the use of SNP markers along with the combining ability of inbred lines is a useful method for heterotic grouping and understanding of genetic relationships of white maize. © 2024 The Authors. Crop Science © 2024 Crop Science Society of America.