Identifying heterotic groups and testers for hybrid development in early maturing yellow maize (Zea mays) for sub-Saharan Africa.

Benjamin Annor,Daniel Nyadanu,Baffour Badu-Apraku,Richard Akromah,Morakinyo A B Fakorede

doi:10.1111/pbr.12822

Abstract

Identification of heterotic groups and efficient testers, which are important prerequisites for the development of outstanding hybrids, has been a major challenge to its success, especially for early and extra‐early germplasm. This study was carried out to (a) identify the most efficient heterotic grouping method for classifying a set of inbred lines and (b) determine the efficiency of testers in classifying inbred lines into heterotic groups. A total of 205 hybrids obtained by crossing 41 inbred lines with five standard testers were evaluated together with five hybrid checks under drought, low soil nitrogen (N), Striga‐infested and optimal environments in Nigeria between 2014 and 2016. The heterotic group's specific and general combining ability (HSGCA) method was more effective in classifying the inbred lines into heterotic groups. Testers TZEI 17 and TZEI 23 were the most efficient across environments and could be invaluable for classifying other lines into heterotic groups and assessing combining ability of maize inbreds. In addition, these testers and heterotic groups represent an invaluable resource for development of outstanding hybrids in sub‐Saharan Africa (SSA).

Highlights

Maize (Zea mays) is a major source of food for human consumption and livestock production
This situation is partly due to the non-availability of high-yielding hybrids with tolerance to drought and low nitrogen in the soil, and resistance to infestation of Striga hermonthica (Del.) Benth
Heterotic grouping of the inbred lines across low nitrogen (low N), drought, Striga-infested and optimal growing environments was performed using the heterotic group's specific and general combining ability (HSGCA) [Mean of Hybrid(ij) - Mean of Tester(i)] of grain

Summary

| INTRODUCTION

Maize (Zea mays) is a major source of food for human consumption and livestock production. It is imperative to identify the heterotic groups of the newly developed or introduced early maturing yellow maize inbred lines so that they could be successfully used for the development of high-yielding hybrids and synthetic varieties for commercialization in SSA. It is of utmost importance to classify the newly developed early maturing maize inbred lines using the most efficient grouping method to identify the best set of new inbred lines for effective use in maize breeding programmes Another important requirement of any successful maize breeding programme is the availability of efficient testers, which could effectively discriminate and classify inbred lines into appropriate heterotic groups for the development of high-yielding hybrids and synthetic varieties. The objectives of the present study were to (a) identify the most efficient of the two heterotic grouping methods, HSGCA, and genetic distance from SNP markers for SSA agro-ecological conditions and (b) determine the efficiency of testers in classifying selected tropical inbred lines into heterotic groups

| MATERIALS AND METHODS

| DISCUSSION

Findings

| CONCLUSIONS