Nicosulfuron-Resistant Maize Hybrid Development via EMS Mutation Breeding

Overview

Weeds cause substantial yield losses in maize production across Ghana. While nicosulfuron-based herbicides offer an affordable and effective weed control solution, many improved hybrid maize varieties and their parental lines are highly susceptible to this herbicide, resulting in yield losses exceeding 85%. This sensitivity creates a significant barrier to the adoption of improved hybrids and inflates seed production costs due to reliance on manual weeding.

This project addresses the challenge by exploiting genetic diversity and inducing new mutations for nicosulfuron resistance using ethyl methanesulfonate (EMS) mutagenesis. The goal is to develop resilient parental lines that can be reconstituted into high-performing hybrids, enabling breeders and seed producers to scale up operations economically while supporting farmers' access to improved, herbicide-tolerant maize seed.

Technical specifications

Approach and methodology:

• EMS mutagenesis applied to three parental lines of released maize hybrids to induce spontaneous, desirable mutations for nicosulfuron resistance
• Sensitivity testing already completed to establish baseline susceptibility levels of parental lines to nicosulfuron-based products
• M2 mutant generation and evaluation for herbicide reaction under controlled experimental conditions
• Hybrid reconstitution using identified resistant mutants to rebuild commercially viable hybrid varieties
• Molecular marker discovery aimed at identifying quantitative trait loci tightly linked to herbicide resistance in tropical maize germplasm, accelerating future breeding efforts

Key benefits for partners:

• Reduced hybrid seed production costs through elimination of manual weeding on large acreages
• Improved pricing competitiveness for locally produced hybrid maize seed
• Access to tropical maize germplasm with novel herbicide resistance traits
• Foundational molecular markers for accelerated development of herbicide-resistant inbred lines

Technology readiness level

The project is at an early-to-mid stage of development. Sensitivity testing of parental lines has been completed, establishing the baseline susceptibility profile. The next steps involve setting up mutagenesis experiments, generating M2 mutant populations, and evaluating their reaction to nicosulfuron. Identified resistant mutants will be used to reconstitute hybrids, with parallel efforts to map quantitative trait loci associated with resistance. The programme is positioned to deliver validated parental lines and molecular tools that can be integrated into commercial hybrid seed production pipelines.