Speakers - 2026

Title: From phenotyping to molecular breeding: Identifying donor genotypes and selection targets for improving salinity tolerance in rice

Abstract

Soil salinity is an increasing constraint to rice production in West Africa, particularly in coastal production systems where salinization has contributed to declining productivity and abandonment of previously productive fields. Although numerous loci associated with salinity tolerance have been reported, their effective deployment in breeding programmes depends on precise phenotypic characterisation of diverse germplasm and identification of robust selection traits. This study aimed to identify superior donor genotypes and selection-relevant traits that can serve as the phenotypic foundation for quantitative trait locus (QTL) discovery and biotechnology-assisted improvement of salinity tolerance.

Twenty-nine rice genotypes, including the tolerant check FL478 and susceptible check IR29, were evaluated under four salinity levels (0, 50, 100 and 150 mM NaCl) from the vegetative stage through maturity under greenhouse conditions. Agro-morphological and yield traits were analysed using combined analysis of variance, quantitative genetic parameters, Pearson correlation, principal component analysis (PCA), stress tolerance indices, and hierarchical clustering.

Salinity significantly reduced grain yield and all major yield components while revealing substantial genetic variation among genotypes. Broad-sense heritability exceeded 80% for most traits, indicating considerable potential for genetic improvement through selection. Correlation analyses demonstrated a shift in yield determination from vegetative traits under non-saline conditions to reproductive traits under severe salinity, where harvest index, spikelet fertility and panicle weight became the strongest determinants of grain yield. PCA further resolved two complementary tolerance strategies: reproductive resilience, represented by FL478 and ART514-derived lines, and vegetative vigour, represented by CRI-MALIMALI and Jasmine 85. Stress tolerance indices and hierarchical clustering consistently identified FL478, ART514-F6-12-B and ART514-F6-16-B as superior donor genotypes, while CRI-MALIMALI, Jasmine 85 and selected NERICA lines exhibited moderate tolerance with desirable agronomic adaptation.

The integration of quantitative genetics, multivariate analyses and stress tolerance indices established a robust phenotypic framework for identifying donor parents and prioritising selection traits for molecular breeding. These findings provide high-value germplasm and biologically meaningful phenotypes that can support subsequent QTL mapping, genome-wide association studies, transcriptomic analyses, candidate gene validation, and CRISPR/Cas-mediated improvement of salinity tolerance in rice. The study provides a foundation for collaborative efforts aimed at accelerating the development of climate-resilient rice varieties for West Africa and other salt-affected production environments.

The audience take away from presentation:

After attending this presentation, participants will be able to:

• Understand how integrated phenotypic and quantitative genetic analyses can identify robust donor genotypes for salinity tolerance.
• Identify reproductive traits that are the strongest predictors of grain yield under severe salinity and should be prioritised in breeding programmes.
• Appreciate how multivariate analyses and stress tolerance indices improve donor selection compared with conventional phenotypic evaluation.
• Recognise opportunities to integrate phenotypic data with QTL mapping, functional genomics, transcriptomics, and genome editing for accelerated improvement of salinity tolerance.

Explore opportunities for international collaboration in developing climate-resilient rice for salt-affected production systems.