Phenotyping Wild Potatoes for Photosynthesis Associated Traits Under Heat Stress

Abstract

Heat stress reduces potato productivity by restricting photosynthesis, assimilation production, and sink partitioning. Potato wild relatives (Solanum sect. Petota, Solanaceae) possess abiotic stress resistance characteristics. However, we must assess physiological parameters like gas exchange, chlorophyll index, and fluorescence to determine whether wild potato genotypes can boost crop yield under adverse conditions. We utilized a factorial experimental design to find substantial trait-based genotype differences. The mixed-model technique ranked the genotypes according to their performance in terms of predicted true genotypic values. For potato breeding, we used PCA and cluster analysis on genotypic values to identify critical features and heat-stress-tolerant genotypes. Ranking by best linear unbiased prediction (BLUP) values and heat comprehensive evaluation values for assessed characteristics indicated that predominantly S. chacoense genotypes performed well. Some of the most important physiological characteristics for investigating heat resistant germplasm genetic diversity are net photosynthetic rates, transpiration rates, stomatal conductance, intracellular/ambient CO₂, water usage efficiency, photosystem II operational efficiency, photochemical quenching, and dry matter content. We were able to find genotypes (BGB083, BGB102, BGB103, BGB109, BGB113, BGB444, BGB451, BGB467, and BGB472) that have a mix of these traits and are better at keeping up their photosynthetic performance, water use efficiency, and chlorophyll content. They also have better photoprotective mechanisms that work better when they are under heat stress. Heat stress is most likely to affect BGB008, BGB096, and BGB107. These characteristics are highly valuable for breeding heat-tolerant potato cultivars that can sustain growth, yield, and tuber quality under the increasing threat of heat stress.