Assessment of morphophysiological traits for selection of heat-tolerant potato genotypes

Since potato production has been expanded into warmer regions, breeding heat-tolerant potato varieties has also been considered among the top priorities in most breeding programs in recent years. Identification of traits related to heat tolerance in potato is crucial for selection of heat-tolerant genotypes. The objective of this study was to evaluate the responses of 17 potato genotypes to high temperature stress for identifying some candidate traits associated with heat tolerance. Haulm dry weight (HDW), leaf area index (LAI), photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), SPAD value, and mean tuber weight (MTW) of potato genotypes at control conditions were significantly and positively correlated with tuber yield of genotypes grown under high temperature conditions, whereas canopy temperature (CT) was negatively associated with tuber yield. Classification of potato genotypes based on heat tolerance was done by principal component analysis with yield-correlated traits. The classification results showed high similarities with the yield performance of genotypes grown under high temperature conditions. The HDW, LAI, Pn, Gs, Tr, CT, and SPAD of potato genotypes grown under normal conditions might be useful traits to screen for heat-tolerant genotypes.