Characterization of a segregating potato (Solanum tuberosum L.) population for frost tolerance by leaf morpho-anatomy analysis and horticultural traits in India

In India, about 80% of the potato crop is grown during winter season and thus it often gets exposed to low temperatures which adversely affect its growth and lead to heavy reductions in tuber yield (approximately 40-60%). Overall aim of this study was to generate frost tolerant potato clones through intervarietal hybridization. In the summer 2018, the segregating progenies were developed through hybridization between J-2/19 (frost tolerant) and MS/7-645 (high yielding). In F1C1 generation, the characterization of 168 potato clones was carried out on the basis of leaf morpho-anatomical (LMA) traits viz., stomatal and trichome density on adaxial and abaxial leaf surfaces, stomatal index and palisade thickness. Seventy-six clones possessing LMA traits associated with frost tolerance were exposed to low temperature and their tolerance behaviour was further confirmed through electrolyte leakage in F1C2 generation. The potato clones exhibited a large and significant variability for both the leaf morpho-anatomical traits and electrolyte leakage. The hierarchical clustering analysis distributed the 168 potato clones into 13 cluster groups based on their proximate composition in twelve LMA traits. Moreover, the electrolyte leakage exhibited a negative correlation with stomatal index (-0.43) and stomatal density on adaxial leaf surface (-0.36). Overall, 11 potential clones exhibiting frost tolerant characteristics with desirable horticultural traits were identified and these were recommended for further evaluation. Thus, LMA traits, particularly stomatal index can potentially be used for preliminary screening of potato genetic resources for frost tolerance in breeding programmes specifically during the non-frost years.