Evaluation of potato clones for resistance to potato virus Y and earliness in the midland agroecological zones of Kenya

Abstract

Potato (Solanum tuberosum L.) is a vital crop for combating poverty and food insecurity, particularly in sub-Saharan Africa (SSA). It is susceptibility to infection by Potato Virus Y disease, and high temperatures, which affect tuberisation and subsequently, earliness. The objective of this study was to identify resilient potato clones to heat stress and resistance to PVY disease in Kenya. The study evaluated 60 potato clones, and was conducted at three midland agroecological sites in Kenya; namely Kakamega, Sang’alo, and Alupe. There were significant genotypic variation across all sites. In Kakamega, genotypic differences significantly influenced major agronomic traits (F = 3.918; P < 0.001; R² = 0.562); while Alupe exhibited significant genotypic effects (F = 2.529; P < 0.001; R² = 0.453) with elevated daytime temperatures (>28 °C) and intermittent drought; suppressing vegetative growth resulting in reduced tuber bulking. Across sites, Sang’alo showed the highest site mean performance (2.6675) with a highly significant model (F = 3.424; P < 0.05; R² = 0.751; adjusted R² = 0.712. Significant clone x site interactions suggested broad adaptability of the evaluated clones. Clones 95, 304, 264, 165, 258, 278, 14 and 299 performed best, with four (95, 278, 304 and 299) advancing to national performance trials. Clone 299 was approved for commercialisation due to its PVY resistance, high yield, and stability. Serological tests confirmed that all clones were PVY-free, highlighting the potential of early-maturing, virus-resistant, and clean potato seed to strengthen Kenya’s potato seed system.