Physiological response of diverse maize genotypes to heat stress and simple sequence repeats markers-based genotyping in Rawalpindi, Punjab Pakistan

The current study was designed to observe the response of maize genotypes under high-temperature stress conditions and to check their diversity using simple sequence repeats (SSR) markers in in-vitro conditions. Maize genotypes (n=10) were subjected to heat stress at ~45 °C for 72 h after growing into young seedlings. Their physiological responses were determined by measuring the changes in proline content (PC), chlorophyll content (CC), cell membrane stability (CMS), relative water content (RWC) and osmotic potential (Ψπ). The analysed data disclosed significant differences (P ≤ 0.01) among all the characters. Comparison between control and heat-treated genotypes depicted a notable increase in PC, Ψπ while a decrease in CC, RWC and CMS index in heat-treated plants. Maize genotypes viz. NCEV-1230, NARC-4, HN Gold and OPV-20 performed better under heat stress and also showed a strong genetic relationship for similarity index in dendrogram based on selected SSR markers related to abiotic stress tolerance. This study is beneficial for understanding the physiological behaviour of maize plants under heat stress and for further genetic studies on maize to select heat-tolerant lines for breeding programs