Cold tolerance of maize inbred lines at the seed germination stage.

Abstract

Maize cultivation in northern regions is limited by the crop's sensitivity to low temperatures. The optimal temperature for its germination and early growth is around 30 °C, making cold stress a key barrier to early sowing. In the context of climate change, improving cold tolerance during germination is essential, particularly at higher latitudes, to support earlier sowing and avoid yield losses caused by summer drought and heat stress. Earlier flowering and reduced grain moisture at harvest are major agronomic advantages of early sowing. This study, conducted at the Agricultural Institute of the HUN-REN Centre for Agricultural Research (Hungary), aimed to evaluate cold tolerance among 56 genetically diverse maize inbred lines, including reference lines W401 (cold-tolerant) and W64A (cold-sensitive). Phenological traits were measured under controlled cold stress conditions. Several lines demonstrated strong cold tolerance, with a percentage of emergence (PE) > 85%, days from sowing to emergence (DSE) < 22 days, and cold tolerance index (CTI) values between 3 and 3.9. These inbred lines can represent promising candidates for future breeding programs targeting cold resilience.