Evaluación de la germinación de semillas y el vigor de plántulas de genotipos nacionales de arroz en condiciones de frío

Rice holds a prominent position among the most relevant crops in our country, and it stands out as a significant producer and trader on a global scale. However, the crop faces significant challenges due to climatic conditions, especially low temperatures at the planting date, directly impacting crop yield. This research focuses on characterizing germinative response and plantlet vigor in cold temperatures for several national rice genotypes from different subspecies and subtypes. The aim is to identify the most promising genotype that would allow planting in low-temperature conditions, enabling an earlier start to the crop cycle to achieve higher yields. Several trials using freshly harvested (one month after harvest) and after-ripened (four months after harvest) seeds were conducted to measure and compare seed viability and germinability, and plantlet vigor at two temperatures: 25 (optimum) and 15 °C (cold). As expected, differences in germination between temperatures were observed because of the expression of seed dormancy in cold conditions, which decreased after four months of dry storage. Germinative responses and plantlet vigor at low temperatures conditions were influenced by origin (defined by subspecies and subtype), where temperate japonica genotypes showed a more favorable response to cold conditions. No differences at the origin level between the tropical japonica subtype and the indica subspecies were observed, although there were differences at the genotype level within these groups. Genotype SLI 17158 exhibited the most noteworthy germinative and plantlet performance in cold, making it an attractive plant material for future breeding programs.