Reproductive performance of southern highbush blueberry cultivars (Vaccinium corymbosum L.) in northeastern Argentina

Abstract

Introduction. Southern highbush blueberry cultivars (SHB, Vaccinium corymbosum L.) have enabled the expansion of blueberry production into warmer, subtropical regions. In these environments, understanding cultivar-specific reproductive responses is essential to improve parental selection and breeding efficiency. Objective. To evaluate the key components of the reproductive performance of southern highbush blueberry cultivars under subtropical conditions of northeastern Argentina. Materials and methods. This study evaluated pollen production and in vitro pollen germination across year × location × cultivar combinations, and fruit set and number of well-developed seeds per fruit across year × location × pollination treatment combinations, in the SHB cultivars ‘Emerald’ and ‘Snowchaser’ grown in Concordia and Bella Vista, Argentina, during 2023 and 2024. Data were analyzed by analysis of variance, and mean comparisons were performed using Tukey’s test (p ² 0.05). Results. Pollen production varied among years and cultivar × location combinations, with generally higher values in 2024, ranging from 8,638.89 to 26,194.44 tetrads per flower. In vitro pollen germination was affected by cultivar, location, year, and their interactions, with the lowest values observed for ‘Emerald’ in Bella Vista and ‘Snowchaser’ in Concordia during 2024. Fruit set was lowest in ‘Emerald’ × ‘Emerald’ and in pollination treatments using ‘Snowchaser’ as the female cultivar in Concordia in 2024, whereas the highest number of well-developed seeds per fruit was recorded in ‘Snowchaser’ × ‘Snowchaser’ in Concordia in 2024. Conclusions. The findings indicate that reproductive behavior in southern highbush blueberry cultivars under subtropical conditions is shaped by genotype, environmental conditions, and their interaction. The contrasting responses of reproductive traits indicate that reproductive success cannot be inferred from a single reproductive attribute.