Deficit irrigation and warming during the late winter and spring affect vegetative growth and reproductive development in young olive trees

IGLESIAS, MARIA AGUSTINA; ROUSSEAUX, M. CECILIA; SEARLES, PETER S.

IRRIGATION SCIENCE

SPRINGER

Año: 2024

0342-7188

To better understand the implications of climate change, the combined responses of olive trees to irrigation amount and warmingneed to be examined. Thus, the objective was to evaluate the effects of moderate deficit irrigation and warming duringlate winter and spring on vegetative growth and biomass, full bloom timing and intensity, and yield components in youngolive trees. Two three month-long experiments were conducted using open top chambers with four treatment combinations:100% irrigation with a control temperature; 100% irrigation with 4 °C warming; 50% irrigation with a control temperature;and 50% irrigation with 4 °C warming. The trees were potted two-year-old, cv. Arbequina trees in the 2018 experiment andthree-year-old, cv. Coratina trees in the 2019 experiment. Flowering was low in the young cv. Arbequina trees in 2018, butit was much greater in the older cv. Coratina trees in 2019. Overall, lower flowering intensity and fruit set or more parthenocarpicfruit contributed to less viable fruit number with warming. These reproductive variables were less affected by deficitirrigation. In contrast, shoot growth and vegetative biomass were decreased by deficit irrigation in cv. Arbequina (2018)when fruit number was low in all trees with less response due to warming. In cv. Coratina (2019), the lower fruit number inwarmed compared to control trees contributed to greater individual fruit weight at the end of the experimental period, andfew significant effects of either deficit irrigation or warming on shoot growth were observed. Fruit yield was greater in thewell-irrigated, temperature control than in the other treatment combinations in cv. Arbequina, while warming reduced fruityield in cv. Coratina. From a production perspective, it does not appear that many early reproductive responses to warmingcan be easily counteracted by adjusting irrigation. Further studies with more mature trees and cultivars over several growingseasons are recommended.