Epsilon Archive for Student Projects

Abstract

Climate change is intensifying water scarcity and increasing pest pressure, threatening pollination and fruit set in strawberry (Fragaria × ananasa). This study investigated how drought, and biocontrol mites (Amblyseius swirskii) interact to affect pollen viability and quantity during strawberry flowering. The aim was to identify how these combined abiotic and biotic stressors influence fertility and to explore whether supplementary pollen can mitigate negative impacts. Pollen viability was assessed through fluorescein diacetate (FDA) staining. In experiment 1, we examined pollen counting methods by comparing manual fluorescence microscope to computer-assisted image-based systems (AO and Trypan Blue Apps). Experiment 2 examined the effects of both abiotic and biotic stress on pollen viability and quantity. Abiotic stress was implemented with two watering regimes (well-watered vs. drought-stressed) and biotic stress by the presence and absence of pollen feeding mites, with and without supplemental pollen application. Water stress significantly reduced pollen viability (0.427: mean ± SE) compared to the control plants (0.502: mean ± SE). Water stress also reduced total pollen production; however, this difference was only marginally significant. Additionally, drought significantly influenced the plants' physiological performance, confirming that the drought treatment had indeed stressed the plants. The mites' impact on floral pollen may have been lessened because thrips were unintentionally present in all treatments, giving them an alternate food source. Thrips significantly reduced pollen viability (thrips-free: 0.574 and thrips-present: 0.359: mean ± SE). Additional pollen improved viability in well-watered conditions, but its influence was minimal under drought stress. Physiological measurements significantly correlated with pollen viability, but this correlation was low. The results demonstrate the use of integrated strategies for sustaining pollen performance and fruit quality under climate stress, including mite release timing, pest tracking, supplemental pollen application, and soil moisture sustenance.