Spatiotemporal Variation in Pollination Deficits in an Insect-Pollinated Dioecious Crop

Abstract

Inadequate quantity and quality of pollen reaching the stigmas decreases the sexual reproductive output of plants, compromising yield. Still, the current extent of pollen limitation affecting yield (i.e., pollination deficits) is poorly quantified. This study is aimed at quantifying pollination deficits in kiwifruit orchards, a dioecious plant with a fruit caliber and market value largely dependent on pollination services. For that, we set up a pollination experiment and quantified services and yield provided by current pollination vectors, and under optimal pollination, over two years in a total of twenty-three orchards covering the kiwifruit production range in Portugal. We characterized nine fruit traits and used: (1) fruit weight to calculate pollination deficits and relate them with pollinator diversity and abundance, and environmental variables; and (2) production values, fruit caliber, and market values to calculate economic impact of pollination deficits. Results showed that pollination deficits were variable in time and space and were significantly and negatively correlated with pollinator abundance, while the opposite pattern was obtained for production, supporting the notion that a higher pollinator’s abundance is related to lower pollination deficits and higher yields. Understanding the factors affecting pollination deficits is crucial to depict the need for nature-based solutions promoting pollinators and to resort to management practices assisting pollination.

Artificial Pollination Technologies: A Review

“…The majority of the artificial pollination systems in Figure 4 are used to supplement available bees, but for some crops, these systems perform adequately by themselves, including kiwifruit [16,19,23,[77][78][79][80], olive [23], date palm [28], walnut [33,81], tomato [59], and hybrid maize seed [35].…”

“…In cases where insect pollinators are abundant, bees perform equivalently or better than artificial pollination for kiwifruit [56,82,83] and kiwiberry [84,85], but when conditions are not optimal, particularly in years where local conditions limit pollinator activity, correctly applied supplemental pollination can increase seed number and fruit size [16,19,23,[78][79][80]. Pollen is typically applied in two or more passes through the orchard [86], but a single pass at petal fall has been effective in Italian kiwifruit orchards [23].…”

Landscape conservation and orchard management influence carob tree yield through changes in pollinator communities

“…Lastly, the effect of pollinator loss on crops might depend on crop breeding system and its dependence on pollinators [28][29][30]. Particularly, dioecious crops, which rely on pollinator visitation to both sexes for reproduction, might be particularly vulnerable to overall pollinator decrease [31], as well as to the loss of the most efficient ones [32]. For this type of crops, optimizing the sex ratio during orchard design could be critical [33].…”

Video abstract production guide

“…Although studying their effects was important, the production process was also full of valuable lessons and should not be dismissed as an important output. So we propose the exploration of one of those videos, adapted from the paper "Spatiotemporal Variation in Pollination Deficits in an Insect-Pollinated Dioecious Crop, " written by researchers from FLOWer Lab (CFE-Center for Functional Ecology, University of Coimbra) and published on 22 June 2021 in the journal Plants (Castro et al, 2021).…”