In this project, the research hypothesis is that in a scenario of climate change (IPCC 2014), the increase of mean air temperature by 2 °C triggers flowering asynchrony between pollen donors and female cultivars on kiwifruit species (Actinidia spp.) Then, the general objective is to model the impact of temperature changes on interaction between pollen donors and the effective pollination period (EPP) of kiwifruit cultivars (Actinidia spp.). In detail, the specific objectives are: (1) to determine flowering phenology and the effective pollination period (EPP) on kiwifruit cultivars; (2) to evaluate the effect of temperature on sensitivity of pollen-pistil interplay; and (3) to develop a dynamic model of kiwifruit pollination on crop value under potential scenarios of temperature changes.
The proposed methodology will be divided in three years. In the first year, flowering phenology of six pollen donors (male cultivars) and two female cultivars (one green-fleshed and other yellow-fleshed) will be characterized. Moreover, in female cultivars the length of time that female flowers can be successfully pollinated, commonly known as the effective pollination period (EPP), will be determined. The EPP may be restricted by limitations in three main events: stigmatic receptivity, pollen tube kinetics and ovule longevity, which will also be evaluated. On the other hand, a dynamic pollination model will be developed using the modeling software Stella®, based initially on literature review and grower information.
In the second year, two experiments will be conducted to evaluate the effect of temperature on sensitivity of pollen-pistil interplay: in planta in the field and in vivo in controlled chambers under heat treatments. Consequently, results of all experiments will be integrated on the dynamic pollination model.
Finally, in the third year, after the construction of the model, data of all inputs and outputs will be collected from several kiwifruit orchards of different regions and conditions. Part of these data will be used to find the model weaknesses and to determine how to improve it. The remaining data will be used on cross validation.
The main expected result is to determine the vulnerability of interaction between pollen donors and female cultivars by the increase of temperature. The dynamic model of kiwifruit pollination will be permit to predict present and future problems, which will help growers to optimize pollination managements (bee hives and/or supplemental pollen applications) in the short term. Furthermore, this model can be complemented with other submodels, as thinning, pruning, etc, in order to study simulations of orchard managements. In the long term, these results of heat stress impact on kiwifruit cultivars will be used in further research for establishing new screening criteria of best-adapted genotypes (pollen donors, for example) to Chilean conditions.