Geostatistical Methods to Build Citrus Cross-Pollination Risk Maps

Valencian citriculture is oriented towards fresh production, which requires fruits with few seeds or seedless fruits. Consequently, parthenocarpic and self-incompatible varieties are mainly cultivated. However, some mandarin varieties, under favorable circumstances, induce seed formation in other mandarins by cross-pollination. This phenomenon depends on the germination capacity of the pollen of the pollinating variety, the number of ovules of the pollinated variety, the distance between them, and the abundance of pollinating insects. Previous studies in Instituto Valenciano de Investigaciones Agrarias (IVIA) have determined the ability to pollinate and be pollinated by all commercial varieties in Europe. Moreover, the Regional Government, Generalitat Valenciana, has georeferenced information on the cultivated varieties. We present two geostatistical models to estimate the risk of plots to be pollinated, depending on the varieties present in their environment, the number of plants, and their distance. Models are used to generate local and regional cross-pollination risk maps. Moreover, the robustness of these models to changes in the values assigned to their main parameters is assessed using different similarity calculations.