The Mode of Pollination Influences the Berry Set and Agronomic Features of Table Grape Cultivars (Vitis vinifera)

Pollination biology of grapevines displays great diversity ranging from self- to cross-pollination due to rich genotypic variability in flower types. Thus, grape growers and breeders should well-understand the genotype-specific pollination requirements to ensure the food demand of ever-increasing population of the world. A soilless culture was established in protected cultivation to study the possible impacts of self-, hand-, open pollinations and vibration on agronomic features of three table grape cultivars (‘Italia’, ‘Michele Palieri’ and ‘Prima’). The treatments had different effects on agronomic characteristics of the cultivars, indicating a cultivar-specific pollination response. In ‘Italia’ and ‘Prima’ the greatest berry set occurred in hand-pollinated clusters (31.9 and 52.4%, respectively) while vibration resulted in the highest berry set in ‘Michele Palieri’ (38.5%). In many features, hand pollination provided remarkable improvements in berry, cluster and seed features, indicating the beneficial effects of cross-pollination. Lightness of the berries did not show remarkable variations in response to the different pollination applications across the studied grapevine cultivars. However, chroma in ‘Italia’ and Hue angle in ‘Michele Palieri’ were significantly different in open pollination, indicating the diverse effects of pollen sources on berry color, a prime feature of visual quality in grapes. The highest soluble solid contents were found in self-pollination across the cultivars. Overall findings indicated that the pollination treatments significantly affected most agronomic characteristics of the studied cultivars. Thus, viticulturists and breeders should consider the biological response of any cultivar to mode of pollination in grape production or breeding.