Fruit Size and Quality Attributes Differ Between Competing Self-Pollinated and Cross-Pollinated Strawberry Fruit

Strawberry flowers are hermaphroditic and most cultivars are self-compatible, but strawberry plants can produce a mixture of fruit that have arisen from self-pollination and cross-pollination. We aimed to determine whether size, shape, color, taste attributes and shelf life differ between self-pollinated and cross-pollinated fruit competing on the same Redlands Joy strawberry plant. Experiments were repeated at three fertilizer levels to determine the consistency of responses across different levels of crop nutrition. Cross-pollinated fruits were 4.2%-7.5% heavier and 2.7%-5.0% longer than self-pollinated fruits, with the differences being greater at lower levels of nutrient supply. They were also darker or redder than self-pollinated fruits. Cross-pollinated fruits sometimes had lower degrees Brix (sugar) or lower acidity than self-pollinated fruits, with the effect on sugar:acid ratio depending on the nutrient level. The shelf life of cross-pollinated fruits was approximately 4 days longer than self-pollinated fruits on plants that received medium or high levels of fertilizer. The results suggest that pollen-parent effects on fruit size become evident when self- and cross-pollinated strawberry fruits compete for resources on the same plant, and that the expression of pollen-parent effects can be affected by the level of crop nutrition.