Leaves are important to obtain consistent red flesh pigmentation in Actinidia chinensis fruit

Abstract Red-fleshed Actinidia chinensis fruit are new to the market and consumers’ acceptance of these kiwifruit is subject to the development of a consistent red flesh pigmentation. We hypothesised that differences in the availability of source carbohydrate have an effect on the variation in fruit red colour within an orchard. In a block-red-fleshed (red colour in the inner and outer pericarp) genotype, effects of shoot types, parent cane types, vine rootstock, fruit position on the shoot, flowering time and light exposure on fruit flesh colour were evaluated. Vine vigour had a consistent effect on the outer pericarp colour of fruit. Fruit from the vines on the more vigorous rootstock ( A. deliciosa ‘Bruno’ seedling) had the most intense and least variable outer pericarp red colour. In addition, fruit from long shoots on small diameter canes (10–15 mm) were also the most intensely pigmented, whilst fruit position on the shoot, flowering time and fruit light exposure did not affect fruit flesh red colour. The vigour of vines due to rootstock, cane and shoot size also affected fruit growth and dry matter accumulation. These results suggest that, similarly to fruit growth (i.e. fresh weight and dry matter), vine vigour, carbohydrate availability and competition for resources between fruit and vegetative shoot growth have a putative role in red colour development in kiwifruit flesh. These finding can be used to develop optimised growing systems for new red-fleshed kiwifruit cultivars that minimise excessive shoot vigour to enhance red pigmentation of fruit flesh.