Effects of the manipulation of carbohydrate supply on fruit dry matter and colour development in a block-red Actinidia chinensis var. chinensis genotype
Achieving consistent fruit pigmentation in red-fleshed Actinidia chinensis var. chinensis genotypes is challenging, and production of fruit with variably coloured flesh is likely to affect the economic returns of orchards. We have reported previously that factors such as vine vigour, carbohydrate availability and source-sink competition affect the expression of red colour in the fruit outer pericarp. In the current study, we manipulated carbohydrate availability to the fruit by a combination of shoot girdling (applied at different stages and for either a short or a long period) and different leaf-to-fruit ratios. We confirmed the importance of source capacity for both red pigmentation and dry matter in fruit, as well as fruit size. Carbohydrate depletion at key developmental stages reduced red colour development and was also associated with lower dry matter at harvest. Limited carbohydrate supply also delayed fruit development, as fruit were less mature (i.e. firmer and with lower soluble solid concentrations) at harvest. The variation in total non-structural carbohydrates and total anthocyanin in fruit supported the changes observed in dry matter and red pigmentation score. This study shows that is important to ensure carbohydrate supply during critical fruit developmental stages, and these results are useful for implementing canopy and crop load management strategies for red-fleshed genotypes.
Nardozza, S., Boldingh, H.L., Kashuba, M.P., McCaughan, L., Philippe, M., Wohlers, M., McGhie, T., Currie, M.B., Montefiori, M. and Richardson, A.C. (2018). Effects of the manipulation of carbohydrate supply on fruit dry matter and colour development in a block-red Actinidia chinensis var. chinensis genotype. Acta Hortic. 1218, 155-162
carbohydrate availability, fruit size, kiwifruit, leaf-to-fruit ratio, red-flesh, shoot girdling, source-sink