Modifying Carbohydrate Supply to Fruit during Development Changes the Composition and Flavour of Actinidia chinensis var. chinensis ‘Zesy002’ Kiwifruit

Abstract

Consumer acceptance of fruit is determined by size, flavour and ripeness. In this study we investigated how altering the carbohydrate supply to Actinidia chinensis var. chinensis ‘Zesy002′ kiwifruit altered the balance between growth and accumulation of metabolites. Canes were phloem girdled and fruit thinned to a leaf-to-fruit ratio (L:F) of either 2 (Low carbohydrate) or 6 (High carbohydrate) at either 38 (Early) or 86 (Late) days after anthesis (DAA) and compared with ungirdled control canes with a L:F of 3. Fruit growth, metabolite accumulation, cytokinin concentrations and maturation were monitored and the sensory attributes of ripe fruit were assessed. The final weight of Early-High and Late-High carbohydrate fruit was 38% and 16% greater compared with control fruit. High carbohydrate fruit had increased starch,soluble sugar and cytokinin concentrations and fruit began to mature earlier and those with a Low carbohydrate had decreased concentrations and matured later compared with control fruit. Control fruit were described by consumers as more acidic and under-ripe compared with those from Early-High carbohydrate canes, but as sweeter than those from Low carbohydrate canes. This study showed that carbohydrate supply can have a major impact on the growth, sugar accumulation and maturity of ‘Zesy002′ fruit sinks.

Effect of Time of Girdling on Leaf Photosynthetic Performance and Kiwifruit Quality Characteristics at Harvest and Post-Storage

“…Similar increases in fruit fresh weight as well as in fruit dry matter at harvest have already been reported by other researchers in kiwifruit [6,24,26] as well as in other fruit species [31,[51][52][53][54][55][56][57], while there are also reports where girdling did not have a significant effect on grape berry weight [58]. The overall increase in the fruit weight and fruit dry matter is attributed to the increased supply of photosynthates to the fruits above the girdle zone [32,34]. According to Le Lievre et al [32], the modification of carbohydrate supply to the fruits, especially during the second stage of fruit sink development, leads to a significant increase of dry weight through the increased dry matter accumulation, as was shown in the present trial.…”

“…The overall increase in the fruit weight and fruit dry matter is attributed to the increased supply of photosynthates to the fruits above the girdle zone [32,34]. According to Le Lievre et al [32], the modification of carbohydrate supply to the fruits, especially during the second stage of fruit sink development, leads to a significant increase of dry weight through the increased dry matter accumulation, as was shown in the present trial.…”

“…This increased accumulation of carbohydrates in the growing fruit leads to the advancement of maturation [12,18,31,32,43,59]. This was not clear in the present experiment, as TSS, chlorophylls, TA, as well as sugar concentration of the pulp and fruit firmness did not exhibit significant differences among treatments.…”

“…The girdling of shoots or the trunk to prevent the basipetal movement of assimilates and plant growth regulators is an old technique that has been applied with variable success in many fruit tree species [12,31]. In kiwifruit, girdling of canes or the trunk during the early fruit developmental stages aims mainly at improving fruit size, while girdling applied during the later stages of fruit development (stages of slower fruit development) focuses mainly on increasing fruit dry matter [32][33][34][35]. In the present experiment, the girdling was applied at the end of summer and early autumn, when fruit growth is slower, aiming at improving fruit quality characteristics and storability.…”

Gibberellic Acid Spray Modulates Fruiting, Yield, Quality, and Shelf Life of Rambutan (Nephelium lappaceum L.)

“…Again, after a dormant winter floral induction in rambutan was initiated at the onset of spring using reserve carbohydrate. Competition between vegetative and reproductive growths creates a carbohydrate shortfall, favoring the flower and fruit drop (Lievre et al 2021), as in the control treatment. On the other hand, GA3 spray at the blooming panicles and young fruitlets facilitated stronger mobilization of C-metabolites to young ovaries and developing fruits for higher fruit retention (Shinozaki et al 2020).…”