Studies on pear parthenocarpy induced by exogenous plant growth regulators
Pear is one of the most important temperate fruits in China. In order to ensure a stable production and good fruit quality, artificial pollination is usually performed in some regions. However, this conventional practice is challenged by increased labor costs. Meanwhile, late frost damage occasionally hampers fruit set in the spring. Therefore, development of techniques to replace hand pollination is favorable for low-cost pear production and also as a temporary remedial measure after frost damage during anthesis. In the previous study, exogenous application of 200-500 mg L-1 of gibberellins (GA4+7) and/or 20-50 mg L-1 CPPU could induce parthenocarpic fruit in Chinese sand pear (Pyrus pyrifolia), but high concentration of GA and/or CPPU resulted in deformed fruit. In this study, auxins (IAA and NAA) and low concentrations of GA4+7 (50 and 100 mg L-1) were used to check the effectiveness in inducing parthenocarpic fruit. It was found that low concentration of GA4+7 was suitable for the induction of parthenocarpic fruit, but auxins did not induce successfully. The combined application of GA4+7 with paclobutrazol, especially uniconazole could improve fruit morphology. The fruit development pattern of the parthenocarpic fruit and pollinated fruit was similar after fruit setting, but the indices of the internal fruit quality (firmness, TSS, sugar, and organic acid) of parthenocarpic fruit tended to be stable earlier, which suggested that GA4+7 could advance fruit maturation. Compared with pollinated fruit, the parthenocarpic fruit showed higher TSS and sugar contents, lower sclereid content, and smaller core (resulting in an increased edible ratio).
Teng, Y.W., Xu, C.C., Bai, S.L., Pan, Z.M. and Tang, Y.X. (2018). Studies on pear parthenocarpy induced by exogenous plant growth regulators. Acta Hortic. 1206, 21-26
Pyrus pashia, parthenocarpic fruit, GA4+7, external fruit quality