Kiwifruit is a dioecious fruit tree that requires pollination for fruit set by female plants. In this study, the plant growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D) was used on Chinese kiwifruit (Actinidia chinensis var. ‘Donghong’) to promote fruit set, improve fruit quality and increase yield. The results showed that exogenous application of 2,4-dichlorophenoxyacetic acid (2,4-D) effectively induced parthenocarpy in Chinese kiwifruit and significantly improved fruit quality. At 140 days after flowering, the fruit set rate of parthenocarpic fruits treated with 2,4-D reached 16.95%. The pollen structure of female flowers treated with 2,4-D and water were different, and pollen viability was not detected. At maturity, the 2,4-D-treated fruits were slightly smaller than those in the control group, and their peel, flesh and core firmness were significantly different from those in the control group. There was no significant difference in the soluble solids content between the 2,4-D-treated fruits and the control fruits at maturity, but the dry matter content of the 2,4-D-treated fruits was lower than that of the pollinated fruits.
In recent years, plant growth regulators (PGR) have been widely used to induce parthenocarpy in various horticultural crops. However, comprehensive studies on the use of growth regulators to induce parthenocarpy in kiwi have not been conducted. In this paper, the effect of the plant growth regulator 2,4-D on parthenocarpy in kiwi of the Dunghong variety and changes in its overall chemical composition were studied. The results obtained provide a scientific basis for the rational use of plant growth regulators to improve kiwi fruit set and overall fruit quality.
The experiment was conducted in the National Kiwi Germplasm Resource Bank of Wuhan Botanical Garden, Chinese Academy of Sciences in 2024. Three healthy, disease-free, five-year-old Actinidia chinensis ‘Donghong’ trees were selected for the experiment, and 250 normally developed flower buds from each tree were used as test material.
Parthenocarpy allows fruit to develop successfully without pollination, which is especially important under pollination-limited conditions. This study showed that parthenocarpy allows fruit set and development without pollination and fertilization, thereby ensuring stable production under suboptimal conditions. The potential of parthenocarpy lies in its ability to increase fruit set under adverse environmental conditions, thereby improving crop quality and yield, especially when pollinator services are limited or absent . Environmental factors such as light intensity, photoperiod, temperature, and humidity can influence 2,4-D-induced parthenocarpy in kiwifruit. Under closed or shaded conditions, changes in light conditions can interact with 2,4-D to alter endogenous auxin metabolism, which can enhance or inhibit parthenocarpic fruit development depending on the cultivar. In addition, maintaining stable temperature and humidity in a controlled environment helps maintain hormone activity and optimize fruit set [39]. Future studies are planned to further explore the optimization of environmental conditions (light, temperature, and humidity) in controlled growing systems to enhance 2,4-D-induced parthenocarpy while maintaining fruit quality. The mechanism of environmental regulation of parthenocarpy still requires further investigation. Studies have shown that low concentrations of 2,4-D (5 ppm and 10 ppm) can successfully induce parthenocarpy in tomato and produce high-quality seedless fruits [37]. Parthenocarpic fruits are seedless and of high quality, making them an ideal choice for consumers [38]. Since the experimental kiwifruit material is a dioecious plant, traditional pollination methods require manual intervention and are too labor-intensive. To solve this problem, this study used 2,4-D to induce parthenocarpy in kiwifruit, which effectively prevented fruit mortality caused by unpollinated female flowers. The experimental results showed that the fruits treated with 2,4-D developed successfully, and the number of seeds was significantly less than that of the artificially pollinated fruits, and the fruit quality was also significantly improved. Therefore, inducing parthenocarpy through hormone treatment can overcome pollination problems and produce seedless fruits, which is very important for commercial cultivation.
In this study, the mechanisms of 2,4-D (2,4-D) on seedless fruit development and quality of Chinese kiwifruit cultivar ‘Donghong’ were systematically investigated. Based on previous studies demonstrating that 2,4-D could induce seedless fruit formation in kiwifruit, this study aimed to clarify the regulatory effects of exogenous 2,4-D treatment on fruit development dynamics and fruit quality formation. The results clarified the role of plant growth regulators in seedless kiwifruit development and established a 2,4-D treatment strategy that provides an important physiological basis for the development of new seedless kiwifruit cultivars. This study has important practical implications for improving the efficiency and sustainability of the kiwifruit industry.
This study demonstrated the effectiveness of 2,4-D treatment in inducing parthenocarpy in the Chinese kiwifruit cultivar ‘Donghong’. External characteristics (including fruit weight and size) and internal qualities (such as sugar and acid content) during fruit development were investigated. Treatment with 0.5 mg/L 2,4-D significantly improved the sensory quality of the fruit by increasing sweetness and decreasing acidity. As a result, the sugar/acid ratio significantly increased, which improved the overall fruit quality. However, significant differences were found in fruit weight and dry matter content between 2,4-D-treated and pollinated fruits. This study provides valuable information on parthenocarpy and fruit quality improvement in kiwifruit. Such application may serve as an alternative for kiwifruit growers aiming to produce fruits and achieve higher yields without using male (pollinated) varieties and artificial pollination.
Post time: Sep-02-2025