Study of the phenological phases of Chinese actinidia (kiwi) and specification of the parameters of primary fruit storage in the conditions of Baghdati Municipality

Abstract

Actinidia is a subtropical and tropical fruit tree that is not yet widely distributed. In subtropical fruit growing, special attention has been paid to the Chinese actinidia, which was bred by farmers in New Zealand as a result of many years of selection work and was named kiwi because of its resemblance to the kiwi bird known in this country. The plant produces delicious and aromatic fruits of the highest quality, which are used for food, both raw and as a processed product. The aim of our research was to study the growth and development dynamics of some varieties of Chinese actinidia (Hayward and Bruno) in the agroclimatic conditions of Baghdati Municipality.

The research object is two varieties of kiwi: Hayward (2 male and 10 female plants), Bruno (3 male and 18 female plants), located on the homestead plot of Baghdati Municipality. The plants are full-fledged.

The determination of the morpho-biological characteristics of the plants was carried out as a result of phenological observations and biometric measurements, using generally accepted observation and recording methods.

To study the growth dynamics of actinidia, a study was conducted in 2022-2023 in Bagdati Municipality, the height of the plant stem, diameter, total height of the plant (total length) were measured, biometric measurements were taken at the end of the vegetation period. The stem of the actinidia plant is conditional, it does not have an axis of symmetry, the stem is a strongly curved stem, which necessarily requires support. The average height of the stem at the site is 69 cm. As for the diameter of the stem, it is on average 10 cm.

During our study period, kiwi vegetation began in early April (April 5-10) in 2023, and in 2024 from March 31 to April 5, when the average daily air temperature exceeded 10–120C. Since the winter was not frosty in both years, bud awakening began earlier. Sharp temperature fluctuations at the end of March pose a threat to still unopened buds. From the second half of April, the study plants actively began intensive shoot growth.

In May, the leaf mass was practically completely removed. In this phase, it is necessary to fight weeds and provide the plant with nutrients (nitrogen, organic matter) so that the plant does not lag behind in development.

Kiwi flowering at our study site began in the third decade of May in both years and lasted 10–15 days. The quality of the flower is directly affected by soil moisture and nutrition.

Strong winds and heavy rain during the flowering period reduce the degree of pollination, which did not occur in our case, that is, during the study period.

Active fruit growth began in June. In Baghdati Municipality and in Imereti in general, summer is constantly humid, which contributed to the even growth of kiwi. The size of the fruit increased most rapidly in July-August. Fruit ripening began in the second half of October. It is generally believed that in the region the harvest is most often harvested at the end of November, but in our case, in the first year of the study, the fruit was harvested in the second decade of November, and in the second year of the study - in the first decade of November. Kiwi is mostly harvested at technical ripeness and then stored, where it finally ripens. Delaying the harvest until the end of November would have given us full ripeness of the fruits, which would have lost their marketable appearance. In both years, the autumn was warm, which had a positive effect on the accumulation of sugar in the fruit, studies have shown that if the autumn is cold and humid, the accumulation of sugar in the fruit slows down.

The end of the vegetation in our case began in the second decade of December in both years. And when the air temperature dropped to 8⁰С, the leaves turned yellow and began to fall off. The plant went into a winter dormancy phase, which lasted about 3–3.5 months.

Based on our research, it became important to clarify the initial storage conditions of the fruit, since kiwi is stored in technical ripeness after picking and reaches consumer ripeness during storage. In particular, the optimal temperature for storing kiwi fruit was found to be 3–50C. Humidity: in an above-ground storage room – 85–87%. Under such conditions, a stable temperature ensures the storage of the fruit for up to 2–3 months. The fruit should be stored in open containers or paper so that it has access to oxygen; It should not be close to products with a strong odor, as kiwi easily absorbs odors.

Conclusion: Imereti is one of the best regions in Georgia for kiwi cultivation, however, proper knowledge of the phenological phases allows the grower-gardener to: properly plan maintenance measures; avoid the risks of late frost and fungal diseases; maximize the quantity and quality of the harvest; Baghdati municipality and the Imereti region in general are characterized by high humidity and mild winters, which are favorable for plant vegetation, although they require appropriate agrotechnical methods - pruning, feeding, weeding, etc.