Kiwi (Actinidia deliciosa var. deliciosa C. Liang and A. R. Ferguson) is a climbing deciduous dioecious brush (separate sexes in male and female plants), that produces a berry type fruit with numerous seeds and that live for many years (perennial plant, commercial plantings can produce over 20 years).
• Root system: Normally the root system is located in the first 60 cm from the soil surface, it has a low explorative capacity, it is very air demanding, succulent, largely ramified, and susceptible to dehydration and nematodes of the Meloydogine genera.
• Sprouts: Its sprouts are vigorous, brittle by the wind, frost susceptible in the first 30-45 days and are screwed when they touch among them or with any other element that stop their growing (climbing adaptation).
• Flower: These are functional unisex, lumped together into bundles from 1 to 3 female and up to 8 male flowers; even though they are impressive, do not produce nectar and their pollen is light and dry, which difficult the pollination by bees.
• Fruit: The fruit weight from 90 to 100 gr, its pedicel healing when harvesting is relatively slow and susceptible to the fugi Botrytis cinerea (produces storage rooting), it is highly susceptible to the Ethylene (accelerates maturity with only 0.01 ppm concentration) and it has high vitamin C content.
• Floral initiation: Flowers are produced in the first 12 leave axils in the annual sprouts which are born from the previous year wood. The flower induction occurs between middle January and April, but the visual differentiation comes only at sprouting re-initiation (end of August), for which requires a synchronized sprouting, resulting in an adequate accumulation of winter cold and warm temperatures at sprouting. Flowers usually present shape aberrations, which produce flat fruits, that normally are eliminated when manual thinning at flower bud stage.
Annual cycle of kiwi (cv. Hayward in Chile)
Stage and Agronomic Management
Dormancy: Winter cold accumulation. Winter pruning and biding.
Sprouting to Flowering: Flower differentiation and natural abortion of buds and sprouts´ breaking by the wind. Thinning of buds, irrigation and fertilizer application (Nitrogen).
Flowering: First peak of root growing and green pruning.
Rapid growing of fruits: In the first 50 days fruits reach 50% of their weight and 75% of their final diameter. Green pruning, load adjustment, fertilizer application (Potassium).
Slow growing and maturity: Increment of roots´ growing. The fruit is maintained with 4-4.5 °Brix. Seeds change from white to dark brown. When going over 5 °Brix, soluble solids are raised at increasing rate, especially when temperatures are reduced.
Post-harvest:Maximum reserves accumulation and root growing rates.
Tree trunk susceptibility to frost damage. Falling of frozen leaves. Soil improvement (porosity). Tree trunk protection in the younger plant less than 4 years old (female zones).