Kiwi Fruit

     Kiwi Fruit         

      Kiwi – actinidia deliciosa

   Kiwis are small fruits that pack a lot of flavor and plenty of health benefits. Their green flesh is sweet and tangy. It’s also full of nutrients like vitamin C, vitamin K, vitamin E, folate, and potassium. They also have a lot of antioxidants and are a good source of fiber. Their small black seeds are edible, as is the fuzzy brown peel, though many prefer to peel the kiwi before eating it.  Other name - Chinese gooseberry.

        About the size of an egg, kiwifruit is wrapped in a russet-brown thin skin with short rather stiff hairs. The kaleidoscope-like almost glistening emerald green firm pulp is dotted with a large amount of dark nearly black tiny edible seeds that create this fruit's characteristic interior starburst pattern. Sometimes the flesh may be yellow, brownish or off-white. Sweet tart with a slightly acidic edge, this decorative fruit's succulent flavour is mainly sweet.

       The most common cultivar group of kiwifruit (Actinidia deliciosa 'Hayward') is oval, about the size of a large hen's egg: 5–8 centimetres in length and 4.5–5.5 cm in diameter. The fruit has a soft texture with a sweet and unique flavour. In 2017, China produced 50% of the world total of kiwifruit.

         Kiwifruit growing on supported vine. Often in commercial farming, different breeds are used for rootstock, fruit bearing plants and pollinators. Therefore, the seeds produced are crossbreeds of their parents. Even if the same breeds are used for pollinators and fruit bearing plants, there is no guarantee that the fruit will have the same quality as the parent. Additionally, seedlings take seven years before they flower, so determining whether the kiwi is fruit bearing or a pollinator is time-consuming.  Therefore, most kiwifruits, with the exception of rootstock and new cultivars, are propagated asexually. This is done by grafting the fruit producing plant onto rootstock grown from seedlings or, if the plant is desired to be a true cultivar, rootstock grown from cuttings of a mature plant.

Three major types of kiwifruit are:

Common kiwi – This is the type of kiwifruit (Actinidia deliciosa) typically found in grocery stores. It is a brown, fuzzy fruit with a thick skin and green pulp. For optimal growth, it requires about a month of cool weather with temperatures ranging from 30 to 45 degrees.

Golden kiwi – Another popular type of kiwi, the golden kiwi (Actinidia chinensis) is sweeter but more delicate compared to the common kiwi. It is closely related to common kiwifruit but is less fuzzy and more yellow. This fruit grows best in zones that experience winter lows ranging from 10 to 30 degrees.

Kiwi berry – This name usually refers to two different kiwi species, the hardy kiwi (Actinidia arguta) and the super-hardy kiwi (Actinidia kolomikta). These kiwifruits are much smaller compared to common and golden kiwis and have a thinner, smooth skin. As their names suggest, this type of kiwi is the most cold-tolerant and can be grown in areas that experience harsh winters. These varieties are sometimes able to produce fruit after just one growing season, in contrast to most others that take years to mature.

      Two characteristics of kiwi fruit need to be taken into account. The first is that plants are dioecious, which means that male and female flowers are borne of different plants. So you will need to buy two plants, one male and one female. However it’s also now possible to buy the male and female plants, grafted onto one rootstock, so only one vine needs to be planted. The second is that kiwi fruit vines will grow rampantly with canes growing to more than 5m in one season, so you need space and strong supports.

     There are around 50 different species of Kiwis, but the commercial Kiwi, Actinidia deliciosa, which is also sometime called the Chinese Gooseberry, is the one widely known to most people from their ready availability in stores. This is a very large plant that will reach at least 30 feet across, so to grow them you need plenty of space. Once they begin to climb up into a tree they can even reach 100 feet long and easily take over a large garden. As well, you also need to grow an equally large male plant, which takes up a lot of room just so that the female plants will produce their fruits. 

Kiwifruit flowering

Kiwifruit plants generally are dioecious, meaning a plant is either male or female. The male plants have flowers that produce pollen, the females receive the pollen to fertilise their ovules and grow fruit; most kiwifruit requires a male plant to pollinate the female plant. For a good yield of fruit, one male vine for every three to eight female vines is considered adequate.  Some varieties can self pollinate, but even they produce a greater and more reliable yield when pollinated by male kiwifruit. Cross-species pollination is often (but not always) successful as long as bloom times are synchronised.

        Male and female flowers grow on separate kiwifruit plants. Male flowers produce pollen from the numerous stamens. Female flowers have a well-developed ovary with long sticky stigmas in the centre. Although female flowers have stamens, they do not produce functional pollen.

     In nature, the species are pollinated by birds and native bumblebees, which visit the flowers for pollen, not nectar. The female flowers produce fake anthers with what appears to be pollen on the tips in order to attract the pollinators, although these fake anthers lack the DNA and food value of the male anthers.

        Kiwifruit growers rely on honey bees, the principal ‘for-hire’ pollinator. But commercially grown kiwifruit is notoriously difficult to pollinate. The flowers are not very attractive to honey bees, in part because the flowers do not produce nectar and bees quickly learn to prefer flowers with nectar.

      And for kiwifruit, honey bees are inefficient cross-pollinators because they practice “floral fidelity”. Each honey bee visits only a single type of flower in any foray and maybe only a few branches of a single plant. The pollen needed from a different plant (such as a male for a female kiwifruit) might never reach it were it not for the cross-pollination that principally occurs in the crowded colony. It is in the colonies where bees laden with different pollen literally cross paths.

Male and Female Flowers of Kiwi fruit

      To deal with these pollination challenges, some producers blow collected pollen over the female flowers.  Most common, though, is saturation pollination, where the honey bee populations are made so large (by placing hives in the orchards at a concentration of about 8 hives per hectare) that bees are forced to use this flower because of intense competition for all flowers within flight distance.

        Even though the skin is edible, the fruit is usually peeled. Slice for garnish. Containing a meat-tenderizing enzyme, place sliced peels with some flesh attached directly on meat; marinate thirty minutes for each inch of the meat's thickness. To make a kiwifruit salsa, blend four peeled kiwis, one teaspoon minced jalapeño pepper, one tablespoon orange juice; one tablespoon chopped fresh mint and a pinch of salt. Serve with grilled swordfish, grilled poultry and roast pork. Bananas, berries, mangoes, strawberries, raspberries and oranges are especially partial to kiwifruit. To store, refrigerate ripe fruit up to ten days. Refrigerated unripe fruit lasts up to one month.

      The main care needed for Kiwi Plants is pruning. Since they are so vigorous they rarely need any added fertilizer, and watering is only needed for established plants during quite severe drought. There are two methods used for pruning. If properly done, your Kiwi Plants should begin to fruit within two or three years of planting, while if just left uncontrolled it may take up to six years to begin fruiting.

      Kiwifruit is rich in vitamin C, having ten times more than the equal weight of a lemon. Two fruits have almost twice the vitamin C of an orange and more potassium than a comparable serving of bananas. High in fiber, it also offers vitamin A, Vitamin E, calcium and iron. Credit goes to all those little black seeds, as they act much like grains, providing lots of nutrition.

       It’s thought that the high amount of vitamin C and antioxidants that kiwis contain can actually help treat people with asthma. One study from 2000 found that there was a beneficial effect on the lung function among those who consumed fresh fruit regularly, including kiwis. Fresh fruit like kiwi may reduce wheezing in susceptible children.

Boosts the immune system

      Kiwis are nutrient-dense and full of vitamin C. In fact, just 1 cup of kiwi provides about 273 percent of your daily recommended value. Vitamin C is an essential nutrient when it comes to boosting your immune system to ward off disease. One study even found that kiwis may support immune function and reduce the likelihood of developing cold- or flu-like illnesses. This is especially true in at-risk groups like adults over the age of 65 and young children.

Reduces blood clotting

       In addition to helping us manage our blood pressure, kiwis can actually reduce blood clotting. A study from the University of Oslo found that eating two to three kiwis a day significantly lowered the risk of blood clotting. They were also found to reduce the amount of fat in the blood. Researchers said that these effects were similar to those of a daily dose of aspirin to improve heart health.

Protects against vision loss

         Macular degeneration is the leading cause of vision loss, and kiwis might help protect your eyes from it. One study found that by eating three servings of fruit a day, macular degeneration was decreased by 36 percent. Kiwis’ high levels of zeaxanthin and lutein are thought to contribute to this effect.

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