By ERNIE REZENTS
For The Maui News—
The first papayas, Carica papaya, were disseminated worldwide by the Spanish and Portuguese sailors from the lowlands of Central and South America. Papayas were introduced into Hawaii in about 1820. These were the large fruited type. In 1911 the “solo” variety was introduced from Jamaica by the University of Hawaii and today it is the only type that is grown commercially. Papayas grown in Hawaii today have undergone major improvement through hybridizing and selection for desirable characteristics.
Both green and ripe papaya fruit supply a very large amount of the vitamin C we need in our daily diet. The ripe fruit is a good source of carotene which the body converts into vitamin A. Papaya is a good source of potassium as well. So it doesn’t only taste good, but it is good for you.
Popular solo papaya cultivars.
People often ask for plants of the “low bearing” type to make it easier to pick the fruit. This expression means that fruit will develop low on the trunk. However, these trees will eventually grow tall and bear fruit high above the ground. It will then be time for tree replacement.
Popular cultivars are:
‘Sunrise‘, or strawberry papaya, has a reddish-orange flesh. It is excellent in taste and has a relatively soft flesh when ripe. Because it bruises easily when ripe, it has a shorter shelf life than some other types. This is a very popular fruit and is sold in most stores.
‘Sunset’ is a new hybrid solo papaya with salmon-pink flesh. The fruit averages about 15% smaller than ‘Sunrise’; it has a firmer flesh than ‘Sunrise’, and has a longer shelf life. ‘Sunset’ plants are low bearing, producing the first fruits at about 32 inches above ground level. The trees produce the first fruits about 10 months after planting. There is little or no flower sterility and the flesh is without lumps and stringiness.
‘Kapoho‘ is a solo strain with fruit about the size of ‘Sunrise’. It is a firm fruit that is ideal for shipment and was developed for planting in Kapoho, Hawaii, where the rainfall is 100 inches a year and the “soil” is Aa lava. If it is planted in dry areas the fruit becomes exceptionally small.
‘Waimanalo‘ low-bearing, or ‘X-77’, is a solo strain that has large fruit with a short neck (more oval rather than shaped like a light bulb). The first flowers appear about 32 inches above ground. The firm flesh is orange-yellow in color, and should be eaten when fully ripe otherwise it might be difficult to spoon. It ships well because it does not bruise so easily.
‘Filipino type‘, or large fruiting types, is a delight to grow because of their sheer size. During high light times of the year they are sweet and at other times they are “so-so”. As a kid we had the watermelon papaya. It was about 15 inches long and about 8 inches in diameter. It had pink colored flesh; at the time we thought it tasted quite good. I have a large fruited, orange fleshed, low bearing, Filipino type papaya at home but it doesn’t come close to having the ‘Sunrise’ papaya fruit quality. The large types are good when cooked green as a squash in dishes such as Chicken and Papaya.
Papaya plants are usually started from seed and planted either in pots or directly in the ground. The seeds should be saved from productive trees with good tasting, well shaped fruit. Preferably one that is not summer sterile- no fruit produced due to female sterility when it is warm. Select from the best! The seed’s gelatinous envelopes should be washed off because it inhibits germination. About 5 seeds are planted in a pot and 10 seeds at a field site. Dried seeds can be kept in the refrigerator for planting later, but I have found that germination is best with fresh seed.
After germination, keep the two or three strongest plants that are separated from each other. Pinch the others out at soil level. Seeds will produce about two thirds hermaphroditic plants and one third female plants. Male plants are few and far between. The two or three plants growing in a pot should be planted in the same hole. The multiple plants per site is to facilitate selection of a plant bearing hermaphroditic flowers and eliminating all others. If all your selected plants have hermaphroditic flowers, the strongest plant is kept and the others are sacrificed. The plants should flower in about six months for you to make this selection.
The Papaya Flower.
If you have papayas in your yard, collect a flower and locate the parts as described here. The hermaphroditic flower has both male and female parts in one flower. The five creamy-colored petals fuse at the top portion of a small papaya fruit (the ovary). At this union, each petal has 2 orange colored male parts (anthers-10 in all). The miniature papaya (ovary) is topped by a stigma with 5 horns. Flowers with less than 5 stigma horns will develop into elongated fruit; some even resembling cucumbers. Pollination occurs when insects transfer pollen from the male’s anthers to the female’s stigma. Fruit development follows. Unfortunately many hermaphroditic plants develop flowers that are female sterile during the summer heat. Summer sterile flowers resemble male flowers because the ovary is extremely tiny and not available for pollination. When checking the plant’s trunk you find a cluster of fruit, then a section without fruit, and then the top-most section has young flowers and small developing fruit. The section without fruit is from the time that “summer sterility” occurred. Opening up a summer sterile flower reveals an undeveloped ovary that is needle shaped and has no similarity to the miniature papaya ovary found in the normal flower.
Female flowers have five petals that remain separate and are attached to the base of the ovary. The ovary, again a large miniature papaya, has pronounced stigma horns at the top. Pollen needs to be transferred from either a hermaphroditic or a male flower to the stigma because of the absence of the male part. These fruits are rounder in shape, have a thinner flesh, and have few to no seeds, but taste the same as fruits from hermaphroditic flowers. The big advantage of having a female tree, along with hermaphroditic trees, is that it does not develop summer sterility and therefore bears more fruit during the winter.
Male flowers look just like the summer sterile hermaphroditic flowers (5 petals, 10 orange male anthers, but no central female ovary or miniature papaya). The flowers appear in clusters at the end of long stems. At times the plant’s hormones cause the female part to grow normal, pollination occurs, and a fruit is formed. You can recognize these trees because the fruit hangs from stems about 2 feet in length.
Commercially, female and male trees are eliminated and only trees with hermaphroditic flowers are kept. However, I have seen female trees in backyards tight with round shaped fruit. Pollen was transferred by insects from close by hermaphroditic plants.
Growing plants in aa lava is not my type of farming. Kapoho, on the Big-Island, has a high rainfall that is well distributed through-out the year. The aa lava is porous and provides excellent drainage. The warm weather, good sunlight, mild winds and use of slow release fertilizers, round out a good growing environment for papayas. Hence it is an area for commercial production of this fruit.
Tillable soils are my preference. Papayas prefer a well drained loamy soil with a pH of 5.5-6.7. Soils more acid than 5.0 will need to be limed. Wet clayey soils will stay wet longer and might lead to root fungal problems. But don’t despair; I have seen papayas growing in Haiku acidic soils. Raising your soil’s pH, planting on a slope, maximizing exposure to the sun, and encouraging wind circulation will help produce home-grown fruit.
What could be more fun than to have papaya for breakfast from your own yard?
Elevation and Temperature.
The temperature of an area influences the type of flowers and quality of fruits formed on a tree. A decrease in temperature results in a decrease of fruit quality. If temperatures are between 60 and 76oF for very long, 99% of the fruit may be deformed while only 12% of the fruit may be deformed if the temperature is between 70 and 81oF.
Papayas will grow up to 4,000 feet elevation. Above 1500 feet, the quality decreases. Best quality fruit is produced below 900 feet in elevation. High elevations produce fruit with hard flesh and low sugar content. So papayas recommended for one area may not do well in another if the growing conditions are different. For home gardeners who live below 900 ft elevation, the Sunrise, Sunset, and Waimanalo cultivars will do well.
I will continue with part II next time. Thank you for the many favorable comments I’ve received. I hope the past 31 articles have helped you become more successful gardeners.