By ERNIE REZENTS
For The Maui News—
It seems that avocados are in abundance because we have been offered several different types for consumption. I am a firm believer that there are basically two types of avocado trees. One type should be planted in gulches because it grows too large and the other is small enough to be planted in a residential lot. With lot sizes decreasing, dwarf or medium sized trees are popular.
The avocado, Persea Americana a, is among the earliest of fruit trees to have been brought to Hawaii. It was introduced by Don Marin and by 1855 was quite common on Oahu and was being planted on the neighbor islands as well.
There are three races. The Mexican race, which the Fuerte variety belongs to, is grown to a limited extent. The West Indian is known as the “summer pear” because it fruits primarily during that time of year. It has a seed that fits loosely in its cavity. The Guatemalan fruits from fall to spring and is called the alligator pear because it has thick, hard, and often rough skin. The seed fits tightly in the cavity. Determining the race of your favorite avocado may be difficult because they cross pollinate and produce seeds that when planted grow into trees bearing a mixture of characteristics.
I judge the quality of an avocado by its taste. I like fruit that is somewhat drier and nutty in taste. It should have a thick flesh and a small seed. Peeling easily is an advantage for slicing. Otherwise a spoon or knife will be needed to separate the fruit from the rind. Some types hold onto their seeds tightly like the Hass does, while others shed their seeds easily but leave a brown skin on the flesh. I would prefer one that has a loose seed that falls out of its cavity brown skin and all. I like small to medium sized trees to facilitate picking and prefer to have year-round production. One tree will usually not provide all the traits a person desires, especially the year round production. Read on to learn how I achieved the impossible.
The avocado’s sex life is intriguing. There are two types based on when the female flower part is receptive and when the male [art is shedding pollen. In the “A” type the female flower part, the pistil, is receptive in the morning. The male flower part, the stamen, sheds pollen on the afternoon of the next day. Ion the “B” type the female flower part, the pistil is receptive in the afternoon but the male flower part, the stamen sheds its pollen during the morning of the following day. So the female and male flower parts within a type “A” or “B” tree are not ready at the same time. They are incompatible. When she is willing, he is not available. When he is “ripe” with pollen, she has already had her fling” The trees solve this incompatibility by obtaining pollen from each other. Flies, bees, and other insects transfer pollen from type B to “A” in the morning and from A” to “B” in the afternoon.
I inspected the avocado trees in my yard and found one type B, the Fuerte, and three type “A”s: Little Cado, Hass, and a graft I call “Miki”. When the female part (pistil) is receptive, it stands straight up and is in plain view. When the stamens are producing pollen the female part is surrounded by 3 “oar-like” appendages. The stamens then become fully exposed to insects. This physical change occurs within the flower around noon. To verify this, check your trees when they are in flower next time.
There are enough type “A” and type “B” trees in your neighborhood to insure pollination of your avocado flowers by insects. I wanted to guarantee this so I grafted a root stock with both Hass, type “A” and Fuerte, type “B”. I call this my “incestuous” tree. The disadvantage of this arrangement is that I must maintain two separate trunks and the Fuerte is a slightly larger tree than the Hass. The Fuerte needs to be on the north side and the Hass on the south to maximize sunlight exposure. Neither of these trees are a dwarf so height adjustments will be needed later on. The fruiting season for Fuerte is from November to June while the Hass is February to October. So I will just about achieve avocados all year round with one tree containing two grafts. A drawback is that Fuerte bears on alternate years. I have just one fruit this year. I had many last year. Hass is consistently a good bearer. It has small immature fruit as well as fruit that are being picked for eating.
The take home message from the avocado sex life is every seed has characteristics from two distinctly differently trees. The resulting seedling will bear fruit but its quality will be better, somewhat similar, or “junk” but never exactly the same as what you planted. It is better to invest in a grafted tree with known fruit quality than to chance it with a home-grown seedling.
Some popular varieties with their flower types and bearing seasons are:
Fall and Winter: Case (B), Kahaluu (B), Semil-34 (A), and San Miguel (A).
Winter & Spring: Greengold (A), Hayes (A), Nishikawa (B), Sharwil (B), Hass (A), and Fuerte (B).
Spring & Summer: Chang (B), Murashige (*B), Ohata (A), OHATSA (JA), ANAHEIM (A), Hass (A), and Little Cado (B).
Hass is a medium large tree and it bears small bumpy-skinned fruit. The rind turns purple when the fruit is ripe. Its oil content is 18% and is the largest commercially produced variety on the mainland. It is a heavy bearer.
The Fuerte grows into a large tree. The fruit is medium in size with a medium-thin green skin. The fruit oil content is 18 percent, and it is the second largest commercially produced variety on the mainland. It bears a good crop on alternate years. (True for my tree).
The Little Cado grows only eight to fifteen feet high. The fruit is medium in size with a medium-thin skin. The fruit oil content is 18 percent. It bears a good crop on alternate years. If all the fruit is picked by December 1st, flowering will occur in the spring for yearly fruiting. (True for my friend’s tree.) This is a good bearer.
Anaheim is a small to average-size tree. The fruit is medium to large in size and contains 10-12 percent oil. Its bearing capacity is fair. Whitsell is such a small tree it develops several leaders. It beavers medium sized fruit with an oil content of 18 percent. It is a heavy bearer for its size. They are short and sparingly looking. I think it looks ugly.
Greengold is a medium sized tree (about 20 feet tall), bears medium size with a green skin. My guess is that its oil content is equivalent to the Hass (18 percent). It is excellent in taste. I have been told that it bears on alternate years. A person should experiment and pick all the fruit by December 1st to determine whether fruit is then produced yearly. This is the case with Little Cado. Fruit quality may not e as good when picked too early – less oil.
Greengold is a seedling of Sharwil.
Sharwil is very similar to Greengold but has fruit every year. It is Hawaii’s main commercially grown variety. It is excellent in taste and originated from Australia.
I would like to continue this next time and discuss avocado selection, planting, caring, and harvesting.