Gardening : Grapefruit: How Sweet They Can Be : Two fairly new varieties lack the bitterness often associated with fruit.

According to John Pehrson, a citrus specialist at the University of California’s Lindcove Field Station, once people sample Melogold or Oroblanco grapefruit, they will probably never again be satisfied with ordinary grapefruits.

The grapefruit Pehrson was referring to are two fairly new grapefruit varieties that lack the bitterness associated with ordinary grapefruit.

Both the Melogold and Oroblanco varieties are almost as sweet as a navel orange, although they have the characteristic flavor of the grapefruit, and both varieties are seedless. Even people who are not fond of grapefruit will probably appreciate these varieties--grapefruit fanciers will be ecstatic over them.

Both were developed by crossing a grapefruit with a pummelo. Both Melogold and Oroblanco were developed at UC Riverside, by geneticists Robert K. Soost and James C. Cammeron.

Both grapefruit will grow and produce in home orchards in much of the Southland. Generally the production will probably be better and the fruit of better quality in warmer areas. However, I live in a mild area of Orange County and I have an Oroblanco tree in my yard that produces marvelous, sweet fruit.

Scarce in Nurseries

Oroblanco trees have been available in local nurseries for about six years, but budwood for Melogold was just released two years ago by the university to wholesale growers for propagation. The trees are scarce in retail nurseries.

I asked John Pehrson which one of these two super-grapefruit actually had the best flavor. He said it all depended on who was doing the testing. For instance, Pherson prefers the Melogold, while his wife favors the Oroblanco.

Pherson suggested I do a taste test and I took him up on it. With the help of five friends, we sampled and compared Oroblanco and Melogold with a standard grapefruit variety (Marsh) and then compared them with each other. In comparison with the standard grapefruit, it was no contest. Both Oroblanco and Melogold won hands down, and one of the tasters remarked that she wondered how she could go back to eating ordinary grapefruit again.

In the contest between Oroblanco and Melogold, five of us preferred Melogold and one favored Oroblanco. The one who opted for Oroblanco thought that there was a slight aftertaste with Melogold. Pehrson acknowledged that a few others had noted the same thing.

Judged Absolutely Superb

The tasters all felt that Melogold was a little juicier, although two tasters felt Oroblanco was sweeter.

Both varieties were judged absolutely superb. In physical appearance, both Oroblanco and Melogold are colored like the typical yellow grapefruit. Melogold, however, has larger fruit than a standard grapefruit.

If you like grapefruit and have room in our yard (there areno dwarf trees yet), I highly recommend either Melogold or Oroblanco. I feel that these are truly the grapefruit of the future. Oroblanco trees are usually easy to locate in nurseries, while Melogold trees are difficult to find at present.

Purchase only healthy, vigorous looking transplants. Avoid trees with long trunks and branches concentrated at the top; the tree should have good skirt branches. If the transplant has any fruit on it, pick it off so the tree’s energies will be devoted to foliage production.

Plant in Sunny Area

Plant your tree in a sunny area and make certain that the grafting union is at least 3 inches above the soil line. Dig a hole twice as wide as the root ball, but only as deep as the tree was originally grown. Plant the tree and refill the hole with the soil you originally removed.

Fertilizer tablets, such as Osmocote Planting Tablets or Jobe’s Tree Spikes, added to the soil at planting time will feed the young tree without burning it. Water thoroughly after transplanting. Wrap the trunk of the new tree with a tree wrap material available at nurseries or paint it with a white latex paint to prevent sunburn.

Irrigate the new tree twice a week, or more frequently during hot weather, then water it on a weekly basis but not as often during late fall and winter. Fertilize in February or March and again in July or August with a general-purpose citrus food. Do not fertilize in late fall. This promotes new tender foliage growth that would be subject to frost damage during the winter.

Depending on your location, Melogold and Oroblanco will be ready for harvest between December and February.