Washington: Custard apple, or cherimoya —‘the most delicious fruit known to man’ as Mark Twain called it — is all set to go seedless, thanks to the efforts by some American and Spanish plant scientists.
“Going seedless could be a big step for the fruit,” said Charles Gasser, professor of plant biology at UC Davis.
“This could be the next banana -- it would make it a lot more popular,” he added.
The custard apple has lots of big, awkward seeds, but researchers at the Consejo Superior de Investigaciones Cientificas, Spain, studied the seedless variety of sugar apple, a relative of the custard apple and found that the ovules, which would normally form seeds, lacked an outer coat.
It looked similar to the ovules of a mutant of the lab plant Arabidopsis discovered by Gasser`s lab in the late 1990s.
In Arabidopsis, the defective plants do not make seeds or fruit. But the mutant sugar apple produces full-sized fruit with white, soft flesh without the large, hard seeds.
The Spanish team then contacted Gasser, who discovered that the same gene was responsible for uncoated ovules in both the Arabidopsis and sugar apple mutants.
“This is the first characterization of a gene for seedlessness in any crop plant,” said Gasser.
Seedless varieties of commercial fruit crops are usually achieved by selective breeding and then propagated vegetatively, for example through cuttings.
The discovery of this new gene could open the way to produce seedless varieties in sugar apple, cherimoya and perhaps other fruit crops. It also sheds light on the evolution of flowering plants, said Gasser.
Cherimoya and sugar apple belong to the magnolid family of plants, which branched off from the other flowering plants quite early in their evolution.
“It`s a link all the way back to the beginning of the angiosperms,” said Gasser.
The finding appeared in the journal Proceedings of the National Academy of Sciences.