CAN WE DEVELOP SELF-FERTILE FRUIT TREES THROUGH GENETIC ENGINEERING?

Fruit production in many fruit tree species is dependent on cross-pollination between varieties.
This is caused by the existence of a self-incompatibility mechanism that prevents fertilisation if pollen and style bear the same S-locus specificity.
In some species, such as sweet cherry and apricot, self-fertile varieties have been produced by mutagenesis and breeding.
The aim of this long-term study was to investigate if the knock-out of one of the pistil S-alleles through genetic engineering results in self-fertility.
Plants of the strongly self-incompatible apple cultivar Elstar were transformed with different S-allele knockout constructs.
During two subsequent years controlled pollination tests were carried out on the different transgenic lines to determine the strength of their self-incompatibility system.
Here we show the results of six transgenic lines bearing an antisense knockout construct.
In three lines, the self/cross fruit set ratio was approximately 1, which indicates that the self-incompatibility mechanism in these lines is switched off.
Besides these completely self-fertile lines, also a moderately self-fertile line, characterised by intermediate levels of self-fertilisation, was obtained.
These results indicate that different levels of self-fertility may be obtained through genetic engineering.

VIII International Symposium on Pear

I. Van Nerum, J. Keulemans, W. Broothaerts

Malus x domestica, apple, self-incompatibility, fruit set, seed set, self-fertility

https://doi.org/10.17660/ActaHortic.2002.596.17