Analysis of the mechanism of parthenocarpy in pear fruits

Abstract

Parthenocarpy is the natural or artificially induced production of fruit without fertilization of ovules. It has been revealed that parthenocarpy is regulated in part by the plant hormones, auxin and gibberellin however, the detailed mechanism is still unknown. Since some cultivars of Chinese and European pears were thought to be parthenocarpic, we investigated which cultivars exhibit parthenocarpy, in detail. As a result, 9 out of 27 Chinese pears and 5 out of 8 European pears showed parthenocarpic fruit development. Out of 257 F2 individuals derived from a cross between self-compatible Japanese pear,"Osa-nijisseiki" and a Chinese pear,"Tsu Li", we found that three individuals were parthenocarpic. One of the three individuals showed male sterility, and in the others, seed development was interrupted. We conducted micro array analysis with them, and found that 39 genes were commonly up- or down-regulated as compared to those of the non-parthenocarpic individuals.