Self-compatibility in ‘Truoito’ Almond and the Effect of Temperature on Selfed and Crossed Pollen Tube Growth

Abstract

Abstract The level of fruit set of ‘Truoito’ almond from hand self-pollination was high (47.7% and 56.8% in 1982 and 1983, respectively) and similar to the fruit set from hand cross-pollination. Fruit set in bagged branches excluding pollinators (honey bees and wind) was high and similar to that from open pollination (38.0% and 40.0%, respectively). Effective self-pollination occurred without pollinators because the stigmatic surface was adjacent to the anthers, in contrast to other cultivars examined in which the stigma was above the anthers. Pollen tube growth in self-pollinated styles was faster than in those cross-pollinated at 10° and 15°C, but similar at 20° and 25° and slower at 30°. Inhibition of pollen tube growth occurred at 30° in 45% of the selfpollinated styles. Optimum temperatures for ‘Truoito’ pollen tube growth in either selfed or crossed styles were between 20° to 25°, and 54 hr elapsed before tubes reached the base of the style after pollination. Pollen tube growth under field conditions was similar in both selfed and crossed styles.