Inhibition of Seed Formation by Anomalous Ovule in ‘Kyo-temari’, a Parthenocarpic Tomato (Solanum lycopersicum L.) Cultivar

Abstract

‘Kyo-temari’, a parthenocarpic tomato cultivar with the pat-2 gene, produces only a few seeds. To elucidate the cause of seed formation restriction in ‘Kyo-temari’, we observed pollen tube elongation and ovule morphology in some parthenocarpic tomatoes. In ‘Renaissance’, a parthenocarpic tomato cultivar with the pat-2 gene, pollen tube elongation was inhibited at the style base; however, in ‘Kyo-temari’, the pollen tubes elongated in the style normally but did not enter the ovules. The percentage of ovules in which a pollen tube entered was 70.4% in ‘Louis 60’, 0.8% in ‘Kyo-temari’, and 5.1% in ‘Renaissance’. From observing transverse sections of ‘Kyo-temari’ ovules, there were many ovules with an abnormal micropyle. Because these anomalous ovules were not observed in ‘Renaissance’, a peculiar factor is considered as the cause of anomalous ovule formation and seed formation restriction in ‘Kyo-temai’.