The effect of cross-pollination on yield and quality of pitaya (Hylocereus spp.)

Pitaya is a new species for Turkey; however, the number of pitaya orchards has increased due to several reasons such as it yields fruits one year after planting, it has an attractive appearance, it is sold for high prices, there is no production surplus, and there is an export opportunity. The increase in the number of orchards has revealed that there have been scientific deficiencies in orchard establishment, pollination biology, cultural practices, and conservation. Therefore, the aim of this study was to determine the most appropriate pollinator cultivar (s) and pollination time for the 'Bloody Mary' (Hylocereus polyrhizus) which is a self-incompatible variety that has been adapted to the conditions in Turkey. Moreover, the germination status of the seeds in each pollination combination was also revealed to provide a basis for future breeding studies. In the study, the following pitaya cultivars were used as a pollinator: 'Cosmic Charlie' (Hylocereus undatus), 'Red Jaina' (Hylocereus polyrhizus) and 'White Jaina' (Hylocereus undatus). Also, the following pollination times were tested: 22.00, 24.00, and 06.00. In the study, the parameters of fruit set ratio, fruit development time, physical properties of the fruit (fruit weight, width, height, skin thickness and fruit flesh hardness), the number of seeds, water-soluble solid content (TSS), the color of the peel and the flesh of the fruit were examined. After harvesting the fruits, the germination rate, average germination time, germination energy, and germination index were determined for each pollination combination after sowing. The results of the study have revealed that the fruit set ratio varied based on the pollinator cultivars. While the varieties of 'Red Jaina' and 'White Jaina' showed a fruit set ratio of 100% for all pollination times, the variety of 'Cosmic Charlie' showed a fruit set ratio of 42%. The optimum pollination time for the fruit set was determined as 24.00, and it was followed by 06.00. While the fruit weight differs according to pollinator cultivars, it was not affected by pollination times. The highest fruit weight was obtained from the pollination with the 'Red Jaina' variety at 22.00, while the lowest fruit weight was obtained from the pollination with the 'Cosmic Charlie' variety at 22.00. While pollinator varieties were found to affect the physical properties of the fruits, pollination time did not cause any difference in the physical properties of the fruits The values of the highest fruit width and length were obtained from pollination with 'Red Jaina' variety at 22.00. It has been determined that there is a correlation between the fruit size and the number of seeds, and the highest number of seeds was obtained from the pollination with the 'Red Jaina' variety, as in the case of the fruit size. The highest water-soluble solid content (17.14%) was obtained from 'Red Jaina' variety with the pollination at 22:00, as in the case of fruit weight, while the lowest value (12.73%) was obtained from 'Cosmic Charlie' with the pollination at 06.00. It has been determined that the pollinator variety and pollination time affected the chroma (C*) value of the color of the peel. On the other hand, it was determined that the pollinator cultivars did not affect the Hue (h) angle value of the peel color, however, only the pollination times affected it. It has been determined that the pollinator variety and pollination time affected the chroma (C*) value of the color of the fruit flesh, as in the case of the color of the peel. Fruits with the darkest flesh color were obtained from the pollination with the 'Cosmic Charlie' variety, and it was followed by the varieties of the 'Red Jaina' and 'White Jaina'. The germination rate was found to be 100% in all combinations of different pollinator varieties and pollination times. On the other hand, the germination time, germination energy, and germination index were found to differ based on the pollinator cultiavars and pollination times. According to the results of this study, 'Red Jaina' and 'White Jaina' were determined as the most suitable pollinators for the Bloody Mary cultiavars. The most suitable pollination times in terms of fruit set, fruit size, and fruit quality were found to be 22.00 and 24.00. Although the species of the pollinator varieties of 'Cosmic Charlie' and 'White Jaina' are different from the main cultivars, cross-pollination did not create a problem in terms of seed germination.This has been found promising for the future crossbreeding studies in pitaya.