A Study of Self and Cross-Compatibility in Some Commercial Cultivars of Peach in Karaj Climatic Conditions

The present research was conducted with the purpose of studying self and cross-compatibility in some commercial cultivars of peach through field and microscopic studies in order to increase the quantity and quality traits of the product. The study was carried out in years 2010 and 2011. In a first experiment, the pollen germination of 10 cultivars of peach was studied in culture medium. The results showed that the pollen from all cultivars, except that from G.H.Hale had sufficient germination. The highest percentage of pollen germination belonged to Suncrest with 91.85% and the lowest to G.H.Hale with a germination rate of 0%.In the second experiment, the effect of self and open pollination on fruit set in 9 cultivars (Red Haven, Springcrest, Early Red, Early Gold, Suncrest, Dixi Red, Anjiri, Spring Time and Elberta) were investigated. The results showed that fruit set, following open pollination (at all the three counting stages) was higher than fruit set, resulting from self-pollination, indicating that self-pollination significantly reduces the fruit set. In addition, in third counting stage (80 days past from pollination), the highest level of fruit set of 24.96%, belonged to Spring Time, while the lowest of 14.93%, to Anjiri peach. In a third experiment, the effect of self pollen and three types of cross pollen on the level of fruit set were studied. The results revealed that in all the four treatments, the level of fruit set from self pollination was higher than that from cross pollination. In a fourth experiment, a microscopic study, flowers were harvested and fixed in F.A.A. solution within 24, 48, 72, 96 and 120 hrs after self and cross pollination. Results showed that 24, 48 and 72 hrs were not enough times for pollen tube to reach the base of the style, but 96 and 120 hrs were suitable time intervals. The number of pistils having pollen tubes at the base of their style increased for 120 hrs following self and cross pollination in some of the crosses as compared with 96 hrs following self and cross-pollination. Results finally indicated that in some crosses, 96 hr and in others 120 hr. past self and cross-pollination, were the proper time intervals for pollen tube to reach the base of the styles.