Study Of Pollen Storage, Germination And Pollen Tube Growth Of Some Citrus Cultivars

Considering the importance of citrus breeding programmers for releasing new cultivars to the citrus industry, the present research was carried out in order to explore the best method of pollen preservation and storage. Long-term pollen storage was sudied on pollens from matured citrus cultivars including Shell-Mahalleh, Yuzu, Troyer and Citromelo. Experimental design used, was a factorial design with two factors based on Randomized Complets Block Design with 3 replications. Factor one was 3 methods of storage (room temperature, refrigerator and freezing) and the second factor was 4 mentioned cultivars. In vitro viability test was performed on pollens after 7, 15,30,60 and 140 days storage at room temperature (+25 °c), refrigerator (+4 °c) and freezer (-18°C). Results based on analysis of variance of data showed significant differences at 1% level between the effects of treatments of storage methods, cultivars and interactions between two factors. Control treatment (fresh pollen) and 7 days storage treatment at freezer showed highest germination percentage (38.77% and 26.93% respectively) and classified in groups a and b respectively. In addition, among studied cultivars Shell-Mahalleh and Yuzu showed 18.94% and 15.49% germination and grouped in classes a and b respectively. Interaction effects of control x Shell-Mahalleh, control x Yuzu, 15 days storage in freezer x Yuzu and 7 days storage in freezer x Shell-Mahalleh showed 50%, 46%, 42% and 36% germination and located in groups, a, b, c and d respectively. Also results from 140 days pollen storage of Shell-Mahalleh cultivars showed 22.2%, germination in the viability test assay. Considering the amount of pollen germination decreased with prolonging of pollen storage period, this finding is very important in citrus breeding programs.