تعيين خودناسازگاري و دوره گرده افشاني موثر در چهار رقم زردآلوي بومي ايران

DETERMINITION OF SELF-INCOMPATIBILITY AND EFFECTIVE POLLINATION PERIOD IN FOUR LOCAL IRANIAN APRICOT (PRUNUS ARMENIACA L.) CULTIVARS

In this research, pollen-incompatibility situation, fruit set percentage in open-pollination and effective pollination period (EPP) were studied in the central climatic conditions of Iran (Gazvin) in four apricot cultivars `Hosseini-e-Karimiʹ, `Shahroodiʹ, ʹNooriʹ and ʹGheisi Isfahanʹ. During the year 2000-2001, several similar branches with flowers at the balloon stage were chosen from each cultivar. The flowers were counted. Half of the branches were protected using a specific bag for natural self-pollination and the other were left for open-pollination. Counting the fruits 8 weeks later, showed that all the cultivars were self-incompatible and fruit set percentage was much higher with open-pollination than self-pollination. During the year 2001-2002 for each cultivar branches with flowers at the balloon stage were selected. The flowers were counted and emasculated. The branches were protected in bags to avoid unwanted pollen contamination. Then, flowers were cross-pollinated with pollen of `Nakhjavanʹ cultivar in days 0, 2, 4 and 6 after emasculation. Fruits were counted 8 weeks later. Results showed that the stigma cannot usually be considered mature at the balloon stage but pistil receptivity reaches its optimum condition between two to four days later and will decrease rapidly thereafter. Therefore, set percentage increased during cross-pollination from day 0 to day 4, and reached its maximum values on day 4 and fell briskly thereafter. The best time for achieving good pollination in breeding programs was days 2 to 4. Also to establish new apricot orchards, it is necessary to use pollinizer cultivars that their anthesis occurring during mean effective pollination period of means cultivar used (day 2 to 4).