In vitro Pollen Grain Germination and Tube Growth of Ten Iranian Jujube (Ziziphus jujuba) Cultivars

Abstract

Jujube (Ziziphus jujuba) is a species particularly prone to erratic fruit set. Several causes such as pollen germination and tube growth involve in this behaviour. Thus, the present research aimed to evaluate and compare of pollen grains germination and tube growth of ten Iranian jujube cultivars on in vitro condition. A factorial trial based on completely randomized design with five replications was carried out. The pollen grains were collected from un-opened-flowers of Al-Ghour’, ‘Bardaskan’, ‘Doroh’, ‘Gazik’, ‘Ghom’, ‘Giouk’, ‘Kangan’, ‘Kalkestan’, ‘Magham Sari’ and ‘Noghab’ cultivars at balloon stage. This study showed that there were significant differences among the cultivars in all measured factors. The highest percentage of pollen grains germination was observed for ‘Gazik’, followed by ‘Bardaskan’, while the lowest was in ‘Al-Ghour’. The percentage of pollen grains germination increased with the increasing time of incubation period up to 36 h. Also, flowering times are found to be effective in germination of pollen grains, which 1 flash had highest percentage of germination of pollen grains than in comparison to other flowering times. The results also showed that the mean time germination varied from 24.52-25.92 h, mean hourly germination from 0.67-1.55, hourly germination speed from 0.64-1.48 and coefficient of velocity of germination of pollen grains from 0.058-0.061. The length of pollen tube was found between 44.4 and 624.8 µm. These data demonstrated that cultivar is the main factor determining pollen grains germination and tube growth in jujube, which this important information can be useful for selection of superior desirable jujube genotypes for bringing to commercial cultivation.