Research on Crops

The objective of this work was to assess the pollen viability, the pollen capacity (germination and tube growth) and the rate of fruit set in 19 cultivars of olive trees field-grown in Chott Mariem (Tunisia) after self-and free-pollination treatments during two seasons 2012 ('on'year) and 2013 ('off ’year). The pollen viability ranged from 60.5% for ‘Meski ’to 88.85% for ‘Gerboui ’during 2012 ('on'year) and between 97.47% for ‘Chetoui ’to 62.38% for ‘Meski ’in 2013 ('off ’year). All the cultivars increased their values of viability and germination during 2013 comparatively to 2012, with important consequences on the fertilization process measured by the initial fruit set rate. Concerning the pollination treatments, generally, the free-pollination improved fruit set when compared with self-pollination, especially for ‘Meski ’. However, a non-pollination of ‘Ascolana ’and ‘Tounsi ’was observed with all pollination modes and during the two years in Chott Mariem. Our results showed a high correlation between the rate of fruit set after self-and free-pollinations during the two years of study 2012 and 2013 (respectively, r²⁼ 0.74 and 0.65). This study highlights some major remarkable differences among cultivars in terms of pollen abilities. In general, concerning the pollination efficiency of olive cultivars, the pollen viability can be an important characteristic to be considered as an indicative parameter of pollen development and functionality. Finally, this is a topic of particular importance for large-scale isolated plantings and in choosing the cultivars in new olive groves plantations.