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The effect of temperature on olive pollen germination
- Vuletin Selak, G., Goreta Ban, S., Perica, S.
- Acta horticulturae 2019 no.1231 pp. 49-54
- Olea europaea, anthers, cultivars, flowering, genotype, olives, plant breeders, pollen, pollen tubes, temperature
- Temperature is an important factor controlling plant growth and development. The reproductive phase has proven to be one of the most temperature sensitive stages in plants. Pollen grains, once released from anthers, act as independent functional units and are exposed to the ambient environment. Therefore, temperature shifts during flowering may severely affect pollen germination and be correlated with low fertilization. In addition, optimum temperature for pollen germination depends on the species and often varies even between cultivars. In this study, the effect of temperature on pollen performance was evaluated in olive (Olea europaea L.), comparing four cultivars (ʽLeccinoʼ, ʽLevantinkaʼ, ʽOblicaʼ, and ʽPendolinoʼ) as pollen donors. We expected different responses to temperatures between cultivars considering their different origin. Germination was evaluated on germination medium in controlled-temperature chambers after 24 h at 15, 20, 25, 30, and 35°C. Pollen germination range was 4.8-19.6% in ʽLeccinoʼ, 8.1-31.1% in ʽLevantinkaʼ, 4.2-25.4% in ʽOblicaʼ and 7.7-37.9% in ʽPendolinoʼ. A significant quadratic relation between pollen germination and temperature was found for all cultivars. Peak values that indicated optimum temperature for pollen germination varied between cultivars. In general, the increasing temperatures up to 30°C accelerated the pollen tube growth and increased germination rate; however, rates were significantly lower at 35°C with more frequently bursting of pollen tubes. These results indicate differences in genotype response to temperature during the reproductive phase, which could be important information for plant breeders towards producing new tolerant olive cultivars.