Abstract
Olea europaea L. is a crop typical of the Mediterranean area that has an important role in economy, society, and culture of this region. Climate change is expected to have significant impact on this crop, which is typically adapted to certain pedo-climatic characteristics of restricted geographic areas. In this scenario, the aim of this study was to evaluate the time-course response of pollen viability to different combinations of temperature and humidity. The study was performed comparing flowering time and pollen functionality of O. europaea from twelve cultivars growing at the same site belonging to the Campania olive collection in Italy. Pollen was incubated at 12 °C, 22 °C, and 36 °C in combination with 50% RH or 100% RH treatments for 5 days. The results highlighted that a drastic loss of pollen viability occurs when pollen is subjected to a combination of high humidity and high temperature, whereas 50% RH had less impact on pollen thermotolerance, because most cultivars preserved a high pollen viability over time. In the ongoing climate change scenario, it is critical to assess the effect of increasing temperatures on sensitive reproductive traits such as pollen viability to predict possible reduction in crop yield. Moreover, the results highlighted that the effect of temperature increase on pollen thermotolerance should be evaluated in combination with other environmental factors such as humidity conditions. The screening of olive cultivars based on pollen thermotolerance is critical in the ongoing climate change scenario, especially considering that the economic value of this species relies on successful fertilization and embryo development, and also that production cycle of Olea europaea can be longer than a hundred years.
Highlights
Climate change will severely impact the Mediterranean Basin with an expected rise in temperatures in the range of 2–5 ◦C [1,2,3]
The screening of olive cultivars based on pollen thermotolerance is critical in the ongoing climate change scenario, especially considering that the economic value of this species relies on successful fertilization and embryo development, and that production cycle of Olea europaea can be longer than a hundred years
The daily relative humidity (RH) values were comparable between the different days, except for a considerable decrease in daily RH values that was recorded from 20 May to 25 May (Figure 1)
Summary
Climate change will severely impact the Mediterranean Basin with an expected rise in temperatures in the range of 2–5 ◦C [1,2,3]. Previous studies have shown that the flowering time of O. europaea is highly dependent on yearly spring temperatures, which are rising steadily over time due to global warming [9,10] In this scenario, the olive phenology may provide useful indications to evaluate the influence of climate change on plant growth for the whole Mediterranean region, since the geographical limits of this cultivation approximately delimit the extent of the Mediterranean climate in Eurasia and North Africa [11,12]. Since the different olive varieties are adapted to specific climatic, edaphic, and lithological conditions, the possible variations occurring in a climate change scenario would have a significant impact on the distribution of these varieties and, on their growth and productivity [13,14] This is especially expected for some old varieties cultivated in narrow geographic niches with specific micro-climatic characteristics [15]. It has been shown that these varieties exhibit greater vulnerability to both short-term climate variability and long-term climate change [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
