Dormancy release dynamics in olive tree (Olea europaea L.) reproductive buds as affected by cold accumulation, tree bearing status, and budburst temperature was studied under natural and controlled conditions, using both cuttings and container- and field-grown plants. The chilling necessary for dormancy release was acquired at different times within the bud population, presenting a progressive pattern of reproductive budburst. Once sufficient chilling is accumulated, 20 °C is a suitable temperature for reproductive budburst, although higher temperature, e.g., 30 °C, during dormancy release can inhibit budburst. While the bearing status of trees determined the amount of return bloom, dormancy release followed a similar pattern for previously bearing and non-bearing trees. Concurrent with investigating budburst factors, the use of shoot cuttings was tested as a method for olive dormancy release studies by contrasting with results from whole trees. It was found it to be valid for studying reproductive budburst, thus providing a useful method to screen chilling requirements in cultivar evaluation and the breeding programs currently ongoing in this species. However, the method was not valid for vegetative budburst, with varying results between cuttings and the whole plant.

Trendy high-density olive fields are often monovarietal orchards, mostly using the cultivar Arbequina. However, Arbequina shows a strong self-incompatibility response, and its yields depend on wind cross-pollination, which is not always available. With the aim of finding suitable self-compatible cultivars that can replace Arbequina, we evaluated pollen–pistil interaction, fruit set and seed paternity in Arbosana under different pollination treatments: self-pollination, open-pollination and three cross-pollination treatments: × Arbequina, × Sikitita and × Koroneiki. All these cultivars are low-vigor cultivars suitable for high-density orchards, making them potential pollinizers for Arbosana. The results show that Arbosana is also self-incompatible with a strong reduction in fruit set due to a lower fertilization level caused by a strong inhibition of pollen tube growth in self-pollinated flowers. Seed-paternity analyses confirmed the self-incompatibility response of Arbosana and suggest that some fruit obtained in bagged shoots under self-pollination were, in fact, a product of cross-fertilization. In conclusion, we recommend against the use of Arbosana in large monovarietal orchards. On the contrary, good results were obtained under cross-pollination with Sikitita, Arbequina and Koroneiki pollen, allowing us to recommend them as pollinizers for Arbosana in appropriate pollination designs. This is the first time Arbosana self-incompatibility has been reported.

Backcrossing between Sikitita and its male parent Arbequina, offers the possibility to check the suitability of different self-incompatibility models proposed for olive. To determine Sikitita’s response to self- and cross-pollination treatments, including pollination with its father Arbequina, we compared the parameters following pollen–pistil interaction, the resulting initial and final fruit set, and the paternity of the seeds produced under different crosses. The results showed that Sikitita behaves as a self-incompatible cultivar due to the inhibition of pollen tube growth in the pistil of self-pollinated flowers. This incompatibility reaction led to a significant reduction of self-fertilization and fruit set. Seed paternity analyses confirmed the self-incompatibility response of Sikitita. A similar incompatibility response was observed in Sikitita flowers when hand-pollinated with pollen of Arbequina and Koroneiki. On the contrary, cross-pollination with Arbosana gave excellent results, with analyses showing that pollen of Arbosana is largely preferred by Sikitita to father its seeds more than the pollen of other cultivars presented in the orchard. The backcross failure of Sikitita with Arbequina pollen suggests that the self-incompatibility system in olives is not of the gametophytic type. In contrast, pollination tests fit features of previously reported sporophytic self-incompatibility systems. However, some amendments are proposed, among them the incompatibility groups for Sikitita and Koroneiki.

Anthracnose, the most critical fruit disease affecting olive crops, necessitates the evaluation of the susceptibility of traditional and new varieties. In Spain and Portugal, anthracnose is caused by several Colletotrichum species, with C. godetiae and C. nymphaeae being dominant and C. acutatum and C. fioriniae being secondary. This study explores the susceptibility of fruits from an F₁ progeny resulting from a cross between ‘Picual’ (resistant) and ‘Arbequina’ (moderately susceptible) cultivars to C. godetiae. While most genotypes showed resistance levels comparable to their parents, seven showed a 50% reduction in disease severity compared with ‘Picual.’ The normal distribution of genotypes’ response to the pathogen suggests a complex resistance mechanism. Furthermore, we assessed the susceptibility of four traditional cultivars, two new cultivars (‘Sikitita-2’ and ‘Martina’), and five advanced selections (pre-commercial genotypes) to C. godetiae and C. nymphaeae. Despite the significant interaction between the olive genotype and Colletotrichum species in this experiment, the new cultivars and advanced selections were classified as susceptible or moderately susceptible against both species. A subsequent analysis of the interaction between ‘Picual’ (resistant) and ‘Hojiblanca’ (susceptible) fruits with the four mentioned Colletotrichum species revealed significant differences among cultivars but no interaction between genotype and pathogen species. Colletotrichum species were categorized as follows: (i) C. godetiae and C. nymphaeae as highly virulent, (ii) C. acutatum as moderately virulent, and (iii) C. fioriniae as weakly virulent. Finally, C. nymphaeae exhibited an enhanced ability to infect and develop acervuli in olive leaves, potentially serving as an inoculum source for this species. The absence of a correlation between leaf and fruit susceptibilities to the pathogen suggests differences in resistance mechanisms. In conclusion, this study provides valuable insights into the complex interactions between olive genotype and Colletotrichum species, essential for cultivar selection and understanding the disease cycle.

The common fig (Ficus carica L.) is susceptible to mycotoxin contamination, raising food safety concerns given the strict maximum levels for aflatoxins (AF) and ochratoxin A (OTA) established by Regulation (EU) 2023/915 for dried figs. We characterized the susceptibility of three commercially relevant cultivars from the Jerte Valley (‘Calabacita’, ‘Cuello Dama Blanco’, and ‘Granito’) to Aspergillus section Flavi colonization under controlled and orchard conditions. These findings were integrated with an industry surveillance dataset (2014–2023; 326 batches), with cultivar comparisons restricted to the comparable period 2020–2023 (184 batches), from a local fig-processing cooperative. Under controlled inoculation, ‘Calabacita’ consistently showed the highest internal colonization and proportion of figs colonized, whereas ‘Granito’ showed the lowest values. Sealing the ostiole reduced colonization across cultivars and abolished cultivar differences, thereby supporting the ostiole as the primary entry route. Fruit susceptibility increased with fruit size across all three cultivars. Dry conidial inoculation, emulating natural airborne spread, resulted in substantially higher colonization than inoculation with an aqueous conidial suspension, both in severity (100% vs. 3.7%) and incidence (100% vs. 7.3%). Orchard assays were consistent with the controlled inoculation results: ‘Calabacita’ showed higher section Flavi colonization than ‘Cuello Dama Blanco’ and ‘Granito’, which did not differ from each other. Fruit position did not affect colonization by section Flavi, but it significantly affected colonization by section Nigri, which was higher in dropped fruits across cultivars. AF-OTA co-occurrence was restricted to ‘Granito’ (3 batches; 2.6%) and was absent in ‘Calabacita’. Surveillance data (2020–2023) were consistent with the experimental findings. ‘Calabacita’ showed predominantly AF-related non-compliance (with AFB₁ and AFTA exceedances reaching 25.7%), whereas ‘Granito’ showed higher OTA exceedance (10.5% vs. 1.4%), reflecting distinct contamination profiles between cultivars. This study informs AF and OTA management strategies in dried figs based on cultivar susceptibility profiling, prescreening systems prior to commercialization, and reduction in fruit–soil contact during drying.

Olive reproductive phenology depends on the balance between winter chilling and subsequent heat accumulation, yet multi-environment Mediterranean observations to assess this dynamic across thermal regimes remain scarce. We monitored Full Budburst (FB) and Full Flowering (FF) during 2021–2024 in 670 cultivars across five germplasm banks in Greece, Italy, Morocco, Spain, and Türkiye. Median dates, periods, dispersion, and phenological stage overlap were related to bioclimatic factors and chilling and heat accumulation. The influence of the germplasm-bank environment, year, and their interaction on the timing of both stages was assessed. The Median Full Budburst (FB₅₀) and Median Full Flowering date (FF₅₀) were strongly correlated. Likewise, budburst dispersion (ID_bb) was positively associated with flowering dispersion (ID_ff), serving as descriptive indicators of phenological synchrony under varying thermal regimes. Warmer conditions between FB₅₀ and FF₅₀ were associated with a shorter transition to flowering. Conversely, warmer pre-budburst conditions and lower chilling accumulation were associated with greater budburst and flowering dispersion and reduced synchrony. These findings indicate that budburst provides an important temporal reference for flowering. Integrating budburst and flowering dispersion with transition gap (T_gap) metrics offers a quantitative framework for characterizing population-level phenological responses under contrasting thermal regimes and enhancing future olive breeding programs.