Assessing the degree of agreement of breeding objectives priorization between breeders and growers is a key element to orientate the public-sector breeding programs. The results of this study suggest a high correlation between them. Likewise, agreement between these two groups could be also inferred from surveys in apple and peach, although the different set of traits valued difficult the comparison (Gallardo et al., 2012; Yue et al., 2013, 2014b). In fact, breeders significantly valued the importance of producers on their decisions regarding prioritization of some of these traits (Gallardo et al., 2012). A dedicated survey for breeders was not available in our work due to the limited extent of breeding activities in olive. Instead, we gathered results from researchers working in different fields, all of them related to olive growing.

Productivity and disease resistance were identified in this work as the most important objective in olive for both researchers and growers. Similarly, productivity was considered an important trait in producers’ surveys in tart and sweet cherry (Yue et al., 2014a) but not in apple or peaches (Yue et al., 2013, 2014b). Besides, surveys to breeders in several Rosaceous crops showed that fruit texture, fruit flavor, postharvest quality, yield/season, and appearance were all considered of similar relative importance in apple, strawberry, peach, and red raspberry, with only slight differences among crops (Gallardo et al., 2012). However, pairwise comparison produced different results by crop: e.g., flavor was scored higher than yield in apple but the opposite in peach. On the contrary, disease and pest resistance and abiotic resistance were considered less important in all of them; these are quite different results than the one obtained here for olive. Apparently, fruit quality traits are more frequently prioritized in fruit fresh products compared to oil quality extracted from olive fruits. Besides, the high ranking obtained for Verticillium wilt resistance could be expected due the increasing importance over the last two decades of this disease in many areas, among them those provinces mainly surveyed in our work. High estimated crop losses in many areas has probably facilitated higher awareness for this disease among different stakeholders, from growers to nursery companies and the olive-oil industry (López-Escudero & Mercado-Blanco, 2011).

It should be noted that, unexpectedly, traits related to early harvest, usually highly valued both from the agronomic and commercial point of view, seems not to be particularly valued in our work. Early harvest is recommended to lower alternate bearing tendency in olive and allows diminishing the potential risks associated to pest, disease and climatic events (Gracia et al., 2012; Rojnic et al., 2015). Concomitantly, early harvest is associated to higher oil quality both from the compositional and sensorial point of view (Alowaiesh et al., 2018). This could represent market advantages and, therefore, higher returns to growers.

The relatively low importance placed for oil quality components (sensorial traits, oxidative stability, chemical composition) strongly contrast with previous works on other fruit tree species. Thus, fruit flavor and other fruit traits such as crispness, firmness, etc. were scored among the most important trait compared with disease resistance and other fruit or plant traits for apple, cherry and peach producers (Yue et al., 2013, 2014a,b). These results from other fruit tree species seem to be highly in agreement with results from consumer studies, i.e. growers production in these crops is highly oriented to market demands, which, unfortunately, seems not to be the situation in the olive oil sector. Probably, the differential price obtained by growers according to different quality grades in these crops favors a higher consideration for these quality traits by growers. Conversely, the olive oil market suffers from the consumers’ product differentiation failure (Salazar et al., 2018), strongly reducing the demand for higher quality olive oils (extra virgin olive oil compared to refined olive oil) when price gap exceeds only 1 euro/liter (Salazar et al., 2021). Thus, the actual differential price in consumers' choices is usually lower and translates into even shorter differential price in origin received by growers, which altogether does not promote the searching for high quality.

Contrarily to our results, important differences in trait prioritization according to grower and orchard characteristics have been previously reported in other fruit breeding programs. Thus, significant location effect has been previously observed that could be associated to climate differences or differences on market dynamics (fresh vs processed), volume, destination, etc. (Yue et al., 2013; 2014ab). These differences were probably less important between the two main provinces surveyed in our work (Córdoba vs Jaén), which could explain the limited location effect found in our work. Years of experience has also been mentioned as an important variable for trait prioritization suggesting different levels of knowledge for growing techniques such as for instance diseases and treatment options (Yue et al., 2013).

Growers were willing to pay for a new cultivar that fulfill their requirements, although a differential overprice was obtained according to the type of orchard management (dry farming vs irrigated). However, specific willingness to pay surveys including attribute levels for choice experiment should be further designed for gaining deeper knowledge on this subject (Zhao et al., 2017).

With respect to the growers and orchards managers opinion on transgenic (GMO) olive, interestingly, its potential use was approved by a majority (74.5%) of interviewees. It should be noted that transgenic olives are not currently available in the market. Moreover, research lines in this topic in olive are scarce, mainly due to restrictions to GMO at the European Union, even though potentially interesting applications for increasing fungal resistance have been reported in olive (Narvaez et al., 2018).

From a methodological point of view, both assessment methods (rating and ranking) have proven to be comparable (Sayadi et al., 2005; Moors et al., 2016). However, both question formats were applied in the same questionnaire (first rating then ranking a subset of objectives), which may increase the degree of agreement (Moore, 1975; de Chiusole & Stefanutti, 2011).

In summary, the two surveys (to researchers and growers/managers) and two methodologies (ranking and rating) carried out in this study allowed us to assess the importance of 25 breeding objectives. Productivity, resistance to diseases (mainly Verticillium wilt and Xylella fastidiosa) and adaptation to water stress were identified as the most important objectives. Quite similar results were obtained according to different categories of the main orchard characteristics and management practices. Limited importance was awarded to several traits usually considered as high priorities from different socioeconomic, commercial, environmental and political levels; such as for instance those related to olive oil quality or climate change. It should be considered whether a higher effort on knowledge transfer will provide higher conscientiousness by growers on these topics. These results should be considered to analyze the scope of current breeding programs and define the main criteria to be considered for future works aiming at developing new olive cultivars.

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