Characterization of two new olive genotypes (Olea europaea L.) for Super-High Density Hedgerow Orchards in Argentina

Abstract

To date, only three cultivars of low vigour (‘Arbequina’, ‘Arbosana’ and ‘Koroneiki’) are widely used in “Super High Density” (SHD) (with over than 1500 trees ha−1 ) hedgerow orchards. Of these cultivars ‘Arbequina’ is so far the most widely planted even though the growing interest in SHD plantings is stimulating the selection and the breed of new cultivars. However, after more than 20 years the limited availability of cultivars suitable for SHD olive orchards still remains as one of the main inconvenients. Thus, this study proposes a preliminary chemical characterization of two genotypes developed by INTA - EEA San Juan's breeding program for a SHD model, and to compare their performance vs. ‘Arbequina’. During 2019/2020 growing season, 50 kg of healthy drupes selected from the mid‐canopy of the entire perimeter of the tree were collected, at an optimal stage of ripeness, from two new genotypes and ‘Arbequina’. After homogenization and cleaning, oils from each genotype were extracted using a centrifugation system (dual-phase decanter). Primary and secondary characterization of these genotypes was performed following the IOC methodologies. Tocopherols and fatty acids composition were identified and quantified by HPLC and GC, respectively; while the total phenol content was determined by the Folin–Ciocalteau method. All determinations were done in triplicate. Statistical differences were estimated by ANOVA test at the 5% level (P ≤ 0.05) of significance, for all parameters evaluated, and also a pair-wise comparison of means by least significant difference (LSD) was carried out. As showed on Figure 1 (a), the two new genotypes presented a similar industrial performance that Arbequina; both exhibit slightly lower oil content than Arbequina (Figure 1). Regarding fatty acids profile, and more specifically for oleic acid, CV 31-10 is particularly interesting, since presented significantly higher values than those of Arbequina (Table 1). All oils were classed as “extra‐virgin” according to IOC normative. The concentration of total tocopherols in both new genotypes (CV 31-9 and CV 31-10) showed higher values than Arbequina, and the same tendency was observed for the total phenol content (Table 1). To conclude we can say that both new olive genotype belonging to INTA's breeding program show promising chemical and industrial characteristics in relation to the Spanish cultivar. However, more evaluations will be necessary in the near future (e.g.: vegetative and productive tree characteristics) to prove its adaptability to super high density hedgerow planting system.