Parental Effect on Agronomic and Olive Oil Traits in Olive Progenies from Reciprocal Crosses

1 Agronomy Department, University of Cordoba (UCO), 14005 Cordoba, Spain; [email protected] (H.M.);[email protected] (M.A.); [email protected] (C.T.)2 Santa Cruz Ingeniería S.L., 41018 Sevilla, Spain3 Hellenic Agricultural Organization ELGO-DIMITRA, Institute for Olive Tree Subtropical Cropsand Viticulture, 73134 Chania, Greece; [email protected] Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University,60121 Ancona, Italy* Correspondence: [email protected] or [email protected]† The authors have contributed equally to this work.Abstract: Olive growing is undergoing a transition from traditional cultivation systems to a moretechnological model characterized by increased mechanization and a higher density of plants perhectare. This shift implies the use of less vigorous varieties that can adapt to the new system.Most traditional varieties are highly vigorous, and breeding programs can provide solutions tothis challenge. This study investigates the parental effect on different agronomic and olive oilcharacteristics and its role in breeding programs. The objectives were to evaluate and characterizedifferent agronomic and olive oil traits in the progenies from ‘Arbosana’ ‘Sikitita’ cross and itsreciprocal cross ‘Sikitita’ ‘Arbosana’. The results showed a high variability of the charactersevaluated in the progenitors of the reciprocal crosses. The highest coefficients of variation wereobserved in traits related to ripening index, phenolic compounds, polyunsaturated fatty acids, andD5-avenasterol, with phenolic content exhibiting the greatest variability. No statistically significantmaternal effect was detected for any of the evaluated traits, although a slight positive maternal effectwas systematically observed in the mean values of the evaluated traits. These results suggest that thematernal effect on olive is quite subtle, although due to a slight tendency of the maternal effect in thedescriptive analyses, future studies are suggested to understand in depth the possible maternal effecton olive breeding.