Agronomic evaluation of seedlings from crosses between the main Spanish olive cultivar ‘Picual’ and two wild olive trees

Abstract

SummaryUntil recently, olive breeding programmes have been based exclusively on cultivated olive germplasm (Olea europaea subsp. europaea var. europaea), in contrast to breeding in other fruit crops where the use of wild relatives has been widely reported. In this study, ten agronomic traits were evaluated in two progenies derived from controlled crosses between the Spanish olive cultivar ‘Picual’ (female) and two wild (O. europaea subsp. europaea var. sylvestris) genotypes (males). The results of this evaluation were compared with the progenies of crosses between ‘Picual’ (female) and the three cultivars, ‘Sikitita’, ‘Meski’, and ‘Zaity’ (male). The two ‘Picual’ × wild genotype progenies had the highest mean values for vigour traits (i.e., tree height and trunk diameter). Progenies from both ‘Picual’ × wild genotype crossess also showed the highest percentages of trees (53.8% and 37.5%) with a short juvenile period, compared to the progenies from crosses between ‘Picual’ and each of the three cultivars ‘Sikitita’, ‘Meski’, and ‘Zaity’ (0%, 5%, and 3.6%, respectively). Significant differences were also observed between progenies in fruit traits as well as in oil contents and fruit weights. Progenies from both crosses with wild olive showed lower values for the fruit traits evaluated than the cultivated olive progenies. However, significant improvements were achieved compared to fruit traits in the wild parents. The implications of these results for the future use of wild germplasm in olive breeding programmes are discussed.