Shoot Proliferation, Rooting, and Genetic Stability of Six Micropropagated Olive (Olea europaea L.) Genotypes

This research aimed to explore the effect of zeatin (6-'gamma,'gamma-dimethylallyl-amino) concentration on the in vitro shoot proliferation of six olive (Olea europaea L.) cultivars, 'Aggizi Shami,' Coratina,' Trantoio,Manzanillo,Picual,' and Toffahi.' The six olive cultivars were reproduced via in vitro multiplication on Rugini olive medium (OM) with three zeatin concentrations (2, 4, and 6 mg L-1) for six subcultures. The Aggizi Shami' and Toffahi' cultivars had the highest shoot numbers. Increasing zeatin concentration improved propagation. The best response was recorded for OM supplemented with zeatin at 6 mg.L-1 ; this treatment resulted in high values for the numbers of shoots, leaves, and intemodes. Then, the rooting ability of shoots was analyzed using two different rooting methods. The regenerated shoots were successfully rooted on 1/2OM supplemented with indole-3-butyric acid (IBA), with the 'Coratina' and Picual' cultivars having the highest rooting percentages. The response of shoots to the two rooting methods was genotype-dependent. Rooting in OM with IBA was more successful than dipping in IBA. Based on the shoot growth and rooting potential of the olive cultivars, 'Coratina' and Picuar were the most adaptable cultivars to the in vitro conditions, followed by Trantoio' and 'Manzanillo.' Aggizi Shami' and l'offahi' were recalcitrant cultivars to the in vitro conditions, as they exhibited low rooting potential. After six subcultures, the genetic stability of the six olive cultivars was determined. Manzanillo showed the highest genetic stability index (96%), while Toffahi' recorded the lowest value (85%), based on the start codon targeted (SCoT) data analysis.

Automated summary

This research aimed to explore the effect of zeatin concentration on in vitro shoot proliferation of six olive cultivars and analyze their rooting ability using two different methods. The results showed that increasing zeatin concentration improved shoot propagation and the response to the two rooting methods varied depending on the genotype. Based on shoot growth and rooting potential, 'Coratina' and 'Picual' were the most adaptable cultivars to in vitro conditions.