In vitro dormant bud break and leaf-based regeneration for efficient pear micropropagation and novel breeding strategies

In vitro bud break methods have gained recognition as rapid and efficient means of introducing and multiplying plant material, particularly for fruit tree species. Moreover, the exploration of alternative approaches for adventitious bud regeneration is of significant interest in the context of innovative breeding strategies. One such approach involves utilizing leaves collected from field material, providing an alternative to the conventional use of micropropagated plants. In this study, we aimed to evaluate the effectiveness of in vitro dormancy release techniques for several pear cultivars, by assessing their potential for micropropagation and investigating the feasibility of regenerating adventitious buds from field-derived leaves tissues. Young green sprouts from ten pear cultivars (‘Abbé Fétel’, ‘Passe Crassane’, ‘Williams Bon Chretien’, ‘Max Red Bartlett’, ‘Doyenné du Comice’, ‘Sanguine d’Italie’, ‘Cocomerina Precoce’, ‘Cocomerina Tardiva’, ‘Conference’, ‘Old Home’) and five breeding lines were collected in late spring from adult trees. After disinfection, the sprouts were divided into uni-nodal segments and placed on a solidified medium enriched with growth regulators. The results revealed significant variations in the response of different pear cultivars and breeding lines to the in vitro conditions, with ‘Abbé Fétel’ exhibiting the highest bud break rate. Furthermore, these leaves were used to investigate regeneration efficiency when cultured on a specific regeneration medium. Various degrees of successful bud formation were observed, with certain cultivars displaying higher rates of regeneration than others. These findings provide valuable insights into the potential of utilizing field leaf explants for adventitious bud regeneration in pear micropropagation, and their applicability to new breeding techniques. The combination of in vitro dormant bud break and leaf-based regeneration techniques offers alternative pathways for the mass multiplication of pear cultivars and breeding lines.