In vitro multiplication of pear tree cultivar Cascatense

Abstract

One main obstacle to the development and expansion of pear tree cultivation in Brazil has been the lack of cultivars adapted to the edaphoclimatic conditions of regions with the potential for pear production. Intending to overcome this hindrance, Embrapa Clima Temperado (Embrapa Temperate Climate) developed and released the cultivar Cascatense, with a low cold requirement (~400 h) better suited for Rio Grande do Sul`s and Santa Catarina`s climate. Still, seedlings of high genetic and sanitary quality are necessary for the establishment of a high-yield orchard. Plants with both sanitary quality and uniformity can be obtained through in vitro micropropagation. Thus, the present study aimed to assess the influence of different culture media (MS, MS¾, WPM, QL, and Himédia), concentrations of sucrose (0, 15, 30, 45, and 60 g L-1), and concentrations of benzylaminopurine (BAP) (0, 0.4, 0.8, 1.2, and 1.6 mg L-1) upon the in vitro multiplication of cultivar Cascatense, to establish an efficient protocol to enhance its propagation and reproducibility. The study included three sequential experiments in which the number of shoots per explant, the length of shoots, the number of axillary buds per shoot, fresh mass, and dry mass of shoots were evaluated. Cultivar Cascatense can be best propagated in vitro with the use of Himédia medium, supplemented with 0.8 mg L-1 of BAP and 30 g L-1 of sucrose.