Micropropagation of three berry fruit species using nodal segments from field-grown plants

Plant micropropagation of blueberry (Vaccinium corymbosum L. cv. Berkeley), blackberry (Rubus sp. cv. Smoothstem) and raspberry (Rubus idaeus L, cv. G radina) was carried out from nodal segments of adult field-grown plants. Ha rdwood and softwood cuttings were studied as explant sources. The cultures successfully established were softwood from all three species, and hardwood only from blueberry. Shoot-bud establishment from blueberry was achieved b y culturing explants in WPM salts with MS vitamins for 15 days, and then 30 days in the same medium with 18 mM Zeatin. The best results of multiplicat ion were obtained in the same medium with 25 mM 2iP. For blackberry, shoot- bud establishment was achieved by culturing explants in MS medium for 15 da ys, and then in the same medium with 4 mM BA and 0.25 mM IBA. This medium w as also the best for blackberry multiplication. Raspberry explants (cvs Gra dina and Willamette) were cultured in MS medium for 15 days and then transf erred to MS medium supplemented with 4 mum BA and 0.25 mM IBA. After 30 day s of culture, only 'Gradina' explants survived, from which shoot-bud establ ishment was obtained in a modified MS medium (Anderson's macronutrients exc ept calcium, with Sequestrene as the iron source) with the same growth regu lators. Multiplication was achieved by subculturing explants in the same me dium either with 4 mM BA plus 0.25 mM IBA or with 8 mM BA plus 0.25 mM IBA. Shoots of at least 1 cm in length from all species were rooted ex vitro in a mixture of peat and Perlite (1:1, v/v) in a mist chamber, and 100% of ro oting plants were acclimated. Bacterial, fungal and viral diseases were det ected in stock plants, while tests carried out in both shoots and regenerat ed plants revealed the absence of any kind of disease.