Effects of Various Plant Growth Regulators on in vitro Propagation of “Chester Thornless” Blackberry Cultivar

Rubus species are highly heterozygous and therefore when they are propagated by seeds the high plant variability is obtained. Generative propagation is not suitable for production of true to type plants for commercial cultivation of selected cultivars. Micropropagation methods became very important and have many advantages compared to the classical propagation methods. In Turkey, blackberries are commonly propagated by hard and soft wood cuttings, by layering and bush division. Propagation by layers requires rather large area for a layerbed, and weed control among the layers is a problem. However, propagation by cuttings is connected with important problem in inadequate rooting, especially in ‘Chester Thornless’ variety which is one of the most commercially grown variety. In addition, limited number of plants can be propagated using classical propagation method and thus demand of growers for the plants can not be satisfied. In vitromicropropagation is an important tool for clonal multiplication and is commonly applied for induction of somaclonal variation to create genetic variability. Optimized and highly efficient regeneration protocols are also important for genetic transformation for improving of new cultivars.This study was focused on optimization of protocol for in vitro propagation of ‘Chester Thornless’ blackberry cultivar using nodal segments. For this purpose, explants were cultured on Woody Plant Medium (WPM) supplemented with combination of plant growth regulators BAP (1.5,2,3 mg/l) with NAA (0,0.1,0.2,0.4 mg/l) to detect the best multiplication medium. For the rooting, different concentrations of IBA and NAA (0, 0.1, 0.2 and 0.4 mg/I) were compared. A concentration of 0.4 mg/l NAA gave the greatest number of roots and maximum root length.