Micropropagation of Saskatoon berry (Amelanchier alnifolia Nutt.)

Merala (Amelanchier alnifolia Nutt), bobičasta je voćna kultura s područja Sjeverne Amerike. Izgledom ploda podsjeća na američku borovnicu, ali prema nutritivnim vrijednostima bolja je od nje. Radi se o voćnoj vrsti koja je adaptabilna našem uzgojnom području i ima veliki gospodarski potencijal. Merala se razmnožava vegetativno, a u novije vrijeme koristi se mikropropagacijska tehnika. Stoga je cilj ovog rada bio ispitati učinke agara, citokinina, PPM-a i giberelinske kiseline na uspješnost mikropropagacije merale. Za uspostavu kulture korišteni su vegetacijski vršci veličine 1-1.5 mm izolirani iz aksilarnih pupova. Dobiveni izdanci korišteni su u daljnjim pokusima. Agar (Plant agar) kao komponenta hranidbenog medija imao je značajan efekt na mikropropagaciju merale. Kako bi se utvrdila optimalna koncentracija hormona rasta korišteni su 6-benzilaminopurin (BAP) i meta-topolin (mT) u koncentraciji od 0.3 i 1 mg/L te medij bez hormona (HFM). Prosječno najveći broj izdanaka (3.1), uzimajući u obzir obadvije koncentracije hormona, postignut je na mediju s mT. U dužini izdanaka nije bilo signifikantne razlike obzirom na vrstu citokinina, ali su signifikantno duži izdanci dobiveni na nižim koncentracijama (0.3 mg/L) citokinina. Kao najbolji tretman (citokinin x koncentracija) za broj izdanaka pokazao se je MS s 1 mg/L mT na kojem je dobiveno 4.7 izdanaka po eksplantatu. Giberelinska kiselina nije značajni faktor za povećanje broja izdanaka, ali nešto bolji rezultati postignuti su na koncentraciji 0.2 mg/L GA3. Antibiotsko sredstvo PPM nije pokazalo značajan utjecaj na mikropropagaciju merale. Uz razmnožavanje, najveći problem mikropropagacije merale je zakorjenjivanje in vitro izdanka. Postotak zakorjenjivanja izdanaka bio je 28% na MS s 2 mg/L NAA.The Saskatoon berries are fruit species from North America. The shape is similar to a blueberry, but the nutrition value is better than blueberry. Saskatoon berries are adaptable to our production area and have huge economic potential. Most common method for propagation of Saskatoon berry is vegetative propagation but micropropagation is used as well. The aim of this work was to investigate the effects of agar, cytokinin, PPM, and gibberellic acid on the success of micropropagation of Saskatoon berries. We have been using shoot tips (1-1,5 mm) isolated from axillary buds for culture establishment. Micropropagated shoots of Saskatoon berries were used in further experiments. Agar (Plant agar) as a component of MS medium had a significant effect on the micropropagation of Saskatoon berry. To determine the optimal concentration of growth regulators we used 6- benzylaminopurine (BAP) and Metatopolin (mT) in the concentration of 0.3 and 1 mg/L and medium without hormones (HFM). Average of highest number of shoots (3.1), considering both concentrations of hormones, was at MS with mT. There was not a significant difference in the length of the shoots considering a type of cytokines. In the length of the shoots, there was not significant, but significant longer shoots were on lower concentration (0.3 mg/L) of cytokinins. As the best treatment (cytokinin x concentration) for a number of shoots was MS with 1 mg/L of mT and they produced 4.7 shoots per explant. Gibberellic acid was not a significant factor for the number of shoots, but better results were at 0.2 mg/L of GA3. Also, biocide (PPM) was not significant in this research. Along with shoot proliferation, the greatest problem of micropropagation is in vitro shoot rooting of Saskatoon berry. Percentage of rooting was 28% on MS with 2 mg/L NAA