MICROPROPAGATION OF POINSETTIA (EUPHORBIA PULCHERRIMA WILLD)BY TISSUE CULTURE TECHNIQUE

Abstract

This study was run in laboratory of plant tissue culture belonging to the Horticulture Department, College of Agricultural Engineering Sciences at University of Duhok, North Iraq Region during the periood from November 2021 to June 2022. The main objective was to develop a authentic microprogation protocol for the ornamental poinsettia plant Euphorbia pulcherrima Willd. The main achieved results can be summarized as follows: Mercuric chloride approved to be the best option after failing to get rid of contamination by using the traditional disinfestation method by sodium hypochlorite. Thus, about 100% healthy cultures were obtained from both kinds explants tested. At shoot multiplication stage, the addition of BA is highly beneficial to raise the values of multiplication parameters as compared to treatment. But, no statistical differences were recorded between the dissimilar concentrations of added BA. The highest number of shoots per explant (2.62 shoots/ explant) and the longest shoots (2.16 cm) were achieved from the addition of 1.0 mg.l-1 BA. The highest number of leaves (20.41 leaves/ explant) was recorded from the addition of 2.0 mg.l-1 BA. Kinetin also was effective while adding dissimilar concentrations to the culture medium as compared with the control. Since, adding 1.5 mg.l -1 of kinetin generated the highest number of shoots and leaves (3.63 shoots/ explant and 18.03 leaves/ explant) respectively. Whereas, the control treatment gave the longest shoots reaching 2.03 cm as compared with 0.58 cm which was recorded for 1.5 mg.l-1 kinetin. Mostly, BA was more effective that kinetin in regard of number of leaves and mean length of shoots. Whereas, kinetin performed much better than BA in regard of number of shoots. At rooting stage, Adding 0.2 mg.l-1 of IBA was higher-up upon the rest treatments although not reaching the significance levels. Since it gave the highest rooting percentage (63.1%), the highest number of roots (2.20 roots/ explant) and the longest roots reaching 5.50 cm which was critically higher than the control which generated only 2.18 cm. On the other hand, the highest rooting percentage (58.2%) was achieved from adding 0.3 mg.l-1 NAA. The highest number of roots (5.10 roots/ explant) was recorded from the addition of 0.1 mg.l-1 NAA. In the current study, IBA was more effective than NAA in regard of rooting percentage. While in regard of number of roots, NAA performed much better than IBA.At acclimatization stage, a good effectuation was found with plantlets transmitted to soil with a high survival rate reached to 100%. Regarding callus induction on leaf disc explants, adding BA and NAA at 2.0 mg.l-1 + 0.5 mg.l-1 NAA and 2.0 mg.l-1+ 4.0 mg.l-1 were the best combined treatments by forming 93.33% callus induction and giving the highest weights of callus (2.60 and 2. 57 g respectively). The consistency of callus was very good with a yellow to green color and compact in texture. A successful plant regeneration was achieved on the generated callus by adding 1.0 mg.l-1 BA and 0.5 mg.l-1 NAA and a very good organogenesis was found in regard of roots and shoots.