THE EFFECT OF EXPLANT SOURCE AND CYTOKININ CONCENTRATION ON THE DIRECT BULB FORMATION OF TULIP (Tulipa gesnerina L.) BY PLANT TISSUE CULTURE TECHNIQUE

The study was conducted in the Plant Tissue Culture Laboratory, Faculty of Agriculture, University of Basrah, Iraq during the 2018/2019 growth season. The results indicate that the Arma cultivar has significant superior in the percentage of healthy cultures compared to the Flaming flag, it was recorded the highest percentage of survival of 77.67%. The Flaming flag had the lowest healthy percentage of 76.00%. Mercuric chloride treatment was significantly superior, which recorded the highest percentage of healthy cultures, which reached 96.00%. But, the sodium hypochlorite recorded the lowest percentage of healthy cultures, which was 57.67%. The apical and lateral buds, disc stem+ apical bud of Arma cultivar have recorded positive results in their response to the shoot proliferation. Whereas, the fleshy leaf segment and disc stem, did not record any response to the shoot proliferation. The lateral bud was significantly superior to the other explants in recording the highest percentage of response to shoot proliferation, which was 83.33%. But the apical bud recorded the lowest response of 58.67%. The higher significant superiority of the Arma cultivar compared to the Flaming flag cultivar in the percentage of the response of the shoots to the bulb formation, the bulb diameter and weight of the tulip plant after eight weeks of culturing, as it reached 70.67%, 1.19 cm and 1.98 g, respectively. The shoots that were cultured on the medium supplemented with 1.5 mg L-1 BA were significantly superior in their response to the bulb formation and the number of bulbs, which reached 72.17% and 2.67 bulbs per shoot, respectively. Whereas, the shoots cultured on the MS medium supplemented with 1.0 mg L-1 BA were significantly higher in diameter and bulb weight, which reached 1.18 cm and 1.86 g, respectively.