In-vitro mutagenesis in guava (Psidium guajava']java L.)

In-vitro mutagenesis followed by micro propagation via axillary bud proliferation in shoot tips of guava (Psidium guajava L.) cultivar Safeda was carried out. Shoot tips were irradiated with 15 to 90 Gy gamma rays using Co-60 gamma cell source and cultured on MS medium containing 3.0% sucrose, 6-benzyleamino purine (BAP), and L-glutamine. The shoot proliferation was observed after 7 weeks of culturing. Best shoot proliferation was recorded on MS medium supplemented with 1.0 mg/L (BAP) and 250 mg/L L-glutamine. Rooting of the cultured shoots were observed on half strength MS medium supplemented with Indole-3-acetic acid (IAA) and Indole-3-butyric acid (IBA). Radio sensitivity was assessed by determining the percentage shoot tips survival and shoot proliferation. The LD50 (the dose at which 50% of the population killed) was observed on 45 Gy. The doses above 75 Gy were found lethal to explants.