In-vitro mutagenesis followed by micropropagation via axillary bud proliferation in shoot
tips of guava (Psidium guajava L.) cultivar Safeda was carried out. Shoot tips were irradiated with 15
to 90Gy gamma rays radiations using 60Co gamma cell source and cultured on MS medium containing
3.0% sucrose, BAP and glutamine. Shoots proliferation was observed 7 weeks after culture initiation.
Higher shoot proliferation rates were recorded on MS medium supplemented with 1.0 mgL-1 BAP and
250 mgL-1 glutamine. Rooting was observed on half-strength MS medium supplemented with IAA and
IBA. Radio sensitivity test was assessed by determining the percentage of shoot tips survival and shoot
proliferation rates. The LD50 (The dose at which 50% of the population killed) was observed on 45
Gy. The doses above 75 Gy were found to be lethal to all explants. Similarly, seeds and bud woods of
guava Cv. Safeda were exposed to gamma rays at 0.05 to 0.3 kGy and 20 to 100 Gy respectively using 60Co gamma source. The LD50 for seeds was determined at 0.19 kGy, and 0.3 kGy was found to be
lethal. Seeds irradiated with low doses germinated earlier as compared to those which received higher
doses of irradiation. The LD50 for surviving bud woods grafted on the rootstocks in the nursery was
determined at 60 Gy. There was constant and continuous reduction in the survival rates of buds as the
doses increased. The bud woods of guava Cv. Safeda were more radiosensitive than seeds of the same
cultivar. The most favourable doses were established between 0.15 and 0.2 KGy and led to mutations
such as: highest number of fruits (40), highest fruit size (59mm) and highest fruit weight of (128.38g).
The highest number of seeds (300) and 100 seed-weight (2.29g) were recorded at 0.05KGy while the
lowest numb