Abstract:
Pear (Pyrus communis L.), belonging to the family Rosaceae, is an economically important clonally
propagated crop widely cultivated in temperate climate zones and the fifth most widely grown fruit
in the world. The Department of Agriculture in Sri Lanka has identified two types of local pear
varieties in Sri Lanka as Ragala and Rahangala pears. Currently, grafting is the most common method
of propagating pears in Sri Lanka. At the commercial level, Pears are difficult to propagate through
grafting due to poor success rates. This study aimed to (a) develop a protocol for producing pear
planting materials using tissue culture techniques with an efficient sterilization protocol and (b)
select the best media composition for pear shoots multiplication. Ragala and Rahangala pear
varieties were used to optimize the surface sterilization procedure at different NaOCl concentrations
(10, 15, and 20%) and shaking times (10, 20, 30 min) using shoots with fifteen replicates in a
completely randomized design. Data was analyzed using a two-way ANOVA. According to the results,
different treatments had significantly affected the survival rate of both Ragala and Rahangala pear
varieties (p<0.05). The shoots sterilized with 20% NaOCl for 20 minutes and established in MS
medium with fungicide and antibiotic were the best sterilization treatments with the highest survival
percentage. In-vitro raised pear shoots were separated from seedlings and transferred to five
different 6- Benzyl Amino Purine (BAP) concentration (1.0, 1.5, 2.0, 2.5 and 3.0 mg L-1) combinations
with 0.1 mg L-1 Naphthalene Acetic Acid (NAA) containing MS medium for stimulate the
multiplication stage. The experiment was laid out in completely randomized design with twelve
replicates and data was analyzed using a one-way ANOVA. There was a significant difference
(p<0.05) between the treatment combinations on the number of shoots and height. Among those, MS
medium containing 2.5 mg L-1 BAP + 0.1 mg L-1 NAA was reported the best shoot regeneration. The
above stated effective sterilization procedure along with shoot multiplication protocol could be used
in development of complete in-vitro propagation protocol for commercial production of pears.
