In vitro preservation of Pyrus germplasm with minimal growth using different temperature regimes

摘要

In vitro cultures of 9 pear genotypes collected from different areas of Azad Jammu & Kashmir were established on MS medium supplemented with 30 g l-1sucrose, 7 g l-1agar and 1 mg l-BAP. Proliferated shoots of these genotypes were excised aseptically, cultured on fresh medium and tested for their survival and regenerative ability at various incubating temperatures regimes i.e., 25, 15, 10 and 5oC, stored for 3, 6, 9 and 12 months. Significant differences were found in all genotypes for the both growth parameters and the highest survival (65.25 %) and regenerability percentage (61.21) were recorded in shoots of Frashishi. The least survival (58.92 %) and regenerability percentage (55.21) were observed in shoots of Btangi. As far as temperatures treatment and storage periods are concerned, the highest survival (84.15 %) and regenerability percentage (77.63) were found in the cultures stored at the lowest temperature (5oC) for the period of 3 months, whereas, the 32.37 % and 28.37 % survival and regeneration were recorded in the cultures stored at 25oC for 12 months. The interaction among three factors (genotypes, temperature and storage periods) revealed that the highest survival percentage (99.33) and regeneration percentage (91.66) were in the cultures of Bagugosha and Raj btung, stored at 5oC for 3 months. Incubating temperature treatments i.e., 5oC and 10oC, proved successful for preservation of apical shoots for 3 months, however, the shoots kept at higher temperature for longer period survived with poor re-growth. Hence the shoot tips of pear genotypes can be successfully stored In vitro for short to medium terms at reduced incubation temperatures.