Effect of plant growth promoting rhizobacteria (PGPR) and IBA treatments on rooting in cuttings of apple (Malus × domestica Borkh.) clonal rootstock Merton 793
The preliminary studies on the effect of different strains of plant growth promoting rhizobacteria (PGPR) alone and in combination with IBA at 1000 ppm on rooting in cuttings of apple clonal rootstock Merton 793 were carried out during 2012-13. The PGPR strains (RG (1)3 – Bacillus sp.), B6 – Bacillus licheniformis and R3 (3) – Sirretia sp. alone failed to induce rooting response in cuttings of apple clonal rootstock Merton 793. The results revealed that IBA 2500 ppm recorded the maximum rooting (65 %), number of primary roots (5.00), length (28.43 cm) and diameter (3.25 mm) of primary roots, fresh (3.67 g) and dry weight (2.59 g) of roots, length of main shoot (134.14cm), diameter of main shoot (8.18 mm), fresh (30.40 g) and dry weight (22.60 g) of shoots in cuttings of Merton 793. However, the PGPR strains RG (1)3 – Bacillus sp., B6 – Bacillus licheniformis and R3 (3) – Sirretia sp. in combination with IBA 1000 ppm showed improvement in rooting of cuttings to the extent of 10, 15 and 5 per cent rooting, respectively and growth of the rooted plants. IBA at 2500 ppm resulted better rooting and growth of rooted plants. Hence, this treatment is suggested for commercial propagation of apple clonal rootstock Merton 793 through cuttings.