Studies on role of plant growth regulators and rooting media on rooting and survival of air-layers of Guava (Psidium guajava) var. G-27

Abstract

The present investigation was taken up during rainy season of 2012-13 at Horticultural Nursery, College of Agriculture, Gwalior. The treatment consisted of 7 levels of PGRs (control, IBA-5000 ppm, IBA-7500 ppm, NAA-5000 ppm, NAA-7500 ppm, IBA+NAA-5000 ppm each and IBA+NAA-7500 ppm each) and two rooting media (Moss grass and Moss grass + coco-peat). Significantly maximum percentage of callus formation (0.948 cm/air layer), number of primary roots (15.50/air layer), length of primary roots (4.56 cm), diameter of primary roots (2.995 mm), number of secondary roots (31.39/air-layer), length of secondary roots (2.551 cm), diameter of secondary roots (0.673 mm), dry weight of roots (0.692 g), rooting success (80.17%), survival percentage of air-layers (72.66%), number of new branches (6.66/air layer) and length of shoots (11.33 cm) were recorded from IBA+NAA-7500 ppm each. Application of IBA at 7500 ppm ranked second and was found significantly superior to rest of the treatments in respect of all root and growth characters. Maximum callusing (0.693 cm/air layer), number of primary roots (10.16/air layer), length of primary roots (3.55 cm), diameter of primary roots (2.430 mm), number of secondary roots (22.90/air-layer), length of secondary roots (1.768 cm), diameter of secondary roots (0.530 mm), dry weight of roots (0.564 g), rooting success (62.80%), survival percentage of air-layers (55.14%), number of new branches (5.38/air layer) and length of shoots (8.83 cm) were noted under the rooting media M2 (Moss grass + coco-peat), which significantly proved superior over rooting media M1 (moss grass) in respect of all these characters. Significantly maximum length of primary root (4.99 cm), diameter of primary root (3.286 mm), number of secondary roots (34.08/ air layer), length of secondary roots (2.858 cm), rooting success (82.68%) and survival percentage (74.39%) was obtained by the treatment combination G6M2 (IBA+NAA 7500 ppm each with Moss grass+coco-peat). Treatment G6M2 (IBA+NAA 7500 ppm each with Moss grass+coco-peat) has secured the highest net return (Rs. 2482.60) followed by G2M2 (Rs. 2334.40) and G6M1 (Rs. 2328.80). But, the treatment G2M2 (IBA 7500 ppm with Moss grass+coco-peat) gave highest B: C ratio (6.12) closely followed by G6M2 (6.04) and G4M2 (5.86).