In vivo propagation of difficult-to-root bougainvillea cultivars by air layering

An air layering experiment was conducted at the Division of Floriculture and Landscaping, Indian Agricultural Research Institute, New Delhi during June, 2013 to May, 2014. Eight bougainvillea cultivars which are difficult-to-root along with check as easy-to-root were used in this study with three replications. The difficult-to-root cultivars used were viz., Sweet Heart, Dr. H.B. Singh, Red September, Chitra, Refulgens, Thimma, and Mahatma Gandhi; whereas, Dr. R.R. Pal and Chitra were used as easy-to-root check. The air-layering technique was carried out during the months of June-July with moist sphagnum moss as rooting media. The results revealed that almost all cultivars had shown significant differences in rooting percentage, survival percentage, growth, flowering, total carbohydrate and nitrogen concentration percentage. Maximum rooting (92.01 and 88.04%) and survival of plants (100.00 and 88.04%) were recorded in Chitra and Dr. R.R. Pal respectively, which were easy-to-root, whereas good rooting percentage was observed in difficult-to-root cultivars such as Sweet Heart (59.33%), Red September (59.02%), Dr. H.B. Singh (53.66%), Mahatma Gandhi (50.66%) and Refulgens (47.98%) respectively. The biochemical investigation of these cultivars showed that the easy to root cultivars have higher carbohydrate content (40.58 and 23.96%) and lower nitrogen content (2.24 and 2.54%) than the difficult-to-root ones i.e. Refulgens (20.85 and 3.76%) and Mahatma Gandhi (19.25 and 3.88%) respectively. On the basis of growth and flowering, all the cultivars studied had differed significantly and each cultivar is having its own significance which can be used for different purpose in landscaping. The air layering technique is a good solution for rooting of difficult-to-root cultivars, and is expected to help nurserymen who take up small scale multiplication of bougainvillea.