Research in Environment and Life Sciences 411 May, 2017  2017 RELS ISSN: 0974-4908 http://rels.comxa.com Res. Environ. Life Sci. rel_sci@yahoo.com 10(5) 411-413 (2017) Effect of pruning and bio regulators on vegetative growth attributes of guava (Psidium guajava L.) Shweta Hiremath*, S.I. Athani, G.S.K. Swamy, P. Choudhry and D.U. Pujar Department of fruit science, K.R.C. College of Horticulture, Arabhavi. University of Horticultural Sciences, Bagalkot-591218, India *e- mail: shwetha167@gmail.com (Received: June 26, 2016; Revised received: November 22, 2016; Accepted: December 02, 2016) Abstract: The present investigation was conducted to ascertain the effect of pruning (10-20cm of shoot length) and bio regulators (NAA 250ppm, Urea 15%, Ethrel 500ppm and Cycocel 50ppm) on vegetative growth parameters of guava variety Sardar. Observations revealed that pruning treatment significantly influenced the vegetative growth parameters of trees. Significantly minimum plant height (3.26m), stem girth (15.60cm) and plant spread (NS 7.06 and EW 7.19m) were noted in pruned plants. Although, plant growth in terms of height, stem girth and overall plant spread restricted under all bio regulator treatments, effect of cycocel was more pronounced. Reduction in the plant height (3.64m) at 120 DAT was recorded in ethrel treated plants, whereas cycocel treated plants exhibited maximum reduction in stem girth (16.51cm) and E-W canopy spread (7.24m) 120 DAT. Minimum plant spread (7.22m) in N-S direction was recorded in NAA treated plants. Key words: Guava, Pruning, Bio regulators, Vegetative growth parameters Introduction Guava (Psidium guajava L.) is very important tropical fruit crop grown throughout the tropical and sub-tropical areas. It is a hardy, prolific bearer and highly remunerative fruit crop and also can be grown satisfactorily even in ad›verse soil and climatic conditions. Presently, the productivity of guava is lesser than productive potential primarily due to management practices. The fruiting potential of guava is largely governed by canopy architecture, density and photosynthetic efficiency (Burondkan et al., 2000, Kallo et al., 2005). Therefore, the main emphasis should be laid on management of tree can›opy to get higher production of good quality fruits per unit area. Tech›niques that restrict the vegetative growth are important in management of tree canopy. As guava tree respond well to canopy modification with respect to vegetative and re›productive growth, therefore, modification of canopy through pruning (Lal 1983, Tiwari et al , 1992) and use of certain bio regulators may be steps to enhance the production efficiency. Serrano et al . (2008) reported that the light pruning increased the number of productive branches and Shigeura et al. (1975), Singh et al. (1991) noticed that Urea or NAA or Ethephon has been applied to guava trees in a vigorous vegetative state of growth to change growth patterns. Cycocel and ethephon may be useful in restriction of vegetative growth as cycocel helps in making the plants dwarf by producing a retarding effect on the growth of tree through inhibition of gibberellin biosynthesis. Similarly, ethephon acts as a growth retardant at higher concen›trations (500 ppm) proved to be quite effective in reducing the plant height (Mohammed et al., 1984). Keeping in view the above mentioned facts, the present research aimed to restrict the vegetative growth of guava variety Sardar. Materials and Methods The present investigation was carried out at in the established orchard, Department of Fruit Science, K. R. C. College of Horticulture, Arabhavi during the years 2014-15. The experimental material consisted of ten- year-old uniform trees of guava variety Sardar. The treatment consisted of two pruning levels, i.e. no pruning (P 1 ), pruning (P 2 ) and five bio regulators treatment, i.e. control = T 1 , NAA 250 ppm = T 2 , Urea 15% = T 3 , Ethrel 500 ppm = T 4 and Cycocel 50 ppm = T 5 all treatments were applied as foliar spray at 50% flowering stage. There were ten treatment combinations each replicated four times in factorial randomized block design. Shoot pruning of current seasons growth was done at 10- 20 cm of shoot length. It was performed in the first week of May. Data were recorded for both before and after the treatment imposition on tree height, stem girth and plant spread. The plant height was measured from ground level to the tip of the growing point with the help of bamboo pole on soil surface near the trunk then measured with meter scale and the height was expressed in meters. The stem girth of the plant was recorded at the collar region by using digital vernier calipers and expressed in