Litchi (Litchi chinensis Sonn.) is one of the most. Influence of plant growth regulators on rooting of litchi (Litchi chinensis Sonn.

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1 THE ASIAN JOURNAL OF HORTICULTURE Volume 7 Issue 1 June, Research Paper Article history : Received : Revised : Accepted : Influence of plant growth regulators on rooting of litchi (Litchi chinensis Sonn.) air layers WINEET CHAWLA, KULDEEP MEHTA 1 AND NEENA CHAUHAN 1 Members of the Research Forum Associate Author : 1 Department of Fruit Science, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, SOLAN (H.P.) INDIA Author for correspondence : WINEET CHAWLA PAU Regional Station, FARIDKOT (PUNJAB) INDIA wineetchawla@yahoo.com Abstract : A field experiment was conducted during to study the influence of different concentration of plant growth regulators (PGR s) on rooting of litchi air layers at Horticultural Regional Research station, Dhaulakuan, Himachal Pradesh. The result indicated that application of IBA 5000 ppm treated layers took lesser days to root initiation (25.99 days) and also gave better results with respect to all the parameters studied including per cent rooting (86%), number of first (27.30) and second (41.20) order roots, total length of first order roots (2.14 m), mean root thickness (1.09 mm), fresh (2.89 g) and dry (1.11 g) weight of roots, fresh (46.29 g) and dry (28.00 g) weight of shoot and root: shoot ratio (0.04) of air layer in comparison to all other treatments. Application of IBA and NAA in combination (IBA 4500 ppm + NAA 200 ppm) also showed significant influence on rooting of air layers and was closely followed by IBA 5000 ppm. Among different concentration of growth regulators NAA 100 ppm showed minimum effect on the rooting of litchi air layers but when compared all the treatments control has minimum effect on rooting of litchi air layers. Key words : IBA, NAA, Rooting, Air-layers, Litchi How to cite this article : Chawla, Wineet, Mehta, Kuldeep and Chauhan, Neena (2012). Influence of plant growth regulators on rooting of litchi (Litchi chinensis Sonn.) air layers, Asian J. Hort., 7(1) : Litchi (Litchi chinensis Sonn.) is one of the most environmentally sensitive subtropical fruit tree. Its fruit has gained popularity as an exotic fruit and that is why demand of planting material of litchi is increasing tremendously. Limited availablity of quality planting material is the main cause of low expansion of area under litchi cultivation. Litchi can be multiplied sexually but owing to disadvantages of seedling plants, it is chiefly propagated through vegetative means. The absence of easy and reliable clonal propagation method limits large scale cultivation of promising varieties and use of modern techiniques like micropropagation has not proved very successful in litchi (Amin et al.,1996). Of the various methods, marcotting or air layering is the most common and convenient method (Bhambota et al., 1968). Nevertheless, the major bottleneck associated with this method of propagation is varying degree of success of air layering, the high mortality of layers after severing them from the mother plant and establishment in nursery on their own root system. Thus, it restricts the availability of propagules of elite genotypes of litchi (Sharfuddin, 1983; Sharma et al., 1990). The use of plant growth regulators especially indole-3- butyric acid (IBA), α- naphthalene acetic acid (NAA) etc. have been adovcated for accelerating rooting in litchi layers (Ram and Majumder, 1983). Nanda and Kochhar (1985) reported the application of root promoting substances during layering to get profuse rooting within a short time period and IBA has been found most effective. However, more information regarding use of growth regulators, ways to overcome higher mortality rate and improving the survival rate of litchi air layers needs to be generated. It was hypothesized that by applying proper concentration of plant growth regulators and use of suitable growing medium will help in the production of quality planting material with better root system of air-layers. Keeping the above difficulties and constraints in view the present investigation was carried out to study the influence of different concentration of plant growth regulators (IBA and NAA) on rooting of air layers. This will further help in lowering the cost of planting HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE

2 WINEET CHAWLA, KULDEEP MEHTA AND NEENA CHAUHAN material which in turn, will be beneficial for the farmer. RESEARCH METHODS A field trial was carried out at the Horticultural Regional Research Station, Dhaulakuan, Sirmour of Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan during the year during The treatment consisted of IBA 4000 ppm (T 1 ), IBA 4500 ppm (T 2 ), IBA 5000 ppm (T 3 ), NAA 100 ppm (T 4 ), NAA 200 ppm (T 5 ), NAA 300 ppm (T 6 ), IBA 4500 ppm + NAA 100 ppm (T 7 ), IBA 4500 ppm+ NAA 100 ppm (T 8 ), IBA 4000 ppm + NAA 200 ppm (T 9 ), IBA 4500 ppm + NAA 200 ppm (T 10 ) and Control (T 11 ) (Only lanoline paste) were laid out in Randomized Block Design (RBD) with replications. The healthy and vigorous trees of litchi cv. Calcuttia of sixteen-year-old were selected for air layering. For performing air layering operation ring of bark, about 2 cm wide just below the bud were removed from one year old healthy and vigorous terminal branch (approx. 25 cm long) measuring 2 to 2.5 cm in diameter. Air layering operation was carried out on the selected branches on the mother plants in the 2 nd fortnight of July after the onset of rains. The exposed cambium was rubbed off and plant growth regulators viz., IBA, NAA and their combination with different concentrations was smeared in lanolin paste at the upper end of the girdled part of the branch. Subsequently girdled area was covered with moistened sphagnum moss grass and wrapped with a piece of 200 gauge polyethylene film of 10 x 10 cm size to prevent desiccation and was firmly tied with the help of a sutli string. The layers were detached from the mother plants after 60 days from the date of operation when the roots were visible. RESEARCH FINDINGS AND DISCUSSION Plant growth regulators IBA and NAA when applied at different concentration alone and in combination had significant influence on the appearance of root causing earliness in rooting of air-layers (Table 1). The minimum number of days taken for root initiation (25.99 days) was recorded with IBA 5000 ppm, which was statistically at par with treatment IBA 4500 ppm + NAA 200 ppm (27.07 days), while control took highest number of days for root initiation (43.60 days). IBA treatments might have resulted in early rise in root co-factors and fall in root inhibitors level leading to early rooting. In addition, exogenous application of auxins could have converted starch into simple sugars, which is required to a greater extent for the production of new cells and for the increased respiratory activity in the regenerating tissues at the time of initiation of new root primordia (Nanda, 1975). Significantly higher per cent rooting (86%) was recorded with IBA 5000 ppm (Table 1, Plate 1). These results are in agreement with the findings of Ray et al. (2001). This might be due to the fact that optimum concentration of IBA may have Plate 1 : Effect of IBA 5000 ppm on rooting of air layers of litc hi caused mobilization and utilization of carbohydrates and nitrogen fraction with the presence of co-factors at wound site which may have helped in better root initiation. Hence, IBA at higher concentration resulted in better rooting of the litchi air layers. Further the superiority of IBA in producing higher percentage of rooting compared to NAA might be due to their respective differences in initializing hydrolysis of nutritional reserves. These results further get support from the findings of Sharma et al. (1990) in litchi and Lal et al. (2007) in guava. The highest number of first and second order roots was observed in IBA 5000 ppm, while lowest was in control. Accelerated rooting in the layering with the increased IBA concentration might be due to increased cell wall elasticity which further may have accelerated cell division and in turn increased number of roots up to certain level. This might be due to increase in carbohydrate and metabolic activities. Bore et al. (2006) also reported increase in the number of second order roots with increase in concentration of IBA, and the increase in treated layers was possibly due to the fact that IBA influenced acceleration of the rate of initiation of root meristems and consequently production of greater number of roots (Sharfuddin and Husain, 1973). These results are corroborated by the findings of the work on litchi (Singh et al., 2009; Ray et al., 2001). Tyagi and Patel (2004) and Lal et al. (2007) also reported similar findings in guava. Maximum total length (2.14 m) of first order roots was recorded with application of 5000 ppm IBA, whereas minimum in control (0.97 m). According to Wada et al. (1998), IBA promotes root length by influencing the synthesis of enzymes Asian J. Hort., 7(1) June, 2012 :

3 INFLUENCE OF PLANT GROWTH REGULATORS ON ROOTING OF LITCHI Table 1 : Effect of plant growth regulators on root initiation and its associated characters of air layers of litchi Days taken to Per cent Number of 1 st Number of 2 nd Total length of 1 st Treatments Concentration (ppm) root initiation rooting order roots order roots order roots (m) Average diameter of 1 st order roots (mm) T 1 IBA (58.48) T 2 IBA (61.12) T 3 IBA a (68.11) T 4 NAA (52.13) T 5 NAA (52.35) T 6 NAA (55.12) T 7 IBA NAA (58.47) T 8 IBA NAA b (61.69) T 9 IBA NAA (60.73) T 10 IBA NAA ab (64.38) T 11 Control (50.95) C.D. (P=0.05) *Figures in the parentheses are arc sine transformed values which are concerned with the cell enlargement. The enzymes involved in cell enlargement process are triggered by the auxin at higher concentration. The increase in root length with different concentrations of growth regulators, IBA (5000 ppm) may be attributed to its primary physiological effect which is known to promote the elongation of cells in the apical region, a reason which has been cited by Singh et al. (2009) in air layers of litchi. The similar results were reported by Bora et al. (2006), Rahman et al. (2002) and Ray et al. (2001) in litchi. Singh et al. (2007) in guava and Bhosale et al. (2010) in pomegranate who also observed higher total length of first order root when treated with IBA at higher concentration. The highest average diameter of first order roots was recorded with IBA 4500 ppm + NAA 200 ppm and was followed by IBA 5000 ppm (Table 1). The combined effect of IBA + NAA was more effective. This may be due to synergism between IBA and NAA. The mixtures of root promoting substances (IBA and NAA) are sometimes more effective than either of the components alone (Hartmann et al., 2007). The increase in diameter of first order roots with IBA and NAA application may have loosened the cell wall components which reduced wall pressure. The cell wall becomes more permeable which initiated more water and mineral uptake that could have resulted in increased root diameter. With IBA 5000 ppm, maximum mean root thickness was obtained, while minimum was recorded in control (Table 2). Kumar (2009) also noticed conspicuous effect which was attributed due to higher concentration of IBA in litchi layers. Slow translocation and higher stability of IBA at higher concentration might be attributed to increase in the mean root thickness. The better effect of 5000 ppm IBA in the present study is in general agreement with the findings of Sinha and Ray (2002) in litchi and Hatibarua (1997) in jackfruit. Both fresh and dry weight of roots were markedly influenced by plant growth regulators (Table 2). The highest fresh and dry weight of roots were recorded with IBA 5000 ppm which Table 2: Effect of plant growth regulators on root biomass characters of air layers of litchi Mean root Fresh weight Dry weight of Treatments Concentration (ppm) thickness (mm) of roots (g) roots (g) Fresh weight of shoot (g) Dry weight of shoot (g) Root : shoot ratio (on dry weight basis) T 1 IBA T 2 IBA T 3 IBA T 4 NAA T 5 NAA T 6 NAA T 7 IBA NAA T 8 IBA NAA T 9 IBA NAA T 10 IBA NAA T 11 Control CD N.S Asian J. Hort., 7(1) June, 2012 :

4 WINEET CHAWLA, KULDEEP MEHTA AND NEENA CHAUHAN performed better as compared to all other treatments and lowest values 1.02 and 0.38, respectively were obtained in control. These results are corroborated by the findings of Ray et al. (2001) and Singh and Jawanda (1981) in litchi. The highest roots weight registered in the present study may be attributed to the fact that exogenous application of auxin generally stimulate the movement of natural auxin and others materials in downward direction from leaves and shoot tips, which accumulate at the incision made on the shoot resulting in the formation of roots with higher root fresh and dry weight. This might be due to more number of primary and secondary roots and also with, more length in case of layers treated with IBA 5000 ppm. Similar findings have been observed by Tyagi and Patel (2004) and Rymbai and Reddy (2010) in guava, Kumar et al. (2007) in jack fruit and Bhosale et al. (2010) in pomegranate. The fresh weight of shoot under different treatments were found to be non significant, whereas dry weight of shoots depicted the effect of plant growth regulators IBA and NAA and their combination effect was significant (Table 2). IBA at 5000 ppm resulted in maximum dry weight of shoot while minimum was found in control. Similar findings were also observed by Shukla and Bist (1994) in pear who concluded that IBA at higher concentration showed maximum dry weight of shoot of cutting. The higher root: shoot ratio was registered in IBA 5000 ppm, while minimum was observed under control. Higher concentration of IBA might have caused increased mobilization and utilization of carbohydrates and nitrogen fraction to the growing litchi layers which helped them to put more vegetative mass by virtue of which more photosynthates were translocated downward to the roots resulting in an increase in the said parameter. Plants with a higher proportion of roots can compete more effectively for soil nutrients, while those with a higher proportion of shoots can intercept and absorb more light energy. Large proportions of shoot production are characteristic of vegetation in early phases, while high proportions of root production are characteristic of late phases. Roots allow a plant to absorb water and nutrients from the surrounding soil, and a healthy root system is key to a healthy plant. Better root: shoot ratio parameter helps to assess the overall health of the plants. From the present study it is concluded that IBA at 5000 ppm proved superior in terms of earlier root initiation, maximum per cent rooting success, number of first and second order roots, total length of first order roots, mean root thickness, fresh and dry weight of roots, fresh and dry weight of shoot and root: shoot ratio. REFERENCES Amin, M.N., Razzaque, M.A. and Anisuzzaman, M. (1996). Regeneration of plants in vitro from seedlling explants of lychee (Litchi chinensis Sonn.). In : Plant Tissue Culture,pp Bhambota, J.R., Singh, K.K. and Saini, H. (1968). Propagation litchi plant. Punjab Hort. J., 8: Bhosale, V.P., Jadav, R.G. and Masu, M.M. (2010). Response of different medias and PGR s on rooting and survival of air layers in pomegranate [Punica granatum (L.)] cv. SINDHURI. Asian J. Hort., 4(2): Bora, N., Lal, R. L. and Singh, A.K. (2006). Effect of IBA and planting containers on shoot and root characters and survival of litchi airlayers. Indian J. Hort., 63(2): Hartmann, H.T., Kester, D.E., Davies, F.T. and Geneve, R. L. (2007). In: Plant propagation: principals and practices.7 th ed. Prentice Hall of India. New Delhi, pp Hatibarua, P., Gogoi, S. and Mazumder, A. (1997). Adventitious rooting in jackfruit (Artocarpus heterophyllus Lam.) air layers induced with etiolation and rooting hormones. Ann. Biol Ludhiana, 13(1): Kumar, M., Lal, S., Kumar, R. and Kamal, S. 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5 INFLUENCE OF PLANT GROWTH REGULATORS ON ROOTING OF LITCHI Shukla, G.S. and Bist, L.D. (1994). Studies on the efficacy of IBA and NAA on clonal propagation by cutting in low chilling pear rootstocks. Indian J. Hort., 51(4): Singh, P.C., Shukla, H.S. and Katiyar, P.N. (2009). Effect of indole butyric acid and p-hydroxybenzoic acid on regeneration of litchi cultivars through air layering. Ann. Hort., 2(2): Singh, P., Chandrakar, J., Singh, A.K., Jain, V. and Agrawal, S. (2007). Effect on rooting in guava cv. Lucknow-49 through PGR and organic media under Chhattisgarh condition. Acta Hort., 735: Singh, S. and Jawanda, J.S. (1981). Propagation studies in litchi. Punjab Hort. J., 21(3-4): Sinha, R. and Ray, S.K.D. (2002). Effect of different growth regulators in air layering of litchi cv. BOMBAI. Hort. J., 15(1): Tyagi, S.K. and Patel, R.M. (2004). Effect of growth regulators on rooting of air layering of guava (Psidium guajava L.) cv. SARDAR. Orissa J. Hort., 32 : Wada, S., Tanimoto, E. and Masuda, Y. (1998). Cell elongation and metabolic turnover of the cell wall as affected by auxin and cell wall degrading enzymes. Plant Cell Physiol., 9(2): *********** Asian J. Hort., 7(1) June, 2012 :