Influence of IBA on root initiation in air layering of different litchi (Litchi chinensis sonn.) varieties under bastar plateau condition

Introduction

Litchi (Litchi chinensis Sonn.) is an important subtropical fruit crop widely cultivated for its high economic value. Air layering is the most common method of propagation; however, its success depends on rapid root formation and subsequent plant growth. The use of plant growth regulators like Indole-3-butyric acid (IBA) plays a crucial role in enhancing rooting and establishment. However, varietal differences and optimal IBA concentration are critical factors affecting propagation success. Therefore, the present study was undertaken to evaluate suitable IBA levels for different litchi varieties under Bastar Plateau conditions.

Material and Methods

The present experiment was conducted at litchi orchard of research cum instructional Farm, Jagdalpur, during the year 2024-25 unifrom vigorous, healthy and disease free plant of cultivar indira litchi-1, shahi, roce secented, china, indira litchi-2 were selected for air layering operation during month of mid-July and August after the onset of rains and maintained with uniform cultural practices as for air layering branch, 45-60 cm long and 2.5 cm thick was selected. Litch Layered branches were treated with four different concentrations of IBA i.e 1000ppm, 2000ppm, 3000ppm and 4000ppm of IBA. Stock solution of IBA were prepared by dissolving two grams of IBA in 500ml of water having a strength of 8000ppm of IBA. Experiment was laid out in Factorial Randomized Block Design (FRBD) with replications. The girdled/exposed region was then covered with moistened soil and wrapped in a 10 × 10 cm piece of 200 gauge polyethylene film to prevent desiccation. A "sutli" string was used to securely tie both ends of the polythene. When the roots were apparent, the layers separated from the mother plants. Only when a significant number of roots had grown were the gootee or the air-layered branch cut off from the mother tree. The gootee was quickly placed in a nursery bed after being severed from the mother tree and the plastic sheet was taken off. After being planted in the nursery, the gootee received irrigation. Days to root appearance, number of roots, root length, number of leaf, percentage survival, days to come leaf after detachment, fresh weight of shoot, dry weight of shoot, fresh weight of root, dry weight of root, relative growth rate and survival percentage on dry weight basis were among the parameters for which data were recorded. Each year's data was statistically analyzed using Factorial Randomized Block Design, year were worked out.

Results and Discussion

Days taken to root appearance Minimum days were recorded in V1 (18.80 days), which was at par with V5 (18.92 days), while maximum in V4 (23.83 days). Among IBA levels, L4 (4000 ppm) recorded minimum days (18.76 days), significantly superior over L1 (22.80 days). This clearly indicates that higher IBA concentration accelerates root initiation due to enhanced cell differentiation.

Number of roots

Maximum number of roots was recorded in V5 (9.53), followed by V3 (9.16), while minimum in V4 (7.13) Among IBA levels, L4 (10.15) was significantly superior. Increased IBA concentration enhances root primordia formation

Root length

Maximum root length was recorded in V5 (12.69 cm), followed by V1 (12.44 cm). Among levels. 14 (12.81 cm) showed superior performance. The increase in root length with higher IBA concentration may be due to increased cell elongation.

Number of Leaves

The highest number of leavesV5 (15.78) and V1 (15.75) recorded maximum leaves at 90 days. Among IBA levels, L4 (15.58) was significantly superior. This indicates better vegetative growth under higher IBA concentration.

Fresh weight of shoot

Maximum fresh weight (34.23 g) and dry weight (26.95 g) were recorded in V5 and V1 respectively. Among IBA levels, L4 showed significantly higher values, indicating better biomass accumulation

Dry weight of shoot

Maximum dry weightof root (26.95 g) were recorded in V5 and V1 respectively. Among IBA levels, L4 showed significantly higher values, indicating better biomass accumulation.

Relative growth rate

Maximum At 90 days, V5 (2.79 mm mm -1 month -1 ) recorded growth rate, followed by V1 (2.65 mm mm -1 month -1 ). Among IBA levels, L4 (2.25 mm mm -1 month -1 ) was superior. This indicates enhanced physiological activity under higher IBA concentration. [7] , Yadav et al. (2019) [11] , Sharma and Singh (2012), [8] and Patel et al. (2021), who reported that higher concentrations of IBA significantly. The number of roots was significantly influenced by both litchi varieties and IBA concentrations. Among the varieties, Indira Litchi-1 (V₅) produced the maximum number of roots (9.53), followed by Rose Scented (V₃) (9.16), whereas China (V₄) recorded the minimum (7.13). These differences may be attributed to genetic variability, endogenous hormone balance, and the differential rooting potential of the varieties. The highest number of roots was observed with 4000 ppm IBA (L₄) (10.15), while the lowest was recorded with 1000 ppm (L₁) (6.89). The promotive effect of higher IBA concentration may be due to its ability to stimulate cell division, increase cambial activity, and accelerate the initiation and development of adventitious roots. These findings indicate that the application of 4000 ppm IBA is most effective for improving rooting in litchi air layering. (2018) [7] , Yadav et al. (2019) [11] , Sharma and Singh (2012) [8] , and Patel et al. (2021), who observed that increasing IBA concentrations significantly. [7] , Yadav et al. (2019) [11] , who observed significantly greater root length in litchi air layers treated with higher concentrations of IBA. The increase in leaf number with higher IBA concentration may be due to improved root development, greater absorption of water and nutrients, and enhanced physiological activity, resulting in better vegetative growth. Similar findings have also been reported by Kumar et al.

(2018), [7] Yadav et al. (2019) [11] , Sharma and Singh (2012) [8] , and Patel et al. (2021), Improving vegetative establishment and overall quality of rooted litchi air layers. Dry shoot weight was significantly affected by both litchi varieties and IBA concentrations. Among the varieties, Indira Litchi-2 (V₁) recorded the highest dry shoot weight (26.95 g), followed closely by Indira Litchi-1 (V₅) (26.10 g) and Rose Scented (V₃) (26.04 g), whereas China (V₄) produced the lowest value (16.20 g). The higher dry matter accumulation in these varieties may be attributed to their superior rooting ability, efficient nutrient uptake, and greater photosynthetic efficiency, which enhanced biomass production. IBA concentration significantly increased dry shoot weight, with 4000 ppm IBA (L₄) recording the highest value (25.60 g), while the lowest was observed at 1000 ppm (L₁) (22.64 g). The improvement in dry matter production at higher IBA concentrations may be due to enhanced root [11] , Sharma and Singh (2012) [8] , and Patel et al. (2021), who observed that higher concentrations of IBA significantly increased shoot dry weight and vegetative biomass in litchi propagated through air layering. [7] , Yadav et al. (2019) [11] , Sharma and Singh (2012) [8] , and Patel et al. (2021), who observed that higher concentrations of IBA significantly.

Conclusion

Based on the present investigation, it can be concluded that Indira Litchi-1 and Indira Litchi-2 are the most suitable

References

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