Effect of girdling, plant growth regulators and potassium nitrate on morpho-physiological attributes of litchi (Litchi chinensis Sonn.) cv. China

The current investigation entitled "Effect of plant growth regulators and potassium nitrate on morpho-physiological attributes of Litchi (Litchi chinensis Sonn.) cv. China" was conducted during 2024-2025 at the experimental site at ICAR-National Research Centre on Litchi, Muzaffarpur, Bihar. The twenty years old (2004-05) litchi trees were chosen for one off-year season from September to May. The experimental design was laid out in randomized complete block design. The treatments such as T1 (Girdling of primary branches), T2 (Soil application of Cultar @ 3 ml/m canopy diameter), T3 (Foliar application of Paclobutrazol @ 50 ppm), T4 (Foliar application of KNO3 @ 2.0%), T5 (Foliar application of ABA @ 100 ppm), T6 (Foliar application of Ethephon @ 100 ppm), and T7 (Control). The morphophysiological attributes such as the maximum leaf area (44.17 cm2) and specific leaf weight (0.096 g/cm2) was recorded under the treatment T5. However, the specific leaf area (12.24 cm2/g) and inter-nodal length (14.50 cm). Therefore, for balanced vegetative and reproductive growth in litchi trees, T5 (Foliar application of ABA @ 100 ppm) and T4 (foliar application of KNO3 @ 2.1%) are promising, especially for improving flowering potential and maintaining compact growth.