​Identification of Low Light Tolerant Blackgram Varieties with Respect to Morpho-physiology and Yield

Background: Blackgram is generally considered as a shade sensitive crop. Nevertheless, it fits well in intercropping, crop rotation and crop mixture in coconut gardens thus forming an integral part of cropping systems of the tropics. To encourage and extend blackgram cultivation in coconut gardens, suitable varieties tolerant to shade, need to be identified. The current study aims to screen shade tolerant blackgram varieties with respect to morpho-physiological characters and yield. Methods: Field experiment was conducted during Rabi 2019 at College of Agriculture, Vellayani, Kerala, India. Uniformly spaced coconut palms of age above 40 years were selected having a light intensity of 40-46.5 Klux. Twelve promising blackgram varieties along with three cultures were evaluated under low light intensity in coconut garden. Morpho-physiological attributes and yields were recorded and analysed statistically. Result: Superior growth attributes and physiological parameters like stomatal frequency, chlorophyll content, photosynthetic rate and transpiration rate were recorded in varieties namely, DBGV 5, Sumanjana and VBN 5. These varieties were found tolerant to low light intensity with DBGV 5 recording significantly higher yield (1183.33 kg ha-1) followed by VBN 5 (916.67 kg ha-1) and Sumanjana (906.67 kg ha-1) and could be recommended as suitable for intercropping in coconut garden.