Morphological characterization and evaluation of cyanide content of lablab purpureus l. (hyacinth bean)

Lablab purpureus L. (Hyacinth bean) is an underutilized leguminous plant with notable nutritional and medicinal value commonly found in tropical regions. This study aimed to characterize the morphological traits of twenty Lablab purpureus accessions and to evaluate the cyanide content in six selected accessions (TLn28, TLn28-B, TLn28-A, TLn37, TLn43, and TLn52). The field experiment followed a completely randomized design with three replicates. Results revealed significant variation (p < 0.05) among the accessions in growth and yield traits. Accession TLn2 showed superior performance in plant height (23.82 cm) and leaf count (12.71), whereas TLn70 exhibited the highest values for leaf length (11.68 cm) and width (11.73 cm). Accession TLn37 excelled in pod count per replicate (36) and seed count per replicate (134), while TLn28, TLn11, and TLn4 demonstrated the highest values for fresh pod weight (37.00 g), pod length (8.03 cm), and pod width (2.10 cm), respectively. The cyanide content, assessed using the alkaline picrate colorimetric method, was significantly lower in TLn37 than in the other five accessions and fell well below the toxicity threshold (36 mg/100 g) for humans and animals. Consequently, accessions TLn2 and TLn70 are promising candidates for breeding and cultivation based on desirable foliar traits, while TLn37 is particularly suited as a low-cyanide planting material for safe hyacinth bean production for human and animal consumption.