Differential chromium tolerance among eight mungbean cultivars grown in nutrient culture

Eight mungbean (Vigna radiata L.) cultivars were evaluated for their tolerance to different levels of chromium (Cr+6) (0, 24, 48, 96, 192, and 384 μM) in nutrient solutions at pH 6.8. Seeds were germinated and grown in the presence of chromium under controlled environmental conditions. Standard growth parameters such as root length, shoot length, root/shoot dry matter production, and root/shoot tolerance index were used as indicators of chromium toxicity. Measurements as early as 24 h after the beginning of the treatments did not yield consistent results. However, root measurements at 48, 72, and 96 h after the beginning of treatments yielded significant differences among the cultivars which were similar to field performance observations made for mungbean growing in chromium‐rich soils. The cultivars, TARM‐22 and K‐851 had enhanced root growth while PDM‐54, Sujata, TARM‐21, LGG‐407, and PDM‐116 showed a reverse trend in root growth in the presence of chromium. The root tolerance index (RTI) and the shoot tolerance index (STI) with respect to the cultivars TARM‐22 and K‐851 were high indicating their tolerance to chromium, while the cultivars PDM‐54 and Sujata showed a low RTI and STL Based on the growth parameters of the eight mungbean cultivars, they were ranked with respect of their tolerance to chromium as follows: TARM‐22>K‐851>Dhauli>PDM‐116>LGG‐407>TARM‐21> Sujata>PDM‐54. Therefore, the nutrient culture method was able to quickly screen the mungbean cultivars for their tolerance to chromium.