Abstract:
Legumes are second only to the Graminae in their importance to humans. Mung bean (Vigna radiata L)
is one of the most important grain legumes cultivated in Sri Lanka. Drought is a major abiotic stress on
Mung bean in the sub-humid, dry and intermediate zones of Sri Lanka. The present study reveals the
response of Mung bean for the water stress at three different growth stages; three weeks after planting
(3 WAP), six weeks after planting (6 WAP) and eight weeks after planting (8 WAP). A pot experiment
was carried out at Faculty of Agriculture, University of Ruhuna, Mapalana, Sri Lanka. Plant height,
number of leaves, number of floral buds, dry matter weight of shoot system, number of lateral roots,
length of tap root, number of root nodules, and dry matter weight of root system were measured after
one week recovery period in 10 day drought stressed plants at three different growth stages and in rele vant control plants. Water stress significantly affects on each of the measured parameters at 6 WAP,
the flowering and pod filling stage of Mung bean. Only number of leaves was significantly affected
when the drought applied at 8 WAP. Further, all the measured parameters other than length of tap
root and number of nodules per plant were significantly affected by drought stress at 3 WAP. Number
of floral buds and number of pods were not affected by the drought stress at 8 WAP though there is no
economical value of these characters as the pod filling efficiency is low in Mung bean under drought
stress.
