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 relevant 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.

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Grain yield in rice is a complex trait and highly dependent on the other agronomic characters. Agronomic characters and grain yield of twenty traditional rice cultivars were evaluated at Faculty of Agriculture, University of Ruhuna in Maha-2010/2011 and in Yala/2011. The experiment was conducted according to the randomized complete block design with three replicates. Twenty plants from each cultivar were evaluated for the selected characters, Plant height, Leaf blade length, Leaf blade width, Number of tillers, Number of reproductive tillers, Panicle length, Number of spikelets per panicle, Number of fertile spikelets per panicle, Number of infertile spikelets per panicle, Seed length, Seed width, 100 seed weight and Yield per plant. Recommended modern rice cultivar Bg 379/2 was used as the reference. Deviations of each character in different traditional rice cultivars from those of recommended rice cultivar Bg 379/2 were recorded. The average plant height of the tallest rice cultivar, Podihatatha was 198 cm and that of the shortest rice cultivar, Rathranwee was 68 cm. The longest leaf blade and longest culm length were also belonged to Podihatatha. The highest number of tillers (9.6 tillers per plant) and the highest average number of reproductive tillers (9 per plant), were recorded by rice cultivar Mahasudu wee. The highest value of 100 seed weight was recorded by rice cultivar Galpa wee. However, the most important economical character, the highest yield per plant (28.52g/plant) was recorded by Thanthiribalan which was significantly higher than that of in the recommended rice cultivar Bg 379/2 (26.5 g/plant). Significant correlations were found between the yield per plant and the characters such as number of reproductive tillers (r = 0.692), panicle length (r = 0.565) and number of spikelets per panicle (r = 0.761). Agronomic data collected in the present study would be important to understand the suitability of an individual rice cultivar for the farmer field.

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C for 1-12 days and gained hypocotyl length was measured after a 4-day recovery period at normal growth conditions. To assess the seedling stage cold tolerance 1-week-old seedlings were maintained at 4 o C for 1-7 days and green plant height was measured after a 5-day recovery period. In all growth stages Hyogokithanishiki showed higher degree of cold tolerance than Hokuriku. Recombinant inbred line population showed normal distribution curves for germination and postgermination stage cold tolearance with transgressive segregants for both higher and lower levels than the parents. At the seedling stage, the inbred populations showed a skew towards the susceptible cultivar but there were two transgressive segregants for greater cold tolerance than Hyogokithanishiki. Identification of such significant differences in the two parental rice cultivars and distribution of the character across the range of different tolerance levels with transgressive segregation indicates that this population is useful for the development of cold tolerant rice cultivars and to understand the basis of the cold regulation of rice using molecular tools.