Browsing by Author "Mahendran, S."
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Item Effects of Moisture Stress on Selected Biochemical Parameters and Yield of Three Tomato (Solarium Iycopersicum Mill.) Cultivars during the Flowering Stage(Uva Wellassa University of Sri Lanka, 2018) Beham, M.S.K.; Mahendran, S.; Puvanitha, S.There is a need to utilize water efficiently and effectively because water availability is scarce in the Dry Zone of Sri Lanka. Tomato is grown in the Batticaloa district to a limited extent. The yield is low because growth of tomato is highly affected by moisture and heat stresses especially during the Yala season. This experiment was conducted in a farmer's field near to the Eastern University of Sri Lanka at Batticaloa district. Investigations were carried out to determine the effect of moisture stress on selected biochemical parameters of three tomato cultivars viz. `Roma', `Thilina' and `KC1' during the flowering stage and to find out the most suitable tomato cultivar which resists to drought without much yield reduction. This experiment was laid out in the Two Factor Factorial Randomized Complete Block Design with six treatments and four replications. Moisture stress was imposed for a period of six days for the treated plants during the flowering stage. The control plants were irrigated daily to the Field Capacity. Free proline and lycopene contents were significantly higher and chlorophyll content was significantly lower in the stressed than that of control treatments. The `KC1' tomato cultivar showed the highest amount of free proline (0.56 mg cm-2) and lycopene (73.6 mg g') contents and lowest amount of chlorophyll (0.28 mg g-I) content than Roma (0.54 mg g-1) and Thilina (0.37 mg g') cultivars. Moisture stress significantly (p<0.05) reduced the yield of `KC1', 'Roma' and `Thilina' tomato cultivars. The highest yield (5252 kg ha") was obtained in the `KC1' with low (14%) yield reduction and the lowest yield (4080 kg ha-1) was found in `Thilina' with high (31%) yield reduction under moisture stress. From these results it could be stated that 'KC 1' was able to resist drought better than the rest of the tomato cultivars and produced the yield well under this condition. Hence, `KC1' tomato cultivar could be suggested for tomato growers in the drought prone areas in Batticaloa District.Item Effects of Salinity on the Growth and Yield of Selected Rice (Oryza saliva) Cultivars at Different Growth Stages(Uva Wellassa University of Sri Lanka, 2016) Puvanitha, S.; Mahendran, S.; Sujirtha, N.Salinity is a limiting environmental factor for plant production and is becoming more prevalent as the intensity of agriculture increases. Limited water and hot dry climates frequently increases the salinity levels that limit crop production in arid and semi-arid regions. It is estimated that 2% of the rain-fed agricultural area is affected by salinity globally. In agriculture, a soil having a salt concentration exceeding an electrical conductivity value of 4 dSm-1 is classified as saline. This experiment was conducted to assess the effects of salinity on the growth and yield of selected rice cultivars. The growth of three rice cultivars namely; "Pachaiperumal", "At 307" and "At 308" were evaluated under saline (6.52 dSm-i) and non-saline (1.76 dSrn-1) conditions. This experiment was laid out in the Completely Randomized Design with two factors in a factorial arrangement. There were six treatments and each one was replicated four times. Root and shoot dry weights and yield of the tested rice cultivars were significantly reduced by salinity. Rice cultivar "At 307" showed the highest root dry weights at all three growth stages, vegetative, reproductive and ripening (0.21, 10.1 and 26.4 g) respectively when exposed to salinity and the lowest root dry weights (0.03, 5.7 and 19.0 g) were found in "Pachaiperumal". The % reduction in root dry weights of "At 307" and "Pachaiperumal" were 19.2, 66.7; 30.3, 51.7 and 36.2, 46.3 during the vegetative, reproductive and ripening stages respectively. Cultivar "At 307" showed the highest shoot dry weights when exposed to salinity during all the three growth stages and the lowest weights were found in "Pachaiperumal". The % reduction in shoot dry weights of"At 307" and "Pachaiperumal" were 25.7, 55.6; 36.7, 52.4 and 29.6, 62.7 during the vegetative, reproductive and ripening stages respectively. Salinity significantly reduced the yield of all the tested rice cultivars. The highest (2.0 t he) and the lowest yields (0.44 t ha-1) were recorded by "At 307" and "Pachaiperumal" respectively. Hence, "At 307" was identified as the most salt tolerant rice cultivar among the three rice cultivars tested which could be grown in the saline tracts of Batticaloa district. Keywords: Growth attributes, Rice cultivars, Salt tolerant, YieldItem Growth, Physiological Attributes and Yield of Selected Groundnut (Arachis hyogaea L.) Cultivars Affected by Moisture Stress during the Flowering Stage(Uva Wellassa University of Sri Lanka, 2019) Sukanya, M.; Mahendran, S.Drought being the most important environmental stress severely impairs plant growth, limits plant production and the performance of crop plants more than any other environmental stress factors. An experiment was conducted at the Agronomy farm of the Eastern University, Sri Lanka during the Yala 2017 to determine the effects of drought on the growth physiology and yield of selected groundnut cultivars. Indi, Lanka jumbo and Tissa groundnut cultivars were used for this study. Polyethylene bags were filled with topsoil, red soil and compost and one hundred and ninety-two bags were used. Moisture stress was imposed for a period of ten days by withholding the water continuously during the flowering stage. The control plants were watered to Field Capacity at two days interval. This experiment was laid out in the Randomized Complete Block Design with six treatments (T1, T3 and T5 were control, T2, T4 and T6 were moisture stressed) and four replications and the treatments were arranged in 3×2 factor factorial design. Moisture stress has significantly (p< 0.05) reduced the measured physiological growth attributes in terms of chlorophyll content, Leaf Area Index and yield compared to the control treatment. The highest values of chlorophylls a (0.98 mg g-1), b (0.79 mg g-1) and total chlorophyll (1.7 mg g-1) were obtained in the groundnut cultivar Indi and the lowest (Chl. a- 0.5 mg g-1, Chl. b- 0.3 mg g-1 and total Chl.- 0.9 mg g-1) were found in Tissa. The highest Leaf Area Index (0.58) was obtained in the groundnut cultivar Indi and the lowest (0.33) was found in Tissa. The highest yield (0.8 t ha-1) was recorded in the cultivar Indi and the lowest (0.3 t ha-1) was found in Tissa under moisture stressed condition. Hence, this study revealed that Indi groundnut cultivar has shown better growth performance and yield than the others when exposed to moisture stress during the flowering stage. As such, this cultivar could be suggested in the arid parts of the Eastern province.Item Impacts on Leaf Area Index, Plant Dry Weight and Yield as Influenced by Salinity Stress in Brinjal (Solanum melongena L.) Cultivars(Uva Wellassa University of Sri Lanka, 2021) Nahila, M.A.F.; Mahendran, S.Brinjal is an important vegetable which is quite popular and widely cultivated crop, mostly grown in the rainy season. In Sri Lanka, brinjal is commonly cultivated in Jaffna, Batticaloa, Polannaruwa and Moneragala districts. In the Batticaloa district, brinjal is widely grown in Kaluthavalai, Vaharai and Eravur areas. Large extent of brinjal cultivation in Kaluthavalai area is affected by salinity. The literature that exists on egg plant‟s tolerance to soil salinity is contradictory; some are classified as moderately sensitive, whereas others reported that it is sensitive to water stress caused by salinity. Considering this, an experiment was conducted in the Sandy Regosols of the Batticaloa district to evaluate salinity response of „Thirunelvely Purple‟, „Palugamum White‟ and „Padagoda‟ brinjal cultivars on the Leaf Area Index (LAI), plant dry weight and yield. A concentration of 100mM NaCl solution was applied for the treated plants and distilled water used as control treatment. The treatments were 100mM NaCl solution for the „Thirunelvely Purple‟ (T2), „Palugamum White‟ (T4) and „Padagoda‟ (T6) brinjal cultivars and distilled water for the „Thirunelvely Purple‟ (T1), „Palugamum White‟ (T3) and „Padagoda‟ (T5) brinjal cultivars were applied to Field Capacity at 3 days interval during the experimental period. This experiment was laid out in the 3 x 2 factor Factorial Randomized Complete Block Design with four replicates. The results showed that salt stress significantly (p<0.05) reduced the LAI of all the tested brinjal cultivars. The highest LAI (0.55±0.02) was obtained in the „Thirunelvely Purple‟ and the lowest (0.23±0.01) was found in the „Palugamum White‟. Salt stress significantly (p<0.05) reduced the plant dry weight of the tested brinjal cultivars. The highest plant dry weight (126.4±1.52g) was found in the „Thirunelvely Purple‟ and the lowest (79.8±0.92g) was recorded in the „Palugamum White‟. Salt stress significantly (p<0.05) reduced the yield of the brinjal cultivars. The highest yield (20.1±0.34 t/ha) was obtained in the „Thirunelvely Purple‟ and the lowest (11.3±0.21 t/ha) was found in the „Palugamum White‟. Therefore, this study concludes that „Thirunelvely Purple‟ brinjal cultivar exhibited the highest growth performance under saline condition and was identified as the most salt tolerant cultivar compared to the other tested ones. Keywords: Brinjal; Leaf Area Index; Plant dry weight; Salt stress; YieldItem Value Addition of Coir Pith by Composting: A Comparison between Coir Pith Compost and Traditional Compost(Uva Wellassa University of Sri Lanka, 2010) Lavanya, S.; Vijitha, N.; Mahendran, S.Coir pith is a natural and renewable resource obtained from coconut husks. Though coir pith has a number of beneficial properties, its direct utilization as a manure is restricted owing to its high carbon: nitrogen (C:N) ratio (100-120:1) and lignin content (30%) which delays natural decomposition. Hence, a study was conducted at the Eastern University, Sri Lanka to convert the raw coir pith to composted coir pith and to analyze its properties and suitability as a manure. The coir pith compost was prepared by using coir pith, spawn of oyster mushroom (Pleurotus sajor caju) and cattle urine and allowed to decomposition. The samples of coir pith compost were analyzed for their properties such as moisture content, porosity, bulk density, particle density, pH, electrical conductivity, organic carbon, macro nutrients and Carbon : Nitrogen Ratio. They were compared with the properties of traditional compost. The results of this study revealed that certain properties of coir pith compost namely, moisture content and porosity were significantly higher than the traditional compost. The Potassium content, bulk density particle density and electrical conductivity of composted coir pith were significantly lower than the traditional compost. However, there were no significant differences in the Nitrogen, Phosphorus and pH of the coir pith compost and traditional compost. Composted coir pith had more Organic carbon than traditional compost. The Carbon: Nitrogen ratio of composted coir pith was reduced to favourable level but, remained higher than that of the traditional compost. Hence, it could be concluded that coir pith can be converted into a manure by composting. The value added final product has favourable physical and chemical properties to be used as organic manure. Key words: Coir pith compost, Properties, Traditional compost