N. Kuruppuarachchi, L. D. B. Suriyagoda, G. K. N. G. Pushpakumara, G. L. L. P. Silva
{"title":"Selection of Model Homegardens: Does the District Heterogeneity Classifies the Homegardens?","authors":"N. Kuruppuarachchi, L. D. B. Suriyagoda, G. K. N. G. Pushpakumara, G. L. L. P. Silva","doi":"10.4038/tar.v34i4.8670","DOIUrl":"https://doi.org/10.4038/tar.v34i4.8670","url":null,"abstract":"Among numerous studies done with homegardens (HGs), few efforts have been drawn up to examine biodiversity, input availability and the influence of the complex environment of households and HGs on its produce. Interventions to improve HGs are generally done within the administrative boundaries of the region and the success of such attempts should be evaluated using appropriate tools. To address this research gap a study was formulated aiming at grouping selected HGs and identifying the variables contributing to grouping; and thereby suggesting the characteristics of a model HG. A HG survey was conducted focusing Ratnapura and Hambantota districts of Sri Lanka. Pooled and separated samples of HGs in the two districts were employed in K-means cluster analysis and the groups obtained were subjected to discriminant function analysis to derive the important variables in discriminating HGs. The HGs in Ratnapura were grouped into three categories and key variables contributing to differentiate those were annual expenditure for HG, labor usage, above ground biomass, disease occurrence, species density of trees, and tree density. There were four groups of HGs in Hambantota and key variables that contributed to their differences were; annual expenditure for HG, pest occurrence, annual income from HG, species density of trees, the total share of produce in HG used for consumption, technical knowledge on farming and land extent. Accordingly, the income-driven and diversity-enhanced components of a HG would make it a model HG achieving maximum productivity. However, due to the heterogeneity of HGs, distinct groups within a district could not be identified, suggesting the inappropriateness of making administrative boundaries-based decisions on the interventions in HGs.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135457995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Plant Diversity, Aboveground Biomass and Carbon Stock in an Isolated Tropical Sub Montane Forest in Sri Lanka","authors":"B. M. B. Weerakoon, S. P. Nissanka","doi":"10.4038/tar.v34i4.8669","DOIUrl":"https://doi.org/10.4038/tar.v34i4.8669","url":null,"abstract":"This study was conducted at Rilagala conservation forest, Nawalapitiya to assess and compare the plant diversity, above ground biomass and carbon stock in the periphery and interior of an isolated sub montane forest in Sri Lanka. All trees above 5 cm Diameter at Breast Height (DBH) in eleven randomly demarcated 25 m × 25 m plots were recorded. Distance up to 100 m from the forest boundary considered as the periphery (8 plots) and over 200 m as the core (3 plots). A total of 1,583 trees belonging to 29 species were recorded and aboveground biomass (AGB) and carbon stocks were calculated using allometric equations. The tree diversity of each plot was calculated using the Shannon diversity index (H’). Results were statistically analysed using single factor ANOVA. The species richness and H’ were the highest at the periphery (n=23, H’= 2.55) while the lowest at forest interior (n=11, H’= 1.97). The highest tree density was recorded at periphery (2,992 trees ha-1) and it decreased to 1,408 trees ha-1 towards the core. The average DBH was 8.5 ± 3.33 cm and it increased towards the forest interior (9.7 ± 4.51 cm) from the periphery (7.2 ± 3.74 cm). Estimated aboveground biomass ranged from 63.99 - 108.13 Mg ha-1 with a mean of 82.53 ± 14.39 Mg ha-1. The above ground C stock was estimated from 31.99 - 54.07 Mg ha-1 with a mean of 41.26 ± 7.2 Mg ha-1. However, there was no significant difference between forest periphery and core in variables, except species richness (p<0.05). The study revealed that the diversity and density of trees decreased towards the forest interior and vice versa was recorded for DBH, AGB and carbon stock. The study highlights the importance of conserving isolated tropical sub montane forest patches for carbon sequestration.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135458274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Seed Treatments on Seed Germination and Seedling Growth of Madhuca longifolia var. longifolia (“Mee”)","authors":"H. Karunarathna, J. Eeswara, M. Iqbal","doi":"10.4038/tar.v34i3.8646","DOIUrl":"https://doi.org/10.4038/tar.v34i3.8646","url":null,"abstract":"Madhuca longifolia (Koenig) J.F. Macb. var. longifolia is a forest tree species with high reforestation potential in the dry zone of Sri Lanka. Seasonality in seed production and lack of plant production are the drawbacks of this species regenerating naturally. Seeds were treated with gibberellic acid (GA3), potassium nitrate (KNO3), distilled water (DW), and scarified in addition to control without any treatment. Data were evaluated for germination and seedling growth under ex vitro and in vitro conditions. The objective of this study is to determine the dormancy associated with M. longifolia seeds and the effect of pre-treatments on seedling growth. Mechanically scarified seeds, under ex vitro conditions, showed higher germination than all the other treatments after 28 days and a significantly higher percentage (p<0.05) than the control under both light (90.00%) and dark (85.45%). Dark conditions stimulated germination significantly within the first seven days of sowing. The highest shoot growth was observed for GA3, KNO3, and DW (8.3, 8.6, and 8.5 cm, respectively) treatments while rooting was not significantly affected by the applied treatments. In vitro germination was tested for de-coated, surface sterilized seeds on half-strength liquid Murashige and Skoog (½ MS) media with different concentrations of benzylaminopurine (BAP) such as 0, 0.2, 0.5, and 1.0 mg/L. The germination percentage of ½ MS with 0.5 mg/L BAP (77.71%) was higher than all the other media compositions. Results revealed that M. longifolia seeds show a lower level of germination due to physical dormancy, and it can be released by mechanical scarification.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48372101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exogenous Salicylic Acid Induced Drought Stress Tolerance in Immature Tea (Camellia sinensis L.) Plants","authors":"M. Damayanthi, T. L. Wijeratne, J. W. Damunupola","doi":"10.4038/tar.v34i3.8649","DOIUrl":"https://doi.org/10.4038/tar.v34i3.8649","url":null,"abstract":"Salicylic acid (SA) has been known to induce drought tolerance in many plant species. In this study, we investigated the potential of exogenous application of SA to enhance drought tolerance in immature tea plants under glasshouse conditions at the Tea Research Institute in Talawakelle, Sri Lanka. One-year-old potted tea cultivars known for drought tolerance were used in the study. The plants were subjected to a drying cycle while being foliar sprayed with different concentrations of SA along with well-watered (WW), water-spray (WS) and no-spray (NS) treatments. Data were collected at 18 hours, 14 days after spraying (DAS), 21 DAS, and during the recovery after re-watering at 21 DAS. Based on the results obtained from the glasshouse study, the effective concentration of 150 mg L-1 SA was selected for further testing under field conditions in Talawakelle using three-year-old tea plants. The field experiment followed a randomized complete block design (RCBD) with three blocks. When the plants reached a moderate moisture stress level, they were foliar-sprayed with 150 mg L-1 SA, WS and NS treatments were included as controls. Data were collected at 7 DAS, 14 DAS, 21 DAS, and during the recovery phase after rain. The results showed that drought stress led to a decline in gas exchange parameters, relative water content, and an increase in the accumulation of osmolytes. However, the exogenous application of 150 mg L-1 SA significantly improved physiological processes such as gas exchange, osmolyte accumulation, and antioxidant activity, thus effectively enhancing drought tolerance in immature tea plants.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46592366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Hearath, D. D. A. Pushpakumara, M. Hewson, P. Wickramagamage
{"title":"A Geospatial and Socio-economic Assessment of Tree Density in Home Gardens as Trees Outside Forests Sources in Agro-ecological Regions: Upper Mahaweli Catchment, Sri Lanka","authors":"H. Hearath, D. D. A. Pushpakumara, M. Hewson, P. Wickramagamage","doi":"10.4038/tar.v34i3.8647","DOIUrl":"https://doi.org/10.4038/tar.v34i3.8647","url":null,"abstract":"Homegardens (HGs) serve as crucial 'Trees Outside Forest Sources' (TOFS) systems, offsetting tree cover loss resulting from extensive deforestation in the Upper Mahaweli Catchment (UMC) over the past two centuries. This study examined the temporal and spatial distribution of HGs in relation to agro-ecological regions (AERs) within the UMC boundary, assessed the tree density of HGs, and analyzed the biophysical and socio-economic factors influencing tree density. Geospatial assessment utilized Landsat Images and tree density estimation was based on a random sample of 500 HGs in the UMC with a minimum diameter at breast height (dbh) of >10cm. Regression analysis was employed to identify factors affecting tree density. The spatial assessment revealed that in 2017, the AER of IM3a covered the highest percentage area (66.5%) whereas IM1a recorded the greatest incremental percentage change (22.8%) from 1992-2017, while the lowest change was observed in IL2 (0.03%). The highest tree density was observed in IU2 (858 trees/ha), and the average density in WM2a (505 trees/ha), comparable to that of South-Asian tropical rainforests. However, there is a concerning trend of rapid spread of exotic species contributing to the high tree density observed in IU2, WM2a, and IU3d. The multiple linear regression model (p<0.01, R2 = 58.62%) indicated spatial, agronomic and institutional factors positively influenced tree density. Conversely, the HG area square, and demographic factors had a significant negative impact on tree diversity (p<0.01). To ensure the ecological sustainability of the UMC, the study proposes to introduce an appropriate incentive package to enhance tree density in HGs, with native species.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44568319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L.N.R. Gunaratna, N. Deshappriya, R. Rajapaksha, D. Jayaratne
{"title":"Allium cepa L. (Onion) Storage Diseases and Effect of Trichoderma asperellum and Trichoderma virens Pre-harvest Treatments on Postharvest Quality","authors":"L.N.R. Gunaratna, N. Deshappriya, R. Rajapaksha, D. Jayaratne","doi":"10.4038/tar.v34i3.8542","DOIUrl":"https://doi.org/10.4038/tar.v34i3.8542","url":null,"abstract":"Substantial yield losses have been reported during the storage of Allium cepa L., and effective methods to minimize postharvest losses are currently lacking. Therefore the objectives of this study were to investigate the impact of pre-treatment with Trichoderma asperellum and Trichoderma virens on post-harvest losses during storage and to evaluate factors associated with these losses. The storage behaviors of Allium cepa L. bulbs after different field treatments with Trichoderma spp. were examined using a complete randomized design. The common onion bulb diseases encountered during storage were basal rot and black mould diseases, with Fusarium sp., Mucor sp., Penicillium sp., Aspergillus niger and Aspergillus flavus being associated with diseased bulbs. The results regarding the percentage of diseased bulbs showed that pre-harvest treatments with Trichoderma asperellum and Trichoderma virens did not have a significant effect on disease control during storage. Furthermore, storage losses of onions were attributed to sprouting, rooting and wilting, which were exacerbated by the prevailing temperature (~30-32°C) and relative humidity (~77%-79%) during the storage period.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43676276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of Two Levels of Dietary Energy Content on Milk Production and Serum Metabolites in Early Lactation Temperate Crossbred Dairy Cows Fed Guinea Grass (Megathyrsus maximus) Based Diets","authors":"W. Weerasinghe, H. Herath, M. Mahipala","doi":"10.4038/tar.v34i3.8582","DOIUrl":"https://doi.org/10.4038/tar.v34i3.8582","url":null,"abstract":"The current study investigated the association of two levels of metabolizable energy (ME) content on milk production, composition, and blood metabolites of temperate crossbred (Jersey x Frieician) dairy cows fed with Guinea grass (Panicum maximum) and concentrates (50:50 on a DM basis) based total mixed ration (TMR). Twelve multiparous temperate crossbred dairy cows were randomly allocated to each dietary treatment (n=6) in a randomized block design. The required energy diet (RE) was predicted to supply the recommended level (100%) of ME, and the high energy diet (HE) was predicted to supply 10% more than the recommended level (110%) of the daily ME requirements of the dairy cows. Dry matter intake, body weight, and milk yield were recorded, and feed and blood samples were obtained for proximate and blood metabolite analysis during the 14 weeks experimental period. No treatment effects were observed (P>0.05) on BW, milk fat, SNF, protein, and milk urea nitrogen or on blood metabolites such as serum non esterified fatty acids, beta-hydroxy butyric acid, Albumin, Ca and P. Compared to the cows fed with RE, HE diet fed cows had high (P<0.05) dry matter intake at 4, 10, 12, and 14 weeks but dietary treatment had no effect on dry matter intake (P>0.05) at 2, 6, and 8 weeks of the experimental period. Until the 4th week of lactation, dietary treatment had no effect (P>0.05) on milk yield, but from the 4th to the 14th week, cows fed with HE had a higher (P<0.05) milk yield than those fed with RE. Thus, the cumulative milk yield of the cows fed with HE were higher (P<0.05) than that of cows fed with RE from the 10th to 14th weeks of lactation. It was concluded that the milk yield of temperate crossbred dairy cows fed diets based on Guinea grass can be enhanced by incorporating high energy content into the diet.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46015022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Lowe, D. D. A. Pushpakumara, H. Weerahewa, W. Vitharana, B. Marambe, B. Punyawardena, G. Silva
{"title":"Enhancing Household Food Security and Dietary Diversity through Homegardens: A Case Study in Selected Districts of Sri Lanka","authors":"W. Lowe, D. D. A. Pushpakumara, H. Weerahewa, W. Vitharana, B. Marambe, B. Punyawardena, G. Silva","doi":"10.4038/tar.v34i3.8645","DOIUrl":"https://doi.org/10.4038/tar.v34i3.8645","url":null,"abstract":"Homegardens are resourceful ecosystems that provide essential services to the environment and mankind. Their contribution to secure household food requirement is among the provisional services of contemporary relevance. A study was conducted in 429 homegardens in Jaffna, Matale, Ratnapura, and Hambantota districts to assess the scope of utilizing homegarden resources on household food security. A questionnaire survey was conducted to gather information on the consumption frequency and the number of food categories that were purchased, produced, and shared. The mean food consumption score (FCS) was 60±23, where 89% of the study population had an acceptable level of FCS (FCS>35). As per the dietary diversity score (HDDS), an average household consumed at least eight food categories per day. Coconut was the most common food commodity produced in homegardens, followed by jackfruit and other fruits (mango, guava, soursop and pomegranate). Households rely on the market-available foods as their primary food source. The study revealed that utilizing at least one food category as a homestead-resource produced, could improve FCS and assist to fulfil the household food demand significantly. However, the majority of the homestead-resources were identified as plant-based, except in Jaffna where the presence of livestock and poultry in homegarden was common. Many of the plant-based resources were from perennial fruit-bearing trees. Therefore, modifying and utilizing the tree composition and viable crops can be considered a timely option to avert household food insecurity. Further, incorporating livestock components (dairy, poultry) as a part of homegardens is beneficial in fulfilling the animal protein demand of the household.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47191633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Determination of the Best Performing Sri Lankan Maize Accessions Based on the Photosynthetic, Biomass and Yield Traits","authors":"M. Mufeeth, A. Mubarak, A. Kumara","doi":"10.4038/tar.v34i3.8648","DOIUrl":"https://doi.org/10.4038/tar.v34i3.8648","url":null,"abstract":"Maize (Zea mays L.) is one of the most widely cultivated cereal crops throughout the world and is extensively grown in Sri Lanka. Information on the photosynthetic, biomass and grain yield of local maize accessions are useful for plant breeding programs. However, due to the scarcity of such information, this study aimed to investigate the potentials of maize accessions to select the best performers utilizing the rank summation and selection index criteria. As the first step, the seeds from 14 maize accessions along with two varieties viz; Pacific-999 and Bhadra (control) were established in the field. The leaf-level photosynthetic and chlorophyll fluorescence traits were analyzed, while biomass and yield traits were obtained at harvest, by employing standard techniques. Our findings revealed that traits related to growth, photosynthesis, and biomass showed greater variations among the maize accessions tested. The number of days taken to 50% flowering (44d-60d), photosynthetic rates (19.7-30.45 μmol CO2 m−2 s−1), transpiration rates (2.45-4.52 mmol H2O m−2 s−1), water use efficiency (5.69-8.13 μmol CO2 mmol H2O-1), and maximum quantum yield (0.68-0.73) among the tested accessions. Additionally, the variations in biomass (111.0-459 g/plant) and final cob yield (38-232 g/cob) were also seen among the maize accessions. According to rank summation index analysis, the maize accessions SEU2, SEU16, SEU15, SEU9 and SEU10 were superior in terms of photosynthetic rates, biomass and yield compared exhibiting with the lowest RSI values of 71, 100, 101, 103 and 117, respectively, than the cv. Bhadra. Therefore, future crop development programs can make use of these five potential maize accessions identified through this study.","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44423259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Marasinghe, S. H. P. P. Karunarane, S. Surendran, K. S. Hemachandra, L. Nugaliadde
{"title":"Insecticide Resistance, Resistance Mechanisms, and Phylogeny of Three Myzus persicae Populations in Cabbage from Three Agroclimatic Zones of Sri Lanka","authors":"J. Marasinghe, S. H. P. P. Karunarane, S. Surendran, K. S. Hemachandra, L. Nugaliadde","doi":"10.4038/tar.v34i2.8621","DOIUrl":"https://doi.org/10.4038/tar.v34i2.8621","url":null,"abstract":"","PeriodicalId":23313,"journal":{"name":"Tropical agricultural research","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43855306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}