Shyama Weerakoon - Academia.edu (original) (raw)

Papers by Shyama Weerakoon

Nusantara Bioscience

Rice (Oryza sativa L.) is a major staple food in the world. There is an extreme need for higher r... more Rice (Oryza sativa L.) is a major staple food in the world. There is an extreme need for higher rice yield to meet the ever-increasing demand with the rise in population despite the hampering impact of climatic changes. Nanotechnology plays a potential role in food security and introduces nano fertilizers as an alternative to conventional fertilizers. Therefore, the present research was carried out to determine the effects of nano micronutrient fertilizers; nano-CuO, and nano-ZnO on the yield of selected rice varieties, Bg360, BW364, Kaluheenati, and Kuruluthuda. Sol-gel and thermal decomposition methods synthesized nano-fertilizers used in the study. Nano-ZnO, nano-CuO, and nano-CuO-ZnO composite treatments were applied as a foliar spray at concentrations of 30 mg L-1 (T1), 60 mg L-1 (T2), and 120 mg L-1 (T3) and double deionized water served as the control (T0). The synthesized nano-fertilizers were applied during the growth stage [at 48-58 days after sowing (DAS)] and grain filling stage [100-105 DAS], while the plants were provided with appropriate levels of N, P, and K fertilizers, as recommended by Department of Agriculture. A Complete Randomized Block Design was employed with three blocks and five replicates in each block. The Yield parameters were recorded at the harvesting stage. Descriptive statistics such as mean and standard error of mean and inferential statistics were performed on the data obtained. ANOVA with interaction terms was performed to assess the significant differences between the treatments. The descriptive analyses show an increase in the yield of the rice varieties under the application of nano-fertilizers. ANOVA suggests a significant effect (p ≤ 0.05) of nano-CuO and nano-ZnO on the yield of rice varieties used in the study. Both traditional and inbred rice varieties indicated yield response to applied nano-fertilizers.

Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevola aemula ... more Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevola aemula R. Br. cv. 'Purple Fanfare' was achieved. High frequency of somatic embryos was obtained directly from petiole and leaf explants using an inductive plant growth regulator signal thidiazuron (TDZ). Petiole explants were more responsive to SE than leaves. Plants derived from somatic embryos of petiole explants germinated more readily into plants. SE occurred more efficiently in half-strength Murashige and Skoog (MS) medium than in full-strength MS medium. Non-embryogenic callus induced by 2, 4-dichlorophenoxyacetic acid was used to investigate the feasibility of obtaining SE with TDZ as a secondary inductive plant growth regulator (PGR) signal. Non-embryogenic callus of S. aemula was able to convert into an "embryogenic competent mode" with PGR signal. Protocol developed for induction of direct and indirect somatic embryogenesis in S. aemula can improve the large scale pr...

The production of a trigenomic hexaploid population using a cross between B. carinata and B. rapa... more The production of a trigenomic hexaploid population using a cross between B. carinata and B. rapa followed by chromosome doubling at Huazhong Agricultural University stimulated the interest in synthesizing hexaploid Brassica. An attempt has been made to synthesize trisomic hexaploid Brassica by crossing B. juncea and B. oleracea followed by chromosome doubling. Five diverse genotypes of B. juncea (var. Zun Yi and Wu Ding -Chinese varieties, R 4355, R 4321 and Sel 21 -Russian varieties) and five diverse genotypes of B. oleracea (Chinese Broccoli, Broccoli (var. Shogun), Cauliflower (var. Snowball and var. Phenomenon Early) and Cabbage (var. Sweet Eureka) were selected for the investigation. Hand pollination was attempted by emasculating the buds of one species and pollination using another species where flowering was synchronous. Crossing was made in both directions. The crosses of B. juncea (♀) x B. oleracea (♂) resulted in 307 mature pod set. The success of pod formation was 25%. T...

Abstract—Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevol... more Abstract—Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevola aemula R. Br. cv. ‘Purple Fanfare ’ was achieved. High frequency of somatic embryos was obtained directly from petiole and leaf explants using an inductive plant growth regulator signal thidiazuron (TDZ). Petiole explants were more responsive to SE than leaves. Plants derived from somatic embryos of petiole explants germinated more readily into plants. SE occurred more efficiently in half-strength Murashige and Skoog (MS) medium than in full-strength MS medium. Non-embryogenic callus induced by 2, 4-dichlorophenoxyacetic acid was used to investigate the feasibility of obtaining SE with TDZ as a secondary inductive plant growth regulator (PGR) signal. Non-embryogenic callus of S. aemula was able to convert into an “embryogenic competent mode ” with PGR signal. Protocol developed for induction of direct and indirect somatic embryogenesis in S. aemula can improve the large scale propagati...

Transgenic Plant Technology for Remediation of Toxic Metals and Metalloids

Abstract Release of heavy metals and metalloids from diverse anthropogenic activities causes a dr... more Abstract Release of heavy metals and metalloids from diverse anthropogenic activities causes a dramatic escalation and prolonged persistence of heavy metals and metalloids, reducing the productivity of an ecosystem while imposing health threats. Potential plant species have been identified for toxic metal and metalloid resistance. This is achieved either via hyperaccumulation or exclusion/avoidance of toxic metals and metalloids. Phytoremediation is a cost-effective and environmentally friendly in situ treatment technology where toxic metal and metalloid hyperaccumulating plants are used to cleanse the environment. Application of genetic engineering to modify plants for metal uptake, transport, and sequestration has enhanced the efficiency of phytoremediation, which is achieved by transformation of the genes of metal hyperaccumulating plants and microbes that are responsible for tolerance, accumulation, and detoxification of metals and metalloids in fast-growing plant species. As more genes related to metal metabolism are discovered, genome sequencing projects could lead to new opportunities to develop efficient transgenic plants for phytoremediation. This chapter discusses the potential of genetic engineering as a strategy to improve the phytoremediation capacity of plants in the context of heavy metals and metalloid detoxification.

Cereal Grains - Volume 2

Rice is the staple food crop in Sri Lanka, which occupies 34% (0.77/million ha) of the total cult... more Rice is the staple food crop in Sri Lanka, which occupies 34% (0.77/million ha) of the total cultivated area. Sri Lanka currently produces 2.7 million tonnes of rough rice annually and satisfies around 95% of the domestic requirement. In Sri Lanka, genus Oryza consists of two species complexes, O. sativa (AA) and O. officinalis (CC). These two complexes are both pan tropical and have very similar overall distribution. Five wild rice species are reported in Sri Lanka, (O. nivara [AA], O. rufipogan (AA) O. eichengeri [CC], O. rhizomatis (CC) and O. granulate (GG). O. rhizomatis has been reported only in Sri Lanka and considered endemic to Sri Lanka. Recent studies demonstrated, the reliance on single source of information could mislead results in the phylogenetic inferences due to analytical inconsistency and biological processes. Therefore, exact number of wild rice species in Sri Lanka becomes uncertain and the necessity arises to assess Oryza species complexes in Sri Lanka using mo...

Herbicide resistant (HR) rice is a novel approach to enhance selectivity and crop safety in rice ... more Herbicide resistant (HR) rice is a novel approach to enhance selectivity and crop safety in rice cultivation. HR crops provide better suppleness in weed management and new solutions to difficult weed management problems. Studies on induced HR in Sri Lankan rice varieties are limited and further research are required to include HR rice in a cropping program. Mutational breeding with molecular methods play an important role in resistant development in modern agriculture. The present study is an attempt to develop HR rice lines through conventional breeding methods using the chemical mutagen EMS. A detailed AFLP analysis was made to identify molecular markers for HR induced varieties. Twenty five cultivated rice varieties were subjected to EMS treatment and after the mutation survived plants were exposed to glyphosate to check herbicide resistance. AFLP analysis was made on EMS mutated rice plants using 16 AFLP primer combinations. Seed-derived calli were obtained from glyphosate-susce...

Weedy rice (Oryza sativa f. spontanea) is one of the most nuisance weeds, referred as “red rice” ... more Weedy rice (Oryza sativa f. spontanea) is one of the most nuisance weeds, referred as “red rice” possess higher morphological variability and varying degrees of similarities to wild and cultivated rice. Close similarity between weedy and cultivated rice prevents use of selective herbicides in controlling weedy rice. Weedy rice affects both quantity and quality of national rice production. Efforts were made to understand morphological and physiological properties of weedy rice and its epidemiology to design controlling methods and to disseminate information to farmers. Weedy rice is strongly characterized by seed shattering and dormancy characters. Long term sympatric distribution has led to similarities between weedy and cultivated rice through natural hybridization and introgression. Major wild rice species (O. nivara and O. rufipogon) are also distributed all over the country. The content of the book discusses levels of genetic diversity of weedy rice populations in different clim...

Journal of the Indian Academy of Wood Science

Journal of Genetic Engineering and Biotechnology

Background The recent recovery of Gyrinops walla as a potential producer of market-quality agarwo... more Background The recent recovery of Gyrinops walla as a potential producer of market-quality agarwood in mature damaged woods and branches has led to the intense illicit felling and exportation of G. walla leading to the verge of extinction from Sri Lankan flora. The sustainable utilization of G. walla undoubtedly enhances the foreign exchange of the country and the non-destructive utilization through tissue culture–based techniques is the only option available for sustainable exploitation and conservation of the vulnerable species. Healthy calli and cell suspensions were chemically and biologically elicited with salicylic acid (SA) and methyl jasmonate (MJ), and the sterilized fungal homogenate (carbohydrate equivalents) of Fusariym oxysporum, Phaeocremonium parasitica, Aspergillus niger, Trichoderma viride, Penicillium commune and Lasidiplodia theobromae fungal strains, respectively. The elicited calli and cell suspensions were harvested at different time periods to extract sesquite...

The EuroBiotech Journal

Aloeswood or Agarwood has long been perfumery commodity traded between Mediterranean Region and S... more Aloeswood or Agarwood has long been perfumery commodity traded between Mediterranean Region and Southeast Asia since ancient times. Oil or chips are obtained by destructive harvesting of several Thymeleaceous genera includes Aquilaria and Gonystylus and are expensive and highly demanded ingredients in the global market. The recent recovery of Gyrinops walla as a potential producer of market-quality agarwood in mature damaged woods and branches, the intense illicit felling and exportation G. walla leading to the verge of extinction from Sri Lankan flora. The sustainable utilization of G. walla undoubtedly enhances the foreign exchange of the country and the non-destructive utilization G. walla through biotechnology is the only option available for sustainable exploitation and conservation of the vulnerable G. walla species. An electro-elicitation apparatuses were designed and built to stimulate calli and cell suspensions. The elicited and calli and cell suspensions were harvested at ...

Rice Crop - Current Developments, Sep 5, 2018

Since studies on herbicide-resistant rice (HRR) are limited in Sri Lanka, the present study condu... more Since studies on herbicide-resistant rice (HRR) are limited in Sri Lanka, the present study conducted to screen the naturally existing glyphosate and glufosinate resistance in traditional and inbred rice varieties. Six traditional varieties and nineteen inbred lines were selected for the study. Complete randomized design with three pots with 10 replicates for each herbicide concentration was employed. Optimal concentrations of glyphosate (0.5 gl −1) and glufosinate (0.05 gl −1) were applied at 3-4 leaf stages. Varieties ≥50% survival percentage was considered as resistant to respective herbicides. Twelve varieties showed resistance (≥50%) at 0.5 gl −1 glyphosate concentration. Survived plants were monitored and agro-morphological and yield characters/parameters were measured. Fifteen varieties were to glufosinate at 0.05 gl −1. Even though no significant differences (p > 0.05) were observed in growth parameters across control and treated plants, there was a yield penalty. Nine varieties (At362,

Information Processing in Agriculture

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

centre for Legumes in mediterranean agriculture newsletter Australian Team Leader, Rob Williams a... more centre for Legumes in mediterranean agriculture newsletter Australian Team Leader, Rob Williams and Seeds of Life technician Roginio, compare yields of newly released and traditional peanut varieties in Baucau, East Timor. Seeds of Life-East Timor was recently reviewed and extended for a further three years. The reviewers were extremely complimentary of the program's progress and made a number of recommendations for expanding both the activities and funding. Seeds of Life is a program within the Ministry of Agriculture Forestry and Fisheries (MAFF) supported by Australia with funding from the Australian Agency for International Development (AusAID) and the Australian Centre for International Agricultural Research (ACIAR). The Australian funding is managed by the University of Western Australia (UWA) through the Centre for Legumes in Mediterranean Agriculture (CLIMA) under ACIAR project no CIM/2003/014. The strength of Seeds of Life lies in the ability of the program to both identify and distribute improved varieties of key food crops. Varieties imported from crop centres belonging to the Consultative Group on International Agricultural Research (CGIAR) is evaluated on research stations, followed by on-farm trialling across a range of ecosystems. Because Seeds of Life is part of the MAFF, it is then a simple process for the Minister to recommend the most promising lines for release and to facilitate their spread through the Government seed production system.

Ceylon Journal of Science (Biological Sciences), 2010

Heavy metal pollution in soil and water is a global environmental concern. In Sri Lanka, accumula... more Heavy metal pollution in soil and water is a global environmental concern. In Sri Lanka, accumulation of heavy metals in soil, water and plant/animal biomass has been widely reported. Phytoremediation, the use of plants and their associated microbes, is an emerging, low-cost, environmental-friendly approach in the cleanup and prevention of environmental pollution. Indian Mustard (Brassica juncea) has been widely used to extract toxic metals from contaminated soils worldwide. Sri Lanka has a genetically diverse mustard collection, but their phytoextarctive potentials are yet to be determined. Present study was conducted to evaluate variation in phytoextractive ability of soil-borne heavy metals by ten different mustard accessions. Heavy metal contents (Mn, Co, Pb and Zn) in 12-week-old mustard plants (whole plant) were estimated during Maha and Yala in 2007-2008 using Atomic Absorption Spectroscopy. Heavy metal content in soils where the plants were grown was also assessed during the two seasons. Soil Mn and Co concentrations were significantly high in Maha than in Yala. Difference in heavy metal concentrations in mustard accessions between the two seasons was not significant. However, significantly high concentrations of Mn were found in accessions 7788, 515 and 8831 (236, 225, 220x10 2 µg/g). Cobolt (Co) was significantly high in accession 5088 (238x10 2 µg/g). Lead (Pb) concentrations were significantly high in accessions 8831 (156x10 2 µg/g) and 5088 (148x10 2 µg/g) and Zn was significantly high in accession 501 (6413x10 2 µg/g). The study suggests that screening the entire mustard germplasm in Sri Lanka is worthwhile to identify potential heavy metal accumulators.

Transgenic Plant Technology for Remediation of Toxic Metals and Metalloids

Abstract Phytoremediation has gained the attention all over the world as one of the most cost-eff... more Abstract Phytoremediation has gained the attention all over the world as one of the most cost-effective and sustainable approaches for removal, sequestration, and/or detoxification of contaminants especially metals and metalloids from land and freshwater bodies. However, field studies indicated that these contaminant removal rates and tolerability of the conventional plant species are inadequate. Therefore, transgenic plants endowed with extended capability for phytoremediation have emerged as a promising solution to overcome common weaknesses of conventional plants that have been used in the remediation process. Scientists were able to develop transgenic plants capable of successful removal of environmental contaminants including heavy metal(loid)s like Cd, Co, Cu, Pb, Zn, Se, As, and Hg. Although transgenic plants bring favorable advantages to phytoremediation, there are many concerns regarding human health and environmental sustainability. Therefore, this chapter extensively discusses the benefits and emerging applications of transgenic plants in phytoremediation to remediate the extraction of heavy metals and metalloids. This chapter also discusses the drawbacks and possible risks associated with the transgenic plants and the regulatory issues that could possibly arise from these transgenic species.

Nusantara Bioscience

A collection of over 2000 traditional rice varieties are conserved at Gene Bank, Plant Genetics R... more A collection of over 2000 traditional rice varieties are conserved at Gene Bank, Plant Genetics Resource Center, Sri Lanka. Oryza sativa varieties grown in Sri Lanka from ancient times to the middle of the last century are known as traditional rice. These varieties show adaptability to biotic and abiotic stresses and, an important component of biodiversity of Sri Lanka. A detailed understanding of the diversity of traditional rice varieties is essential for effective utilization of rice genetic resources and identification of potential parents possessing valuable genetic traits for future crop improvement. Study objectives were phenotypic and molecular characterization of one-hundred traditional rice varieties and to identify a core collection for phenotypic and genetic diversity. Rice varieties were grown in a plant house following RCBD with 4 replicates and 5 plants per replicate. Thirty-two agro-morphological characters were observed/collected. Genomic DNA was extracted from 20-daysold seedlings. Thirty-three microsatellite (Simple Sequence Repeat-SSR) primer pairs were used to assay genetic variation and PCR products were subjected to fragment analysis by capillary electrophoresis. Descriptive statistics and basic inferential statistical analyses were performed to access variation of agro-morphological characters among rice varieties. Cluster analysis and Multidimensional scaling produced 07 groups which were further analyzed using Classification and Regression Analysis to extract the diagnostic agromorphological features. Groups of rice varieties were characterized by lemma palea color, awn color at maturity, seedling height, and flag-leaf angle. Traditional varieties represent distant clusters on agro-morphological features. Molecular analyses revealed all 33 loci displayed polymorphism (66.7-96.9%) among 100 traditional rice varieties with a total of 387 alleles identified with an average of 11.72 alleles per variety. All varieties were genetically structured into fifteen well-separated groups. UPGMA analysis based on Jaccard's similarity separated varieties into 05 major clusters. Genetic diversity information is useful in the efficient use of Sri Lankan rice germplasm and managing in situ and ex situ germplasm collections in conserving traditional rice varieties.

Nusantara Bioscience

Rice (Oryza sativa L.) is a major staple food in the world. There is an extreme need for higher r... more Rice (Oryza sativa L.) is a major staple food in the world. There is an extreme need for higher rice yield to meet the ever-increasing demand with the rise in population despite the hampering impact of climatic changes. Nanotechnology plays a potential role in food security and introduces nano fertilizers as an alternative to conventional fertilizers. Therefore, the present research was carried out to determine the effects of nano micronutrient fertilizers; nano-CuO, and nano-ZnO on the yield of selected rice varieties, Bg360, BW364, Kaluheenati, and Kuruluthuda. Sol-gel and thermal decomposition methods synthesized nano-fertilizers used in the study. Nano-ZnO, nano-CuO, and nano-CuO-ZnO composite treatments were applied as a foliar spray at concentrations of 30 mg L-1 (T1), 60 mg L-1 (T2), and 120 mg L-1 (T3) and double deionized water served as the control (T0). The synthesized nano-fertilizers were applied during the growth stage [at 48-58 days after sowing (DAS)] and grain filling stage [100-105 DAS], while the plants were provided with appropriate levels of N, P, and K fertilizers, as recommended by Department of Agriculture. A Complete Randomized Block Design was employed with three blocks and five replicates in each block. The Yield parameters were recorded at the harvesting stage. Descriptive statistics such as mean and standard error of mean and inferential statistics were performed on the data obtained. ANOVA with interaction terms was performed to assess the significant differences between the treatments. The descriptive analyses show an increase in the yield of the rice varieties under the application of nano-fertilizers. ANOVA suggests a significant effect (p ≤ 0.05) of nano-CuO and nano-ZnO on the yield of rice varieties used in the study. Both traditional and inbred rice varieties indicated yield response to applied nano-fertilizers.

Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevola aemula ... more Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevola aemula R. Br. cv. 'Purple Fanfare' was achieved. High frequency of somatic embryos was obtained directly from petiole and leaf explants using an inductive plant growth regulator signal thidiazuron (TDZ). Petiole explants were more responsive to SE than leaves. Plants derived from somatic embryos of petiole explants germinated more readily into plants. SE occurred more efficiently in half-strength Murashige and Skoog (MS) medium than in full-strength MS medium. Non-embryogenic callus induced by 2, 4-dichlorophenoxyacetic acid was used to investigate the feasibility of obtaining SE with TDZ as a secondary inductive plant growth regulator (PGR) signal. Non-embryogenic callus of S. aemula was able to convert into an "embryogenic competent mode" with PGR signal. Protocol developed for induction of direct and indirect somatic embryogenesis in S. aemula can improve the large scale pr...

The production of a trigenomic hexaploid population using a cross between B. carinata and B. rapa... more The production of a trigenomic hexaploid population using a cross between B. carinata and B. rapa followed by chromosome doubling at Huazhong Agricultural University stimulated the interest in synthesizing hexaploid Brassica. An attempt has been made to synthesize trisomic hexaploid Brassica by crossing B. juncea and B. oleracea followed by chromosome doubling. Five diverse genotypes of B. juncea (var. Zun Yi and Wu Ding -Chinese varieties, R 4355, R 4321 and Sel 21 -Russian varieties) and five diverse genotypes of B. oleracea (Chinese Broccoli, Broccoli (var. Shogun), Cauliflower (var. Snowball and var. Phenomenon Early) and Cabbage (var. Sweet Eureka) were selected for the investigation. Hand pollination was attempted by emasculating the buds of one species and pollination using another species where flowering was synchronous. Crossing was made in both directions. The crosses of B. juncea (♀) x B. oleracea (♂) resulted in 307 mature pod set. The success of pod formation was 25%. T...

Abstract—Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevol... more Abstract—Direct and indirect somatic embryogenesis (SE) from petiole and leaf explants of Scaevola aemula R. Br. cv. ‘Purple Fanfare ’ was achieved. High frequency of somatic embryos was obtained directly from petiole and leaf explants using an inductive plant growth regulator signal thidiazuron (TDZ). Petiole explants were more responsive to SE than leaves. Plants derived from somatic embryos of petiole explants germinated more readily into plants. SE occurred more efficiently in half-strength Murashige and Skoog (MS) medium than in full-strength MS medium. Non-embryogenic callus induced by 2, 4-dichlorophenoxyacetic acid was used to investigate the feasibility of obtaining SE with TDZ as a secondary inductive plant growth regulator (PGR) signal. Non-embryogenic callus of S. aemula was able to convert into an “embryogenic competent mode ” with PGR signal. Protocol developed for induction of direct and indirect somatic embryogenesis in S. aemula can improve the large scale propagati...

Transgenic Plant Technology for Remediation of Toxic Metals and Metalloids

Abstract Release of heavy metals and metalloids from diverse anthropogenic activities causes a dr... more Abstract Release of heavy metals and metalloids from diverse anthropogenic activities causes a dramatic escalation and prolonged persistence of heavy metals and metalloids, reducing the productivity of an ecosystem while imposing health threats. Potential plant species have been identified for toxic metal and metalloid resistance. This is achieved either via hyperaccumulation or exclusion/avoidance of toxic metals and metalloids. Phytoremediation is a cost-effective and environmentally friendly in situ treatment technology where toxic metal and metalloid hyperaccumulating plants are used to cleanse the environment. Application of genetic engineering to modify plants for metal uptake, transport, and sequestration has enhanced the efficiency of phytoremediation, which is achieved by transformation of the genes of metal hyperaccumulating plants and microbes that are responsible for tolerance, accumulation, and detoxification of metals and metalloids in fast-growing plant species. As more genes related to metal metabolism are discovered, genome sequencing projects could lead to new opportunities to develop efficient transgenic plants for phytoremediation. This chapter discusses the potential of genetic engineering as a strategy to improve the phytoremediation capacity of plants in the context of heavy metals and metalloid detoxification.

Cereal Grains - Volume 2

Rice is the staple food crop in Sri Lanka, which occupies 34% (0.77/million ha) of the total cult... more Rice is the staple food crop in Sri Lanka, which occupies 34% (0.77/million ha) of the total cultivated area. Sri Lanka currently produces 2.7 million tonnes of rough rice annually and satisfies around 95% of the domestic requirement. In Sri Lanka, genus Oryza consists of two species complexes, O. sativa (AA) and O. officinalis (CC). These two complexes are both pan tropical and have very similar overall distribution. Five wild rice species are reported in Sri Lanka, (O. nivara [AA], O. rufipogan (AA) O. eichengeri [CC], O. rhizomatis (CC) and O. granulate (GG). O. rhizomatis has been reported only in Sri Lanka and considered endemic to Sri Lanka. Recent studies demonstrated, the reliance on single source of information could mislead results in the phylogenetic inferences due to analytical inconsistency and biological processes. Therefore, exact number of wild rice species in Sri Lanka becomes uncertain and the necessity arises to assess Oryza species complexes in Sri Lanka using mo...

Herbicide resistant (HR) rice is a novel approach to enhance selectivity and crop safety in rice ... more Herbicide resistant (HR) rice is a novel approach to enhance selectivity and crop safety in rice cultivation. HR crops provide better suppleness in weed management and new solutions to difficult weed management problems. Studies on induced HR in Sri Lankan rice varieties are limited and further research are required to include HR rice in a cropping program. Mutational breeding with molecular methods play an important role in resistant development in modern agriculture. The present study is an attempt to develop HR rice lines through conventional breeding methods using the chemical mutagen EMS. A detailed AFLP analysis was made to identify molecular markers for HR induced varieties. Twenty five cultivated rice varieties were subjected to EMS treatment and after the mutation survived plants were exposed to glyphosate to check herbicide resistance. AFLP analysis was made on EMS mutated rice plants using 16 AFLP primer combinations. Seed-derived calli were obtained from glyphosate-susce...

Weedy rice (Oryza sativa f. spontanea) is one of the most nuisance weeds, referred as “red rice” ... more Weedy rice (Oryza sativa f. spontanea) is one of the most nuisance weeds, referred as “red rice” possess higher morphological variability and varying degrees of similarities to wild and cultivated rice. Close similarity between weedy and cultivated rice prevents use of selective herbicides in controlling weedy rice. Weedy rice affects both quantity and quality of national rice production. Efforts were made to understand morphological and physiological properties of weedy rice and its epidemiology to design controlling methods and to disseminate information to farmers. Weedy rice is strongly characterized by seed shattering and dormancy characters. Long term sympatric distribution has led to similarities between weedy and cultivated rice through natural hybridization and introgression. Major wild rice species (O. nivara and O. rufipogon) are also distributed all over the country. The content of the book discusses levels of genetic diversity of weedy rice populations in different clim...

Journal of the Indian Academy of Wood Science

Journal of Genetic Engineering and Biotechnology

Background The recent recovery of Gyrinops walla as a potential producer of market-quality agarwo... more Background The recent recovery of Gyrinops walla as a potential producer of market-quality agarwood in mature damaged woods and branches has led to the intense illicit felling and exportation of G. walla leading to the verge of extinction from Sri Lankan flora. The sustainable utilization of G. walla undoubtedly enhances the foreign exchange of the country and the non-destructive utilization through tissue culture–based techniques is the only option available for sustainable exploitation and conservation of the vulnerable species. Healthy calli and cell suspensions were chemically and biologically elicited with salicylic acid (SA) and methyl jasmonate (MJ), and the sterilized fungal homogenate (carbohydrate equivalents) of Fusariym oxysporum, Phaeocremonium parasitica, Aspergillus niger, Trichoderma viride, Penicillium commune and Lasidiplodia theobromae fungal strains, respectively. The elicited calli and cell suspensions were harvested at different time periods to extract sesquite...

The EuroBiotech Journal

Aloeswood or Agarwood has long been perfumery commodity traded between Mediterranean Region and S... more Aloeswood or Agarwood has long been perfumery commodity traded between Mediterranean Region and Southeast Asia since ancient times. Oil or chips are obtained by destructive harvesting of several Thymeleaceous genera includes Aquilaria and Gonystylus and are expensive and highly demanded ingredients in the global market. The recent recovery of Gyrinops walla as a potential producer of market-quality agarwood in mature damaged woods and branches, the intense illicit felling and exportation G. walla leading to the verge of extinction from Sri Lankan flora. The sustainable utilization of G. walla undoubtedly enhances the foreign exchange of the country and the non-destructive utilization G. walla through biotechnology is the only option available for sustainable exploitation and conservation of the vulnerable G. walla species. An electro-elicitation apparatuses were designed and built to stimulate calli and cell suspensions. The elicited and calli and cell suspensions were harvested at ...

Rice Crop - Current Developments, Sep 5, 2018

Since studies on herbicide-resistant rice (HRR) are limited in Sri Lanka, the present study condu... more Since studies on herbicide-resistant rice (HRR) are limited in Sri Lanka, the present study conducted to screen the naturally existing glyphosate and glufosinate resistance in traditional and inbred rice varieties. Six traditional varieties and nineteen inbred lines were selected for the study. Complete randomized design with three pots with 10 replicates for each herbicide concentration was employed. Optimal concentrations of glyphosate (0.5 gl −1) and glufosinate (0.05 gl −1) were applied at 3-4 leaf stages. Varieties ≥50% survival percentage was considered as resistant to respective herbicides. Twelve varieties showed resistance (≥50%) at 0.5 gl −1 glyphosate concentration. Survived plants were monitored and agro-morphological and yield characters/parameters were measured. Fifteen varieties were to glufosinate at 0.05 gl −1. Even though no significant differences (p > 0.05) were observed in growth parameters across control and treated plants, there was a yield penalty. Nine varieties (At362,

Information Processing in Agriculture

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

centre for Legumes in mediterranean agriculture newsletter Australian Team Leader, Rob Williams a... more centre for Legumes in mediterranean agriculture newsletter Australian Team Leader, Rob Williams and Seeds of Life technician Roginio, compare yields of newly released and traditional peanut varieties in Baucau, East Timor. Seeds of Life-East Timor was recently reviewed and extended for a further three years. The reviewers were extremely complimentary of the program's progress and made a number of recommendations for expanding both the activities and funding. Seeds of Life is a program within the Ministry of Agriculture Forestry and Fisheries (MAFF) supported by Australia with funding from the Australian Agency for International Development (AusAID) and the Australian Centre for International Agricultural Research (ACIAR). The Australian funding is managed by the University of Western Australia (UWA) through the Centre for Legumes in Mediterranean Agriculture (CLIMA) under ACIAR project no CIM/2003/014. The strength of Seeds of Life lies in the ability of the program to both identify and distribute improved varieties of key food crops. Varieties imported from crop centres belonging to the Consultative Group on International Agricultural Research (CGIAR) is evaluated on research stations, followed by on-farm trialling across a range of ecosystems. Because Seeds of Life is part of the MAFF, it is then a simple process for the Minister to recommend the most promising lines for release and to facilitate their spread through the Government seed production system.

Ceylon Journal of Science (Biological Sciences), 2010

Heavy metal pollution in soil and water is a global environmental concern. In Sri Lanka, accumula... more Heavy metal pollution in soil and water is a global environmental concern. In Sri Lanka, accumulation of heavy metals in soil, water and plant/animal biomass has been widely reported. Phytoremediation, the use of plants and their associated microbes, is an emerging, low-cost, environmental-friendly approach in the cleanup and prevention of environmental pollution. Indian Mustard (Brassica juncea) has been widely used to extract toxic metals from contaminated soils worldwide. Sri Lanka has a genetically diverse mustard collection, but their phytoextarctive potentials are yet to be determined. Present study was conducted to evaluate variation in phytoextractive ability of soil-borne heavy metals by ten different mustard accessions. Heavy metal contents (Mn, Co, Pb and Zn) in 12-week-old mustard plants (whole plant) were estimated during Maha and Yala in 2007-2008 using Atomic Absorption Spectroscopy. Heavy metal content in soils where the plants were grown was also assessed during the two seasons. Soil Mn and Co concentrations were significantly high in Maha than in Yala. Difference in heavy metal concentrations in mustard accessions between the two seasons was not significant. However, significantly high concentrations of Mn were found in accessions 7788, 515 and 8831 (236, 225, 220x10 2 µg/g). Cobolt (Co) was significantly high in accession 5088 (238x10 2 µg/g). Lead (Pb) concentrations were significantly high in accessions 8831 (156x10 2 µg/g) and 5088 (148x10 2 µg/g) and Zn was significantly high in accession 501 (6413x10 2 µg/g). The study suggests that screening the entire mustard germplasm in Sri Lanka is worthwhile to identify potential heavy metal accumulators.

Transgenic Plant Technology for Remediation of Toxic Metals and Metalloids

Abstract Phytoremediation has gained the attention all over the world as one of the most cost-eff... more Abstract Phytoremediation has gained the attention all over the world as one of the most cost-effective and sustainable approaches for removal, sequestration, and/or detoxification of contaminants especially metals and metalloids from land and freshwater bodies. However, field studies indicated that these contaminant removal rates and tolerability of the conventional plant species are inadequate. Therefore, transgenic plants endowed with extended capability for phytoremediation have emerged as a promising solution to overcome common weaknesses of conventional plants that have been used in the remediation process. Scientists were able to develop transgenic plants capable of successful removal of environmental contaminants including heavy metal(loid)s like Cd, Co, Cu, Pb, Zn, Se, As, and Hg. Although transgenic plants bring favorable advantages to phytoremediation, there are many concerns regarding human health and environmental sustainability. Therefore, this chapter extensively discusses the benefits and emerging applications of transgenic plants in phytoremediation to remediate the extraction of heavy metals and metalloids. This chapter also discusses the drawbacks and possible risks associated with the transgenic plants and the regulatory issues that could possibly arise from these transgenic species.

Nusantara Bioscience

A collection of over 2000 traditional rice varieties are conserved at Gene Bank, Plant Genetics R... more A collection of over 2000 traditional rice varieties are conserved at Gene Bank, Plant Genetics Resource Center, Sri Lanka. Oryza sativa varieties grown in Sri Lanka from ancient times to the middle of the last century are known as traditional rice. These varieties show adaptability to biotic and abiotic stresses and, an important component of biodiversity of Sri Lanka. A detailed understanding of the diversity of traditional rice varieties is essential for effective utilization of rice genetic resources and identification of potential parents possessing valuable genetic traits for future crop improvement. Study objectives were phenotypic and molecular characterization of one-hundred traditional rice varieties and to identify a core collection for phenotypic and genetic diversity. Rice varieties were grown in a plant house following RCBD with 4 replicates and 5 plants per replicate. Thirty-two agro-morphological characters were observed/collected. Genomic DNA was extracted from 20-daysold seedlings. Thirty-three microsatellite (Simple Sequence Repeat-SSR) primer pairs were used to assay genetic variation and PCR products were subjected to fragment analysis by capillary electrophoresis. Descriptive statistics and basic inferential statistical analyses were performed to access variation of agro-morphological characters among rice varieties. Cluster analysis and Multidimensional scaling produced 07 groups which were further analyzed using Classification and Regression Analysis to extract the diagnostic agromorphological features. Groups of rice varieties were characterized by lemma palea color, awn color at maturity, seedling height, and flag-leaf angle. Traditional varieties represent distant clusters on agro-morphological features. Molecular analyses revealed all 33 loci displayed polymorphism (66.7-96.9%) among 100 traditional rice varieties with a total of 387 alleles identified with an average of 11.72 alleles per variety. All varieties were genetically structured into fifteen well-separated groups. UPGMA analysis based on Jaccard's similarity separated varieties into 05 major clusters. Genetic diversity information is useful in the efficient use of Sri Lankan rice germplasm and managing in situ and ex situ germplasm collections in conserving traditional rice varieties.