Genetic variation of Oryza sativa L. landraces (LRs) collected from the saline coastal belt of Ba... more Genetic variation of Oryza sativa L. landraces (LRs) collected from the saline coastal belt of Bangladesh, modern varieties (MVs), as well as Pokkali, Nona Bokra and salt tolerant modern varieties (SMVs) derived from the last two were analyzed with 60 evenly distributed rice microsatellite DNA markers. A total of 196 reproducible polymorphic alleles were identified from the band loci. Heterozygosity among the 31 LRs was found to be 0.57, 0.46 in the 5 MVs and 0.40 in the 8 SMVs. Computation of genetic similarity with this data, using Jaccard's coefficient followed by UPGMA clustering, divided the landraces into 6 distinct groups. Three groups were composed of LRs only from the highly saline southwest. Two groups consisted of LRs from the mild to moderately saline mid-east and northeast coasts. The sixth group was heterogeneous, with LRs from the northeast, LRs from the southwest and Nona Bokra. Pokkali and Gunshi, a LR of the southwest, branched out individually. When all the 46 O. sativa L. cultivars were clustered together, most of the MVs and SMVs were found to be linked within the heterogeneous group. The measure of seedling Na and K concentration, Na/K ratios, affected leaf area as well as survival under salinity stress in hydroponics identified 6 LRs from the highly saline southwest as the most tolerant. These group with Pokkali when UPGMA clustering using the Pearson product-moment correlation coefficient suitable for the quantitative physiological data on seedling saline stress was computed. Morphological observations of plant type and height, days to maturity and yield components in non-saline soil indicated low variability among the different LRs. When yield performance as well as tolerance scores were considered, 7 LRs from the southwest and 1 LR from the mid-northeast show potential as donors for breeding salt tolerant rice. The microsatellite fingerprinting analysis thus revealed that some of the salt tolerant landraces of the coastal region have unique polymorphic loci, quite distinct from the popular salt tolerance donor Pokkali. The similarity matrices between the O. sativa L. cultivars chosen for the study can be used as a valuable tool for the proper choice of parents for mapping or breeding purposes.
Good donors in breeding for salt tolerance are a prerequisite for food security under changing cl... more Good donors in breeding for salt tolerance are a prerequisite for food security under changing climatic conditions. Horkuch, a farmer-popular salt tolerant rice (Oryza sativa L.) variety from the south-west coast of Bangladesh was characterised up to maturity under NaCl stress, together with a modern variety (BRRI dhan41), a sensitive control (BRRI dhan29) and Pokkali, the salt-tolerant benchmark for rice. Horkuch had low reduction in shoot biomass, a low Na : K ratio in flag leaves, a low percent reduction in yield and good partitioning of Na in the older leaves, and maintained high levels of Ca and Mg in the flag leaves. In order to understand the physiology at the molecular level, the expression of salt-responsive genes was investigated using microarray analysis. Salt-stressed cDNA of Horkuch seedlings were hybridised with cDNA probes synthesised mainly from database sequences of Arabidopsis thaliana (L.) Heynh. The upregulated genes included transcription factors, signal transdu...
There has been much debate within the language research community about whether the ability to pe... more There has been much debate within the language research community about whether the ability to perceive speech is uniquely human. One view, that Speech is Special proposes that both speech production and speech perception are uniquely human abilities ( ...
A sample of ethanolic extracts of the husk of Theobroma cacao L. was scrutinized using a UHPLC/DA... more A sample of ethanolic extracts of the husk of Theobroma cacao L. was scrutinized using a UHPLC/DAD/MS Thermo scientific Dionex Ultimate 3000 RS coupled to a Thermo scientific LTQ XL mass spectrometer. In addition, about seven different chemical compounds were tentatively identified in this species based on chromatography retention time (Rt), UV and MS/MS spectra and compared with those of isolated authentic compound and literature data. Information obtained from these studies can be used as markers in the identification and standardization of this plant as a herbal remedy and also towards monograph development on the plant.
Genetic variation of Oryza sativa L. landraces (LRs) collected from the saline coastal belt of Ba... more Genetic variation of Oryza sativa L. landraces (LRs) collected from the saline coastal belt of Bangladesh, modern varieties (MVs), as well as Pokkali, Nona Bokra and salt tolerant modern varieties (SMVs) derived from the last two were analyzed with 60 evenly distributed rice microsatellite DNA markers. A total of 196 reproducible polymorphic alleles were identified from the band loci. Heterozygosity among the 31 LRs was found to be 0.57, 0.46 in the 5 MVs and 0.40 in the 8 SMVs. Computation of genetic similarity with this data, using Jaccard's coefficient followed by UPGMA clustering, divided the landraces into 6 distinct groups. Three groups were composed of LRs only from the highly saline southwest. Two groups consisted of LRs from the mild to moderately saline mid-east and northeast coasts. The sixth group was heterogeneous, with LRs from the northeast, LRs from the southwest and Nona Bokra. Pokkali and Gunshi, a LR of the southwest, branched out individually. When all the 46 O. sativa L. cultivars were clustered together, most of the MVs and SMVs were found to be linked within the heterogeneous group. The measure of seedling Na and K concentration, Na/K ratios, affected leaf area as well as survival under salinity stress in hydroponics identified 6 LRs from the highly saline southwest as the most tolerant. These group with Pokkali when UPGMA clustering using the Pearson product-moment correlation coefficient suitable for the quantitative physiological data on seedling saline stress was computed. Morphological observations of plant type and height, days to maturity and yield components in non-saline soil indicated low variability among the different LRs. When yield performance as well as tolerance scores were considered, 7 LRs from the southwest and 1 LR from the mid-northeast show potential as donors for breeding salt tolerant rice. The microsatellite fingerprinting analysis thus revealed that some of the salt tolerant landraces of the coastal region have unique polymorphic loci, quite distinct from the popular salt tolerance donor Pokkali. The similarity matrices between the O. sativa L. cultivars chosen for the study can be used as a valuable tool for the proper choice of parents for mapping or breeding purposes.
Good donors in breeding for salt tolerance are a prerequisite for food security under changing cl... more Good donors in breeding for salt tolerance are a prerequisite for food security under changing climatic conditions. Horkuch, a farmer-popular salt tolerant rice (Oryza sativa L.) variety from the south-west coast of Bangladesh was characterised up to maturity under NaCl stress, together with a modern variety (BRRI dhan41), a sensitive control (BRRI dhan29) and Pokkali, the salt-tolerant benchmark for rice. Horkuch had low reduction in shoot biomass, a low Na : K ratio in flag leaves, a low percent reduction in yield and good partitioning of Na in the older leaves, and maintained high levels of Ca and Mg in the flag leaves. In order to understand the physiology at the molecular level, the expression of salt-responsive genes was investigated using microarray analysis. Salt-stressed cDNA of Horkuch seedlings were hybridised with cDNA probes synthesised mainly from database sequences of Arabidopsis thaliana (L.) Heynh. The upregulated genes included transcription factors, signal transdu...
There has been much debate within the language research community about whether the ability to pe... more There has been much debate within the language research community about whether the ability to perceive speech is uniquely human. One view, that Speech is Special proposes that both speech production and speech perception are uniquely human abilities ( ...
A sample of ethanolic extracts of the husk of Theobroma cacao L. was scrutinized using a UHPLC/DA... more A sample of ethanolic extracts of the husk of Theobroma cacao L. was scrutinized using a UHPLC/DAD/MS Thermo scientific Dionex Ultimate 3000 RS coupled to a Thermo scientific LTQ XL mass spectrometer. In addition, about seven different chemical compounds were tentatively identified in this species based on chromatography retention time (Rt), UV and MS/MS spectra and compared with those of isolated authentic compound and literature data. Information obtained from these studies can be used as markers in the identification and standardization of this plant as a herbal remedy and also towards monograph development on the plant.
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