Traditional Rice Landraces Research Articles

The Green Revolution shaped the population structure of the rice pathogen Xanthomonas oryzae pv. oryzae

The impact of modern agriculture on the evolutionary trajectory of plant pathogens is a central question for crop sustainability. The Green Revolution replaced traditional rice landraces with high-yielding varieties, creating a uniform selection pressure that allows measuring the effect of such intervention. In this study, we analyzed a unique historical pathogen record to assess the impact of a major resistance gene, Xa4, in the population structure of Xanthomonas oryzae pv. oryzae (Xoo) collected in the Philippines in a span of 40 years. After the deployment of Xa4 in the early 1960s, the emergence of virulent pathogen groups was associated with the increasing adoption of rice varieties carrying Xa4, which reached 80% of the total planted area. Whole genomes analysis of a representative sample suggested six major pathogen groups with distinctive signatures of selection in genes related to secretion system, cell-wall degradation, lipopolysaccharide production, and detoxification of host defense components. Association genetics also suggested that each population might evolve different mechanisms to adapt to Xa4. Interestingly, we found evidence of strong selective sweep affecting several populations in the mid-1980s, suggesting a major bottleneck that coincides with the peak of Xa4 deployment in the archipelago. Our study highlights how modern agricultural practices facilitate the adaptation of pathogens to overcome the effects of standard crop improvement efforts.

Genomic analyses reveal selection footprints in rice landraces grown under on-farm conservation conditions during a short-term period of domestication.

Traditional rice landraces grown under on‐farm conservation conditions by indigenous farmers are extremely important for future crop improvement. However, little is known about how the natural selection and agriculture practices of indigenous farmers interact to shape and change the population genetics of rice landraces grown under on‐farm conservation conditions during the domestication. In this study, we sequenced DNA from 108 core on‐farm conserved rice landraces collected from the ethnic minority regions of Yunnan, China, including 56 accessions collected in 1980 and 52 accessions collected in 2007 and obtained 2,771,245 of credible SNPs. Our findings show that most genetic diversity was retained during the 27 years of domestication by on‐farm conservation. However, SNPs with marked allele frequency differences were found in some genome regions, particularly enriched in genic regions, indicating changes in genic regions may have played a much more prominent role in the short‐term domestication of 27 years. We identified 186 and 183 potential selective‐sweep regions in the indica and japonica genomes, respectively. We propose that on‐farm conserved rice landraces during the short‐term domestication had a highly polygenic basis with many loci responding to selection rather than a few loci with critical changes in response to selection. Moreover, loci affecting important agronomic traits and biotic or abiotic stress responses have been particularly targeted in selection. A genome‐wide association study identified 90 significant signals for six traits, 13 of which were in regions of selective sweeps. Moreover, we observed a number of significant and interesting associations between loci and environmental factors, which implies adaptation to local environment. Our results provide insights into short‐term evolutionary processes and shed light on the underlying mechanisms of on‐farm conservation.

Leaf photosynthesis and antioxidant response in selected traditional rice landraces of Jeypore tract of Odisha, India to submergence.

Submergence tolerance in rice is important for improving yield under rain-fed lowland rice ecosystem. In this study, five traditional rice landraces having submergence tolerance phenotype were selected. These five rice landraces were chosen based on the submergence-tolerance screening of 88 rice landraces from various lowland areas of Jeypore tract of Odisha in our previous study. These five rice landraces were further used for detailed physiological assessment under control, submergence and subsequent re-aeration to judge their performance under different duration of submergence. Seedling survival was significantly decreased with the increase of plant height and significant varietal difference was observed after 14days of complete submergence. Results showed that submergence progressively declined the leaf photosynthetic rate, stomatal conductance, instantaneous water use efficiency, carboxylation efficiency, photosystem II (PSII) activity and chlorophyll, with greater effect observed in susceptible check variety (IR 42). Notably, higher activities of antioxidative enzymes and ascorbate level were observed in traditional rice landraces and were found comparable with the tolerant check variety (FR 13A). Taken together, three landraces such as Samudrabali, Basnamundi and Gadaba showed better photosynthetic activity than that of tolerant check variety (FR 13A) and showed superior antioxidant response to submergence and subsequent re-aeration. These landraces can be considered as potential donors for the future submergence tolerance breeding program.

Use of Descriptor Codes in Agro-Morphological Characterization: Qualitative assessment of 20 LandRaces of Rice (Oryza sativa L.) from West Bengal

Rice is one of the very few crop species endowed with rich genetic diversity which is embodied in the traditional rice landraces or folk varieties. It is one of the most researched crops. Rice genetic resources and human welfare are intricately interlinked. Rice has shaped the history, culture, diet and economy of billions of people of Asia. The diversity data generated in time and space have been valuable to communities, scientists and policy managers to formulate and implement conservation strategies of in situ, on-farm as well as ex situ conservation and management of genetic resources. West Bengal has rich rice genetic wealth. But this genetic wealth is being silently depleted due to the onslaught of the high-yielding varieties (HYVs) and neglect. Descriptor codes were used for the qualitative evaluation of genetic diversity among the 20 rice genotypes collected from different parts of West Bengal, following the Standard Evaluation System (SES) for rice developed by the International Rice Research Institute (IRRI). There is an urgent need to document, characterize and conserve these varieties.

Genetic variability, heritability, correlation and path analyses of yield components in traditional rice (Oryza sativa L.) landraces

The presence of sufficient genetic variability, the knowledge of nature of association among different characters and relative contribution of different characters to yield is a prerequisite to any breeding programme. The aim of the present study was to estimate genetic parameters of thirteen yield and yield attributing traits in 40 landraces of rice with a view to select better yield attributes in rice. The higher value of phenotypic co-efficient of variation (PCV) compared to the corresponding genotypic coefficient of variation (GCV) for all the studied traits indicated that there was an influence of the environment. Number of unfilled grains per panicle exhibited high estimates of PCV and GCV followed by number of filled grains per panicle, number of grains per panicle, flag leaf area. High heritability coupled with high genetic advance was observed in flag leaf area, pollen fertility, number of grains per panicle and number of filled grains per panicle which reflected that the direct selection of these characters based on phenotypic expression by simple selection method for yield improvement would be more reliable Grain yield per plant showed significant and positive association with days to 50% flowering, days to maturity, flag leaf area, number of total tillers per hill, number of effective tillers per hill, pollen fertility, number of grains per panicle, number of filled grains per panicle indicating selection of these characters for yield improvement may be rewarding. Both at phenotypic and genotypic level, days to 50% flowering, flag leaf area, number of effective tillers per hill, pollen fertility, panicle length, number of grains per panicle and 100 seed weight had direct positive effect on yield per plant indicating their importance during selection in yield improvement program. Moreover, the information generated from this study, can be exploited in future rice breeding program. J. Bangladesh Agril. Univ. 17(1): 26–32, March 2019

English

The assessment of genetic diversity of the traditional rice varieties or landraces is an essential component in germplasm characterization and conservation to identify potential parents. In the present study SSR markers (588 SSR markers) were used for the assessment of genetic diversity and relatedness among 31 rice accessions. These included 18 accessions from Sudan and 13 from IRRI. Among the SSR markers used only 483 generated polymorphic patterns, and showed 1274 alleles. The number of alleles per locus ranged from 2 (about 214 markers) to 5 (RM16820 and AP3206a) with an average of 2.64 alleles per locus. The polymorphic information content (PIC) values ranged from 0.06 (RM3138, RM10671, SKC3, R1M7, R6M30, S07101 and S12041B) to 0.69 (RM7643), with an average of 0.39. The major allele frequency per locus varied from 32% (RM7643) to 97% (RM3138, RM10671, SKC3, R1M7, R6M30, S07101 and S12041B), with an average of 64%. Among the primers used in the present investigation, RM7643 was highly informative as it recorded the highest PIC value (0.69). The UPGMA resulted in allelic richness of four major clusters in which cluster I is composed of a high number of accessions. The pairwise genetic dissimilarity indices revealed the highest genetic dissimilarity of 62.3% between Pipanfary Red1 and FL478. The lowest genetic dissimilarity was found between NBGS3 and NBGS2 (4.1%), but they showed wide dissimilarity with other accessions. The study highlighted the usefulness of the application markers for efficient characterization of the Sudanese rice accessions. Key words: Rice accessions, genetic diversity, SSR markers, polymorphism.

Characterization of Rice Landraces from Dibrugarh District of Assam

Twenty five different traditional rice landraces from Dibrugarh district of Assam were characterized. In case of morphological characters, high heritability coupled with high genetic advance was recorded for number of grains per plant and number of panicle per plant. For biochemical parameters, high heritability coupled with high genetic advance was recorded for amylose and fat contents. Correlation coefficient analysis revealed that number of grains per plant, plant height, stem length and panicle length exhibited positive correlation with grain yield per plant. Thus, stem length and numbers of grains per plant can be considered in breeding programme. The landraces were with low to intermediate gelatinization temperature range (55–74 oC) indicating good cooking quality. The study identified Kolajoha, Miatong, Bor Aijung, Ronga Bordhan, Bor Salpona, Dolkochi, and Athabora as promising landraces that could be utilized in the development of high yielding landraces.

A northern Chinese origin of Austronesian agriculture: new evidence on traditional Formosan cereals

BackgroundGenetic data for traditional Taiwanese (Formosan) agriculture is essential for tracing the origins on the East Asian mainland of the Austronesian language family, whose homeland is generally placed in Taiwan. Three main models for the origins of the Taiwanese Neolithic have been proposed: origins in coastal north China (Shandong); in coastal central China (Yangtze Valley), and in coastal south China. A combination of linguistic and agricultural evidence helps resolve this controversial issue.ResultsWe report on botanically informed linguistic fieldwork of the agricultural vocabulary of Formosan aborigines, which converges with earlier findings in archaeology, genetics and historical linguistics to assign a lesser role for rice than was earlier thought, and a more important one for the millets. We next present the results of an investigation of domestication genes in a collection of traditional rice landraces maintained by the Formosan aborigines over a hundred years ago. The genes controlling awn length, shattering, caryopsis color, plant and panicle shapes contain the same mutated sequences as modern rice varieties everywhere else in the world, arguing against an independent domestication in south China or Taiwan. Early and traditional Formosan agriculture was based on foxtail millet, broomcorn millet and rice. We trace this suite of cereals to northeastern China in the period 6000–5000 BCE and argue, following earlier proposals, that the precursors of the Austronesians, expanded south along the coast from Shandong after c. 5000 BCE to reach northwest Taiwan in the second half of the 4th millennium BCE. This expansion introduced to Taiwan a mixed farming, fishing and intertidal foraging subsistence strategy; domesticated foxtail millet, broomcorn millet and japonica rice; a belief in the sacredness of foxtail millet; ritual ablation of the upper incisors in adolescents of both sexes; domesticated dogs; and a technological package including inter alia houses, nautical technology, and loom weaving.ConclusionWe suggest that the pre-Austronesians expanded south along the coast from that region after c. 5000 BCE to reach northwest Taiwan in the second half of the 4th millennium BCE.

Physiological characterization and allelic diversity of selected drought tolerant traditional rice (Oryza sativa L.) landraces of Koraput, India.

Water-deficit stress tolerance in rice is important for maintaining stable yield, especially under rain-fed ecosystem. After a thorough drought-tolerance screening of more than 130 rice genotypes from various regions of Koraput in our previous study, six rice landraces were selected for drought tolerance capacity. These six rice landraces were further used for detailed physiological and molecular assessment under control and simulated drought stress conditions. After imposing various levels of drought stress, leaf photosynthetic rate (PN), photochemical efficiency of photosystem II (Fv/Fm), SPAD chlorophyll index, membrane stability index and relative water content were found comparable with the drought-tolerant check variety (N22). Compared to the drought-susceptible variety IR64, significant positive attributes and varietal differences were observed for all the above physiological parameters in drought-tolerant landraces. Genetic diversity among the studied rice landraces was assessed using 19 previously reported drought tolerance trait linked SSR markers. A total of 50 alleles with an average of 2.6 per locus were detected at the loci of the 19 markers across studied rice genotypes. The Nei's genetic diversity (He) and the polymorphism information content (PIC) ranged from 0.0 to 0.767 and 0.0 to 0.718, respectively. Seven SSR loci, such as RM324, RM19367, RM72, RM246, RM3549, RM566 and RM515, showed the highest PIC values and are thus,useful in assessing the genetic diversity of studied rice lines for drought tolerance. Based on the result, two rice landraces (Pandkagura and Mugudi) showed the highest similarity index with tolerant check variety. However, three rice landraces (Kalajeera, Machhakanta and Haldichudi) are more diverse and showed highest genetic distance with N22. These landraces can be considered as the potential genetic resources for drought breeding program.

Phytonutrients analysis in ten popular traditional Indian rice landraces (Oryza sativa L.)

Antioxidant potentials of native indigenous landraces of rice have been of great interest in the last decade, since a positive correlation of reduced chronic diseases due to consumption of rice has been established. Hence, the study focused on the analysis of phytonutrients in ten traditional rice landraces, such as in three pigmented (Mapillai samba, Kala namak and Iluppai poo samba) and seven non-pigmented (Poongar, Seeragasambha, Karnal, Kuzhiyadichan, Madumuzhungi, Salem sannam and Kitchili samba) varieties collected from different parts of India. Till date, there is no study on analyzing the phytonutrients in these traditional Indian rice landraces. The phytochemical analysis indicated Mapillai samba rice had highest vitamin E content (26.73 ± 0.49 µg/g), whereas Kala namak rice showed highest phenolic content (43.19 ± 0.54 mg/g). The total flavonoid and anthocyanin contents were again highest in Kala namak 7.18 ± 0.52 mg/g and Mapillai samba 42.21 ± 0.28 mg/g respectively. The antioxidant properties and reducing power of the ten rice landraces were analyzed, among them Kala namak rice showed significantly higher antioxidants levels, inhibition of lipid peroxidation and reducing power. These results suggest that traditional land races possess higher vitamin E content and phytonutrients required to combat chronic diseases associated with their deficiencies. Among the varieties of rice tested, Kala namak pigmented rice variety had comparatively higher levels of vitamin E content and antioxidant potential. Hence, the pigmented traditional rice landraces can be used as a source of phytonutrients and it warrants conservation to preserve its precious genome information.

Screening of drought tolerant rice through morpho-physiological and biochemical approaches

Abstract Drought is one of the major abiotic stresses that delimit rice production and yield especially in rainfed ecosystems. To identify the promising drought tolerant rice cultivars, an effort was made in the present study to screen few traditional rice landraces of Assam, India, aimed at investigating effect of low water potential on growth. Seeds of twenty one traditional rice cultivars along with ‘Sahbhagi Dhan’ (tolerant) and ‘IR64’ (sensitive) were subjected to drought stress. Drought was imposed in one week old seedlings by 15% PEG-6000 in Yoshida medium for 7 days followed by 20% PEG-6000 for another 7 days until the drought symptoms appeared. All the experiments were conducted in randomized block design with three replicates. Germination percentage, root length, shoot length, root fresh and dry weight, shoot fresh and dry weight, chlorophyll content and relative water content (RWC) were evaluated after stress treatment. On the basis of Standard Evaluation Score, 8 rice varieties showing high drought tolerability were finally selected for further biochemical analyses. Proline content, lipid peroxidation level and hydrogen peroxide concentration in shoots and roots were investigated. Increase in proline content and decrease in hydrogen peroxide and lipid peroxidation implied its protective role in tolerant rice cultivars against drought stress. To identify the drought tolerant rice cultivars, a thorough understanding of the various mechanisms that govern the yield of rice under drought condition is a prerequisite.

Genotypic variation of photosynthetic gas exchange and stomatal traits in some traditional rice (Oryza sativa L.) landraces from Koraput, India for crop improvement.

Variations in photosynthetic gas exchange, stomatal traits and photosystem (PS) II activity were investigated in three popular rice (Oryza sativa L.) landraces namely Kalajeera, Machakanta and Haladichudi from Koraput, India and compared with high yielding modern varieties (IR 64 and IR 42) to judge the possibility of using them in crop improvement programmes. The leaf CO2 photosynthetic rate (PN), stomatal conductance (gs), water use efficiency and carboxylation efficiency were significantly higher in traditional landraces as compared to the high yielding variety. In contrast, the transpiration rate, internal CO2 concentration, special analysis device (SPAD) index and chlorophyll were higher in high yielding varieties. In addition, the traditional landraces showed better stomatal traits such as stomatal density (SD), stomatal size (SS) and stomatal index. Further, multiple correlations between different gas-exchange characteristics and other physiological traits revealed that the PN was not dependent on the leaf pigment content or PS II activity. However, it was dependent on stomatal traits like gs, SD and SS. Taken together, the traditional landraces such as Kalajeera, Machakanta and Haladichudi had superior PN and stomatal efficiency compared to the high yielding variety under prevailing environmental condition. Further research is required to elucidate the genetic diversity of these popular landraces compared to high-yielding ones in relation to photosynthesis efficiency for future crop improvement programmes.

Screening of rice landraces (Oryza sativa L.) for seedling stage salinity tolerance using morpho-physiological and molecular markers

Traditional rice landraces of coastal area in Bangladesh are distinct regarding their phenotype, response to salt stress and yield attributes. With characterization of these landraces, suitable candidate genes for salinity tolerance could be identified to introgress into modern rice varieties. Therefore, the aim of this experiment was to uncover prospective rice landraces tolerant to salinity. Relying on morphological, biochemical and molecular parameters 25 rice genotypes were tested for salt tolerance at germination and seedling stage. At germination stage 0 and 12 dSm−1 salinity were imposed on rice genotypes. Ward’s cluster analysis divided rice genotypes into three clusters (susceptible, moderately tolerant and tolerant) based on the physiological indices. The tolerant rice landraces to salinity were Sona Toly, Nakraji and Komol Bhog. At seedling stage screening was performed following IRRI standard protocol at 12 dSm−1 salinity level. Based on all morphological and biochemical parameters Komol Bhog was identified as the highly salinity tolerant landrace while Bolonga, Sona Toly, Dud Sail, Tal Mugur and Nakraji were found as tolerant to salinity. Molecular characterization using two simple sequence repeats (SSR) markers, viz. RM121 and RM337 displayed Bolonga, Til Kapor, Panbra, Sona Toly, Bina Sail, Komol Bhog, Nakraji, Tilkapur, Gajor Goria and Gota were tolerant landraces through genetic similarity in dendrogram. These identified salt-resistant landraces can be used as promising germplasm resources for breeding salt-tolerant high-yielding rice varieties in future.

Study of morphological diversity of traditional aromatic rice landraces (Oryza sativa L.) collected from Assam, India

Rice is one of the major cereal grain consumed more than half of the world’s population. Aromatic rice is one of the most widely accepted rice due its pleasant aroma. Traditionally, many varieties of aromatic rice are grown by the farmers of Assam maintaining a diverse gene pool. In the present study, morphological variation was studied in 22 aromatic rice landraces using qualitative and quantitative traits. Keteki Joha is very popular indigenous aromatic rice grown in a small pocket of Assam for its high yield. Though Kola Kunkuni Joha is relatively smaller grain size and low yield but have high demand due to its high aroma as compared to other landraces. Significant positive correlations was occurred at 0.05 level between kernel length and seed weight with seed width (r = 0.6734*) and (0.5881*) as well as seed weight with kernel width (r = 0.5433*). The correlation between seed width and kernel width (0.9663**) showed significantly positive relationship which shown at 0.01 level. Characterization of aromatic rice landraces of Assam would be a boon for the breeders for designing further rice improvement programme.

InDel marker based genetic differentiation and genetic diversity in traditional rice (Oryza sativa L.) landraces of Chhattisgarh, India.

Rice has been cultivating and utilizing by humans for thousands of years under diverse environmental conditions. Therefore, tremendous genetic differentiation and diversity has occurred at various agro-ecosystems. The significant indica–japonica differentiation in rice provides great opportunities for its genetic improvement. In the present investigation, a total of 42 polymorphic InDel markers were used for differentiating 188 rice landraces and two local varieties of Chhattisgarh, India into indica and japonica related genotypes based on ‘InDel molecular index’. Frequency of japonica alleles varied from 0.11 to 0.89 among landraces. Results revealed that 104 rice landraces have indica type genetic architecture along with three tested indica cultivars Swarna, Mahamaya and Rajeshwari. Another 60 landraces were placed under ‘close to indica’ type. It was found that three rice landraces i.e. Kalajeera, Kapri, Tulsimala were ‘close to japonica’ type and 21 landraces were ‘intermediate’ type. The result from the calculation of ‘InDel molecular index’ was further verified with STRUCTURE, AMOVA, PCA and cluster analysis. Population structure analysis revealed two genetically distinct populations within the 190 rice landraces/genotypes. Based on AMOVA, ‘intermediate’ type, ‘close to japonica’ type and Dongjinbyeo (a japonica cultivar from Republic of Korea) displayed significant genetic differentiation (ɸPT = 0.642, P = 0.000) from ‘indica’ and ‘close to indica’ groups. The PCA scatter plot and dendrogram demonstrated a clear pattern of two major group differentiations. ‘Close to japonica’ type and ‘intermediate’ type landraces/genotypes were grouped with Dongjinbyeo and formed a separate cluster at 30% Jaccard’s similarity level from rest of the landraces/genotypes which were ‘close to indica’ or ‘indica’ type. Such a significant genetic differentiation among the locally adapted landraces could be exploited for the development of rice varieties introgressing higher yield potential and better plant types of japonica type as per the need of consumers and rice traders.

Morphological diversity of panicle traits in Kam fragrant glutinous rice (Oryza sativa)

Panicle traits are the most intuitive and representative features of rice germplasm resources that have been utilized in the determination of its identity, genetic diversity, yield, and quality. Based on the approaches of ethnobotany, cultural anthropology and plant morphology, we analyzed the panicle traits of 95 traditional Kam fragrant glutinous rice landraces according to folk classification in Qiandongnan Prefecture of Guizhou Province in the past 10 years. A total of 95 Kam fragrant glutinous rice landraces were tested, of which 91% consisted of those with awns, and landraces with awn lengths of 2–6 cm comprised 62%. The coefficient of variation (CV) of awn color, husk color and Grain color was more than 50%, thereby indicating extensive morphological variations among the traditional Kam fragrant glutinous rice landraces. The average Shannon–Wiener value (diversity index, H′) for panicle qualitative traits was 0.50, which was significantly higher than that of quantitative traits (0.22), thereby indicating a relatively higher degree of genetic diversity among qualitative traits. Cluster analysis of panicle morphological traits showed that 95 Kam fragrant glutinous rice landraces could be divided into five categories, using the Euclidean distance of 0.68 as threshold. Each cultivar manifested unique panicle traits. The present study on the morphological diversity of Kam fragrant glutinous rice landraces provided basic information that may be utilized for the conservation and sustainable use of Kam fragrant glutinous rice landraces.

Leaf Traits and Antioxidant Defense for Drought Tolerance During Early Growth Stage in Some Popular Traditional Rice Landraces from Koraput, India

Three popular traditional rice landraces, namely Kalajeera, Machakanta and Haladichudi, from Koraput, India were used to analyse the leaf traits and antioxidant defence for drought tolerance. When rice plants were exposed to different levels of drought stress by varying concentrations of polyethylene glycol (PEG) 6000, seed germination and growth parameters were significantly declined in all the rice landraces compared to the control. Drought stress also altered the leaf phenotypic traits based on chlorophyll fluorescence parameters and chlorophyll index, with more significant differences in susceptible variety IR64 than in traditional landraces. Furthermore, activities of antioxidative enzymes and proline and protein contents overtly increased under drought stress. The traditional rice landraces showed higher relative ratios for different parameters compared to the susceptible variety IR64. Taken together, the traditional landraces had superior leaf physiological efficiency compared to the susceptible and tolerant check varieties under drought stress.

Whole Genome Sequencing Reveals the Islands of Novel Polymorphisms in Two Native Aromatic Japonica Rice Landraces from Vietnam.

Elucidation of the rice genome will not only broaden our understanding of genetic characterization of the agronomic characteristics but also facilitate the rice genetic improvement through marker assisted breeding. However, the genome resources of aromatic rice varieties are largely unexploited. Therefore, the whole genome of two elite aromatic traditional japonica rice landraces in North Vietnam, Tam Xoan Bac Ninh (TXBN), and Tam Xoan Hai Hau (TXHH), was sequenced to identify their genome-wide polymorphisms. Overall, we identified over 40,000 novel polymorphisms in each aromatic rice landrace. Although a discontinuous 8-bp deletion and an A/T SNP just upstream the 5-bp deletion in exon 7 of BADH2 gene were present in both rice landraces, the number of SNP high resolution regions of TXBN was six times higher than that of TXHH. Furthermore, several hot spot regions of novel SNPs and indels were found in both genomes, providing their potential gene pools related to aroma formation. The genomic information of two aromatic rice landraces described in this study will facilitate the identification of fragrance-related genes and the genetic improvement of rice.

Screening of Sri Lankan rice (Oryza sativa L.) landraces for drought tolerance

Twenty four (24) traditional Sri Lankan rice landraces were screened for drought tolerance at seedling stage in the greenhouse at the Open University of Sri Lanka, Nawala. Four week old seedlings grown in pots filled with soil were exposed to drought condition by disconnecting water supply for two weeks. Drought tolerance was evaluated by measuring plant height and leaf width after two weeks of recovery. Agro-morphological characterization of rice landraces was made on vegetative characters and yield attributed characters. The Simple Sequence Repeat (SSR) marker analysis was employed to determine the association between allelic diversity and drought tolerance of traditional rice landraces. Comparatively, the landraces Suwandal, Kirimurunga and Suduru samba showed tolerance to drought. Meanwhile, the SSR marker RM252 have shown the potential candidacy for tracing drought tolerance compared to other markers used in the study.

An ethnobotanical study of traditional rice landraces (Oryza sativa L.) used for medical treatment in selected local communities of the Philippines

Ethnopharmacological relevanceRice (Oryza sativa L.) remains as one the most important staple food of the Philippines with an overabundance of varieties and gastronomic use. Despite this, no published comprehensive ethnobotanical information exists for the exclusive subject on Philippine traditional rice varieties and their ethnomedicinal value. Aim of the StudyTo identify and collect traditional rice landrace with ethnomedicinal application from local communities of the Philippines; and document the application, traditional preparation and administration of these plants. Materials and methodsThe ethnobotanical study was performed in nine areas distributed across four provinces: Palawan, Zamboanga del Norte, Zamboanga del Sur and North Cotabato for a period of two years (2014–2015). A total of 39 key informants were identified and interviewed using semi-structured interviews and informal discussion. Descriptive statistics was used to analyze and organize the collected information from the surveys. ResultsNineteen (19) traditional rice were identified for the native treatment and control of 22 community health concerns. Predominant use of the plants collected were for the treatment of some types of nutritional disorders (18%), digestive system disorders (18%), ill-defined symptoms (13%); viral infections (13%); and several cultural diseases and disorders (11%). Grains were the most frequently used plant part and oral administration was the most preferred mode of treatment. ConclusionThis study is the first to formally confirm that certain traditional rice have a role in the healthcare system of selected local communities in the Philippines. The novel findings open a paradigm for scientists towards therapeutic investigations and development of probable high value products from the highlighted landrace.