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Search Results: 1 - 10 of 3734 matches for " rice "
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Iron Nutrition vis-à-vis Aconitase Activity and Ferritin Accumulation in Tropical Indica Rice Cultivars Differing in Grain Iron Concentration  [PDF]
Binay Bhusan Panda, Srigopal Sharma, Pravat Kumar Mohapatra, Avijit Das
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.518299

Effect of Fe nutrition on Fe acquisition, aconitase enzyme activity and assimilation of the element in ferritin protein was studied in two indica rice cultivars viz. Sharbati and Lalat having contrasting grain Fe concentration. Young rice seedlings were grown in hydroponics with different levels of Fe. For comparison, the two cultivars were also grown in the field under natural conditions of rice culture. Iron accumulation, aconitase activity and ferritin level were higher in the high Fe containing cultivar, Sharbati than that in the low Fe containing cultivar, Lalat. While aconitase activity increased consistently with the increase in concentration of Fe in the growing medium, the same was not found to be true for accumulation of ferritin protein. The leaf ferritin level increased up to a certain level of Fe in the growing medium and declined thereafter. Levels of Fe in the growing medium giving maximum ferritin synthesis were found to be different in the two rice cultivars. In both cultivars, aconitase activity attained maximum level after 20 days of panicle emergence (heading). Pattern of Fe accumulation in the leaves in response to increasing Fe level in the nutrient solution paralleled with that of the aconitase activity indicating a positive correlation. It was concluded that accumulation of both ferritin protein and aconitase enzyme were influenced not only by the Fe level in the growing medium but also by the internal Fe concentration of the two cultivars.

QTL Analysis of Yield Components in Rice Using a Cheongcheong/Nagdong Doubled Haploid Genetic Map  [PDF]
Gyu Hwan Park, Jin-Hee Kim, Kyung-Min Kim
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.59130

In this study, only two of 12 quantitative trait loci (QTLs) affecting yield and yield components were identified in a single year, indicating that individual QTLs are probably sensitive to the environment. A rice growth survey of “Cheongcheong” and “Nag dong” in a doubled haploid population in 2012 revealed that yield capacity was influenced by climate change. Analysis of yield and yield components indicated that five average traits are high in “Cheongcheong”. Frequency distribution tables indicated that panicles per plant (PPP), spike lets per panicle (SPP), and 1000-grain weight (TGW) were normally distributed. The strongest relationship was identified between SPP and seed set percentage (SSP) among phenotypic correlations related to yield and yield components found on chromosomes 2, 3, 6, 8 in 2012. SPP and SSP was a very relevant requisite about quantity. Analysis of QTL about quantity was total 9. In the present study, a doubled haploid population was used to analyze the epistatic effects on yield and yield components in rice. Although other epistatic QTLs were not included in any of the main-effect QTLs, they significantly influenced the traits. These results indicated that epistatic interaction plays an important role in controlling the expression of complex traits. Thus, the utilization of marker-assisted selection in rice breeding programs should take epistatic effects into consideration. Hence, the QTLs responsible for major effects are more suitable for marker-assisted selection programs to improve yield and related traits across different environments.

Determination of Paraquat in Several Commercially Available Types of Rice  [PDF]
Thais Lopes Lima, Maria Aparecida Nicoletti, Camila Munhoz, Gabriel Ramos De Abreu, Julia Zaccarelli Magalh?es, Esther Lopes Ricci Ricci, Paula A. Faria Waziry, Júlia Nathalia Alves da Costa, Ana Carolina Nascimento Ant?nio, André Rinaldi Fukushima
Food and Nutrition Sciences (FNS) , 2018, DOI: 10.4236/fns.2018.912098
Abstract: Introduction: Paraquat (1,1’-dimethyl-4,4’-bipyridine-dichloride) is a herbicide used to combat weeds and improve crop productivity. Its acute toxicity can cause fatal poisoning in humans and animals and several studies have shown a strong correlation between paraquat and Parkinson’s disease. Objective: To determine the concentration of paraquat in different types of rice in Brazil. Method: Paraquat quantification is based on a complexation reaction with sodium dithionite, which generates a blueish color compound, whose absorbance was read in a spectrophotometer at the 600 nm wavelength. Results: Five samples were found to be above the maximum allowed limit, while one sample had a concentration in the upper allowed limit. The method employed did not allow quantification of black rice. Conclusion: There is a need for identification of the type of pesticide used in each examined crop as well as their respective dates of remission in order to improve the safety of agricultural practices.
Effect of Winter Flooding on Weeds, Soybean Yield, Straw Degradation, and Soil Chemical and Biochemical Characteristics  [PDF]
Clifford H. Koger, Robert M. Zablotowicz, Mark A. Weaver, Melanie R. Tucker-Patterson, J. L. Krutz, Timothy W. Walker, Joe E. Street
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.47A2002
Abstract: Winter flooding of harvested rice fields attracts migratory waterfowl and may assist in degrading rice straw residue. Field studies were conducted between 2003 and 2005 in Stoneville, MS to evaluate the impacts of winter flooding of harvested rice fields on rice straw degradation, winter weeds, soybean yield, and soil biochemical and chemical properties. The experimental area each year consisted of a harvested rice field that remained no-till after harvest and that was dissected into 7.6- by 15-m bays with constructed levees to accommodate winter flooding treatments. Flooding treatments (10-cm depth) consisted of: 1) flooded from mid-October to early March; 2) flooded mid-October to early January; 3) flooded mid-December to early March; 4) flooded mid-December to mid-January; and 5) no flood. Winter weeds were counted, biomass determined as well as residual rice straw before flooding and in early April of each year. Winter flooding reduced rice straw biomass 32% to 60% compared to 21% to 31% reduction for no winter flood with the longest flood duration resulting in the greatest loss of carbon and nitrogen from straw residues in both years. Winter flooding treatments reduced weed populations and weed biomass from 43% to 99% when compared to no flooding treatment. Soybean yields ranged from 3295 kg.ha-1 with the longest winter flooding regime to 4295 kg.ha-1 with no flooding. Significant reductions in soil nitrate levels were most consistent in the upper 0 to 2.5-cm surface soil. Soil enzymatic activity (dehydrogenase and fluorescein diacetate hydrolysis) was increased by flooding in 2003, while minimal effects were found in the second year consistent with more anaerobic conditions attained in 2003 compared to 2004. Environmental benefits of accelerated straw decomposition and weed control is achieved by winter flooding; however, there are negative consequences of nitrogen losses and reduced soybean yield.
Adopting the system of rice intensification (SRI) in Tanzania: A review  [PDF]
Zacharia Katambara, Frederick C. Kahimba, Henry F. Mahoo, Winfred B. Mbungu, Fikiri Mhenga, Paul Reuben, Muyenjwa Maugo, Anthony Nyarubamba
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.48053

The demand of water for irrigation purposes in Tanzania outstrips the amount of water available for irrigation and other demands. On the other hand, the demand for more food to feed the growing population is increasing, calling for the need to have technologies and farming practices that ensure more food production while minimizing water uses. Rice is among cereal crops grown in Tanzania, and it can assist in meeting the food demand for the nation. Majority of rice producers in Tanzania and Sub-Saharan Africa(SSA) are subsistence farmers and they practice continuous flooding, a technique that requires much water. In addition to using large amounts of water, the conventional practices of growing paddy using local varieties transplanting process are implemented when seedlings are more than 21 days old, and 3-4 seedlings are transplanted in one hole. This practice results in low yields, and low water productivity and water use efficiency. The system of rice intensification (SRI) on the other hand, is a promising new practice of growing paddy rice that has proven to be very effective in saving water and increasing rice yields in many parts of the world. SRI practice is spreading fast and it has been adopted in many countries. The SRI practice has been introduced in Tanzania during the last 3 years as such it is not widely practiced. This paper reviews SRI practice at global, regional and country (Tanzania) level, and evaluates the challenges, opportunities and implications for its adoption in Tanzania. Knowledge gaps at each level have been identified and discussed as well as suggestions for researchable areas.

Determination of the Effect of the System of Rice Intensification (SRI) on Rice Yields and Water Saving in Mwea Irrigation Scheme, Kenya  [PDF]
Kepha G. Omwenga, Bancy M. Mati, Patrick G. Home
Journal of Water Resource and Protection (JWARP) , 2014, DOI: 10.4236/jwarp.2014.610084

Irrigated rice cultivation has long been associated with large amounts of water. Currently convectional rice production is faced with major challenges of water shortage as a result of increasing population sharing the same water resources, as well as global environmental changes. The System of Rice Intensification (SRI), as opposed to conventional rice production, involves alternate wetting and drying (AWD) of rice fields. The objective of this study was to determine the optimum drying days period of paddy fields that has a positive effect on rice yields and the corresponding water saving. The experimental design used was randomized complete block design (RCBD). Four treatments and the conventional rice irrigation method were used. The treatments were the dry days allowed after draining the paddy under SRI before flooding again. These were set as 0, 4, 8, 12 and 16 day-intervals. Yield parameters were monitored during the growth period of the crop where a number of tillers, panicles, panicle length and panicle filling were monitored. Amount of water utilized for crop growth for each treatment was measured. Average yield and corresponding water saving were determined for each treatment. The results obtained show that the 8 days drying period gave the highest yield of 7.13 tons/ha compared with the conventional method of growing rice which gave a yield of 4.87 tons/ha. This was an increase of 46.4% above the conventional method of growing rice. Water saving associated with this drying regime was 32.4%. This was taken as evidence that SRI improved yields with reduction in water use.

Contribution of Rice Plants and Cover Crop Biomass Amended Soil on Methane Emission  [PDF]
Md Mozammel Haque, Jatish Chandra Biswas, Muhammad Ashraful Alam, Pil Joo Kim
American Journal of Climate Change (AJCC) , 2018, DOI: 10.4236/ajcc.2018.73029
Abstract: Rice plant and soil are playing vital role for produce of methane (CH4) emission from flooded rice soil. Contribution of rice plants and cover crop biomass amended soil on methane emission has not been yet studied under different cover crop biomass incorporated in paddy fields. Closed-chamber method was used to estimate CH4 emission rates during rice cultivation under soil plus rice plants and soil alone condition. Soil plus rice plants chambers 62 × 62 × 112 cm3 and soil alone chambers 20 × 20 cm2 were placed at the same time during rice cultivation (0 days after rice transplanting). Therefore, to evaluate the contribution of soil plus rice plants and soil alone on methane (CH4) emission under different rates of cover crop biomass incorporated soil during rice cultivation. Methane emission from soil plus rice plants increased up to 53 days after transplanting (DAT) and then it’s decreased and continued till harvesting. It was found that ca. 47% - 52% CH4 was mediated by rice plants and ca. 48% - 53% through rice soil alone under 12 Mg·ha-1 cover crop biomass incorporated treated plots. Whereas, only ca. 9% - 10% CH4 emission was mediated by rice plants and ca. 90% - 91% by rice soil alone when 0 and 3 Mg·ha-1 cover crop biomass was incorporated. Therefore, it could be concluded that rice soil alone was more influenced for CH4 emission than rice plants in paddy fields.
SCS123 Pérola: A Brazilian Rice Variety for Risotto  [PDF]
Ester Wickert, Adriana Pereira, Alexander de Andrade, Fabiana Schmidt, Klaus Konrad Scheuermann, Rubens Marschalek, José Alberto Noldin, Gabriela Neves Martins, Eduardo Hickel, Marcos Lima Campos do Vale, Laerte Reis Terres
Agricultural Sciences (AS) , 2018, DOI: 10.4236/as.2018.912111
Abstract: Specialty rices can present differences in some aspects related to grain pericarp color, shape, size, amylose content or aroma. Most of these rice types are related to cultural traditions and ceremonies, and some of them have also different nutritional value. As a specific market, the economic values of these grains are also higher than common milled rice. Santa Catarina State has the ideal conditions to produce specialty rices. The objective of this work was to develop a rice cultivar with special attributes for the well-appreciated risotto. Two rice lines were combined, evaluated and selected during ten years for characteristics related to Italian food. One line was selected and becomes the new rice variety SCS123 Pérola, developed to attend the economically important specialty rices market of Italian food, specifically the risotto. Experimental tests performed with this variety showed that it can be recommended to all rice-producing regions of Santa Catarina State, Brazil. Cooking tests showed that the grains are appropriated for risotto.
Evaluation of coffee intercropped with rice and plantain at early stage of field establishment in Nigeria  [PDF]
Amos Olatunde Famaye, Gerald O. Iremiren, Kayode Olufemi Ayegboyin, Kayode Babatunde Adejobi
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.33039
Abstract: An intercropping experiment involving coffee (sole), coffee/rice, coffee/plantain and coffee/ rice/plantain was carried out between 2007 and 2008 at the Cocoa Research Institute of Nigeria (CRIN) Uhonmora Substation, Edo State situated in a derived Guinea Savanna agro-ecological zone of Nigeria. The experiment was a Randomized Complete Block Design (RCBD) with above mentioned treatment and replicated three times. The spacing used for coffee and plantain was 3 m apart respectively while rice was sown 30 cm apart. Morphological parameters such as plant height, stem girth, leaf area and canopy score were taken on coffee monthly while the survival count were taken after two months of field establishment. Yields of the component crops were also collected at maturity. Data collected were subjected to statistical analysis of variance and LSD used to separate the means that were significant. Result obtained showed 98% survival without any significant difference among the treatments. On vegetative growth, coffee/rice and coffee/plantain were significantly higher (p < 0.05) than coffee sole and coffee/rice/plantain in plant girth and leaf area but not significantly higher in all the months. Plant height however did not follow the same trend as height in coffee sole was slightly higher than coffee/rice. However, the difference was not significant. But coffee/plantain was still significantly higher (P < 0.05) than coffee/rice/plantain. The least was recorded in coffee/rice/plantain intercrop. Grain and bunch yields from rice and plantain respectively in the intercrops compare favourable well to what obtain from coffee sole. From the result obtained, it could be concluded that there was no deleterious effect on growth when rice and plantain were intercropped with coffee. Therefore coffee/rice and coffee/plantain intercropped with better performance could be recommended to coffee farmers in Nigeria rather than sole planting of coffee.
Variation in Senescence Pattern of Different Classes of Rice Tillers and Its Effect on Panicle Biomass Growth and Grain Yield  [PDF]
Ekamber Kariali, Sunita Sarangi, Rashmi Panigrahi, Binay B. Panda, Pravat K. Mohapatra
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.38125
Abstract: In rice, the initiation of tillers is staggered and temporally spaced, but maturity is synchronous. Duration of growth in a later-initiated tiller on a higher culm node is shorter and it contributes less biomass and grain yield. The present investigation attempts to discover the manner in which ordered pattern of senescence in basipetal succession impacts source capacity of tillers in two contrasting rice cultivars, namely Lalat (high tillering) and MGD-106 (medium tillering) during the dry season of 2009 and ascertain how tiller production capacity influences dry matter partitioning and tiller dynamics of the plant. In both the rice cultivars, the progress of senescence among different types of tillers was indicated by gradual decline of photosynthetic pigments, total nitrogen and protein concentrations and increase of lipid peroxidation and peroxidase activity of the flag leaf, which affected photosynthetic efficiency. The effects were more pernicious on the newer tillers compared to older tillers. It was observed that metabolic dominance of the older tillers over newer tillers could be accrued due to higher photosynthetic source capacity of the former than that of the latter. It was concluded that flag leaf of a later-initiated tiller is less tolerant to senescence induced photo-oxidative stress, which decreases both source and sink activities. Increase of tiller number and order in rice increases vulnerability of the later-initiated tillers for oxidative stress and grain filling.
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