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Made available in DSpace on 2022-04-29T08:36:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Techniques to increase grain production such as nitrogen fertilization and plant growth regulators are essential to enable and enhance rice yield. Therefore, our goal was to evaluate the effect of nitrogen fertilization and application of trinexapac-ethyl on vegetative and reproductive traits of upland rice. Experiments were established in Registro, Brasil during the 2011 and 2014 growing seasons and treatments tested consisted of N rates (0; 50; 100; 150; and 200 kg N ha−1) and timings of TE application: V4, V7, R1 and control (without TE). Upland rice grain yield at N rates greater than 117 kg ha−1 applied as topdress combined with TE application at V7 will start to decrease grain yield. In addition, application of TE at V7 combined with N rates equal to or close to 117 kg ha−1 will lead to higher yields and shorter plants. The combination of N application at topdress combined with TE application at V4 led to a linear increase in the number of grains per panicle of rice plants. Nitrogen topdressing was found to increase plant height in the absence to TE or when TE is sprayed at V4 or R1. In addition, nitrogen topdressing had a positive increase in the number of tillers, stems, panicles, and SPAD index in rice plants. College of Agricultural and Technological Sciences São Paulo State University (Unesp), Dracena. Rod. Cmte João Ribeiro de Barros, km 651 - Bairro das Antas, Dracena São Paulo State University (Unesp) Campus of Registro, SP Tropical Root and Starches Center São Paulo State University (Unesp), SP College of Agriculture and Veterinary Sciences São Paulo State University (Unesp), SP Department of Soil Water and Climate Southwest Research and Outreach Center University of Minnesota, 23669, 130th, St. College of Agricultural and Technological Sciences São Paulo State University (Unesp), Dracena. Rod. Cmte João Ribeiro de Barros, km 651 - Bairro das Antas, Dracena São Paulo State University (Unesp) Campus of Registro, SP Tropical Root and Starches Center São Paulo State University (Unesp), SP College of Agriculture and Veterinary Sciences São Paulo State University (Unesp), SP

In the present study, we examined the synergistic effect of phosphate solubilizing bacteria (PSB) and the chemical phosphate on the growth, photosynthetic efficiency, phosphorus (P) uptake, antioxidant activity, and yield of upland rice. Three effective bacterial strains with potent P solubilizing activity viz., Bacillus licheniformis (688.18 µg ml−1), Pantoea dispersa (570.90 µg ml−1), and Staphylococcus sp. (551.81 µg ml−1), were isolated from rice rhizosphere to study their impact on upland rice growth and yield under field conditions for two consecutive years. The experiment data revealed significant increments in shoot height, shoot dry weight, total chlorophyll, carotenoid, chlorophyll fluorescence (fv/fm), P uptake, antioxidant activity, and yield characteristics in upland rice treated with individual PSB or their consortia alone, compared to uninoculated control. However, the integrated use of PSB with 50% recommended P dose showed maximum increment in growth indices (21.25%, 21.86% increase in shoot length and 87.18%, 97.06% increase in shoot dry weight), P uptake (110.37%, 122.78% increase), and yield (50.58%, 35.64% increase) compared to uninoculated control for 2018 and 2019, respectively, indicating a reduction in the dependence of chemical P fertilizer by 50%. Therefore, it can be concluded that combined application of PSB and 50% recommended dose of chemical P can be implied for the sustainable cultivation of upland rice systems to give maximum benefits to the farmers and the environment.

Made available in DSpace on 2022-04-29T08:31:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Research has shown the occurrence of the hormesis effect in some upland rice cultures resulting from low-dose application of glyphosate. Glyphosate herbicide is widely used in Brazilian agriculture for controlling the large quantity of weeds. The aim of this work was to verify the effects of low-dose application of glyphosate herbicide on agronomic characteristics in upland rice. The experimental design used was randomized blocks comprising five low-dose applications of glyphosate herbicide (10, 20, 40, 70, and 100 g acid equivalent [a.e.] ha−1) and the control, in two stages of development of the rice culture (tillering [V4] and floral differentiation [R1]) with four repetitions. The agronomic traits of upland rice were evaluated. Data were subjected to variance analysis, polynomial regression analysis for the quantitative factor, and Tukey’s test for the qualitative factor at p < 0.05. The grain yield and the number of spikelets per panicle increased with the application of 10 g a.e. ha−1 of glyphosate at the floral differentiation stage. Until the low dose of 75 g a.e. ha−1, there was an increase in the number of panicles. Low doses between 70 and 100 g a.e. ha−1 applied in R1 provided less spikelets per panicle, lower 100-grain weight, and lower grain yield. The leaf flavonoid content increased due to the increase in the low doses of glyphosate herbicide. College of Agricultural and Technological Sciences São Paulo State University (Unesp) São Paulo State University (Unesp) Campus of Registro College of Agricultural and Technological Sciences São Paulo State University (Unesp) São Paulo State University (Unesp) Campus of Registro

Made available in DSpace on 2021-06-25T10:29:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Silicon, although not an essential element for plant, when it is absorbed can alter cells flexibility, and then may affect plant architecture; reduce leaf senescence and deleterious effects caused by abiotic stresses. Rice is a Si accumulator, surpassing even nitrogen and potassium accumulation when compared. Thus, we evaluate the effect of foliar application of Si on the development and grain yield of upland rice. We used a randomized block design consisting of foliar application of the following five doses of Si: 0; 126.0; 252.0; 378.0; and 504.0 g ha−1 of Si applied as potassium and sodium silicate, with five replications. We balanced potassium concentrations in the solutions applied to all treatments. We divided foliar fertilization into three applications, at 30, 60, and 90 days after emergence (DAE). We evaluated foliar contents of Si and N, relative chlorophyll content (RCC), and grain yield. Si application increased silicon contents linearly, which reached 8.34 and 12.17 g kg−1 when evaluated at 60 and 90 DAE, respectively, with a dose of 504.0 g ha−1 of Si. Positive gradient of Si doses absorption represented increased grain yield by 252.0 g ha−1 of Si, and after this grain yield decreased. However, foliar silicon application up to the dose of 252.0 g ha−1 under water stress increased the grain yield of rice grown in rainfed system in approximately 9%. The application of 252.0 g of Si ha−1 promotes a grain yield (5778 kg ha−1) and also a higher differential revenue (the US $ 129.49 per hectare). The economic analysis is determined by the spraying costs. School of Agronomy of the Federal University of Goiás Federal University of Goiás São Paulo State University (UNESP) São Paulo State University (UNESP)

Plant growth-promoting rhizobacteria (PGPR) are known to stimulate plant growth because of their versatility in nutrient transformation. However, the success of PGPR inoculation depends not only on their ability to promote plant growth but also on their capacity to metabolize substrates that can be used as energy for the development and survival of the crops. Given the important influence of seed germination and vigor on crop yield, this study investigated the biochemical characteristics and effectiveness of multi-trait PGPR isolates in enhancing upland rice seedling growth and vigor. Biochemical identification was done using Biolog GEN III Microbial Identification System. Isolates were characterized based on their ability to metabolize all major classes of biochemicals in the carbon source utilization and chemical sensitivity assays. Identified rhizobacterial isolates were tested in vitro to evaluate their inoculation effects on the growth of PSB Rc23 upland rice seedlings. Biochemical identification results showed that rhizobacterial isolates have extensive metabolic activities in a wide range of carbon sources. Inoculation effects revealed that isolate IBBw1a was the most effective in enhancing root length and vigor index of rice seedlings in vitro, yielding a significant increase of 60% and 53%, respectively, over the uninoculated control. This study suggests that rhizobacterial isolates from upland rice may have commercial significance to improve seedling growth and vigor. These isolates will undergo a further assessment of their effectiveness in actual upland rice field conditions as they were already proven effective growth promoters in laboratory and screenhouse conditions. Such future activity can uncover their efficacy as potential biofertilizers in the actual soil environment.

Made available in DSpace on 2021-06-25T10:26:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The use of herbicides and growth regulators in agricultural crops to reduce vegetative growth is widely studied worldwide. This study aimed to evaluate the agronomic traits of upland rice subjected to low doses of glufosinate-ammonium applied at different development stages. The treatments consisted of five low doses (0; 15; 30; 60; and 100 g a.i. ha−1; a.i.: active ingredient) of glufosinate-ammonium herbicide: a single low dose between active tillering (AT) and floral differentiation (FD); a single low dose after FD; low dose divided into two applications, the first at the beginning of the AT and the second between AT and FD; low dose divided into three applications, the first at the beginning of the AT, the second between AT and FD and the third after the FD, with four replications. The agronomic traits of upland rice were negatively affected due to the application of low doses of glufosinate-ammonium, with reduction in grain yield, 1000-grain weight, number of panicles, full spikelets and spikelets per panicle. Glufosinate-ammonium has no potential to be used as hormesis effect in rice plants due to loss in grain yield. College of Agricultural and Technological Sciences São Paulo State University (UNESP) College of Agricultural and Technological Sciences São Paulo State University (UNESP)

The rice root-knot nematode (Meloidogyne graminicola) is one of the key pests of rice (Oryza sativa L.) in irrigated and upland rice ecosystems inflicting about 20–80% yield loss. While chemical nematicides are widely used to combat this pest, they have a negative impact on the environment as well as on animal and human health. The present study evaluated the efficacy of organic amendments like biochar and vermicompost in managing the rice root-knot nematode (RRKN) at 0.6, 1.2, 2.5, and 5% (w/v) concentrations. Our result showed that biochar and vermicompost exudate neither exhibit any direct killing ability nor altered the infectivity of RRKN second-stage juveniles (J2). Second-stage juvenile hatching was, however, reduced in two higher doses (2.5% and 5%) of vermicompost exudates. When final nematode population was normalized with root weights at 21 days’ post inoculation, a reduction in population build-up was observed with increased doses of vermicompost. A reverse trend was observed for biochar treatments. Overall, our study showed that application of 1.2% biochar and 5% vermicompost could be helpful in mitigating the RRKN stress in rice. Hence, application of biochar and vermicompost could be an effective alternative to toxic chemical nematicides and recommended as eco-friendly management options against M. graminicola in rice.

Lodging resistance in upland rice requires adequate knowledge of the mechanical basis of culm morphological traits (CMTs) with potential for improved structural integrity under orthosilicic acid (OSA) fertilizer. However, assessment of lodging in NERICAs has been based solely on visual scoring which is inadequate to establish resistance to lodging. Ten upland rice cultivars, comprising NERICAs 1 to 8, Moroberekan, and Ofada were grown on loamy-sand soil under four rates (0, 250, 500 and 750 ml ha− 1) of OSA. At 20 days after heading, CMTs related to lodging were assessed among the rice cultivars. Application of 500 and 750 ml ha− 1 of OSA gave the highest CMTs with reduced lumen diameter. Lodging resistance index (LRI) varied significantly among the cultivars (0.34 in NERICA 1 to 0.70 in Ofada). Moroberekan had the highest CMTs with average LRI (0.47). Using Genotype and Genotype × Environment (GGE) comparisons bi-plot, NERICAs 4,6,7,8 and Moroberekan compared well with NERICA 1 for LRI. Bending stress had the highest but negative significant correlation (-0.74**) with LRI. Assessment of CMTs in NERICAs under OSA fertilizer can reveal variations in lodging resistance obscured by visual scoring. OSA fertilizer can improve lodging resistance through increased culm wall thickness and reduced lumen diameter in resistant cultivars such as Moroberekan and NERICA 4. NERICA cultivars with lower LRI will be more desirable to minimize lodging at moderate rate(s) of foliar OSA fertilizer. The need to characterize the CMTs of other NERICAs to establish LRI that confers susceptibility, moderate and high resistance to lodging was emphasized.

Lead is a hazardous heavy metal pollutant present in the environment, and iron is an essential micronutrient with numerous cellular functions in normal physiology. However few studies have focused on the influence and interaction of lead and iron changes during plant growth. So the present study investigated the mechanism how lead and iron affected in upland rice (Oryza sativa L.) in order to clarify the relationship between iron and lead. The seeds of upland rice were supplied with iron (Fe), lead (Pb), and Fe and Pb together, respectively. Then the seed germination, ion absorption, gibberellins (GAs) and abscisic acid (ABA) metabolism and sugar utilization were determined. Lead treatment delayed upland rice seed germination, deactivated GA, inhibited GA signal transduction and increased ABA synthesis in the seed. In addition, the soluble sugar concentration in seeds was reduced alongside reduction in the activity levels of α-amylase (EC 3.2.1.1) and β-amylase (EC 3.2.1.2) during the earlier stages, but these increased in a time-dependent manner, reaching a stable level in response to lead-induced stress at 72 h. In contrast, iron alleviated the lead-induced changes in seed germination stage. Notably, the interaction between iron and lead increased GA signal transduction and inhibited ABA synthesis, whilst increasing starch hydrolysis and sugar consumption to augment rice seed germination. The results suggest that iron (such as in iron fertilizers) may be promising additives for agricultural use, improving plant germination, whilst simultaneously reducing the toxicity of lead in widely contaminated soils.

This study explored the response in grain yield and quality of upland and wetland rice varieties to a combination of zinc (Zn) and nitrogen (N) fertilizers under two water management regimes. A factorial arrangement based on a randomized complete block design composed of three factors was carried out with three independent replications. Upland and wetland rice varieties were grown with three fertilizer treatments; the optimum N rate (86 kg N ha−1) without Zn application, the optimum N rate with Zn (50 kg ZnSO4 ha−1), and the high N rate (172 kg N ha−1) with Zn under waterlogged and well-drained conditions. Grain yield was 27% lower in the well-drained than in the waterlogged condition in wetland rice, while there was no effect in upland rice. Application of optimum N with Zn application produced the highest grain yield in upland rice, while yield was the highest in wetland rice in high N with Zn application. Upland rice grown in the well-drained condition with the optimum and high N with Zn treatments enhanced Zn concentration by 45% and 29% higher than the treatment without Zn, respectively, while it had no difference among three treatments in the waterlogged condition. Wetland rice variety grown under the well-drained condition in optimum and high N rate with Zn treatments were equally effective in improving grain Zn concentration at the average of 88% compared to the control. While rice grown under the waterlogged condition in the high N with Zn treatment had improved 92% the concentration. The optimum N rate with Zn application increased grain yield in upland rice, while the higher N input is required for wetland rice. Grain Zn concentrations of upland and wetland rice varieties were enhanced by applying Zn fertilizer; however, the increased level was depended on N application rate in the individual water condition.

Genetic assessment of rice landraces is important for germplasm evaluation and genetic resource utilization. Rice landraces in peninsular Thailand have adapted to unique environmental stresses over time and have great significance as a genetic resource for crop improvement. In this study, rice landraces derived from rice research centers and farmers from different areas of peninsular Thailand were genetically assessed using 16 polymorphic InDel markers from putative stress-related genes. A total of 36 alleles were obtained. The average PIC value was 0.27/marker. The F(ST) varied from 0.46 to 1.00. Genetic diversity was observed both within and between populations. AMOVA indicated that genetic variations occurred mainly between populations (70%) rather than within populations (30%). The dendrogram, population structure, and PCoA scatter plot clearly demonstrated the differentiation of the two major groups, i.e., landraces from upland and lowland rice ecosystems. The unique alleles of Indel1922, -2543, -6746, -7447 and -8538, which lie in genes encoding putative WAX2, heavy metal-associated domain-containing protein, GA20ox2, PTF1, and PLETHORA2, respectively, were only found in rice from upland ecosystems. Putative WAX2, GA20ox2, and PLETHORA2 are likely related to drought and salt stress. Our findings demonstrate the diversity of landraces in peninsular Thailand. The preservation of these landraces should be facilitated with effective markers to maintain all variant alleles and to protect the genetic diversity. Indel1922, -2543, -6746, -7447 and -8538 have the potential to differentiate upland rice from lowland rice. Furthermore, Indel1922, -6746 and -8538 might be effective markers for drought and salt tolerance. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12298-020-00816-z) contains supplementary material, which is available to authorized users.

This study evaluated the effects of plant growth-promoting rhizobacteria (PGPR) isolates in enhancing upland rice growth and yield. Bacteria were isolated, screened for growth-promoting activities in vitro, biochemically identified, and tested under screenhouse conditions at the Philippine Rice Research Institute (PhilRice). Isolates exhibited growth-promoting activities, such as indole-3-acetic acid (IAA) production, tricalcium phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, siderophore production, and starch hydrolysis. The screenhouse experiment was conducted with upland rice (PSB Rc23) as the test crop, sterilized and natural soils, and recommended rate of inorganic fertilizers (RRIF) as other source variables. Results showed that significantly heavier shoot and root fresh weights are evident in plants grown in sterilized soil. Plants treated with full RRIF exhibited superior growth in terms of plant height, shoot and root weights, and grain yield. Among inoculated and fertilized plants, comparable growth promotion was obtained with Acidovorax delafieldii combined with half inorganic fertilizer rate, in terms of root fresh weight, shoot and root dry weights, plant height, grain yield, and nitrogen, phosphorus, and potassium (NPK) uptake. Overall findings show that PGPR (A. delafieldii) in combination with 50% RRIF is as effective as full RRIF in enhancing growth and yield of PSB Rc23 rice, implying that dependence on chemical fertilizer can be reduced utilizing this PGPR. However, further evaluation of these bacterial isolates in actual field conditions is necessary to uncover their efficiency as potential biofertilizer.

The adaptation to aerobic environments enables upland rice to produce a sustainable grain yield under suboptimal conditions. In order to understand the molecular mechanisms involved in providing the adaptation of upland rice to aerobic environments, we previously developed introgression lines (ILs) with the irrigated rice variety Minghui63 (MH63) as the recipient parent and the upland rice variety Luyin46 (LY46) as the donor parent for subsequent identification of the relevant genes. In this study, IL-U135 was analyzed in detail because of its adaptation to aerobic conditions. Transcriptome profiling revealed 20 and 8 differentially expressed genes (DEGs) between IL-U135 and MH63 under anaerobic and aerobic conditions, respectively. In contrast, 306 and 188 DEGs were identified between LY46 and MH63 under anaerobic and aerobic conditions, respectively. Gene ontology (GO) analysis indicated that the adaptation of upland rice to aerobic environments is intimately associated with CLV3/ESR-related (CLE) signal transduction pathways, CLAVATA1 kinase activity, and salicylic acid related metabolism biosynthetic pathways. The IL-U135, LY46 and MH63 genomes were resequenced to map the genes responsible for adaptations to aerobic conditions. One the basis of an integrated analysis of the transcriptomic and genomic profiles, we propose that genes encoding an NBS-LRR protein (LOC_Os11g10570) and an ATP-binding protein (LOC_Os11g31480) may contribute to the adaptation of upland rice to aerobic environments. Our results may provide new insights into the molecular mechanism underlying the adaptation of rice to aerobic conditions.

The occurrence of diseases in rice, mainly rice blast (Magnaporthe oryzae), is the main cause of yield reduction, and it has been controlled with the abusive use of fungicides in the conventional production system. To produce rice in an agroecological system, some measures, such as biological control, facilitates the transition from one system to another. The biological agent C24G classified as Cladosporium cladosporioides has been isolated from the phylloplane of rice plants and is a potential antagonist to rice pathogens. The aim of this study was to verify the efficiency of C. cladosporioides C24G under field conditions, in an agroecological system. During two growing seasons, C. cladosporioides was tested in a randomized block design in 4 replicates. The treatments consisted of: microbiolized rice seeds with C. cladosporioides, plant sprayed (2 applications), microbiolized rice seeds with C. cladosporioides + plant sprayed (2 ap.), plant sprayed (8 ap.) and microbiolized rice seeds with C. cladosporioides + plant sprayed (8 ap.) and control (no microbiolization and no spray). We evaluated leaf and panicle blast severity, physiological parameters associated with gas exchange, and grain yield. Leaf and panicle blast suppression was up to 85.58% and 79.63% in growing season 2016/2017, respectively, and 83.06% and 74.98% in growing season 2017/2018. At growing season 2016/2017, we observed an increase of the following parameters: photosynthetic rate (A) of 70.99% and 53.52% and transpiration (E) of 22.98% and 59.73% at vegetative and reproductive stage respectively, stomatal conductance (gs) of 126.66% at reproductive stage, water use efficiency (WUE) was up to 55.29% at vegetative stage, biomass 34.56% and yield 51.30%. At the growing season 2017/2018, we observed an increase at the photosynthetic rate (A) of 29.71%, at reproductive stage, biomass, 89.40%, and yield, 34.19%. We conclude that the treatments, microbiolized rice seeds or plant sprayed, allows the insertion of C. cladosporioides into the agroecological system, facilitating the agroecological transition with considerable grain yield, and leading to a final product without residues.

Popular African upland rice variety Nerica4 performs poorly under phosphorus (P) deficiency; the objective was to identify plant and soil traits likely to improve its P efficiency. Field and glasshouse experiments compared P uptake and root parameters between the popular rice genotype Nerica4, and a known P-efficient genotype, DJ123. Glasshouse experiments used fresh field soil, sterilized soil and sterilized soil resupplied with 15% fresh field soil to assess microbial effects. DJ123 had faster crown root development and higher proportions of fine roots, leading to larger root surface area (RSA). Additionally, it acquired more P per RSA, thus had more efficient roots. Higher root efficiency of DJ123 compared to Nerica4 was detected in fresh field soil, sterile soil, and sterile+resupplied soil, indicating that plant-specific factors rather than soil microbiome effects explained higher root efficiency in DJ123. In non-sterile soils both genotypes were colonized by arbuscular mycorrhizal fungi (AMF), and high expression of an AMF-induced rice P transporter gene (OsPT11) indicated the symbiosis was functional. We identified plant traits present in DJ123 such as rapid crown root development, higher proportions of fine lateral roots, as well as superior overall root efficiency that make it a promising donor to improve the performance of Nerica4 in P-deficient environments. In addition, Nerica4 appears more susceptible to growth-inhibitory effects of the soil microbiome.

Bacteria with potential to alleviate abiotic stresses in combination with plant growth promotion are extremely useful in sustainable agriculture. The present study involves the isolation and evaluation of 14 bacterial isolates obtained from four upland rice roots in varying concentrations of PEG-6000. Three potential isolates MKA2, MKA3 and MKA4 were selected for further experiments. A pot experiment was conducted with four treatments under well watered and drought conditions. Water deficit treatment was imposed by reducing the amount of water added to 25% of the field capacity. Twenty days post stress results showed that drought stress affected the physiological and biochemical parameters of uninoculated wheat seedlings. Inoculation with the three bacterial isolates diluted the adverse effects of drought on relative water content and membrane stability index, and thus improved the water use efficiency over the uninoculated control. Inoculation also improved the shoot and root biomass of wheat plants in comparison to uninoculated control treatment under drought stress. Increased levels of super oxide dismutase and catalase activities were observed in treated plants as compared to control plants thus protecting the plants from oxidative damage. Thus, these potent bacterial isolates could be used effectively to ameliorate plant water intake efficiency and improve sustainability in wheat crop under drought conditions.

Although livelihoods in rural Panama have changed significantly in recent times, and purchasing rice has become common, swidden rice cultivation has continued. I explore small-scale farmers’ preferences regarding swidden rice production and consumption in a campesino community through semi-structured interviews with 55 households and participant observation of food production and consumption. The rice farmers cultivated an average of 6,217 m2 of swidden and harvested 344 kg of unhulled rice per year. With decreasing rice production and poor economic efficiency, people enjoy the particular taste of swidden rice, arroz nuevo, and colored rice, which symbolizes the cultural identity, tradition, and dignity of rural life.

Genetic diversity among 30 upland rice genotypes (Oryza sativa L.) was evaluated using morphological and SSR markers. Roger’s distance was calculated for all the data sets as a measure of genetic distance between accessions. The distance matrices were used to generate a dendrogram based on the UPGMA method. The minimum genetic distance based on morphological marker was 0.04 which was found between Megha Rice-1 and Megha Rice-2. The maximum genetic distance was 0.75 observed between Aizawng New and Majinlu, Aizawng New and Mima-Mitong-Jang, Mibisa and Chakhao Poireiton, Chakhao Poireiton and Vepvu Tsuk with an average of 0.395. The number of alleles per SSR marker varied from 2 to 8, with an average number of 4.286 alleles per locus. Polymorphism information content (PIC) values ranged from 0.062 to 0.799 per locus with an average of 0.425. The minimum and maximum genetic distances based on Roger’s distance, were found to be 0.00 (Bhalum-1 and Bhalum-2) and 0.84 (Aizawng New and Mibisa), respectively. In cluster analysis, morphological and molecular marker-based genetic distance grouped the local landraces together with the improved lines and Gene Bank lines. Correlation analysis between morphological data and molecular data revealed a very poor association (r = 0.051 at p = 0.271). The diverse genotypes revealed from morphological-based dendrogram were the following pairs viz., Aizawng New and Majinlu, Aizawng New and Mima-Mitong-Jang, Mibisa and Chakhao Poireiton, Chakhao Poireiton and Vepvu Tsuk, Buh Pui (Tuirel) and Chakhao Poireiton, Marow and Chakhao Poireiton, Kba Tlang and Majinlu, Lokhumo (Tall) and Chakhao Poireiton. While Aizawng New and Mibisa, IC 583129 and Mibisa, Bhalum-1 and Mibisa, Bhalum-2 and Mibisa, Marow and Mibisa pairs were identified as the diverse genotypes based on molecular dendrogram which may be used as parent for hybridization during further rice improvement.

Serratia spp., strain BRM 32114, is a plant growth-promoting rhizobacteria that show strong potential to solve two major challenges of upland rice production in a no-tillage system: initial vigor and grain yield improvement. No-till practices dictate the sustainability of cropping systems as they improve precipitation use, sequester C, mitigate atmospheric CO2 enrichment, restore soil health, and stimulate interest in crop diversity and rotation design. This study was intended to analyze the effect of the Serratia spp. on growth promotion and grain yield improvement in upland rice, under four N rates. Two field experiments were conducted during growing seasons 2015/2016 and 2016/2017, in two different experimental areas managed under a no-tillage system in the Brazilian Cerrado soil. The experimental design was a complete randomized block in a 4 × 2 factorial scheme, with four replications. Treatments comprised of four N fertilizer rates (0, 40, 80 and 120 kg N ha−1) with or without BRM 32114. In BRM 32114 treatment, rice seeds were microbiolized and bacterial suspension were sprayed at soil/plant in the field on the 7th and 15th DAS (day after sowing). Morphophysiological (gas exchange, shoot nutrients content and biomass production), and agronomic (grain yield and its components) traits were estimated. Results revealed increase in stomatal conductance (~ 20%); N, Ca and Mg (7, 11 and 9%) contents; shoot dry matter (8%); number of grain per plant (17%); mass of 1000 grains (2%) and yield (~ 22%) in BRM 32114-treated rice and cultivated in soil fertilized with 0, 40 and 80 kg N ha−1. However, the efficacy of this strain was reduced when combined with the highest rate of N (120 kg ha−1) added to the soil. It is possible to get higher yields levels of upland rice, cultivated under no tillage system, with the complimentary use of Serratia sp., strain BRM 32114, than the application of chemical fertilizers alone. The improvement in soil health could be extra benefit for fertilizer’ savings.

Biochar and inorganic fertilizer when co-applied have been reported to increase crop yield and enhance soil fertility. However, studies on this complementary effect on soil properties and rain-fed upland rice performance in Sub-Saharan Africa are still scanty. Field factorial studies conducted over 2 years was set up to investigate the interactions between rice husk biochar and inorganic nitrogen (N) fertilizer on a sandy clay loam Alfisol. A two-factor (4 × 4) in RCBD where rice husk biochar was incorporated at four doses, 0, 3, 6, and 12 t/ha−1, inorganic N fertilizer (urea) at four rates, 0, 30, 60 and 90 N kg/ha−1, and their combinations was adopted. Results showed that combination of biochar and N fertilizer exerted significant (P > 0.05) interactive effect on rice harvest index, grain and straw yield and N-use efficiency. Interaction between biochar and N fertilizer increased agronomic efficiency by 140% and grain nutrient recovery by 191% over 2 years. Combination of biochar and N fertilizer reduced soil bulk density, increased water holding capacity and soil chemical status such as pH, N, P, K, Corg, Ca, ECEC and base saturation, all within the top 10 cm depth of the soil. Overall, the results established that rice husk biochar can be used as a soil conditioner to enhance upland rice yield on an Alfisol. The combined dose of 3–6 t/ha−1 biochar and 30 kg/ha−1 of N fertilizer is thus recommended for upland rice farmers in the study area.

If future rice production is to contribute to food security for the increasing population of sub-Saharan Africa (SSA), effective strategies are needed to control weeds, the crop’s fiercest competitors for resources. To gain better insights into farmers’ access to, and use of, herbicides as part of weed control strategies, surveys were conducted in key rice production locations across SSA. Farm surveys were held among 1965 farmers across 20 countries to collect data on rice yields, farmer’s weed management practices, herbicide use, frequencies of interventions and information sources regarding herbicides. Markets were surveyed across 17 countries to collect data on herbicide availability, brand names and local prices (converted to US$ ha−1). Herbicides are used by 34% of the rice farmers in SSA, but adoption ranges from 0 to 72% across countries. Herbicides are more often used by men (40%) than by women (27%) and more often in irrigated (44% of farmers) than in rainfed lowland (36%) or upland rice growing environments (24%). Herbicides are always used supplementary to hand weeding. Following this combination, yield loss reductions in irrigated lowlands and rainfed uplands are estimated to be 0.4 t ha−1 higher than hand weeding alone. In rainfed lowlands no benefits were observed from herbicide use. Sixty-two percent of the herbicides sold at rural agro-chemical supply markets are unauthorized. These markets are dominated by glyphosate and 2,4-D, sold under 55 and 41 different brand names, respectively, and at relatively competitive prices (below average herbicide price of US $17 ha−1). They are also the most popular herbicides among farmers. For advice on herbicide application methods, farmers primarily rely on their peers, and only a few receive advice from extension services (

Assessing soil organic carbon (SOC) stocks under different land uses and future climate change (CC) conditions is important to provide better land use planning strategies. In South and Southeast Asia, Quercus forests are widely distributed but are exploited as a source of raw materials and shifting cultivation. Rice is a major staple food grain crop, often cultivated with terracing as upland rice. However, few studies on SOC stocks and simulated SOC dynamics under climate change conditions are available in these regions for these important land uses. Here, we present a case study related to Manipur state in North East region (NER) of India. We used the RothC model to evaluate the short-term changes of SOC stocks in Quercus forests and nearby upland rice fields and the effects of CC on SOC stocks, based on two General Circulation Models (GCMs) and two CO2 Representative Concentration Pathways (RCPs) during three 20-year time periods. Under CC conditions (2019–2078), results differed among land uses, GCMs, RCPs, and time periods, and Quercus forests were more sensitive to climate change than upland rice. For Quercus forests, as average of all GCMs and RCPs, SOC decreased by 0.42 t C ha−1 year−1 in the first time period and by 0.17 t C ha−1 year−1 as sixty years average. In upland rice, SOC decreased by 0.20 t C ha−1 year−1 in the first time period and by 0.12 t C ha−1 year−1 as sixty years average. Results indicated that management strategies for Quercus forests and upland rice are needed for CC mitigation and adaptation particularly in very close CC scenarios.

Meloidogyne graminicola is one of the most important plant-parasitic nematodes in rice. Breeding for natural resistance and tolerance is considered one of the most economical and sustainable approaches to control this damaging pathogen. Quantitative trait loci (QTL) mapping was carried out in a recombinant inbred line (RIL) population derived from a cross between the Asian rice genotypes IR78877-208-B-1-2 and Dinorado. IR78877-208-B-1-2 is an aerobic rice genotype that is resistant and tolerant to M. graminicola. Dinorado is a traditional upland rice genotype from the Philippines that is characterized by its aroma and prized for its cooking quality. The host response of 300 F4 lines derived from this cross was evaluated in both nematode infested and non-infested concrete beds in the dry seasons of 2013 and 2014. Five genotypes were found consistently resistant while 13 genotypes were consistently partially resistant to M. graminicola. QTL mapping for M. graminicola resistance/tolerance, yield-contributing traits, and yield revealed four main effect QTLs (qJ2RS2.1, qJ2GRT2.1, qJ2RS3.1, and qJ2GRT3.1) associated with reduced nematode reproduction on chromosomes 2 and 3 and two QTLs (qGR3.1 and qGR5.1) associated with reduced root galling on chromosomes 3 and 5. Twenty main effect QTLs associated with yield-contributing traits and yield were also found. Our study further identified co-locating QTLs associated with nematode resistance, yield-contributing traits, and yield on chromosomes 3 and 5. QTLs harboring candidate genes, such as OsBAK1, OsDST, OsIPT4, and DUF26, for higher grain yield and tolerance to abiotic and biotic stress, were identified. These QTLs and the RILs that are consistently resistant and tolerant to M. graminicola, and which are high-yielding in nematode-infested fields, can be utilized in breeding programs to improve the resistance and tolerance of Asian rice to this important pathogen.

The upland rice crop system located within Brazilian savannas and Amazon Rainforest is the largest rainfed rice growing area in Latin America. To develop and release higher yield and adapted cultivars for this large region, the upland rice breeders need to conduct multiple-location trials aiming to model the genotype × location (G × L) and evaluate the germplasm yield adaptability. Here we hypothesize that regional patterns of G × L across this extensive region can be modeled by integrating factorial regression models with a geographic information system (GIS). Two sets of advanced yield trials from different germplasm pool were used in this study. From GIS tools, we collect and process geographic covariates and produce thematic maps of yield adaptability. One advantage of the methodology is that adaptability can be dissected into genotypic-sensibility coefficients related to the reaction norm for the geographic gradient. Then, breeders can discriminate different types of adaptability over a region, such as responsiveness for elevation, longitudinal or latitudinal adaptation, identifying possible ideotypes to solve current adaptation gaps for target regions. We observed that about of 53–59% of the G × L effects are due to predictable geographic-related factors. However, the upland rice germplasm is better adapted to higher elevations (> 700 m), which may indicate limitations in cultivar development because these regions do not represent the current upland rice growing region. We suggest to exploit geographic-related factors by increasing breeding efforts for northern and western Brazil environments located at lower elevations (

Drought avoidance is an important strategy exhibited by cereals for maintaining productivity under water deficit conditions. Most of the modern rice varieties stop their root growth during drought whereas few traditional cultivars have the ability to maintain root growth. An upland rice genotype Nootripathu was found to maintain its root growth under drought when compared to a shallow rooted IR20. Drought responsive transcriptome profiling of roots of IR20 and Nootripathu revealed that tolerant Nootripathu showed relatively more number of DEGs (4287) than susceptible IR20 (3081). Drought stress significantly affected expression of genes encoding cellulose synthases and expansins, two major gene families involved formation of cell walls in the shallow rooted drought susceptible genotype IR20. Genes involved in the biosynthesis of phytohormones namely ABA and Brassinosteroids were found to be significantly up-regulated in roots of Nootripathu during drought. Up-regulation of autophagy related genes involved in degradation of denatured/misfolded proteins in roots of IR20 indicates the severe progression of stress in IR20. Co-localization analysis of DEGs against QTL hotspots identified several putative candidate genes including a zinc finger domain containing protein, a bZIP transcription factor, a MYB factor and an OsMADS7 requiring further functional validation.

As one of the most widely promoted water-saving irrigation strategies for rice, alternate wetting and drying irrigation (AWD) can not only save water but also increase mineral nutrient use efficiency. In this study, we compared the growth conditions of four rice varieties (two lowland and two upland varieties) under three irrigation regimes: continuously flooded (CF), alternate wetting and moderate soil drying (AWD15) and alternate wetting and severe soil drying (AWD30). AWD15 and AWD30 enabled the plants to receive fewer irrigation events and less irrigation water than CF, thereby saving both water resources and labor. AWD15 reduced redundant vegetative growth, promoted root growth, and increased the root-shoot ratio and harvest index. AWD15 increased the grain yield, water use efficiency (WUE) and phosphorus use efficiency (PUE) of upland rice and maintained the grain yield while increasing the WUE and PUE of lowland rice. More developed root systems under AWD helped upland rice to maintain a higher water status than lowland rice when plants were subjected to soil drying, which resulted in superior performance in grain yield in upland rice. AWD30 could not reconcile the demands of higher yield and the desire to reduce irrigation water use because it decreased grain yield. The results indicate that AWD15 irrigation of rice can not only increase rice yield and WUE but also enhance PUE, which can potentially reduce the use of phosphorus fertilizers. The results provide theoretical and technical support for improving rice cultivation.

The current study was employed to investigate the effect of solvent type, extraction time and bran ratio on the rice bran oil (RBO) properties from three varieties of rice bran namely Bario, lowland and upland rice. RBO was extracted by using soxtherm extraction method using methanol solvent at different extraction time (3, 4 and 5 h) and bran ratio (10, 20 and 30 g). Free fatty acid (FFA), total phenolic content (TPC) and antioxidant properties were assessed. Solvent that has low polarity exhibited the attraction of polar component of oil with the highest yield by ethanol (16.16%), followed by methanol (15.38%). FFA contents occurred higher in lowland types of rice bran in all types of solvents at $$P

Rice is the third most important crop in Kenya after maize and wheat. Plant parasitic nematodes (PPN) are a major rice production constraint. The objective of this study was to determine the distribution and abundance of rice PPN in Kenya and their association with environmental variables. Soil and plant samples were collected from rainfed upland and irrigated lowland rice fields in Kirogo, Thiba, Nyangati, Ombeyi, Kombura, Kakola and Mwambe Sub-locations. Twenty-two PPN genera were identified across all Sub-locations with the highest (20) number of nematode genera recorded in rainfed upland rice fields. The nematode genera Scutellonema, Hoplolaimus, Ditylenchus, Hemicycliophora, Heterodera, Paralongidorus and Tylenchus were not recorded in the irrigated lowland rice fields while Criconemella and Tylenchorhynchus were not observed in rainfed upland fields. Canonical correspondence analysis of the relationship between soil properties and nematode abundance revealed a significant (P

Asian rice (Oryza sativa L.) is widely cultivated in Asia, where it has been classified into Indica and Japonica Group, the latter is further classified into Tropical and Temperate Japonica Subgroup. O. rufipogon is believed to be the closest ancestor to O. sativa, but it remains unclear whether the two groups arose from a single ancestor or different ancestors. Therefore, here, we investigated the matrilineal ancestors of O. sativa using markers for organelle (chloroplast and mitochondrial) genomes, and 119 O. sativa landraces, 10 O. glaberrima Steud., 115 O. rufipogon Griff. from Asia, and 39 accessions from other wild rice species with AA genomes. We screened 18 organelle markers developed based on polymorphic loci in the organelle genomes. In addition, we used the open reading frame 100 of a chloroplast marker. The results indicated that O. rufipogon first differentiated into two lineages and then further differentiated into Indica and Japonica Group, respectively. Accessions of O. rufipogon (R-1f and R-2d types) from Myanmar appear to be the closest ancestors of Tropical Japonica Subgroup and Indica Group, respectively. Therefore, these wild strains may have made a strong contribution to the domestication of rice landraces in Myanmar.

Pot and field trials were conducted in 2012 and 2013 cropping seasons in Nigeria to determine the damage of Heterodera sacchari on the growth and yield of upland New Rice for Africa (NERICA) derived from hybridisation of Oryza sativa and O. glaberrima. NERICA rice (NR) cultivars selected were NR1, NR2, NR3, NR8 and NR14. In screenhouse experiments, rice seedlings were inoculated with 2500, 5000 and 10000 eggs and second-stage juveniles of H. sacchari, three weeks after sowing. In addition, two consecutive field experiments were carried out on a naturally infested field. Data on plant growth, yield, and final H. sacchari population densities were taken at the end of the experiments. Significant reductions of 34, 60 and 78% were observed in plant height, fresh root and total seed weights, respectively. Infected plants also produced chlorotic tillers and showed delayed panicle emergence. In field experiments, rice yield was reduced by approximately 50 and 85% in the first and second cropping seasons, respectively. Nematode population densities in soil and roots of rice plants increased significantly in infected plants compared to the controls. The results of this study indicate that H. sacchari is a serious pathogen of susceptible upland NR cultivars and may cause total crop failure when NR is continuously cultivated in cyst nematode infested fields.

We studied varietal difference in radiocesium accumulation by using Japanese and World rice collection for future development of low accumulation varieties. As a result, the radiocesium activity concentration varied by 12- and 22-fold in seed grains and straws, respectively. When we examined the seed grain to straw ratio of radiocesium activity concentration, paddy rice cultivars of Japonica sub-species showed a lower result than Indica and Javanica paddy rice cultivars. These observations suggest that the Japonica paddy rice cultivars may have the property of repressing radioactive cesium translocation to edible parts.

The resource and environmental challenges faced by rice production call for resource-saving and environment-friendly rice varieties. Water-saving and drought-resistance rice (WDR) is a new type of cultivated rice combining both high yield potential and acceptable grain quality as a current lowland paddy rice, as well as water-saving and drought resistance as a traditional upland rice. The lowland and upland rice are two ecotypes adapted to contrasting soil water status, originating mainly because of their differentiated drought resistance. Upland rice, domesticated in a water–limited environment and experiencing a bidirectional selection process, has better drought resistance and especially better drought avoidance. Though the potential tradeoff between drought resistance and productivity is very common in rice, the bidirectional selection could overcome this tradeoff and accumulate recombination genotypes. It is very important to choose elite parents on the basis of studies on the great genetic diversity of rice yield and drought resistance among the rice germplasm resources and adapt the bidirectional selection strategies to especially integrate drought avoidance, drought tolerance, high water use efficiency, and productivity in WDR breeding. The breeding history and genomic studies indicated that lowland paddy rice and upland rice hybridization breeding with suitable selection in different environments is an effective approach to improving complex traits such as yield potential and drought resistance. Meanwhile, molecular technology shows higher efficiency on value-added breeding such as transferring and pyramiding pest- and disease-resistant genes, which helps WDR obtain other green characters. Twenty-two WDR varieties were registered and distributed to farmers in recent years and could be planted in both irrigated and rainfed ecosystems, thus showing promising application prospects. The major crop management technology of WDR in lowland paddy fields with water-saving cultivation and in rainfed fields by dry seeding with aerobic cultivation were also discussed in this article.

Background As an elite japonica rice variety, Kongyu-131 has been cultivated for over 20 years in the third accumulated temperature zone of Heilongjiang Province, China. However, the cultivated area of Kongyu-131 has decreased each year due to extensive outbreaks of rice blast. To achieve the goals of improving blast resistance and preserving other desirable traits in Kongyu-131, a genome-updating method similar to repairing a bug in a computer program was adopted in this study. A new allele of the broad-spectrum blast resistance gene pi21 in the upland rice variety GKGH was mined by genetic analysis and introgressed into the genome of Kongyu-131 to upgrade its blast resistance. Result QTL analysis was performed with an F2 population derived from a cross between Kongyu-131 and GKGH, and a blast resistance QTL was detected near the pi21 locus. Parental Pi21 sequence alignment showed that the pi21 of the donor (GKGH) was a new allele. By 5 InDel or SNP markers designed based on the sequence within and around pi21, the introgressed chromosome segment was shortened to less than 634 kb to minimize linkage drag by screening recombinants in the target region. The RRPG was 99.92%, calculated according to 201 SNP markers evenly distributed on 12 chromosomes. Artificial inoculation at the seedling stage showed that the blast resistance of the new Kongyu-131 was improved significantly. Field experiments also indicated that the improved Kongyu-131 had enhanced field resistance to rice blast and grain-quality traits similar to those of the original Kongyu-131. Conclusions It is feasible to improve resistance to rice blast and preserve other desirable traits by precisely improving the Pi21 locus of Kongyu-131. Linkage drag can be eliminated effectively via recombinant selection on both sides of the target gene.

The application of biochar in soils is a well-established strategy to improve their physical and chemical properties, but the effects should be evaluated for each soil particularly. This study was conducted in a greenhouse of the Agricultural Sciences Unit (ASU) of Rio Grande do Norte Federal University (UFRN), in Macaiba, RN, Brazil, to evaluate the effect of biochar addition to sandy soil. The experiment was carried out in 10-L pots in a completely randomized design with four doses of biochar (0, 3500, 7000, and 10,500 kg ha−1) and four replications. The soil was collected from the top layer of a field adjacent to ASU and the biochar feedstock was wood from pruning cashew trees. The pots were cultivated with upland rice (Oryza sativa L.) and cowpea (Vigna unguiculata (l.) Walp.) in succession. The soil was sampled at 150 and 220 days after application of the treatments. The soil variables determined were pH, soil organic matter, contents of phosphorous (P), potassium (K), and calcium (Ca) plus magnesium (Mg), in addition to cation exchange capacity and exchangeable sodium percentage. Statistical analysis of experimental data included analysis of variance of the effect of biochar and regression analysis for variables with significant effect of those doses. The biochar obtained from cashew tree wood used in the experiment showed potential for use as a soil conditioner, since pH and K and P contents increased with rising doses of biochar. However, using this type of biochar can pose a risk regarding salinization, as indicated by the increase in exchangeable sodium percentage (ESP).

The identification of rice drought tolerant materials is crucial for the development of best performing cultivars for the upland cultivation system. This study aimed to identify markers and candidate genes associated with drought tolerance by Genome Wide Association Study analysis, in order to develop tools for use in rice breeding programs. This analysis was made with 175 upland rice accessions (Oryza sativa), evaluated in experiments with and without water restriction, and 150,325 SNPs. Thirteen SNP markers associated with yield under drought conditions were identified. Through stepwise regression analysis, eight SNP markers were selected and validated in silico, and when tested by PCR, two out of the eight SNP markers were able to identify a group of rice genotypes with higher productivity under drought. These results are encouraging for deriving markers for the routine analysis of marker assisted selection. From the drought experiment, including the genes inherited in linkage blocks, 50 genes were identified, from which 30 were annotated, and 10 were previously related to drought and/or abiotic stress tolerance, such as the transcription factors WRKY and Apetala2, and protein kinases.

Rotation with nonhost crops is an important practice used for root-knot nematode (RKN) management. Screenhouse experiments were conducted to evaluate the response infection of 27 cultivars belonging to 14 crops (blackgram, cabbage, cauliflower, chickpea, cowpea, garlic, ginger, greengram, groundnut, maize, potato, sesame, soybean, sunflower), which are grown in rotation with rice in lowland and upland rice-based ecosystems, to the RKN Meloidogyne graminicola. Root galling indices observed on all crop rotation cultivars were significantly lower compared with the rice cv. Thihtatyin, used as positive control. Differences in host response to M. graminicola infection were observed between cultivars. All 27 cultivars were poor or non-hosts of M. graminicola, except cv. Yezin 4 of chickpea considered as good host. No significant differences in plant growth were observed between non-inoculated and inoculated plants of all plant/species cultivars, with the exception of a reduction in root length in the chickpea cv. Yezin 4 (good host) and the garlic cv. Shan (poor host). Rotation crops identified as poor or non-hosts of M. graminicola could be useful in the management of RKN in rice-based cropping systems.

In the uplands of Eastern Himalayan Region (EHR) of India, dry-seeded rain-fed rice occupies considerable area. However, productivity of rice in this region is very low and is mainly due to frequent occurrence of intermittent soil moisture stress, weed infestation, and poor crop establishment. Keeping this in view, a field experiment on rain-fed direct-seeded rice was conducted during two consecutive years 2011 and 2012 at the EHR of India (27° 95′N latitude and 94° 76′E longitude, 662 m above MSL) to evaluate the effect of seed priming (SP) with different durations (0, 12, 18, and 24 h) and in situ furrows at various row intervals as moisture conservation measures (MCM) on seed germination, plant stand, profile moisture recharge, rice productivity, water and energy use efficiency, and harvest monetary benefits. Results revealed that SP for 24 h duration significantly (p

In this study, we evaluated the damage caused in the field by Tibraca limbativentris Stål adults at different levels of infestation (0, 1, 2, and 4 stink bugs) per three rice plants during three growth stages (V8, V13, and R4 stages) of upland rice cultivated in southwestern of Pará State, Amazon Rainforest region, Brazil. Heading time (panicle exertion) was affected by T. limbativentris infestations mainly in the vegetative stage and the whiteheads percentage in treatments ranged from 18.2 to 38%. The dead hearts percentages varied between 0 and 21.5%, and the mean number of primary branches (ramifications) ranged from 5.9 ± 0.4 to 12.3 ± 0.2. The number of empty spikelets was only affected in infestations with four insects/three plants, while the quantity of filled grains per panicle was affected only when infestations occurred during the vegetative stage. The total number of spikelets (filled + empty) per panicle decreased significantly in all phenological stages, and the percentage of damage ranged from 17 to 44% among treatments. Based on the proportion of damage observed, we suggest doubling the number of insects presently used as action threshold to 2 and 4 stink bugs per 15 stalks sampled for the vegetative stage, and of 1 or 2 stink bugs per 15 stalks sampled at the beginning of reproductive stage (R3/R4). Also, the field should be monitored during the entire vegetative stage, since most damage was observed in this phenological stage.

A field experiment on integrated nutrient management in rainfed upland rice was conducted during kharif season (July to October) of 2007 and 2008 in the farm of Krishi Vigyan Kendra, Tirap (27°26′N latitude, 95°27′E longitude and at 185 m a.s.l.), Arunachal Pradesh, India. The experimental soil is sandy loam in texture (55 % sand, 26 % silt and 17 % clay), acidic in reaction (pH 5.4), medium in available N (290 kg ha−1), but low in available P (7.7 kg ha−1) and K (125 kg ha−1). The results showed that integrated use of 75 % recommended dose of nitrogen (RDN) through farm yard manure (FYM)/vermicompost (VC) and 25 % recommended dose of fertilizer (RDF) produced taller plants, higher number of tillers m−2, higher leaf area index, dry matter accumulation and crop growth rate than those of other treatments. It recorded markedly greater number of panicles m−2 and grains panicle−1 that led to higher grain yield by 89.6 % over control and by 29.9–35.6 % over other treatments. The growth parameters showed strong and positive correlations with grain yield. Use of 75 % RDN through FYM/VC and 25 % RDF through chemical fertilizer seems to be conducive for improving growth and productivity of rainfed upland rice in the hill region of northeastern India.

Rice production is currently expanding from the south-eastern regions of Australia into northern Australia where indigenous species of wild rice occur widely. A survey of fungal diseases on wild (Oryza australiensis, Oryza spp.) and cultivated rice (Oryza sativa) in North Queensland, Australia, in May 2014 revealed a diverse range of fungal genera species, including important pathogens of cultivated rice. Whilst a single isolate of Magnaporthe oryzae (causal agent of rice blast) was obtained from wild rice, Bipolaris oryzae (causal agent of brown spot) was the predominant pathogen detected under North Queensland conditions. For the first time for Australia, we report Rhizoctonia oryzae-sativae (causal agent of aggregate sheath spot) occurring on wild rice. Other pathogens detected on wild rice included Curvularia lunata, Cochliobolus intermedius, Cochliobolus geniculatus, and Fusarium equiseti present in the majority of wild rice samples. Nearby cultivated rice fields harboured additional pathogens not found in wild rice including Fusarium graminearum, Leptosphaeria spegazzinii and Cochliobolus lunatus, causing scab disease, glume blight and leaf blight, respectively. We also confirmed that Bipolaris oryzae from wild rice can infect cultivated rice. This study highlights the importance of wild rice species as alternative hosts harbouring pathogens of cultivated rice and the likely disease threats to expansion of cultivated rice into the same region(s) where wild rice is endemic.

During surveys of wild and cultivated rice in northern Queensland in 2014 and 2015, 92 fungal isolates were obtained from plants that were afflicted by foliar diseases, including the rice blast pathogen, Pyricularia oryzae, and the brown spot pathogen, Bipolaris oryzae. Seven species of Curvularia were found, viz. Curvularia aeria, C. alcornii, C. asianensis, C. clavata, C. lunata, C. muehlenbeckiae and an undescribed species. To remove uncertainty about the identity of the host plants from which the fungi were isolated, a DNA barcoding strategy was developed using regions of the chloroplast genome. Pathogenicity tests using wild rice isolates of P. oryzae indicated that many local rice varieties are susceptible to infection.

The study was conducted to analyse and compare nutrient contents of farmyard manure, farmyard manure treated with effective microorganisms and effective microorganism solutions, also, to determine the effect of farmyard manure and activated effective microorganisms on rice growth, development and yield. Farmyard manure and effective microorganism solutions were characterized for nutrient status in the laboratory. A 3 × 3 factorial experiment in randomized complete block design and replicated thrice involved farmyard manure and activated effective microorganisms. Farmyard manure at rates 0, 5 and 10 t ha−1 was applied 2 weeks before sowing by broadcasting and incorporated into the soil. Activated effective microorganism solution at 0, 20 and 40 l ha−1 was sprayed weekly at vegetative stage. Farmyard manure and effective microorganism solution contained both macro- and micronutrients at varying proportions. Application of farmyard manure increased rice yields from 1.35 to 3.31 t ha−1, 1.35 to 3.03 t ha−1 activated effective microorganism solution, and 1.35 to 3.33 t ha−1 in both farmyard manure and activated effective microorganisms when integrated. Adoption of organic soil amendments would improve soil fertility for sustainable crop production to small-scale farmers.

The objective of this study was to assess the effect of preceding crops (soybeans, sunn hemp, upland rice, and sweet sorghum) on the succeeding sugarcane yield, total bioethanol production, and soil chemical properties within the sugarcane cropping system. Treatments with upland rice and sweet sorghum provided the greatest increase in soil available P, compared to uncultivated land (control) at the final sampling, preceding the sugarcane harvest. Treatments effects were not significantly different for soil organic matter. At sugarcane harvest, the upland rice treatment provided the highest cane yield compared to the unplanted land, yet was not significantly higher than the yield of the sweet sorghum treatment. The highest sugarcane ethanol yields were observed in the sweet sorghum–sugarcane and upland rice–sugarcane treatments. However, the total ethanol yield in both preceding and succeeding crops was found to be highest in the sweet sorghum treatment, followed by the upland rice treatment. Upland rice proved to be most suitable for farming systems which emphasized food security, whereas sweet sorghum was most desirable for farming systems which emphasized alternative biofuel production. Both crops improved the sustainable production of soil and sugarcane.

We investigated dissemination processes of New Rice for Africa (NERICA) varieties in central Benin in 2009 through structured interviews with 1,390 farmers and semi-structured interviews with 203 farmers. By 2009, 74 % of farmers belonging to a farmer group had experience of growing NERICA varieties, while only 29 % of farmers who did not belong to the group had such experience. This difference was attributed to approaches used by the public extension service, which has mainly worked with farmer groups as an entry point for NERICA dissemination. As women accounted for 70 % of farmers in farmer groups, this approach achieved gender equality on the adoption of NERICA varieties. The seed production business has become an incentive for farmers to grow NERICA varieties, as their seed may be purchased at higher than local market price by the public sector for further dissemination. Male farmers tended to sell greater amounts of NERICA varieties, as female farmers have limited land for their cultivation. Around 20 % of farmers had stopped growing NERICA varieties, because they did not receive proper information on their characteristics and the cultivation methods required. They therefore could not be involved in the seed business. Farmers who had never grown NERICA varieties reported that they had limited access to seed. Thus, opportunities to access technologies and business opportunities should be made equal for farmers, especially when they are introduced. In particular, farmer-to-farmer seed exchange needs to be enhanced.

Cover plants are intended to cover the soil, protecting it from erosion, nutrient leaching, and providing nutrients through recycling or biological fixation. The objectives of this study were to evaluate the dry biomass productivity and total accumulation of nutrients in the cover crops shoots and in the upland rice grown in succession; and evaluate the effect of the isolated and combined use of cover crops and urea on upland rice crop, grown under no-tillage system. The field experiment was conducted at Selviria-MS, Brazil, in an Oxisol (Rhodic Ilaplustox), cerrado (savannah) phase. The experimental design was randomized blocks, in a 5x3 factorial scheme. The treatments were four cover crops species: sunn hemp (Crotalaria juncea L.), pigeon pea (Cajanus cajan L.), green velvet bean (Mucuna prurens), millet (Pennisetum glaucum L.), and spontaneous vegetation (fallow in off-season) combined with 20 kg N ha-1 applied at sowing, 20 kg N ha-1 applied at sowing + 60 kg N ha-1 at plus topdressing, and without mineral N fertilizer application. The millet recycled large amounts of K, Mg, S, and micronutrients, but negatively influenced the rice grain yield grown in succession. There was no response to topdressed mineral N fertilizer when the crop was grown in rotation to legume cover crops. Upland rice under no-tillage showed a positive response to the N fertilization at seeding and when it is grown in rotation with the use of millet or fallow in the off-season. Upland rice also showed a response to N fertilization applied at topdressing.

This study was aimed at unravelling the molecular basis of root growth behavior in a drought-tolerant upland rice genotype, Nootripathu. Root tips of Nootripathu were found to possess shorter root caps and a greater number of dividing cells, favoring faster elongation compared to shallow-rooted IR20. Width and length of cortical cells in the roots of rapidly growing Nootripathu were found to be two to three times higher than IR20. Evaluation of shallow-rooted IR20, deep-rooted Nootripathu and their Recombinant Inbred Lines (RILs) for root characteristics revealed the presence of genetic variation for root traits among RILs. 2D-PAGE analysis of proteins in roots of IR20, Nootripathu and bulks of extreme RILs differing in root traits resulted in the identification of proteins co-segregating with root growth behavior and co-localized with QTLs for root traits. A putative candidate gene, OsARD4, encoding an “acireductone dioxygenase” was validated for its role in modulating the root growth pattern through genetic transformation. Transgenic ASD16 rice plants engineered for the overexpression of OsARD4 exhibited root growth characteristics similar to those of Nootripathu, including faster radical emergence, more rapid elongation of primary roots, early initiation of crown/lateral roots, and higher root biomass than the non-transgenic plants.

Upland rice production plays an important role in both household consumption and crop rotation. Until now, a blast resistant upland variety has not been released in Thailand. The bimodal pattern of rain distribution in Thailand’s upland rice production areas create a favorable environment for the outbreak of leaf blast when seedling-tillering, and neck blast within the heading stage. The use of genetically resistant cultivars has proven to be an effective way to cope with this problem. In this study, 256 indigenous upland rice plants were screened for blast resistance under greenhouse and field conditions. Ten indigenous upland rice varieties, ULR292, ULR242, ULR219, ULR162, ULR161, ULR134, ULR109, ULR098, ULR081, and ULR066, were identified as resistant to leaf blast disease in both natural infection and artificial inoculation, under greenhouse conditions. Additionally, six of the ten varieties, ULR162, ULR161, ULR134, ULR109, ULR098, and ULR081, were found to be resistant to neck blast under field conditions. These new sources of blast resistance identified from indigenous upland rice varieties proved more resistant than the check varieties, depicting their potential for further use in Thailand’s rice blast resistance improvement program.

Background Rice cultivation is a new practice to Tselemti district of Tigray region, Ethiopia. Adoption of rice technologies is very slow in spite of its potential in the area. This research intended to identify factors affecting adoption of rice technologies. Methods A multistage sampling technique was employed to select 150 sample households for this study. Descriptive statistics and inferential statistics were employed to see mean and percentage differences between adopter and non-adopter categories. Besides, binary logistic regression model was employed to identify the factors affecting adoption of rice technology. Results Result of the descriptive and inferential analysis showed that adopters had better farm size, livestock holding, farm income, labor availability, education level, perception on rice yield, access to credit service, contacts with extension agents, participation in off-farm activities, participation in training and field days as compared to non-adopters. Moreover, the binary logistic regression model result showed that the level of education, perception on rice yield, access to credit service, participation in off-farm activities, participation on field day and participation in training were found to positively and significantly influence the adoption decision of rice technology at 1%, 5% and 10% significant level. However, market distance influences rice technology adoption negatively and significantly at 10% significant level. Conclusions The variables education, rice yield, access to credit, off-farm activities, market distance, participation on field day and training determine the farmers’ continued adoption decision behavior of rice technology. Therefore, the adoption of rice technology should be sustained by paying attention and moving along with those variables which influenced the adoption significantly.

Drought regularly affects rainfed lowland and upland rice ecosystems in Malaysia. Three drought yield QTLs, viz qDTY 2.2 , qDTY 3.1 and qDTY 12.1 successfully pyramided into MRQ74 to increase its yield under reproductive stage drought stress (RS). Forty-eight genotypes comprising 39 pyramided lines (PLs) with different qDTYs combinations, four parents including MRQ74 (recipient) and five checks were evaluated for morpho-physiological traits under RS and non-stress (NS). This study aims to determine which traits influenced by individual qDTY and qDTY combinations and to gain better understanding of QTL interactions in enhancing grain yield (GY) under RS. Results showed plant height, number of panicles, root length, root weight, relative water content and 100-grain weight increased while chlorophyll content and GY decreased under RS compared to NS. No significant difference was observed in days to flowering, leaf rolling and grain length between selected PLs and MRQ74 under RS. Six PLs with yield advantage (YA) of 208.17–1751.63 kg ha−1 compared to MRQ74 in RS but yielded similar to MRQ74 under NS were further selected. Under RS, qDTY class analysis showed qDTY 12.1 individually and combination qDTY 12.1 + qDTY 2.2 produced the highest yield of 1521.77 and 1092.30 kg ha−1 respectively. qDTY 12.1 as single or combination with other qDTY is the best qDTY in stabilizing GY under RS. PL-77 with qDTY 12.1 is the best PL with YA of more than 1100 kg ha−1 compared to MRQ74 in both RS and NS conditions can be recommended for cultivation in normal and drought-prone areas.

Alternative splicing (AS) of precursor mRNA is often regulated by different developmental stages, environments, and genotypes. Little is known about how AS is regulated between different rice cultivars with distinctive response to certain abiotic stress. This study aimed to elucidate the AS patterns in contrasting rice (Oryza sativa L.) cultivars and examine its role during rice adaptation to drought environment. By comparing AS patterns between IRAT109 and ZS97 rice cultivars under drought stress, drought tolerant and susceptible respectively, 8034 shared, 11,086 ZS97-specific, and 12,057 IRAT109-specific AS events were observed where intron retention is the predominant AS pattern. Gene ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analyses suggested that the spliceosome and DNA repair represented the most significant functional categories among the genes with genotype-specific AS patterns. Other categories include basal transcription factors, environmental information, adaptation related pathways, oxidative phosphorylation, etc. Through integrating the drought-response related quantitative trait locus (QTLs) from 2006 to 2016 manually and mapping spliceosome and DNA repair genes with different AS patterns on chromosomes, we identified 14 out of 31 genes involved in splicesome and 4 out of 14 genes in DNA repair co-localized in drought stress related QTLs. We therefore propose that during long domestication, genes responsive to drought stress evolved specific AS patterns in upland rice, and spliceosome and DNA repair genes play potential roles in rice tolerance to drought stress. Genes with diversity AS patterns and co-localized with drought QTLs will serve as important resources for genetic improvement of rice adaptation to drought stress.