Rice Scheme Research Articles

Occurrence of plant-parasitic nematodes on rice (Oryza sativa) in Kenya with a focus on Hirschmanniella oryzae

Summary Rice ranks as the third most important staple cereal food crop in Kenya, following maize and wheat. The demand for rice has been increasing at a faster rate than most cereals, occasionally requiring imports to meet local needs. In response, the Kenyan government has been implementing a programme to increase rice production by expanding irrigated lowland rice schemes from 32 988 to 171 676 ha, while increasing rain-fed upland production areas four-fold to 42 000 ha by 2030. However, with continued rice monocropping in irrigated lowland fields and intensification in rain-fed upland ecosystems, there is a growing concern that plant-parasitic nematodes may emerge as a significant problem across rice ecosystems. This study characterised the nematode genera associated with rice in Kenya and assessed their diversity and distribution across rice ecosystems, with a focus on Hirschmanniella species. Eleven nematode genera were identified in both ecosystems, indicating a relatively high diversity. These genera, ranked by prominence, included Hirschmanniella, Hoplolaimus, Pratylenchus, Helicotylenchus, Meloidogyne, Ditylenchus, Trichodorus, Xiphinema, Rotylenchus, Longidorus and Paratylenchus. The family Tylenchidae was also found to be an important component of the nematofauna. Both morphological and molecular analyses confirmed the presence of Hirschmanniella oryzae in irrigated lowland and rain-fed upland rice, which represents the first documented report for Kenya. A notably large molecular variation was also observed for these Kenyan populations on the 18S region, with intraspecific variation up to 10 bp difference. Understanding the diversity, distribution, and species composition of nematodes in rice ecosystems is important for raising awareness among plant protection services, farmers, cooperatives and extension agents about plant-parasitic nematodes and their challenges in rice production. Future research should build on this knowledge to support extensive studies on population dynamics and damage threshold, focusing on local rice cultivars to develop effective management strategies, including breeding programmes and other cultural practices.

Projecting Irrigation Water and Crop Water Requirements for Paddies Using WEAP-MABIA under Climate Change

Monitoring future irrigation water demand as a part of agricultural interventions is crucial to ensure food security. In this study, the impact of climate change on paddy cultivation in Brunei is investigated, focusing on the Wasan rice scheme. This research aims to project irrigation water requirement (IWR) and crop water requirement (CWR) or the main and off season using the WEAP-MABIA model. Historical data analysis over the past 30 years and future projections up to 2100 are employed to assess potential impacts. An ensemble of statistically downscaled climate models, based on seven CMIP6 GCMs under shared socioeconomic pathways (SSPs) (SSP245, SSP370, and SSP585), was utilised to project the IWR and CWR. Using downscaled CMIP6 data, three future periods were bias-corrected using quantile delta mapping (QDM) for 2020–2046 (near future), 2047–2073 (mid future), and 2074–2100 (far future). The WEAP-MABIA model utilises a dual crop coefficient approach to evaluate crop evapotranspiration (ETc), a critical factor in computing IWR. Results indicate that changes in future temperatures will lead to higher average ETc. Consequently, this results in elevated demands in irrigation water during the off season, and it is especially prominent in high-emission scenarios (SSP370 and SSP585). While the main season experiences a relatively stable or slightly increasing IWR trend, the off season consistently shows a decreasing trend in IWR. Moreover, the off season benefits from substantial rainfall increases, effectively reducing IWR despite the rise in both maximum and minimum temperatures. This study also highlights some recommendations for implementing possible improvements in irrigation management to address the effects of climate change on rice cultivation in the region. Future investigation should focus on enhancing crop yield predictions under climate change by integrating a dynamic crop growth model that adjusts for changing crop coefficient (Kc) values.

Farmers’ perception and management of water scarcity in irrigated rice-based systems in dry climatic zones of West Africa

Water scarcity threatens irrigated agriculture in sub-Saharan Africa (SSA). Knowledge of farmers’ perceptions and drivers for decision-making in view of coping with water scarcity is so far lacking but needed to improve local technologies and frame policies fostering their adoption. Here, for the first time, we investigated farmers’ perception of water scarcity, key adaptation strategies, and the determinants of their adoption in irrigated rice schemes in dry climatic zones of West Africa. We surveyed 572 farming households and conducted expert interviews with key informants in four contrasting irrigated rice schemes in Burkina Faso between April 2018 and August 2019. Information was gathered on biophysical field characteristics, grain yields, agronomic and water management practices, farmers’ perception of water scarcity, their adaptive responses, and social-economic attributes of adopting households. Nearly 80% of the respondents reported having experienced water scarcity during the past 5 years. To cope with the adverse effect of water scarcity, farmers implemented seventeen different adaptation strategies that could be categorized into seven groups. Most popular among those were “water and soil conservation practices” (consisting mainly of field bunding and leveling), “no rice cultivation,” and “crop rotation.” Farmers in drier areas (Sudano-Sahelian zone) were less likely to adopt and implement several adaptation strategies to water scarcity compared to farmers in wetter areas (Sudanian zone). Belonging to farming associations increased the probability of implementing several strategies to alleviate water scarcity, while female-headed households tended to have a lower propensity to adopt and implement concomitantly several adaptation strategies in comparison with their male counterpart. The dissemination of scheme- and household-specific technology options could contribute to mitigating water scarcity in irrigated rice-based systems in the dry climatic zones of West Africa, thus contributing to rural livelihood and food security.

A clinical case of immune-mediated pneumonitis after nivolumab in a patient with Burkitt lymphoma

Immunotherapy is a promising method in the treatment of cancer. PD-1 (programmed cell death protein 1) receptor and its ligand, which contribute to the reactivation of T-cells exerting their cytotoxic function against the tumor, are one of the targets of antitumor drugs. The effectiveness of immune checkpoint inhibitors has been demonstrated in the treatment of melanoma and non-small cell lung cancer. The spectrum of side effects of antitumor immune drugs differs from the classical ones observed in the cytostatics treatment. Immune-mediated adverse events can affect multiple organs, including skin, gastrointestinal tract, endocrine and nervous systems, and lungs. Pneumonitis is a potentially life-threatening complication and often requires immediate administration of corticosteroids. This article presents the case of a patient with relapsed Burkitt lymphoma treated with nivolumab and R-ICE (rituximab, ifosfamide etoposide, carboplatin) scheme. The therapy was effective, but complicated by immune-mediated pneumonitis. Corticosteroids administration resolved this complication and anti-cancer treatment was completed. The following nivolumab administrations were free of side effects.

Exploring farmers’ perception, knowledge, and management techniques of salt-affected soils to enhance rice production on small land holdings in Tanzania

Salt-affected soils among the key constraints to land productivity in irrigated rice schemes, posing a decline in grain yield. This study was conducted to explore the farmers’ perception, knowledge, and management practices of salt-affected soils in selected rice irrigation schemes of the representative districts in Tanzania. Whereas salt-affected soils were perceived as one of the constraints in the studied irrigation schemes, the extent of coverage and the severity of the effect are rarely documented. Therefore, the primary hypothesis of this study is that salt-affected soils could have an effect on rice production across irrigation schemes; and that farmers differ in perception, knowledge, and coping mechanisms. The Participatory Rural Appraisal (PRA) approach was employed to explore the farmers’ information from Mbarali, Iringa, Same, and Moshi districts, whereby 323 rice-growing farmers were interviewed using semi-structured questionnaires. Moreover, 120 farmers were involved in focus group discussions and 24 key informants. Our study showed that a majority (78%) of farmers attributed a decline in rice yield largely to salt-affected soils. The perception of farmers on the extent to which they experience salt-affected soils in their rice farms differed significantly (χ2 = 50.373; p = < 0.001). In contrast, farmers’ responses on salt-affected soils across the districts were not significantly (χ2 = 6.133; p = 0.408) different, which is an interesting result indicating that salt constraints were equally important in rice producing irrigation schemes. Enhancing farmers’ knowledge and providing effective and affordable management technologies can improve rice production in small land holdings affected by salts.

Effects of Irrigation Water Sufficiency on Water Fee Collection Rate in Uganda’s Large-Scale Paddy Irrigation Schemes

Improving irrigation performance is crucial for increased agricultural productivity. As an indicator of performance, among other factors, improving the water Fees Collection Rate (FCR) is required, but FCR has remained low in most African and Asian countries. In this research, taking the Doho rice scheme in Uganda as a case study, we analyzed the relationship between water sufficiency and FCR. We hypothesized that FCR is influenced by the hydraulic position of the paddy field along the canal. We then used quantitative data for analysis through multiple regression. Later we used qualitative data obtained through interviews for additional explanations of water management activities. As a result, the FCR decreases from upstream to downstream at block, strip, and plot levels; the FCR decreases linearly with an increase in the delivery canal length; the FCR is higher in strips with fewer plots, and FCR is higher within the rotational irrigation blocks. We concluded that inadequate water supply due to high hydraulic positions resulted in low FCR downstream at all the canal levels. To improve FCR, we recommend blending water management activities that secure farmers’ agreement with onsite technical measures to counter the effect of hydraulic positions such as shorter strips and rotational irrigation.

Atom Equivalent Energies for the Rapid Estimation of the Heat of Formation of Explosive Molecules from Density Functional Tight Binding Theory.

Atom equivalent energies have been derived from which the gas-phase heat of formation of explosive molecules can be estimated from fast, semiempirical density functional tight binding total energy calculations. The root-mean-square deviation and maximum deviation of the heats of formation from the experimental values for the set of 45 energetic molecules compiled by Byrd and Rice [ J. Phys. Chem. A, 2006, 110, 1005-1013] are 10.4 and 25.5 kcal/mol, respectively, using 4 atom equivalent energies and 7.4 and 15.0 kcal/mol, respectively, using 7 atom equivalent energies. These errors are around a factor of 2-3 larger than those obtained from density functional theory calculations but are smaller than those obtained from other semiempirical electronic structure methods. Heats of formation calculated with density functional tight binding theory using the 4 and 7 atom equivalent energies, the Byrd and Rice scheme, and the atom pair contribution method for a new set of 531 energetic molecules that contain only carbon, hydrogen, nitrogen, and oxygen are provided.

Effect of Ploughing Techniques on Water Use and Yield of Rice in Maugo Small-Holder Irrigation Scheme, Kenya

The objective of this study was to determine the effect of paddy rice ploughing techniques on water use and the yield of rice crop, as well as water use efficiency for rice growing in small-holder irrigation schemes. The study was conducted at a farmer’s field in Powo B sub-block of Maugo Irrigation Scheme. The period of study was from July 2019 to January 2020, which is the rice season. The experimental site was located in the vicinity of Olare Shopping Centre, Kamenya Sub-location, Kochia East Location, Kochia Ward, Rangwe Sub-County, Homa Bay County, Nyanza Region, Kenya in Maugo rice scheme in Kenya. In the study, four irrigation tillage practices were applied: ox-plough, conventional ox-plough, hand hoe and tractor ploughing. The results showed that conventional ox-ploughing consumed the highest amount of water at 1240 mm. The highest water use efficiency of 0.49 kg/m3 and highest yield of 5.7 tons/ha were observed for hand hoe ploughing. Use of the hand hoe ploughing technique increased yields by 20 percent, as compared to the conventional ox-ploughing. Therefore, the use of water for ploughing is not necessary in the study area. Future research will be needed to see how farmers are adopting the technology before scaling up to full mechanization, as partial mechanization was not profitable.

Effect of Tillage Techniques on Depth, Furrow Slice and Water Retention in Maugo Smallholder Rice Scheme in Kenya

This study was conducted with the aim of determining the influence of tillage techniques on depth, furrow slice and water retention in Maugo Smallholder Rice Scheme in Kenya. Treatments were arranged in randomized complete block design with four replicates. Four tillage treatments were used. The first one was conventional ox plough practiced by farmers where they first flood the field with water before ploughing. The other three treatments were ox plough, hand hoe and tractor ploughing all with no flooding before ploughing. Data collected included depth of ploughing and harrowing during land preparation. Furrow slices during ploughing and harrowing as well as water retention were recorded. Tractor ploughing had the highest mean depth of ploughing of 42.00 ± 0.81 cm followed by conventional ox ploughing with 17.75 ± 0.75 cm, ox ploughing15.75 ± 0.62 cm and hand hoe ploughing had the lowest mean depth 15.50 ± 0.28 cm. Tractor ploughing had the largest mean furrow size of 62.00 ± 0.91cm followed by conventional ox ploughing 32.25 ± 0.85 cm, ox ploughing 30.25 ± 0.85 cm while hand hoe ploughing had the smallest mean furrow slice of 16.5 ± 0.50 cm. Highest mean of retained water was recorded in week 4 in paddy rice fields prepared using conventional ox ploughing (10.5 cm), ox ploughing (10 cm), hand hoe ploughing (11.5 cm) and tractor ploughing (11.5 cm) while the lowest was recorded in week 15 for conventional plots. There were significant differences in mean depths during both ploughing and harrowing. Tractor ploughing mean depths were significantly different from the other treatments. The weekly mean water depths retained in the plots were more than 6 cm for the entire growing period of rice.

Foraging Behaviour of the Black-Headed Heron at Kibimba Rice Scheme, Eastern Uganda

Variations in the factors affecting prey availability directly impact on the spatial dispersion of foraging birds. The feeding success and efficiency of the Black-headed Heron (Ardea melanocephala) was examined in the different growth stages/phases of paddy rice, namely: Ploughed fields, Phase 1 fields (2 weeks-1 month after sowing) and Harvested fields. Feeding success of the Black-headed Heron varied significantly across the rice growth stage. This variation was explained by a combination of factors such water depth, waterbird abundance, Nearest Neighbor Distance (NND) and food or prey abundance (except amphibian abundance). Statistical analysis were conducted using Genstat Version 8.1 (VSN Intl.2003, in which a General Linear Mixed Model were used to examine the variation in each behavioural measure. Foraging in aggregations on rice paddies seems to be more beneficial to the Black-headed Heron. The closeness to a conspecific had a positive effect on the feeding efficiency of the Black-headed Heron as they foraged on fields with abundant prey (Phase 1) and a negative effect on fields with less abundant prey (Ploughed fields). Generally, the data seem to suggest that there is a functional relationship between the Black-headed Heron, and prey abundance, and the absence of interference competition on rice fields.

Factor Influencing Adaptation Choices Employed by Farmers Against Climate Change to Improve Rice Yield in Bugarama Wetland in Rwanda

The changing climate poses a great challenge to many wetlands productivity worldwide. Rice production in wetlands is a major source of livelihood in developing countries such as Rwanda. This study aimed at determining the factors influencing adaptation methods when farmers perceive the changing climate at Bugarama Wetland Rice Scheme in Rwanda. A descriptive research design was used by this study, whereby quantitative and qualitative data was collected. The analysis was based on data collected from 300 selected farmers using systematic random sampling method. We employed descriptive statistics to assess how farmers perceive the effects of climate change and descriptively measured the new adaptation methods used by farmers in Bugarama to increase their yields. The study adopted Heckman two-step model to determine factors that influence adaptation choices, this analysis procedurally required farmers’ knowledge of perception that makes them respond to the effects of changes in climatic conditions by the use of new adaptation methods. The results deduced that level of education (p =0.019), extension access (p=0.001), market distance (p=0.002) and rice income (p &lt; 0.001) had a probability of influencing farmers perceptions about climate change thus need to adapt. Based on the outcome model, results showed that extension access (p &lt; 0.001), household size (p= 0.098), market distance (p= 0.047), rice income (p =0.032), farmers-to-farmers contact (p &lt; 0.001) and effects of climate change on rice (p=0.038) had a greater probability of influencing farmers choice of adaptation method used to improve rice yields. To conclude, the study found that access to informational facilities and rice income, influenced farmers’ perceptions while extension access, rice income, market distance, farmers-to-farmers contact and effects of climate change on rice yield strongly had a probability of determining farmers’ choice of adaptation. This study recommends that the Rwandan government and local administrators need to develop a strategy that would allow farmers to access information facilities about new technology so as to adapt to the effects of climate change thus improve their rice yields.

Pesticide Application Practices and Knowledge among Small-Scale Local Rice Growers and Communities in Rwanda: A Cross-Sectional Study

Background: Agriculture contributes a third of Rwanda’s GDP and is the main source of income for rural households, with 80% of the total population involved in crop and/or livestock production. The Government of Rwanda established the Muvumba rice project in 2011 amidst a policy shift towards rice as a national staple crop. However, the indiscriminate use of pesticides by local, low-income rice growers has raised concerns about potential human, animal and ecosystem health impacts as pesticide distribution and application are not strictly regulated. Although pesticide use can directly influence farmer health and ecosystems, little is known about small-scale farmers’ pesticide application practices and knowledge. We aimed to assess local application practices and understanding of pesticides to identify gaps in farmers’ knowledge on safe pesticide use and deviations from established standards and recommended practices. Methods: We conducted a cross-sectional study consisting of observations of pesticide practices and interviews with 206 small-scale rice growers in Nyagatare District, Rwanda, in March 2017. Descriptive statistical analyses (sample means, standard deviation and range) were performed, and we evaluated the association between farmers’ personal protective equipment (PPE) use and their education level and literacy status. Results: Over 95% of observed farmers did not comply with minimum standards for safe pesticide use, and 80% of respondents reported that they stored pesticides in their homes without personal protection measures. Education and literacy level were not significantly associated with PPE use. Additionally, 90% of respondents had experienced adverse health effects after using pesticides including intense headache, dizziness, stomach cramps, skin pain and itching, and respiratory distress. All respondents also reported animals in and around the rice scheme (cattle, birds, and fish) behaving abnormally or with signs consistent with pesticide exposure in the six months preceding the study, which may be linked to pesticide-contaminated water. Conclusions: Our study demonstrates potential for high exposure to pesticides for farmers, their families, and animals sharing rice-growing or downstream environments and points to the need for training on safe and effective pesticide use.

Ecology of the African Rice Gall Midge, &lt;i&gt;Orseolia oryzivora&lt;/i&gt; (Diptera: Cecidomyiidae) in Western Burkina Faso, West Africa

The African rice midge, Orseolia oryzivora H. & G., is an important insect pest in Burkina Faso. Our study was conducted from 2017 to 2019 in three irrigated rice schemes including Banzon, Karfiguéla and Vallée du Kou in Western Burkina Faso. The objective of this study was to investigate the ecology of the insect pest. In each rice scheme, four plots of 500 m2 each, spread 50 m apart were randomly selected in farmers’ fields and used for the study. In each plot, a light trap was implemented along one of the diagonals of the plot. Each light trap consisted of a yellow plastic round bowl containing soapy water almost at half the bowl and a torch. The bowl had a capacity of 4.5 l, a diameter of 28 cm and a height of 10.5 cm. The torch had 3 batteries of 1.5 V each, 30 cm long and 1 cm diameter. The torches were lit every night at 6 pm and off at 6 am. Four hundred tillers were collected per month from the cultivated rice and from each of the alternative hosts of the rice midge in order to evaluate the monthly gall count, pre-imaginal populations and parasitism associated with O. oryzivora and its cousin, O. bonzii that is hosted by Paspalum scrobiculatum. The number of O. oryzivora’s adults caught in the light traps was higher during the wet season than the dry season. The level of larval parasitism ranged from 6.16% (Banzon) to 14.29% (Vallée du Kou). The highest level of pupal parasitism (13.73%) was recorded in Vallée du Kou. The damage of O. oryzivora was observed on the wild rice species, O. longistaminata in all three sites. The highest levels of parasitism associated with O. bonzii were recorded in Karfiguéla (20.08% and 25.21% for larval parasitism and pupal parasitism, respectively). These findings are useful in the development of a sustainable control strategy of O. oryzivora.

English

This study was conducted in five randomly selected rice schemes in Morogoro region to obtain information on farmers’ knowledge, attitude and practice in respect to management strategies undertaken for controlling insect pests both in rice fields and stores as an aid to reduce crop loss. A total of 150 farmers were randomly selected from 5 villages (30 respondents per village) and interviewed using semi structured questionnaires. Each village represented only one rice scheme. The study reveals that 61.3% of farmers cultivate rice under 0.5 to 1 acres showing that the crop is grown largely by small scale farmers. About 94.4% of farmers reported to have faced insect pest problems in rice fields with no farmer reported damage in store. It was reported that 82% of farmers control insect pests in their rice field when they notice their presence. Most of farmers (84%) used synthetic insecticides where some of them do nothing and others use non-chemical method. However, among those farmers who use pesticides, majority (83%) of them reported that they have never attained any training on the proper handling and application of chemicals suggesting a need for trainings to farmers on how to handle pesticides. Key words: Rice, scheme, insect, management.

PENGATURAN PERSEDIAAN BERAS DI PERUM BULOG DIVRE SULTENG DENGAN METODE ECONOMIC ORDER QUANTITY (EOQ)

Perum BULOG of Central Sulawesi Division is a national rice logistic company that its responsibility is to guarantee the sufficiency to meet the rice needs. Perum BULOG also responsible to keep rice price stability. One of the rice price component is the inventory costs that need to be managed. In this research the management is refered to the rice scheme demand of four storages, that are Olaya, Lawanga, Jaya Kencana Toili and Galang. This study uses EOQ (Economic Order Quantity) that consist of five priorities, that are determining the of economical order, determining the amount of safety stock, determining the maximum inventory quantities, determining the reorder point and determining total inventory cost. The results showed that the number of economical order storage of Olaya is 1.817.120,57 kg/message, Lawanga is 1.893.400,78 kg/message, Jaya Kencana Toili is 1.575.543,38 kg/messages and Galang is 1.578.742,75 kg/message. The total Inventory Security for Olaya is 32.371,28 kg, Lawanga is 41.020,07 kg, Jaya Kencana Toili is 30.630,61 kg, and Galang is 57.307,99kg. The maximum inventory for Olaya is 1.849.491,85 kg, Lawanga is 1.934.420,85 kg, Jaya Kencana Toili is 1.606.173,99 kg, and Galang is 1.636.050,74 kg. The reorder point is proposed when rice stock of Olaya reaches 323.664,52 kg, Lawanga reaches 357.282,87 kg, Jaya Kencana Toili reaches 249.620,29 kg and Galang reaches 277.188 kg. The total inventory cost that use Economic Order Quantity is Rp. 2.507.626,39 for Olaya, Rp. 2.612.893,07 for Lawanga, Rp.2.174.249 ,87 for Jaya Kencana Toili, and Rp 2.178.665,00 for Galang. The Efficiency cost of rice supplies BULOG Division is Rp.40.405,29 for Olaya, Rp. 719.256,02 for Lawanga, Rp. 51187.63 for Jaya Kencana Toili, and Rp. 153.528,73 for Galang. These result gives greatest efficiency at the cost of supplies of Perum BULOG Division Central Sulawesi for Lawanga 22% as much.

Perception by farmers of the determinants of irrigated rice yield in Mali

Recommendations for crop management are based on agronomic diagnoses of yield determinants at plot scale usually without the farmers being involved in the evaluation process. Farmers may consequently not apply the recommendations that do not account for their own perception of yield determination. We assumed that (i) farmers have their own perceptions of yield determination; (ii) it is possible to access these perceptions through individual discussions with farmers; (iii) subsequent group discussions allow knowledge to be exchanged between farmers and a common viewpoint to be reached; (iv) agronomists can use this common viewpoint as a basis for building improved solutions in collaboration with the farmers. In this study, we used participatory methods to identify and discuss the visual references the farmers consider the crop growth as indicators to forecast the yield of their plot and the drivers they think affect these indicators. The study was conducted in two sites in the Office du Niger irrigated rice scheme in Mali and comprised three steps: (i) individual discussions with rice producers about their perception of how yield is determined, (ii) group discussions to share their individual perceptions and reach a common viewpoint, (iii) analysis of these perceptions. Seven production indicators and 29 factors that may affect these indicators were identified. The three mains indicators used by farmers were tiller abundance, hill density, and grain weight per panicle. Crop practices and constraints may prevent farmers from achieving high yields, such as a delay in the supply of fertilizers or in crop establishment. They had a complex perception of yield determination that was often close to agronomic knowledge. Here we demonstrate for the first time that farmers in the Office du Niger scheme have technical knowledge to which extension services could refer to provide relevant advice and tools for managing their constraints and improving yield.

Gene action and combining ability estimates of newly developed CMS based heterotic rice hybrids (Oryza sativa L.)

An insight knowledge nature and relative magnitude of gene actions involved and combining ability is useful for a breeder to assess nicking ability in self-pollinated crops. In this connection, an attempt was made to esti- mate the gene action and combining ability of 70 newly developed CMS based heterotic rice hybrids developed from ten newly developed CMS lines and seven testers were evaluated for grain yield and its components at Hybrid rice scheme, ZARS, V. C. Farm, Mandya. Among the lines, CMS 2 had significant gca effects at 1% level of significance in desired direction for four traits viz., panicle weight, pollen fertility, spikelet fertility and number of spikelets per pan- icle. Out of seven testers, KMR 3 found to be good general combiner for five traits viz., days to 50 per cent flower- ing, plant height, number of tillers per plant, number of panicles per plant and grain L/B ratio. Among the 70 hybrids, CMS1 × KMR3 was good specific combiner for grain yield per plant and grain L/B ratio. It further revealed that SCA variances were higher than the GCA variances for all the characters which indicated preponderance of non-additive gene action. Hence, CMS 2 and KMR 3 are identified as promising lines which can be used in further breeding pro- gramme.

Dualistic roles and management of non-cultivated plants in lowland rice systems of East Africa

An ethnobotanical study in lowland rice areas in East Africa was undertaken to assess farmers' knowledge on the usage of non-cultivated plants occurring in paddy fields, and to understand what rice farmers in this region do with useful species once they encounter them in their crop. Inventories of weed species in 19 rice schemes in Tanzania and Kenya were followed by interviews among 380 experienced rice farmers, community elders and traditional healers, grouped into 19 informant groups. Among informant groups, a high degree of consensus about uses of weeds growing in rice paddies was observed. From a total of 222 observed rice weed species, the informant groups identified 67 species with usages described in 1300 use reports. Among these 67 species, 20 are among the most commonly cited weed species in rice paddies in sub-Saharan Africa. Only in 42 cases (3% of the total use reports) did the farmers indicate that they collected (13 species) or spared (four species) these weeds during weeding. In all other cases, such plants were removed or killed during weeding, irrespective of their usefulness. Non-cultivated plants that are spared are those of which the putative agronomic qualities (i.e. for crop protection or soil improvement) are considered more important than their crop competition effects (i.e. Azolla filiculoides and Marsilea crenata) and those that are found in the field margins, which do not compete with the crop. Non-cultivated plants that are collected during weeding have food, fodder or medicinal purposes or a combination of purposes. The most cited species that are collected or spared during weeding were Bidens pilosa, Ipomoea aquatica, Corchorus olitorius and Stachytarpheta jamaicensis. This study revealed that lowland rice farmers in East Africa generally have a high level of understanding and consensus on the usefulness of the non-cultivated plants growing in lowland rice schemes. When they occur in their crop however, the vast majority of these species are primarily seen as weeds and consequently removed or killed.

The research on thermoplastic properties cement composites impregnated with the waste of sulfur

The process of creating special polymerized sulfur composites through application of industrial waste material is a thermal treatment process in the temperature of about 150–155 ^{circ }hbox {C}. The result of such treatment is a special polymerized sulfur composite in a liquid state. This paper presents the effective plastic constants and coefficients of thermal expansion of stochastic special polymer sulfur composites, with isotropic porous matrix, reinforced by disoriented ellipsoidal inclusions with orthotropic symmetry of the thermoplastic properties. The investigations are based on the stochastic differential equations of solid mechanics. A model and algorithm for calculating the effective characteristics of special polymer sulfur composites are suggested. The effective thermoplastic characteristics of special polymer sulfur composites, with disoriented ellipsoidal inclusions, are calculated in two stages: First, the properties of materials with oriented inclusions are determined, and then, effective constants of a composite with disoriented inclusions are determined on the basis of the Voigt or Rice scheme. In this paper, the review of the literature has been done, among other things, about selecting and using special polymerized sulfur coating in buildings, about the methods of surface protection against corrosion of concretes, and about the methods of the evaluation of the protection layer on these materials. Special polymerized sulfur as polymer coating impregnation, which has received little attention in recent years, currently has some very interesting applications. An innovative overlay for use in areas where freezing and thawing are prevalent has been developed.

The analysis of thermoplastic characteristics of special polymer sulfur composite

Specific chemical environments step out in the industry objects. Portland cement composites (concrete and mortar) were impregnated by using the special polymerized sulfur and technical soot as a filler (polymer sulfur composite). Sulfur and technical soot was applied as the industrial waste. Portland cement composites were made of the same aggregate, cement and water. The process of special polymer sulfur composite applied as the industrial waste is a thermal treatment process in the temperature of about 150–155 ^{circ }hbox {C}. The result of such treatment is special polymer sulfur composite in a liquid state. This paper presents the plastic constants and coefficients of thermal expansion of special polymer sulfur composites, with isotropic porous matrix, reinforced by disoriented ellipsoidal inclusions with orthotropic symmetry of the thermoplastic properties. The investigations are based on the stochastic differential equations of solid mechanics. A model and algorithm for calculating the effective characteristics of special polymer sulfur composites are suggested. The effective thermoplastic characteristics of special polymer sulfur composites, with disoriented ellipsoidal inclusions, are calculated in two stages: First, the properties of materials with oriented inclusions are determined, and then effective constants of a composite with disoriented inclusions are determined on the basis of the Voigt or Rice scheme. A brief summary of new products related to special polymer sulfur composites is given as follows: Impregnation, repair, overlays and precast polymer concrete will be presented. Special polymer sulfur as polymer coating impregnation, which has received little attention in recent years, currently has some very interesting applications.