Lowland Fields Research Articles

Agronomic performance of Ciherang near-isogenic lines for nitrogen use efficiency trait in irrigated lowland paddy field

Abstract Nitrogen (N) is an essential nutrient that affects plant growth and productivity. The consumption of N fertilizer is continuously increasing with the rapid demand for agricultural production. However, the rise in N fertilizer utilization causes higher production costs and leads to a negative impact on the environment. Improvement in nitrogen use efficiency (NUE) of rice plants is therefore important for sustainable rice production to reduce N fertilizer consumption while maintaining high grain yield. To improve the NUE of Indonesian elite cultivars, near-isogenic lines (NILs) with Ciherang genetic background have been developed by introducing genes related to N use efficiency, qRL6.1, and actpk1 through backcross breeding. Preliminary yield trials were conducted to evaluate the agronomic performance of CiherangNILqRL6.1 and CiherangNILactpk1 rice lines under optimum N fertilizer conditions in irrigated lowland fields for two seasons, wet season 2021/2022 and dry season 2022. Observations were performed on flowering time, biomass, yield, and yield component of NILs and Ciherang. The result from this preliminary observation indicated that under optimum N fertilizer, the agronomic performance of the NILs was comparable to Ciherang as the genetic background. Some NILs showed higher grain yield compared to Ciherang and were selected for further experiments to evaluate their performance under different N fertilizer conditions.

On-Farm Assessment of the System of Rice Intensification (SRI) Under Rainfed Lowland Fields of Southern Cambodia

On-Farm Assessment of the System of Rice Intensification (SRI) Under Rainfed Lowland Fields of Southern Cambodia

Analyzing the hydraulic performance of water gates due to the impact of extreme rainfall on tidal lowlands: a case study in Katingan rice fields area, Central Kalimantan

Rice fields in the Katingan tidal lowlands are inundated due to spring tides and extreme rainfall. Excessive inundation in the rice fields causes crop failure. Therefore, the study was conducted to analyze the use of water gates in the secondary canals for controlling the inundation. The unsteady flow simulation boundary conditions are the upstream discharge with a return period of 5 and 25 years and measured tidal. The water flow is controlled by closing the sluice gates at the water level elevation of +3.50 m, and flap gates close during high tide and rainfall. This research shows that controlling the water flow by gates decreases the water level and inundation area. Under rainfall with a return period of 5 years, the inundation area decreased by 79.03 %, and the maximum water level decreased by 0.14 m. In the rainfall with a return period of 25 years, the inundation area decreased by 75.31%, and the maximum water level decreased by 0.11 m. The water gates’ operation incompletely decreases the inundation and water level beneath rice crops’ threshold inundation depth and duration. Therefore, there is a need for additional water control to optimize the decrease of inundation in the rice fields.

Maintenance of Balanites aegyptiaca scattered trees for improving sesame (Sesamum oriental) grain yield and soil properties in lowlands of Tigray, Ethiopia

A species of dryland tree called Balanites aegyptiaca provides numerous environmental and socioeconomic benefits. Those trees are cultivated by agriculturalists in their fields in lowlands of Tigray, but there was insufficient scientific data on how Balanites aegyptiaca trees affected the study area's soil characteristics and sesame yields. The purpose of this study was to look into the behavior of Balanites aegyptiaca to improve sesame yields and soil properties in Kafta-Humera District. Two variables were utilized to think about soil physicochemical properties and collect 48 pooled tests: separate from the tree trunk at four levels and soil profundity at two levels, reproducing the RCBD calculate framework on six trees. To study sesame yield, four-level log spacings were used, replicated six times.In addition, ANOVA was used to determine sesame seed yield and soil physicochemical properties. The outcomes demonstrated that the sesame seed yield was significantly (using p<0.05) from the Balanites aegyptiaca tree. Under the canopy as opposed to outside of it, and in the topsoil as opposed to the subsoil layer, the BD was significantly (p<0.05) lower. Findings for additional soil chemical parameters, including pH, OC, total N, available P, K, Ca, and CEC, showed a significant (p<0.05) increase in the crown area relative to the field and surface area over the subsurface layer. Under its canopy, the multipurpose tree Balanites aegyptiaca generally improves soil fertility; when grown on agricultural land, it can also boost soil and plant productivity in drought-prone areas when managed properly.

Effects of water regime and inoculation with arbuscular mycorrhizal fungi on mycorrhizal communities of roots of rice and pearl millet in upland and lowland fields

Effects of water regime and inoculation with arbuscular mycorrhizal fungi on mycorrhizal communities of roots of rice and pearl millet in upland and lowland fields

Survey of rice (Oryza sativa L.) production ecosystems in northern Ghana confirms low risk of exposure to potential toxic elements from local grain consumption

Expanding local rice production to meet consumer demand is a priority action under the Government of Ghana’s Planting for Food and Jobs initiative. While studies on yield-enhancing interventions abound, fewer studies focus on food safety issues (e.g., the potential toxic element status of the production ecosystems). This study was, therefore, conducted to bridge the knowledge gap. Chemical analyses were conducted on water, soil, and rice grain samples from different production ecosystems in the Northern and Upper East regions of Ghana. Statistical analysis of the data showed that soil and rice grain arsenic concentrations were significantly higher ( P < 0.001) in the Upper East region. In the Northern region, mean cadmium concentration in rice grains from the irrigated lowland fields (0.023±0.003 mg/kg) was significantly higher than in grains from the rainfed fields. All recorded concentrations of rice grain arsenic, cadmium, and lead were, however, within permissible limits, indicating a low risk of dietary exposure. The observed differences in concentrations within and between regions suggest that soil texture and other geogenic factors could influence the potential toxic element status of the rice production ecosystems. Regular monitoring is, therefore, recommended to maintain the safety of Ghana’s locally produced rice for human consumption.

Estimation of flowering time and its effect on grain yield of photoperiod sensitive varieties in rainfed lowland rice in Northeast Thailand

Flowering time of photoperiod sensitive varieties is an important determinant of grain yield of rainfed lowland rice, and is affected by the growing environment. The present study aimed to quantify variety specific flowering time response to photoperiod under irrigated conditions and demonstrate the usefulness of delay in flowering observed in rainfed lowland fields as an index of severity of water deficit affecting yield. Both irrigated on-station and rainfed lowland on-farm experiments were conducted with 4 popular photoperiod sensitive varieties in Northeast Thailand. The irrigated experiment was conducted with 12 sowing times throughout a year and flowering time was quantified with prevailing daylength and temperature. Among the 4 varieties, the minimum time to flowering varied from 68 to 77 days, and maximum daylength required for panicle initiation varied from 12 hrs 21 min to 12 hrs 39 min. Flowering time of all varieties was delayed in 3–4 sowings due to cold during vegetative stage; these sowings did not coincide with farmers’ common sowing time. On-farm flowering time and yield data were obtained from 108 crops grown under rainfed lowland conditions across 8 provinces in Northeast Thailand in 2013–2015, and were used for validating flowering time and grain yield simulation based on the sequential sowing experiment. Both curvilinear and linear equations to estimate time to flowering from sowing time gave a similar result. Delay in flowering due to water deficit observed on-farm was estimated as the difference between the observed on-farm and simulated flowering time under irrigated conditions, and the estimated delay was related to grain yield reduction due to water deficit. It is concluded that simulated flowering time under irrigated conditions together with observed flowering time in farmer’s fields can be used to determine flowering delay under rainfed conditions, and the delay is an indication of the severity of water deficit reducing yield. Extension material may be developed in which estimated flowering time of key varieties under well-watered conditions may be tabulated for various sowing times and locations in the region, and then farmers can determine delay in flowering and likely yield reduction for their own and neighboring crops.

Temporal variation of aquatic insects biodiversity in selected rice fields of Saran district of Bihar

Rice is a major food crop of India. The rice cultivation has maintained its priority status in the agricultural sector of the country. The intensive management practices adopted by the practitioners have resulted in genetic erosion, thus affecting the species composition of the rice field ecosystems. There is obvious difference in species composition and community structure in upland and lowland rice fields and lowland fields has minimum pests affecting production of yield per hectare. This paper presents a work carried out on the biological diversity of lowland rice field ecosystems of India, and proposes the need for conservation strategies to ensure the sustainability of these rice growing ecosystems in the long run.

Optimization of lowland productivity through fertilization as a food buffer against the impact of climate change

Lowland is an agroecosystem that can be cultivated for agricultural production activities. Its wide potential and planting time are generally carried out in the dry season resulting in lowland areas being the main national food buffer during El-Nino. Its management, which is not optimal results in low production. Increased productivity of lowland land can be done by applying the optimum fertilizer. This study aims to determine the effect of NPK fertilizer on the growth and productivity of rice in lowland fields in South Sumatra. The study used a completely randomized block design with four treatments and six replications. The indicator plant uses rice variety Inpari 42. The results showed that the highest production was obtained in the combined treatment of 250 kg NPK ha-1 + 150 kg urea ha-1 + 1,000 kg dolomite ha-1 with a yield of 5.81 t ha-1. These results indicate that NPK and urea fertilization combined with dolomite can increase the productivity of lowland rice fields as a buffer zone for rice production against the impacts of climate change.

Differential Expression of Iron Deficiency Responsive Rice Genes under Low Phosphorus and Iron Toxicity Conditions and Association of OsIRO3 with Yield in Acidic Soils

With the hypothesis that iron (Fe) deficiency responsive genes may play a role in Fe toxicity conditions, we studied five such genes OsNAS1, OsNAS3, OsIRO2, OsIRO3 and OsYSL16 across six contrasting rice genotypes for expression under high Fe and low phosphorus (P) conditions, and sequence polymorphism. Genotypes Sahbhagi Dhan, Chakhao Poirieton and Shasharang were high yielders with no bronzing symptom visible under Fe toxic field conditions, and BAM350 and BAM811 were low yielders but did not show bronzing symptoms. Hydroponic screening revealed that the number of crown roots and root length can be traits for consideration for identifying Fe toxicity tolerance in rice genotypes. Fe contents in rice roots and shoots of a high-yielding genotype KMR3 showing leaf bronzing were significantly high. In response to 24 h high Fe stress, the expression levels of OsNAS3 were up-regulated in all genotypes except KMR3. In response to 48 h high Fe stress, the expression levels of OsNAS1 were 3-fold higher in tolerant Shasharang, whereas in KMR3, it was significantly down-regulated. Even in response to 7 d excess Fe stress, the transcript abundances of OsIRO2 and OsNAS3 were contrasting in genotypes Shasharang and KMR3. This suggested that the reported Fe deficiency genes had a role in Fe toxicity and that in genotype KMR3 under excess Fe stress, there was disruption of metal homeostasis. Under the 48 h low P conditions, OsIRO2 and OsYSL16 were significantly up-regulated in Fe tolerant genotype Shasharang and in low P tolerant genotype Chakhao Poirieton, respectively. In silico sequence analysis across 3 024 rice genotypes revealed polymorphism for 4 genes. Sequencing across OsIRO3 and OsNAS3 revealed nucleotide polymorphism between tolerant and susceptible genotypes for Fe toxicity. Non-synonymous single nucleotide polymorphisms and insertion/deletions (InDels) differing in tolerant and susceptible genotypes were identified. A marker targeting 25-bp InDel in OsIRO3, when run on a diverse panel of 43 rice genotypes and a biparental population, was associated with superior performance for yield under acidic lowland field conditions. This study highlights the potential of one of the vital genes involved in Fe homeostasis as a genic target for improving rice yield in acidic soils.

Prediction of the soil properties of Malagasy rice soils based on the soil color and magnetic susceptibility

ABSTRACT Accurate assessments of soil properties are required to improve fertilizer management practices for crop production. Conventional chemical analysis in the laboratory is costly and time-consuming. Soil color is related to different soil compositions, while soil magnetic susceptibility (MS) has been found to reflect the abundance of magnetic minerals relevant to soil properties. Improving proximal sensing techniques for the analysis of soil color and MS provides opportunities for affordable and rapid assessments of soil properties. The aim of this study was to evaluate the potential use of soil color parameters and MS values to predict soil properties using stepwise multiple linear regression (SMLR), random forest (RF), and nonlinear regression approaches in lowland and upland fields in the central highlands of Madagascar. The target properties included the contents of soil organic carbon (SOC), total nitrogen (TN), oxalate-extractable phosphorus and iron (Feox), and the soil texture. The model prediction accuracy was assessed using the coefficient of determination (R2), root-mean-square error (RMSE), and the ratio of performance to interquartile distance (RPIQ). The use of soil color parameters yielded an acceptable prediction accuracy of the Feox content (loge Feox) for all rice fields (R2 = 0.54, RMSE = 0.55, RPIQ = 1.70) using the RF algorithm, while the SMLR approach gave the most accurate prediction for upland fields with acceptable reliabilities for SOC, Feox, and clay and sand content prediction, with R2 ranging from 0.43 to 0.67 and RPIQ from 1.63 to 1.77. In lowland fields, TN content was predicted with acceptable accuracy (R2 = 0.34, RMSE = 0.49, RPIQ = 1.71) using SMLR with the color parameter. The combination of the soil color parameters with the MS value as predictor variables increased SOC prediction for lowland fields using the RF approach (R2 = 0.57, RMSE = 6.37, RPIQ = 1.96). Use of the soil color and MS parameters was revealed to be a promising way to simplify the assessment of soil properties in upland and lowland ecosystems by using RF and SMLR approaches. A combined use of the soil color and MS parameters improved the prediction accuracy for the SOC content.

Genetic analysis of root vascular traits in a population from two temperate japonica rice ecotypes

ABSTRACT The genetic basis for root vascular traits in rice, despite its direct impacts on root axial and radial hydraulic conductivity, has not been widely studied compared with deep rooting traits. We used five phenotyping datasets (i.e. from maturity stage grown in upland field in 2013, and from vegetative and maturity stages grown in upland and lowland fields in 2019) to quantify the genotypic variations and genomic regions of root vascular traits in a temperate japonica mapping population (from lowland Otomemochi (OTM) and upland Yumenohatamochi (YHM)). YHM had larger stele transversal area (STA) and total late metaxylem area (LMXA), as well as higher deep root ratio and total root length at deeper layers (>30 cm) than OTM. Root vascular traits were significantly different among progenies in each dataset, and the size of genotype-by-environment interactions was comparable. Root vascular traits were not positively correlated with deep rooting traits. From the multi-environment analysis of all five datasets, four key genomic regions related to STA in both joint and separate analyses were detected on chromosome 2 (RM3703-RM6379, RM6933-RM3857), chromosome 4 (RM1388-RM5503) and chromosome 12 (RM247-RM155), with the first and third collocated with deep rooting traits. QTL-by-environment interaction was comparable to the main additive effect. This study is the first report on genomic regions of root vascular traits in a japonica mapping population.

Evaluation of different strains of Saccharomyces cerevisiae for ethanol production from high-amylopectin BRS AG rice (Oryza sativa L.)

Ethanol is the main biofuel produced by fermentation route and the search for new feedstocks to produce fuel ethanol is still a great challenge. This work aims to compare the ethanol production from a new irrigated rice cultivar BRS AG to the conventional cultivar BRS PAMPA applied in Brazil. Six different commercial strains of Saccharomyces cerevisiae (BG-1, CAT-1, FT-858, JP-1, PE-2, and SA-1) were applied in fermentation reactions. Fermentations performed with BRS PAMPA rice revealed that the highest yields were achieved with strain SA-1, corresponding to 93.0% of the theoretical maximum and final ethanol concentration of 58.92 g L−1, and with CAT-1, a yield of 92.7% and final ethanol concentration of 58.93 g L−1. For the fermentations with BRS AG rice, the highest yields were obtained with strain FT-858, exhibiting a 89.6% yield and final ethanol concentration of 62.45 g L−1, and with CAT-1, 87.9% yield and final ethanol concentration of 61.25 g L−1 were achieved. The most appropriate microorganism for ethanol production using BRS PAMPA rice and BRS AG rice was CAT-1. Comparatively, the ethanol yield and productivity using BRS AG were higher than those observed for BRS PAMPA for all strains, except for PE-2 and SA-1 that led to very similar results. The experimental results showed that the giant rice BRS AG is an excellent feedstock for fuel ethanol production in lowland fields.

Model for Predicting Rice Yield from Reflectance Index and Weather Variables in Lowland Rice Fields

Smallholder rice farmers need a multi-purpose model to forecast yield and manage limited resources such as fertiliser, irrigation water supply in-season, thus optimising inputs and increasing rice yield. Active sensing tools like Canopeo and GreenSeeker-NDVI have provided the opportunity to monitor crop health and development at different growth stages. In this study, we assessed the effectiveness of in-season estimation of rice yield in lowland fields of northwest Cambodia using weather data and vegetation cover information measured with; (1) the mobile app-Canopeo, and (2) the conventional GreenSeeker hand-held device that measures the normalised difference vegetative index (NDVI). We collected data from a series of on-farm field experiments in the rice-growing regions in 2018 and 2019. Average temperature and cumulative rainfall were calculated at panicle initiation and pre-heading stages when the crop cover index was measured. A generalised additive model (GAM) was generated using log-transformed data for grain yield, with the combined predictors of canopy cover and weather data during panicle initiation and pre-heading stages. The pre-heading stage was the best stage for grain yield prediction with the Canopeo-derived vegetation index and weather data. Overall, the Canopeo index model explained 65% of the variability in rice yield and Canopeo index, average temperature and cumulative rainfall explained 5, 65 and 56% of the yield variability in rice yield, respectively, at the pre-heading stage. The model (Canopeo index and weather data) evaluation for the training set between the observed and the predicted yield indicated an R2 value of 0.53 and root mean square error (RMSE) was 0.116 kg ha−1 at the pre-heading stage. When the model was tested on a validation set, the R2 value was 0.51 (RMSE = 925.533 kg ha−1) between the observed and the predicted yield. The NDVI-weather model explained 62% of the variability in yield, NDVI, average temperature and cumulative rainfall explained 3, 62 and 54%, respectively, of the variability in yield for the training set. The NDVI-weather model evaluation for the training set showed a slightly lower fit with R2 value of 0.51 (RMSE = 0.119 kg ha−1) between the observed and the predicted yield at pre-heading stage. The accuracy performance of the model indicated an R2 value of 0.46 (RMSE = 979.283 kg ha−1) at the same growth stage for validation set. The vegetation-derived information from Canopeo index-weather data increasingly correlated with rice yield than NDVI-weather data. Therefore, the Canopeo index-weather model is a flexible and effective tool for the prediction of rice yield in smallholder fields and can potentially be used to identify and manage fertiliser and water supply to maximise productivity in rice production systems. Data availability from more field experiments are needed to test the model’s accuracy and improve its robustness.

Application of infrared spectroscopy for estimation of concentrations of macro- and micronutrients in rice in sub-Saharan Africa

Determination of the concentration of nutrients in the plant is key information for evaluating crop nutrient removal, nutrient use efficiency, fertilizer recommendations guidelines, and in turn for improving food security and reducing environmental footprints of crop production. Diffuse infrared (IR) reflectance spectroscopy is a powerful, rapid, cheap, and less pollutant analytical tool that could be substituted for traditional laboratory methods for the determination of the concentration of nutrients in plants. However, its accuracy for predicting the concentration of nutrients in rice plants is poorly known. This study aimed i) to determine macro- and micronutrients concentration that can be accurately predicted by near-infrared (NIR, 7498–4000 cm−1), mid-infrared (MIR, 4000–600 cm−1), or their combination (NIR-MIR, 7498–600 cm−1) spectra, ii) to identify the most suitable spectral range with the best prediction potential for the simultaneous analysis of nutrients concentrations in rice plants (straw and paddy) and iii) to assess the influence of agro-ecological zone and production system on nutrients concentrations in straw and paddy (unhulled grains) samples. Second-derivative spectra were fitted against plant laboratory reference data using partial least-squares regression (PLSR) to estimate six macronutrients (N, P, K, Ca, Mg, and S) and seven micronutrients (Na, Fe, Mn, B, Cu, Mo, and Zn) concentration in paddy and rice straw samples collected at harvest from 1628 farmers’ fields in 20 sub-Saharan African (SSA) countries. The modeling prediction potential was assessed by coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), and ratio of performance to interquartile distance (RPIQ). Good prediction models (0.75 < R2 ≤ 0.95) were obtained for 7 nutrients concentrations consisting of N, P, K, Ca, Mg, Mn, and Cu. Satisfactory predictions (0.62 ≤ R2 ≤ 0.75) were obtained for S, Fe, and B. NIR, MIR, and combined NIR-MIR diffuse reflectance spectroscopy demonstrated the best prediction potential for 3, 1, and 6 of these 10 well-predicted nutrients concentrations, respectively. All nutrients concentrations both in straw and paddy were moderate to highly variable (CV = 15–111%). Agro-ecological zone and production system had a significant impact on most nutrients concentrations both in rice straw and paddy. N, P, and K concentrations in rice in irrigated lowland (IL) fields were higher than in rainfed lowland (RL) and upland (RU). From the studied fields, 2%, 16%, and 16% of straw samples were deficient in N, P, and K, respectively. K deficiency occurred in all three production systems, whereas P deficiency mainly occurred in the rainfed upland systems. Overall, the combined NIR-MIR diffuse reflectance spectroscopy has a good potential to be applied as an alternative method in the determination of macronutrient concentrations in rice plants. Further investigation on the relationships between soil attributes, rice productivity, and nutrients concentration data determined in this study is needed for providing fundamental information for site-specific soil management and fertilizer recommendations in SSA.

Leaf gas exchange of lowland rice in response to nitrogen source and vapor pressure deficit

AbstractBackgroundIn anaerobic lowland fields, ammonium (NH4+) is the dominant form of nitrogen (N) taken up by rice plants, however, with the large expansion of water‐saving irrigation practices, nitrification is favored during drained periods, leading to an increased availability of nitrate (NO3−).AimSince the uptake and assimilation of the two N‐sources differ in their demand of photosynthates, leaf gas exchange may be subject to adjustments in response to N‐sources, particularly at high evaporative demand, when stomatal conductance (gs) is very sensitive.MethodsThree experiments were carried out to study leaf gas exchange of various lowland rice varieties in response to N‐source at low and high vapor pressure deficit (VPD). In the first experiment, seedlings of 12 rice varieties were grown at high VPD for 3 weeks. From this, four rice varieties differing in gs and CO2 assimilation rate (A) were selected and grown for 2 weeks at low VPD, and after that, they were shifted to high VPD for 1 week, whereas in the third experiment, the same varieties were grown separately at low and high VPD conditions for 2 weeks. In all three experiments, plants were grown hydroponically in nutrient solution with N‐sources as sole NH4+ or NO3−.ResultsAt high VPD, NO3− nutrition led to a higher gs and A in four out of 12 varieties (IR64, BT7, NU838, and Nipponbare) relative to NH4+ nutrition, while no effect was observed at low VPD or after a short‐term exposure to high VPD. Further, varieties with a high intrinsic water‐use efficiency (WUEi; IR64 and BT7) showed the strongest response to N‐source. Higher gs was partially supported by increased root/shoot ratio, but could not be fully explained by the measured parameters. However, higher A in NO3−‐fed plants did not always result in increased plant dry matter, which is probably related to the higher energy demand for NO3− assimilation. Our results suggest that at high VPD, NO3− nutrition can improve leaf gas exchange in varieties having a high WUEi, provided a sufficient water supply.ConclusionTherefore, intensified nitrification under water‐saving irrigation measures may improve leaf gas exchange and the growth of rice plants under high transpirational demand. However, choice of variety seems crucial since large varietal differences were observed in response to N‐source. Further, breeding strategies for genotypes adapted to aerobic soil conditions should consider responses to NO3−, potentially using gas exchange measurements as a screening tool.

Analysis of the current state of natural gas resources in domestic deposits and a forecast of domestic gas production until 2030

Natural gas is the basic fossil fuel in the global economy. According to the information published by Polskie Górnictwo Naftowe i Gazownictwo SA in the document Company Presentation, gas consumption in 2018 amounted to 19.7 billion m3. Due to the fact that the domestic reserves of natural gas are increasingly depleted, the demand for natural gas will be satisfied by growing imports. Balancing gas demand will require precise knowledge of the volume of domestic natural gas production. On the other hand, every year the Polish Geological Institute – National Research Institute (PIG – BIP) publishes Balance of mine resources in Poland. According to the publication on the state of resources as of December 31, 2018, 298 natural gas fields have been documented in Poland, 5 in the Baltic Sea region, 35 in Carpathians, 105 in Carpathian Foreland and 153 in Polish Lowland. The balance presented by PIG – BIP for 2018 showed the state of natural gas contingent resources in the amount of 139.93 billion m3 (total balance resources). The volume of industrial reserves of natural gas deposits as at December 31, 2018 was 66.64 billion m3. It should be emphasized that all data published in the Balance of mine resources in Poland are given in normal cubic meters. Therefore, the data published by PIG – BIP do not take into account the actual calorific value of natural gas produced from various fields. Starting from 2014, the basic accounting unit in Poland is the energy unit (kWh). Due to the introduction of the settlement in energy units, the value of 1 m3 of nitrogen-rich gas produced from the fields located in the Lowland region is lower than the value of gas produced from the Carpathian Foreland fields and the Carpathians. The average calorific value of gas produced from the Lowland fields is about 8.0 kWh/m3, while the average calorific value of gas produced from the rest of the Foreland is about 11.2 kWh/m3. The main goal of this article was to make a forecast of gas production from domestic deposits based on the Balance of mine resources in Poland published by the Polish Geological Institute –National Research Institute. The forecast of gas extraction from domestic deposits was made for the years 2020–2030. The production forecast was prepared for each gas-bearing region separately. In order to adjust the reported volumes to the applicable energy units, the gas production forecast for the Lowland fields was converted into high-methane gas production.

IRRIGATION WATER MANAGEMENT TECHNIQUES FOR LOWLAND FURROW-IRRIGATED SOYBEAN IN SOUTHERN BRAZIL

Different water management strategies should be investigated to ensure adequate water supply to furrow-irrigated soybean plants in lowlands. This study examined the performance and efficiency of furrow irrigation techniques and related them to the soybean yield potential in lowland fields of Southern Brazil in the 2017/18 growing season. An experiment was conducted on raised seedbeds to evaluate furrow irrigation techniques: full irrigation with cutback, irrigation during the advance phase with low inflow, irrigation during the advance phase (cutoff), surge irrigation, and no irrigation. The design parameters, efficiency of the techniques, agronomic characteristics, and the grain yield of the soybean crop, were evaluated. The overall performance of the cutback technique in furrow irrigation was superior, followed by the surge irrigation, cutoff, and low inflow techniques. Furrow irrigation increased soybean yield in lowlands, and the cutback technique was the best to guarantee the soybean yield potential in lowlands, resulting in a 29% yield increase compared to non-irrigated.

Identification of Swarna x O. nivara (RPBio4918) advanced backcross lines performing well under acidic soil conditions

Aim: To evaluate a set of ABLs (Advanced Backcross Lines) to identify lines perfoming well under acidic soil and iron toxicity hydroponics conditions. Methodology: A total of 194 ABLs were randomly used in lowland field randomly following augmented experimental design. Selected lines were screened in hydroponics condition using Yoshida’s solution for iron toxicity tolerance. Results: Under field conditions, several deficiencies and toxicities often co-exist, and it becomes difficult to partition the effect of different stresses on the genotypes. Therefore, screening genotypes in artificial hydroponics conditions allows us to dissect the response of a genotype to one particular nutrient toxicity or deficiency. Based on different traits superior, average and inferior performing lines were selected from field condition. Hydroponic experiment was conducted using Yoshida’s solution for iron toxicity screening, different superior and inferior lines were identified based on the parameters like root growth, root and shoot biomass. Four lines K 408, K 455, S 304, S 203 were identified that performed well in both field and Fe toxic hydroponic conditions. Interpretation: The information generated would help to identify suitable parents for breeding program under acidic soils, and the phenotypic data on ABLs may serve as a base for future mapping of loci responsible for yield under acidic soils and iron toxic conditions. Key words: Acidic soil, Advanced backcross lines, Hydroponic condition, Iron toxicity, Seedling stage screening

Chromosomal introgressions from Oryza meridionalis into domesticated rice Oryza sativa result in iron tolerance.

Iron (Fe) toxicity is one of the most common mineral disorders affecting rice (Oryza sativa) production in flooded lowland fields. Oryza meridionalis is indigenous to northern Australia and grows in regions with Fe-rich soils, making it a candidate for use in adaptive breeding. With the aim of understanding tolerance mechanisms in rice, we screened a population of interspecific introgression lines from a cross between O. sativa and O. meridionalis for the identification of quantitative trait loci (QTLs) contributing to Fe-toxicity tolerance. Six putative QTLs were identified. A line carrying one introgression from O. meridionalis on chromosome 9 associated with one QTL was highly tolerant despite very high shoot Fe concentrations. Physiological, biochemical, ionomic, and transcriptomic analyses showed that the tolerance of the introgression lines could partly be explained by higher relative Fe retention in the leaf sheath and culm. We constructed the interspecific hybrid genome in silico for transcriptomic analysis and identified differentially regulated introgressed genes from O. meridionalis that could be involved in shoot-based Fe tolerance, such as metallothioneins, glutathione S-transferases, and transporters from the ABC and MFS families. This work demonstrates that introgressions of O. meridionalis into the O. sativa genome can confer increased tolerance to excess Fe.