Irrigation Conditions Research Articles

Heading and maturity date prediction using vegetation indices: A case study using bread wheat, barley and oat crops

Contemporary crop research programs involve the evaluation of numerous micro-plots spread across extensive experimental fields. As a result, there is a growing need to depart from labor-intensive manual measurements when assessing phenological data. The growing significance of high throughput phenotyping platforms (HTTP), including unmanned aerial vehicles (UAVs), has rendered these technologies essential in crop research. The overall objective of this study is to explore and validate the use of HTTP methodologies, specifically the potential of vegetation indices (VIs) derived from conventional RGB images, to forecast the date of heading (DH) and maturity (DM) for various cereal crops under different irrigation conditions. To pinpoint DH and DM prediction, a total of nine UAV surveys were conducted throughout the entire crop cycle. Prediction models for DH and DM using VIs were successfully developed for various crop species, explaining 65 % of the variance in bread wheat and 75 % in oats. The highest percentages of variance explained were achieved when models were developed separately for the two irrigation conditions (well-irrigated and rainfed). However, the percentage of variance explained by these models decreased when applied to barley (R²<0.5 for DH). Notably, including final plant height as a predictor increased the percentage of variance explained by the models only for irrigated bread wheat. Furthermore, the utilization of multi-temporal equations, which amalgamated data from diverse UAV surveys, notably enhanced the percentage of variance explained by the model (+160.71 % improvement in DH predictions), particularly those tailored to each specific crop species and irrigation condition. The investigation additionally established a thorough protocol for modeling the phenological aspects of cereal crops utilizing data acquired from UAVs, thereby enhancing the accessibility of this technology for measurements of phenology in large crop research programs.

Effect of Nitrogen Fertilizer and Seed rates on Yield and Yield Components of Bread Wheat in the Irrigated Condition of South West Shewa, Central Highland of Ethiopia

Inappropriate seed density and fertilizer management can lead to unstable crop yields. Excessive fertilizer application can potentially cause yield loss and nitrogen (N) leaching that leads to environmental pollution. The aim of this study was to explore the optimal N application rate and seed rate on bread wheat with different nitrogen responding under irrigation condition at two experimental sites in the South West Shewa, Ethiopia. A year field experiment was conducted to explore the effects of five N application rates (N0, N23, N46, N69, and N92) and three seed rates on bread wheat yield components like; - aboveground biomass, harvest index, number of tillers per plant, spike length, number of kernels per plant, grain yield and net return. The results showed that N application rate and seed rate were significantly interaction (P&amp;lt; 0.05) effect on aboveground biomass, harvest index, number of tillers per plant, spike length, number of kernels per plant and grain yield. Generally, spike length, number of tillers per plant and number of kernels per spike of wheat were increased with increased at some level in nitrogen fertilizer rate for the three seed rate at both locations. Highest number of kernels per spike (42.00, 44.00) and the highest mean above ground biomass yield (13.70 t ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;, 7.5 t ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;) were obtained for 150 kg ha &amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; seed rate with 69 N kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; application at Ameya and Woliso sites respectively. The highest net benefit of 171531.88 EB ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; with marginal rate of return of 351.14% was obtained from 175 kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; seed rate with application of 69 kg N ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. Therefore, 175 kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; seed rate with application of 69 kg N ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; is economical feasible for bread wheat production at Ameya area and also the highest net benefit of 51675 EB ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; with marginal rate of return of 115.22% was obtained from 150 kg ha &amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; seed rate with application of 69 kg N ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; at Woliso area.

Genome‐Wide Association Studies Predicted Drought Stress Occuring at Anthesis and Post‐Anthesis Stages in Novel Diverse Germplasm of Bread Wheat (Triticum aestivum)

ABSTRACTThis study employed genome‐wide association studies (GWAS) to identify the crucial marker–trait associations (MTAs) for agronomic and physiological traits in bread wheat grown under full irrigation and 40% reduced irrigation. One hundred twenty‐four genotypes derived from three‐way crosses of landraces and synthetic bread wheat were evaluated for 2 years in the field conditions of CIMMYT Obregon, Mexico. Irrigation was not provided at anthesis and post‐anthesis stage for the drought treatment, and data of 12 traits were recorded. Most of the traits were reduced significantly under drought conditions except for vigour, wax and spike length (SL); genotypes were significantly different for the eight traits except for days to heading (DTH), number of grains spike−1 (NGS), normalized difference in vegetation index (NDVI) and canopy temperature depression (CTD); and differences were also significant for five traits between the years. Moreover, GY was significantly and negatively correlated with wax and CTD. Our GWAS results indicated 117 significant (p ≤ 0.001) MTAs distributed on all the wheat chromosomes except chromosomes 4B and 4D explaining 10%–21.5% of the phenotypic variation of the corresponding traits. Moreover, 22 MTAs were recorded for grain yield and explaining the phenotypic variations up to 14.7% with one common association under both irrigated and drought conditions. Additionally, we also identified the associations for NDVI, CTD and SL at chromosome 1B, suggesting that genotypes are sustaining superior grain yield through better values of traits like NDVI, CTD, and SL under the challenging conditions of anthesis and post‐anthesis drought stress.

Experimental investigation on heating performance of long- and short-term PCM storage in Chinese solar greenhouse

Phase change material (PCM) board on north wall of the greenhouses can absorb and store solar heat during the daytime, then releases it at night to provide the thermal environment for crop growth. However, its capability to regulate the greenhouse temperatures in severe winter is limited, necessitating an additional heat source. The heat gap within the greenhouse can be replenished flexibly and promptly by controllable triggering of supercooled salt hydrate for long-term heat storage. This study proposed a synergetic energy storage and release system, combining the short-term storage and passive release of the PCM wallboard with the long-term storage and active triggering solidification of the supercooled salt hydrate in separate storage unit. The temperature regulation effect of this synergetic system was experimentally investigated in a test Chinese greenhouse. The results showed that the combination of the PCM north wallboard with the supercooled salt hydrate storage unit reduced the daytime average temperature by 2.0 °C ~ 3.8 °C compared with the control greenhouse. In sunny days, the PCM north wallboard could meet the nighttime heat demand of the greenhouse with the average temperature rise of 5.2 °C ~ 6.7 °C. In severe weather, by triggering supercooled sodium acetate trihydrate (SAT, CH3COONa·3H2O, Tm = 58.0 °C) at late night, the temperature rose by 5.3 °C in 1 h, effectively heating for 5 h. While supercooled sodium thiosulfate pentahydrate (STP, Na2S2O3·5H2O, Tm = 48.5 °C) was triggered, the temperature rose by 3.3 °C in 1 h, effectively heating for 4 h. Furthermore, the synergetic system was still effective for greenhouses under ventilation and irrigation conditions during the day. This study provides guidance for the development of synergetic PCM systems with long- and short-term solar thermal storage and release for greenhouse heating.

Remote sensing monitoring of irrigated area in the non-growth season and of water consumption analysis in a large-scale irrigation district

Globally, water scarcity threatens food security, especially in arid and semi-arid food-producing regions, such as the Hetao Irrigation District (HID), where the water consumption during the non-growth season (spring irrigation, autumn irrigation) accounts for more than 30 % of the total irrigation volume. Meanwhile, mapping the characteristics of spatial and temporal evolution of the area of cropland irrigated in the spring and autumn and the pattern of water consumption is crucial for strengthening the management of agricultural water use. Evaporation and infiltration of irrigation water are difficult to capture in time due to insufficient timeliness or accuracy of single remote sensing data. This study integrates seven remote sensing datasets (Landsat5, Landsat7, Landsat8, HJ-1A/B, GF-1, Sentinel-2 and MODIS) for the first time to build a high spatial-temporal resolution dataset, and combines the water index NDWI and MNDWI to extract the maximum water range formed after irrigation by manually adjusting the threshold method. In addition to the global land use/cover dataset (GLC FCS30–1985_2020), the cropland layer was superimposed to accurately identify the cropland spring irrigation and autumn irrigation range from 2000 to 2021 in the HID. In the past 20 years, spring-irrigated (SI) areas increased by 1012.60 km2 (+49.96 %), and the autumn-irrigated (AI) areas decreased by 512.63 km2 (-11.02 %). Combined with the quantity of water diversion and displacement, the characteristics of irrigation water consumption in the non-growth season were further analysed. The results showed that the water consumption of spring irrigation increased by 0.67×108 m3 (+22.26 %), and that of autumn irrigation increased by 4.34×108 m3 (+38.82 %). The decrease of autumn- irrigated area and the increase of water consumption were mainly related to the stability of autumn irrigation water, imperfect irrigation and drainage conditions and insufficient field water management. In 2020­2021, the area of non-growth “autumn irrigation - spring irrigation” repeated irrigation is about 1271.52 km2, which can be used as a key control area. This study provides a theoretical basis and direction for rational water use in non-growth seasons of irrigation districts.

Mathematical Modeling for Predicting Growth and Yield of Halophyte Hedysarum scoparium in Arid Regions under Variable Irrigation and Soil Amendment Conditions

Growing degree days (GDDs) and leaf area index (LAI) greatly influence the growth and yield of many crops grown in arid regions. Therefore, variation in LAI due to GDD can provide a theoretical basis for predicting crop growth, water consumption, plant development, and yield in arid agriculture via the development of mathematical growth models. This study described the relationship between plant biomass production and variation in LAI due to GDD in arid regions under different types of irrigation (fresh water and saline water) and soils amended with different substances (manure+sandy soil, compost+sandy soil, clay+sandy soil, and sandy soil). Mathematical models for LAI were established for GDDs. In addition, different water quality irrigation techniques were used as independent variables to calculate the LAI of halophytic plants (Hedysarum scoparium) in arid regions under different soil amendment treatments. Furthermore, mathematical models for plant biomass production were developed by using the LAI and GDDs. For this purpose, Logistic, Gaussian, modified Gaussian, and Cubic polynomial models were used. Modified Gaussian and Cubic polynomial models are the best among all developed models, but Cubic polynomial models are more suitable among all developed models because of their simple quadratic equations that can be solved by using the first derivative. It was observed that with increased salt concentration in the irrigation water, the growth of per plant production decreased. However, soil amendments like manure and compost enhance salt tolerance against salt stress and enable plants to sustain their growth. Furthermore, Hedysarum scoparium attains maximum LAI when its GDD is about 1117.5 °C under both irrigation regimes and in all soil amendment treatments. It was concluded that these predicted mathematical models can provide crucial insights for enhancing production in arid regions by using eco-friendly soil amendments to improve water use efficiency across diverse types of water irrigation.

Grapevine varieties show different sensitivities to flavonoid alterations caused by high temperatures under two irrigation conditions

This study aimed to assess the response of four red grapevine (Vitis vinifera L.) varieties to elevated temperature, drought and their combination, focusing on the concentration and profile of grape flavonoids. Fruit-bearing cuttings of Tempranillo, Cabernet Sauvignon, Merlot and Grenache grew in greenhouses under, either ambient temperature (T) or ambient temperature + 4 °C (T+4). Plants also received either full irrigation (FI, substrate field capacity) or deficit irrigation (DI, 50 % substrate field capacity). In general, T+4 decreased the concentration of anthocyanins, but DI mitigated this effect. T+4 and DI increased the abundance of methylated anthocyanins and flavonols with additive effects. Grapes under T+4 had higher abundance of acylated anthocyanins, while DI increased the proportion of tri-hydroxylated anthocyanins and flavonols. The impact of interacting elevated temperature and drought on grape composition was genotype dependent. In terms of anthocyanin concentration and profile, Tempranillo was the most affected variety, whereas Grenache was less sensitive.

Current status and obstacles of narrowing yield gaps of four major crops.

Maize, wheat, rice and soybean production are intimately linked to food security. Identifying the key factors affecting crop yields and determining the countries where increased irrigation and nitrogen application most effectively enhance yields are essential steps towards achieving sustainable development goals and ensuring food security. Identifying these areas is crucially dependent on yield gaps. However, the lack of comparability between different regions in current regional-scale yield gap studies stems from varied methodologies. Moreover, global yield gap research, relying on statistical models and regression methods, tends to neglect the crop growth process. In this study, we used a random forest model, based on statistical and meteorological data, to pinpoint the key factors influencing crop yields. Subsequently, using unified yield data from the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), derived from crop models simulations, we applied the yield gap method to calculate the potential yield increase for four crops across countries, under conditions of full irrigation and nitrogen application. Our research finds that nitrogen application is the main factor affecting yields globally, while irrigation plays a crucial role in the major producing countries. The countries with high potential for yield increases are located at the border between Africa and Eurasia. The global average yield of the four major crops increased 13.7-29.8% under full irrigation, 2.9-39.1% under full nitrogen application and 29.4-97.8% under both conditions. This study provides crucial insights into global crop yield changes and their determinants, which are highly important for global sustainable agriculture and food security efforts. © 2024 Society of Chemical Industry.

Sustainability in the winemaking industry and the assessment of grape seed characteristics during processing: Evidence from Azerbaijan

In the context of Azerbaijan’s evolving winemaking landscape, this study investigates the sustainability of viticulture with a particular focus on grape seeds, which are crucial for grapevine propagation, oil extraction, and overall vineyard health. The research aimed to examine the morphological, technological, and biochemical characteristics of grape seeds to optimise grape production methods and promote sustainable viticultural practices. To achieve this, seed samples from twelve grape varieties, both local and introduced, were carefully collected and analysed under varying irrigation conditions, including both irrigated and rainfed settings, to allow for a comprehensive assessment. The investigation revealed significant effects of irrigation on seed properties. Specifically, seeds from irrigated grapes were found to be larger, heavier, and richer in oil content compared to those from rainfed grapes. Detailed analyses showed that the nitrogen content of the seeds ranged from 0.96% to 1.46%, cellulose content varied from 18.8% to 25.3%, ash content ranged from 1.9% to 3.1%, nitrogenous compounds fluctuated between 5.5% and 7.2%, and non-nitrogen extractive substances registered between 16.6% and 22.0%. Notably, correlations between seed properties and the efficiency of cold press oil extraction were identified, providing valuable insights. This research ultimately contributes to the advancement of sustainable viticulture practices in Azerbaijan, ensuring the long-term health and productivity of vineyards within the region

Enhancing Solanum lycopersicum Resilience: Bacterial Cellulose Alleviates Low Irrigation Stress and Boosts Nutrient Uptake.

The use of natural-origin biomaterials in bioengineering has led to innovative approaches in agroforestry. Bacterial cellulose (BC), sharing the same chemical formula as plant-origin cellulose (PC), exhibits significantly different biochemical properties, including a high degree of crystallinity and superior water retention capacity. Previous research showed that natural-origin glucose-based chitin enhanced plant growth in both herbaceous and non-herbaceous plants. In this study, we produced BC in the laboratory and investigated its effects on the substrate and on Solanum lycopersicum seedlings. Soil amended with BC increased root growth compared with untreated seedlings. Additionally, under limited irrigation conditions, BC increased global developmental parameters including fresh and dry weight, as well as total carbon and nitrogen content. Under non-irrigation conditions, BC contributed substantially to plant survival. RNA sequencing (Illumina®) on BC-treated seedlings revealed that BC, despite its bacterial origin, did not stress the plants, confirming its innocuous nature, and it lightly induced genes related to root development and cell division as well as inhibition of stress responses and defense. The presence of BC in the organic substrate increased soil availability of phosphorus (P), iron (Fe), and potassium (K), correlating with enhanced nutrient uptake in plants. Our results demonstrate the potential of BC for improving soil nutrient availability and plant tolerance to low irrigation, making it valuable for agricultural and forestry purposes in the context of global warming.

Integrated analysis of yield response and early stage biochemical, molecular, and gene expression profiles of pre-breeding rice lines under water deficit stress

Breeding high yielding water-deficit tolerant rice is considered a primary goal for achieving the objectives of the sustainable development goals, 2030. However, evaluating the performance of the pre-breeding-promising parental-lines for water deficit tolerance prior to their incorporation in the breeding program is crucial for the success of the breeding programs. The aim of the current investigation is to assess the performance of a set of pre-breeding lines compared with their parents. To achieve this goal a set of 7 pre-breeding rice lines along with their parents (5 genotypes) were field evaluated under well-irrigated and water-stress conditions. Water stress was applied by flush irrigation every 12 days without keeping standing water after irrigation. Based on the field evaluation results, a pre-breeding line was selected to conduct physiological and expression analysis of drought related genes at the green house. Furthermore, a greenhouse trial was conducted in pots, where the genotypes were grown under well and stress irrigation conditions at seedling stage for physiological analysis and expression profiling of the genotypes. Results indicated that the pre-breeding lines which were high yielding under water shortage stress showed low drought susceptibility index. Those lines exhibited high proline, SOD, TSS content along with low levels of MDA content in their leaves. Moreover, the genotypes grain yield positively correlated with proline, SOD, TSS content in their leaves. The SSR markers RM22, RM525, RM324 and RM3805 were able to discriminate the tolerant parents from the sensitive one. Expression levels of the tested drought responsive genes revealed the upregulation of OsLEA3, OsAPX2, OsNAC1, OSDREB2A, OsDREB1C, OsZIP23, OsP5CS, OsAHL1 and OsCATA genes in response to water deficit stress as compared to their expression under normal irrigated condition. Taken together among the tested pre-breeding lines the RBL112 pre-breeding line is high yielding under water-deficit and could be used as donor for high yielding genes in the breeding for water deficit resistance. This investigation withdraws attention to evaluate the promising pre-breeding lines before their incorporation in the water deficit stress breeding program.

Influence of site-specific nutrient management (SSNM) on growth and yield of finger millet (Eleusine coracana L.) in Vertisols under irrigated condition

Influence of site-specific nutrient management (SSNM) on growth and yield of finger millet (Eleusine coracana L.) in Vertisols under irrigated condition

Effectiveness of local isolates of Trichoderma spp. in imparting drought tolerance in rice, Oryza sativa

Rice is a crop that requires high amount of water, and the drought is a major constraint in paddy cultivation. Water stress condition frequently prevails due to shortage of rain which results in significantly reduced plant growth and yield of rice. In the present study capability of Trichoderma spp. in imparting drought tolerance to rice, Oryza sativa was explored. Eleven local strains of Trichoderma spp. were applied to rice cv. Swarna Sub-1 through soil application (2 g/kg soil) and seed treatment (20 g/kg seed) under 0, 25, 50 and 75% less watering of the recommended amount. The soil application of T. harzianum AMUTHZ84 significantly promoted the shoot and root length (23.6 and 21.3%) followed by seed treatment (19.7 and 18.2%) under recommended level of irrigation condition (100% irrigation). Next in effectiveness was T. viride AMUTVR73 (21.5 and 18.1%) over untreated control. However, under 75% water availability, soil application with T. harzianum AMUTHZ82 was found superior over other isolates in enhancing shoot and root length (17.7 and 16.4%). The same isolate was also recorded to be superior under 50% (12.4 and 10.1%) and 25% water availability (9.3 and 8.1%) in enhancing the plant growth and biomass of rice cv. Swarna Sub-1. The isolate also significantly enhanced the leaf pigments, and photosynthesis in the rice plants grown under 25–75% water stress condition. In general, soil application of Trichoderma isolates was found more effective than seed treatment, and the T. harzianum AMUTHZ82 provided 8–17% enhancement in the plant growth, biomass, leaf pigments and photosynthesis of rice cv. Swarna Sub-1 grown under 25–75% water stress condition.

Wheat food security indicators under improved irrigation conditions in Assiut Governorate

Wheat food security indicators under improved irrigation conditions in Assiut Governorate

Heat transfer processes in 'Shine Muscat' grapevine leaves in solar greenhouses under different irrigation treatments

The use of solar greenhouses in China is increasing because they permit environmental conditions to be controlled. Studies of the heat transfer processes in the leaves of plants cultivated within solar greenhouses are needed. Here, we studied heat transfer processes in 'Shine Muscat' grapevine leaves under moderate deficit irrigation (MDI), severe deficit irrigation (SDI), and full irrigation (FI) treatments under varying weather conditions. The stomatal conductance, leaf temperature, and transpiration rate of both shade and sun grapevine leaves were measured, and the effects of ambient temperature and relative humidity on these variables were determined. A thermal physics model of the leaves was established to explore the heat dissipation process. On sunny days, the transpiration heat transfer of sun leaves in the MDI, SDI, and FI treatments was 2.62 MJ m−2·day−1, 2.44 MJ m−2·day−1, and 3.86 MJ m−2·day−1and 0.818 MJ m−2·day−1, 0.782 MJ m−2·day−1, and 1.185 MJ m−2·day−1 on rainy days, respectively. There was a significant difference in transpiration heat transfer under fully irrigated and deficit irrigation conditions under different weather conditions. Furthermore, transpiration heat transfer accounted for 41.49 % and 25.03 % of the total heat transfer of sun leaves in the FI treatment and 33.94 % and 29.43 % of the total heat transfer of shade leaves on rainy days, respectively, indicating that relative humidity plays a key role in determining transpiration heat transfer and leaf temperature and that its effect was greater on sun leaves than on shade leaves.

Effect of nitrogen fertilizer and zinc sulfate on growth, physiological, biochemical and nutrient use efficiency in fodder maize under irrigation regimes

To investigate the effect of nitrogen fertilizer and zinc (Zn) sulfate on growth, physiological, biochemical, and nutrient use efficiency in fodder maize under drought stress, an experiment was conducted during two cropping years 2019 and 2020. The experiment was performed as a split-factorial in the form of a randomized complete block design with four replications. The main factor was irrigation regimes in three levels: full irrigation (without stress or 100% of field capacity), irrigation based on 75% of field capacity, and irrigation based on 50% of field capacity. The first sub-factor included urea fertilizer at three levels of 0, 69, and 138 kg ha−1. The second sub-factor included foliar application of zinc sulfate at three levels of 0, 2, and 4 mg kg−1. The results showed that the highest fresh weight of maize fodder was obtained under conditions of full irrigation and the use of 138 kg ha−1 of N. The use of zinc at all irrigation levels increased the fresh weight of maize fodder. These results confirmed that if higher amounts of N are used, more zinc should be used to achieve a higher yield of maize forage. With the increase in the severity of drought stress, the concentration of nitrogen and phosphorus in the crop tissue, as well as the efficiency of using nitrogen and phosphorus, decreased. The highest value of nitrogen use efficiency was obtained in full irrigation conditions, using 69 kg ha−1 of N and 4 mg kg−1 of zinc. In addition, at all irrigation levels, the efficiency of using this element decreased with increasing zinc consumption.

Development of a novel critical nitrogen concentration–cumulative transpiration curve for optimizing nitrogen management under varying irrigation conditions in winter wheat

Accurate nitrogen (N) nutrition diagnosis is essential for improving N use efficiency in crop production. The widely used critical N (Nc) dilution curve traditionally depends solely on agronomic variables, neglecting crop water status. With three-year field experiments with winter wheat, encompassing two irrigation levels (rainfed and irrigation at jointing and anthesis) and three N levels (0, 180, and 270 kg ha−1), this study aims to establish a novel approach for determining the Nc dilution curve based on crop cumulative transpiration (T), providing a comprehensive analysis of the interaction between N and water availability. The Nc curves derived from both crop dry matter (DM) and T demonstrated N concentration dilution under different conditions with different parameters. The equation Nc = 6.43T−0.24 established a consistent relationship across varying irrigation regimes. Independent test results indicated that the nitrogen nutrition index (NNI), calculated from this curve, effectively identifies and quantifies the two sources of N deficiency: insufficient N supply in the soil and insufficient soil water concentration leading to decreased N availability for root absorption. Additionally, the NNI calculated from the Nc-DM and Nc-T curves exhibited a strong negative correlation with accumulated N deficit (Nand) and a positive correlation with relative grain yield (RGY). The NNI derived from the Nc-T curve outperformed the NNI derived from the Nc-DM curve concerning its relationship with Nand and RGY, as indicated by larger R2 values and smaller AIC. The novel Nc curve based on T serves as an effective diagnostic tool for assessing winter wheat N status, predicting grain yield, and optimizing N fertilizer management across varying irrigation conditions. These findings would provide new insights and methods to improve the simulations of water-N interaction relationship in crop growth models.

Trade-offs between grain number, grain weight and fruiting efficiency of different bread wheat genotypes in response to anthesis drought stress

Cereal crops in Morocco are mainly cultivated under rainfed conditions of dryland regions. Under these conditions, they are mostly exposed to drought stress that affects different yield components. We studied the effect of anthesis drought stress on the relationships among the components of grain number (GN), thousand grains weight (TGW), fruiting efficiency (FE) and yield. And we examined fruiting efficiency (FE= grains set per g of spike dry weight at anthesis) as promising trait for further increasing yield without compromising yield components. Greenhouse experiments were conducted on 2019/2020, 2020/2021 and 2021/2022 cropping seasons. Two contrasting water regimes, irrigated and stressed treatments at anthesis growth stage were assessed. Results showed that anthesis drought stress affects negatively all components studied. Substantial decrease of 10%, 16%, 9% and 34% were recorded for GN, TGW, FE, and yield, respectively, under water stress compared to irrigated treatments. Two genotypes, namely 15/42 and Achtar, were found to be the most adapted to both stressed and irrigated conditions. Under stressed conditions yield becomes less correlated with GN (r = 0.36) and FE (r = 0.37) and more correlated with TGW (r = 0.56*). GN becomes less correlated with FE (r = 0.02) and TGW (r = -0.14). While, FE becomes more correlated with TGW (r = 0.73*). To the extent of this study, FE was found as promising selection criterion under stress conditions without compromising TGW component.

Optimization of fertilizer use efficiency, soil quality and oil palm (Elaeis guineensis Jacq.) growth with biochar under drip irrigation conditions irrigation conditions

Biochar (BC) is an eco-friendly product characterized with high content of carbon and usually obtained by heating biomass without oxygen. Utilizing BC as organic material to amend the problematic soils and improve plant growth and yield has been proved previously. This study investigated the effect of vetiver grass biochar (VGB) on fertilizer use efficiency, soil quality, and oil palm growth performance. A net house experiment was conducted at the Farm Unit, UiTM Sarawak Branch, between August 2022 and March 2023. A factorial randomized complete block design (RCBD) with five treatments and four replications was devised. Treatments applied were: T0) absolute control; T1) 100% NPK fertilizer; T2) 100% vetiver grass biochar; T3) 50% vetiver grass biochar + 50% NPK fertilizer; and T4) 25% vetiver grass biochar + 75% NPK fertilizer. The BC application significantly improved the fertilizer use efficiency through reducing the rate of fertilizer applied. It also significantly enhanced most soil-measured chemical properties and soil nutrients. The growth performance of oil palm plant was significantly enhanced by BC application in terms of plant height, hump diameter, leaf number, chlorophyll content, and plant biomass. The BC application demonstrated its usefulness in managing soil and cultivating oil palm plant sustainably by reducing the rate of fertilizer applied and improve the fertilizer use efficiency. Based on the output, we suggest that treatment T3 (50% vetiver grass biochar + 50% NPK) can be used to improve the growth performance of oil palm.

Manifestation of the Effect of Growth Heterosis in Intraspecific Hybrids of Soft Wheat

The presented article presents the results of the study of height inheritance in hybrid combinations of the first generation (F1) of bread wheat. The research was conducted in the 2019-2020 growing season at the Apsheron District Experimental Farm under irrigation conditions. In 32 combinations of hybrids of the first generation (F1), obtained as a result of reciprocal crossing of 9 local varieties («Mirbashir-128», «Azeri», «Gobustan», «Fatima», «Gyrmyzy gul-1», «Murov-2», «Askeran», «Matin» and «Onur»). Studied the height of plants in comparison with parental forms and determined the degree of true heterosis and dominance. In the studied hybrid combinations, a variety from high dominance to depression was found in the transmission of heredity. When analyzing hybrids of bread wheat of the first generation (F1) according to the inheritance of plant height, high dominance was determined in 19 combinations (59.4%), depression — in 8 combinations (25.0%), intermediate heredity - in 5 combinations (15.6% ). Positive heterosis was revealed in 19 combinations (59.4%), negative heterosis - in 13 combinations (40.6%). As a result of the research, it is possible to initially conclude that it is possible to obtain low-growing hybrids by involving in the hybridization a variety of the same height.