Flag Leaf Emergence Research Articles

Long-term investigation of the irrigation intervals and supplementary irrigation strategies effects on winter wheat in the U.S. Central High Plains based on a combination of crop modeling and field studies

Implementing optimized irrigation strategies to achieve acceptable wheat yield while conserving groundwater resources is critical for extensively irrigated regions. Field experiments regarding winter wheat irrigation management were conducted for two growing seasons (2013–2014 and 2014–2015) to calibrate and validate the AquaCrop model. To determine proper parameterization of the AquaCrop model for various data availability conditions, the model performance was tested for calibration based on three different datasets, including a) calibration based on a full irrigation condition (CA 1), b) calibration based on a dryland condition (CA 2), and c) calibration based on diverse irrigation conditions, which included full irrigation, different deficit irrigation levels, and dryland (CA 3). The CA 3 calibration scenario resulted in the model's highest accuracy in simulating biomass, grain yield, total soil water, and seasonal evapotranspiration during the calibration and validation process. However, the model performance was also convenient when calibration based on full irrigation conditions was pursued. The calibrated and validated AquaCrop model based on the CA3 was used to analyze long-term (36-year) irrigation management scenarios for identifying the optimized water-conservative winter wheat irrigation strategies. The long-term analysis emphasized that increasing irrigation intervals from 7 to 15 or 20 days could reduce groundwater withdrawal by 52–64 % while expecting a 14–19 % reduction in grain yield. By implementing one 25 mm irrigation after planting and two 25 mm depth irrigation events at jointing or leaf growth stages, 91 % of Kansas's average winter wheat yield (2.88 tons/ha) could be achieved. During wet years, the 1.2 ton/ha reduction in biomass and 0.27–0.62 ton/ha reduction in grain yield is expected irrespective of irrigation management strategies. Considerable uncertainty was detected in grain yield production during dry years under dryland (rainfed) conditions. The maximum winter wheat production could be achieved under normal years, establishing a balance between precipitation and heat units. Our agro-hydrological analysis revealed that the highest irrigation water use efficiency could be attained by the application of two 25 mm irrigation events at jointing or flag leaf growth stages during normal years, the application of two irrigation events during jointing or heading during wet years, and two 25 mm irrigations at heading or flowering during dry years. The results of this research could be used as a baseline for producers of the U.S. Central High Plains and semi-arid regions with similar climate characteristics to cope with water scarcity in winter wheat production.

Yield improvement with antitranspirant application in droughted wheat associated with both reduced transpiration and reduced abscisic acid

AbstractIn Mediterranean-type climates, terminal drought induces grain yield losses in wheat. Antitranspirants can reduce the impacts of terminal drought and improve yield, but the mechanisms involved are not fully understood. Among other impacts, drought elevates endogenous abscisic acid (ABA) concentration. Here, the effectiveness of a film antitranspirant (di-1-p-menthene) was studied in relation to plant water status and spike ABA. The objective was to determine whether drought amelioration with di-1-p-menthene was solely mediated through a reduction in ABA by comparing its effects to that of fluridone (an ABA inhibitor). The treatments were assessed in a randomized complete block design in two field experiments in spring and summer of 2020, with six and eight replicate blocks, respectively, at Harper Adams University, UK, to compare their effects on spike ABA, gas exchange and agronomic traits under progressive drought conditions. Di-1-p-menthene was applied at 1 l/ha; and fluridone at 10, 20 and 50 μM concentrations, at flag leaf emergence, growth stage 37 (GS37). Drought increased spike ABA and downregulated photosynthesis. Di-1-p-menthene and fluridone at some concentrations, reduced spike ABA and photosynthesis. Di-1-p-menthene suppressed transpiration and spike ABA, each by 21% but increased grain yield by 27%. In contrast, although fluridone (at 10 and 50 μM) also reduced spike ABA (by 16%), overall, it did not alter transpiration or grain yield. The results suggest that yield improvement with di-1-p-methene is mediated through mechanisms that involve conservation of plant water linked to reduced transpiration, with inhibition of spike ABA playing a secondary role.

Increase of Bacterial Leaf Streak in Hard Red Spring Wheat in North Dakota and Yield Loss Considerations.

Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, has increased in both prevalence and severity in the major hard red spring wheat (HRSW)-producing state North Dakota. The disease is readily observed after flag leaf emergence and can quickly lead to defoliation and severe yield loss. The objectives of this research were to document the prevalence and incidence of BLS in North Dakota and provide estimations of yield and economic losses. Trained field scouts determined the incidence and prevalence of BLS in ND on HRSW plants between Feekes growth stage (FGS) 8 and FGS 11.2 from 2015 to 2021, and data were used to determine BLS-affected hectares. Yield data in combination with BLS ratings were obtained from HRSW performance trials to estimate the impact of BLS on yield. The combination of variety identity, hectarage data, BLS-affected hectarage estimates, and yield loss estimates was used to estimate economic losses from BLS in 2019 and 2020. Our data suggest that BLS-affected hectares ranged from 747 to 141,680 between 2015 and 2021. Yield loss was observed at multiple HRSW performance trial locations, with estimated yield losses as high as 60% on susceptible varieties. The amount of BLS-affected hectares was the highest in 2019 and 2020, and direct economic losses for North Dakota HRSW producers were estimated to be as high as $4.7 and $8.0 million, respectively. These data highlight the importance of BLS in HRSW and the need to procure resources for breeding efforts and grower education on management of BLS.

Calibration, validation and testing of a rotational displacement transducer for measuring wheat leaf elongation rates

Flag leaf growth has been emphasized in the literature as an important secondary trait for wheat breeding under drought stress. To measure leaf elongation rate (LER) in monocotyledons such as wheat, the rotational displacement transducer (RDT) has already been used in several studies, mostly on maize. Still, a comprehensive calibration and measurement protocol of the sensor is lacking. To fill this gap, several experiments were performed: (i) to calibrate the sensor and test its resilience to physical disturbances and changes in environmental conditions, (ii) to validate the calibration on growing plants, and (iii) to compare growth rate in flag leaves of well-watered and drought-treated wheat (Triticum aestivum L.) plants. The study showed that calibration of RDT sensors with a height gauge resulted in very accurate and robust measurements of growth rate and drought stress dynamics in monocotyledons, such as wheat. To correctly interpret the sensor measurements and derive the underlying mechanism, it is however important to consider the complex architecture of the plant, as the RDT not merely measures leaf growth, but also any potential growth of supporting parts.

The Effect of Foliar Zinc Application on the Leaf Chlorophyll Concentrations and Grain Yields of the Winter Wheat (Triticum aestivum L.) in the Field Experiments of Two Seasons

This research examined the effectiveness of zinc foliar fertilizers. Two winter wheat varieties, GK Pilis and Zvezdana, were tested in a Zn-limited meadow chernozem soil. Crop yields and chlorophyll concentrations of the leaves were examined in the growing seasons of 2020/2021 of favorable weather conditions and 2021/2022 of drought weather conditions. In the experiment, three treatments were carried out with monozinc foliar fertilizer of a concentrated 12% (w/v) zinc sulfate heptahydrate solution, and the fourth plot was designed as the untreated control. The first monozinc treatment was applied at a dose of 1 L ha−1 and the second monozinc treatment at a dose of 2 L ha−1. These treatments were applied at tillering (BBCH 21–22). The third monozinc treatment was applied at a dose of 1 L ha−1 at tillering and flag leaf emergence (BBCH 21–22, BBCH 37). Samples were taken several times in the vegetation period, and measurements were made using different methods (SPAD, determination of total chlorophyll concentration from acetone solution) before and after Zn treatments. In 2020/2021 of favorable weather conditions, the yield of Zvezdana was 5.47 t ha−1 and that of Gk Pilis was 6.11 t ha−1, compared to 2021/2022 of drought weather conditions, in which year the yield of Zvezdana was 3.14 t ha−1 and that of Gk Pilis was 2.79 t ha−1. Yields of both varieties increased with increasing NPK nutrient doses. In 2021/2022, even at nutrient level D (NPK basal fertilizer and two-times N topdressing), we harvested on average twice as much as in 2020/2021 at nutrient level A (N basal fertilizer and once N topdressing). No significant effects were found between the foliar fertilizers in 2020/2021. In 2021/2022, Zn treatments, mainly at four nutrient levels tended to increase the yields of both varieties. The first treatment resulted in a grain yield reduction of 3% for GK Pilis, and the second treatment resulted in a grain yield reduction of 1.2% for Zvezdana. After the second and third treatments, grain yield reductions were 0.1%–0.5%. Although there was no significant difference in terms of the main averages, foliar fertilizer was found to be effective in the second year. The relationship between chlorophyll and grain yield was found to depend on the year and variety. A weak correlation (r = 0.33, p < 0.05) was found between the total chlorophyll concentration in leaves for Zvezdana in 2021, and a medium correlation for GK Pilis (r = 0.67, p < 0.05). Concerning grain yield and chlorophyll concentration, a strong correlation (r = 0.81, p < 0.05) was found for Zvezdana in 2022, and a weak correlation (r = 0.44, p < 0.05) for GK Pilis. A strong correlation was found between the total leaf chlorophyll concentration and SPAD index in both years (r = 0.81, p < 0.05)

The Interaction of Fungicide and Nitrogen for Aboveground Biomass from Flag Leaf Emergence and Grain Yield Generation under Tan Spot Infection in Wheat

Pyrenophora tritici-repentis (Died.) Drechs., the causal agent of tan spot, is one of the most serious biotic diseases affecting wheat worldwide (Triticum aestivum L.). Studying the interaction between different fungicide mixtures and nitrogen (N) rates under tan spot outbreaks is of key importance for reducing aboveground biomass and grain yield losses. Taking this into account, our study took a mechanistic approach to estimating the combined effect of different fungicides and N fertilization schemes on the severity of tan spot, green leaf area index, SPAD index, aboveground biomass dynamics, and yield in a wheat crop affected at the reproductive stage. Our results indicated that reductions in green leaf area, healthy area duration (HAD), and the chlorophyll concentration (SPAD index) due to increases in the percentage of damage led to decreases in biomass production (-19.2%) and grain yield (-48.1%). Fungicides containing triazole + strobilurin + carboxamides (TSC) or triazole + strobilurin (TS) combined with high N doses showed the most efficient disease control. The positive physiological effects of TSC fungicides, such as extending the green leaf area, are probably responsible for the greater production of aboveground biomass (+29.3%), as well as the positive effects on grain yield (+15.8%) with respect to TS. Both fungicide treatments increased grains per spike, kernel weight, spikes m-2, grains m-2, and grain yield. The increase in biomass in the TSC tended to cause slighter non-significant increases in grains per spike, 1000-kernel weight and grain yield compared with TS. The linear regression revealed positive associations among the extension of HAD and biomass (+5.88 g.m-2.HAD-1.day-1), grain yield (+38 kg.ha.HAD-1.day-1), and grain number (100.7 grains m2.HAD-1.day-1), explained by the interactions of high N doses and fungicides. Our study is the first report of the positive effect of TSC fungicides with high N doses on grain yield related-traits under tan spot infections in wheat.

Shifting sensitivity of septoria tritici blotch compromises field performance and yield of main fungicides in Europe.

Septoria tritici blotch (STB; Zymoseptoria tritici) is a severe leaf disease on wheat in Northern Europe. Fungicide resistance in the populations of Z. tritici is increasingly challenging future control options. Twenty-five field trials were carried out in nine countries across Europe from 2019 to 2021 to investigate the efficacy of specific DMI and SDHI fungicides against STB. During the test period, two single DMIs (prothioconazole and mefentrifluconazole) and four different SDHIs (fluxapyroxad, bixafen, benzovindiflupyr and fluopyram) along with different co-formulations of DMIs and SDHIs applied at flag leaf emergence were tested. Across all countries, significant differences in azole performances against STB were seen; prothioconazole was outperformed in all countries by mefentrifluconazole. The effects also varied substantially between the SDHIs, with fluxapyroxad providing the best efficacy overall, while the performance of fluopyram was inferior to other SDHIs. In Ireland and the UK, the efficacy of SDHIs was significantly lower compared with results from continental Europe. This reduction in performances from both DMIs and SDHIs was reflected in yield responses and also linked to decreased sensitivity of Z. tritici isolates measured as EC50 values. A clear and significant gradient in EC50 values was seen across Europe. The lower sensitivity to SDHIs in Ireland and the UK was coincident with the prevalence of SDH-C-alterations T79N, N86S, and sporadically of H152R. The isolates' sensitivity to SDHIs showed a clear cross-resistance between fluxapyroxad, bixafen, benzovindiflupyr and fluopyram, although the links with the latter were less apparent. Co-formulations of DMIs + SDHIs performed well in all trials conducted in 2021. Only minor differences were seen between fluxapyroxad + mefentrifluconazole and bixafen + fluopyram + prothioconazole; the combination of benzovindiflupyr + prothioconazole gave an inferior performance at some sites. Fenpicoxamid performed in line with the most effective co-formulations. This investigation shows a clear link between reduced field efficacy by solo SDHIs as a result of increasing problems with sensitivity shifting and the selection of several SDH-C mutations. The presented data stress the need to practice anti-resistance strategies to delay further erosion of fungicide efficacy.

Microbial Diversity in Four Rhizocompartments (Bulk Soil, Rhizosphere, Rhizoplane, and Endosphere) of Four Winter Wheat Varieties at the Fully Emerged Flag Leaf Growth Stage.

Community composition and recruitment are important elements of plant-microbe interactions and may provide insights for plant development and resilience. The results of 16S rRNA amplicon sequencing from four rhizocompartments for four wheat cultivars grown under controlled conditions and sampled after flag leaf emergence are provided. Data demonstrate differences in microbial communities according to rhizocompartment.

Recovery of Grain Yield and Protein with Fertilizer Application Post Nitrogen Stress in Winter Wheat (Triticum aestivum L.)

Unfavorable weather conditions and lack of appropriate farm machinery often delay N application. This results in nitrogen (N) deficiency during the vegetative and early reproductive growth stages of winter wheat. The objective of this study was to evaluate the impact of N application timings (from tillering to flag leaf growth stages) on winter wheat grain yield and protein. The study was conducted across 12 site–years in Oklahoma, US. The treatments included a non-fertilized check, a pre-plant application of 100 kg N ha−1, and ten in-season application timings at 100 kg of N ha−1. The in-season treatment applications were initiated at the point when an N deficiency was visually identified by comparing the pre-plant treatment to the non-fertilized check. The treatments were applied in a progressive order every seven growing degree days (GDD > 0 °C) until a cumulative GDD of 63 was reached after visual deficiency (DAVD). All in-season treatments increased grain yield and protein as compared to the non-fertilized check, showing that N was a yield-limiting factor. The nitrogen applications made post Feekes 8 decreased grain yield when compared to pre-plant applications. Across this data set, that timing corresponded to a range of 21 to 63DAVD. The results suggested that forgoing N application until the growth stage Feekes 7, even when the visual N deficiency was highly apparent before that stage, had no negative impact on the yield, and it even increased the yield as compared to the pre-plant application in some cases. The plant developmental stage at which the N application takes place is more critical than the level of N deficiency. Our results show that N fertilizer applications should be made posteriorly to the crop dormancy to maximize both yield and protein, and that plants can recover from N deficiency when applications are made until the late-vegetative phase (Feekes 7). This document shows that winter wheat producers have a much wider N application window than traditionally believed.

Effect of malt barley varieties and nitrogen levels on crop phenology, PAR interception, GDD, RUE and thermal use efficiency under saline water irrigation

Barley is one of the most salt tolerant crops and can be adopted in a condition where the irrigation quality of the water is saline in nature. Due to uncertainty of rainfall and scarcity of water, farmers of Haryana often irrigate the crops with poor quality water and this situation is likely to become more alarming with the depleting water resources. Therefore, an experiment was conducted at CCS Haryana Agricultural University, Hisar during rabi seasons of 2017-18 and 2018-19 to evaluate the effect of different malt barley varieties and nitrogen levels on crop phenology, PAR interception, GDD, radiation use efficiency and thermal use efficiency. The experiment was laid out in split plot design by keeping four varieties (BH 902, BH 946, BH 885 and DWRB 101) in main plots and four nitrogen levels (0, 30, 60 and 90 kg/ha) in sub plots with four replications. Variety BH 902 recorded significantly higher grain yield and took maximum number of days for flag leaf emergence, spike initiation and physiological maturity than variety BH 946, BH 885 and DWRB 101, respectively. Highest GDD, radiation use efficiency and thermal use efficiency was recorded by variety BH 946 which was statistical at par with DWRB 101 and significantly higher than BH 902 and BH 885. Application of 90 kg N/ha took maximum number of days for flag leaf emergence, spike initiation and physiological maturity as well as recorded higher GDD, radiation use efficiency and thermal use efficiency as compared to 0, 30 and 60 kg N/ha.

Macroscopic and Microscopic Phenotyping Using Diverse Yellow Rust Races Increased the Resolution of Seedling and Adult Plant Resistance in Wheat Breeding Lines

We characterized yellow rust (YR) resistance in sixteen winter wheat breeding lines using three different pathogen races and macroscopic and microscopic phenotyping in lab and greenhouse. Three rust races were used on seedlings and two races on fifth and flag leaf growth stages. The wheat lines were previously characterized to possess none or different quantitative trait loci for YR resistance in field trials. At the seedling stage, twelve lines showed race-specific seedling resistance whereas four lines gave strong seedling resistance to all three races. Seven of eight lines with QTL.1B showed strong seedling resistance against the two races also used at fifth and flag leaves. Microscopic phenotyping of line NOS50906215 (QTL.1B) showed small fungal colonies stopped within 3 dpi associated with extensive hypersensitive response (HR). The lines NOS51014910 and NOS51014911 (QTL.3D alone) showed strong adult plant resistance (APR) from the fifth leaf stage. The lines NOS70140801 and NOS70140808 (QTL.3D + 7B) showed strong APR to one race but partial resistance to the other race at all growth stages. Microscopic phenotyping of line NOS70140801 (QTL.3D + 7B) showed more fungal growth and less HR against the race revealing strong APR compared to the one revealing partial resistance. Line NOS51010312 (QTL.7B alone) showed strong APR response against both races whereas line NOS51010313 (QTL.7B) was susceptible. A partial APR response was observed on line NOS51005019 (no QTLs reported). In conclusion, the approach of combining macroscopic and microscopic phenotyping and diverse pathogen races facilitates the identification of multiple and diverse seedling and adult plant resistance responses to yellow rust in wheat.

Diversity and Structure of Bacterial Communities in Different Rhizocompartments (Rhizoplane, Rhizosphere, and Bulk) at Flag Leaf Emergence in Four Winter Wheat Varieties

ABSTRACTUnderstanding basic interactions at the plant-soil interphase is critical if we are to exploit natural microbial communities for improved crop resilience. We report here 16S amplicon sequencing data from 3 rhizocompartments of 4 wheat cultivars grown under controlled greenhouse conditions. We observed that rhizocompartments and cultivar affect the community composition.

Efficacy of spot form of net blotch suppression in barley from seed, fertiliser and foliar applied fungicides

Spot form of net blotch (SFNB), caused by Pyrenophora teres f. maculata is a prevalent and damaging foliar disease of barley (Hordeum vulgare). Fungicides are commonly used to manage SFNB infection and reduce production loss in susceptible varieties. This study determined the efficacy of suppression of SFNB and associated grain yield and quality improvements from application of fungicides to seed, fertiliser and/or foliar treatments. Eight field experiments were conducted in south-eastern Australia during 2016–2018. Two experiments compared single applications of different commercially available seed, fertiliser and foliar fungicides. Six experiments evaluated different growth stage application timings of either a single application or combinations of seed applied fluxapyroxad and foliar applied prothioconazole + tebuconazole. Spot form of net blotch caused grain yield loss of up to 1.2 t/ha (20%), reduced grain retention (percentage seed width greater than 2.5 mm) and weight by up to 15% and 13%, respectively, and increased screenings (percentage seed width less than 2.2 mm) by up to 18%. Seed applied fluxapyroxad was the most effective fungicide treatment providing the greatest SFNB suppression, grain yield and quality increase of the single fungicide applications. The combination of seed applied fluxapyroxad with a foliar application of prothioconazole + tebuconazole at flag leaf emergence significantly increased grain yield and quality further in one experiment. The dual foliar fungicide application of prothioconazole + tebuconazole at stem elongation (Z31) and flag leaf emergence (Z39) was not as effective in providing SFNB suppression according to AUDPC but provided comparable grain yield and quality to the seed and foliar treatment. Of the foliar fungicides, prothioconazole + tebuconazole and bixafen + prothioconazole provided the best SFNB suppression, grain yield and quality. These fungicide applications strategies provide improved SFNB management options for barley growers, particularly in high yielding crops where grain yield exceeds 5 t/ha.

Metabolic and film antitranspirants both reduce drought damage to wheat yield despite having contrasting effects on leaf ABA

AbstractFilm antitranspirants (e.g. di‐1‐p‐menthene) and metabolic antitranspirants (e.g. exogenous ABA) can be used to protect grain crops from drought, particularly during reproductive development. Here, we compared effects of di‐1‐p‐menthene (1.0 L/ha) and exogenous ABA (100 µM) on well‐watered and droughted spring wheat in two glasshouse experiments. Progressive drought was imposed in the first experiment, controlled drought in the second, both from flag leaf emergence. Antitranspirants were applied at flag leaf emergence, except in the controlled drought experiment where additional ABA applications were made at four further stages up to anthesis‐complete. Measurements were taken for endogenous ABA, stomatal conductance and photosynthesis during reproductive development, and yield components at maturity. Both progressive and controlled drought elevated leaf ABA, less so in di‐1‐p‐menthene‐treated plants, whereas in exogenous ABA‐treated plants leaf ABA was elevated further. Overall, both antitranspirants improved yield under reproductive‐stage drought, more so for controlled drought. Grain yield was negatively associated with reproductive‐stage leaf ABA concentration except that raising leaf ABA concentration with multiple exogenous ABA applications was associated with high yield. In conclusion, both antitranspirants generally reduced effects of reproductive‐stage drought on yield despite having contrary effects on leaf ABA.

Growth response and water production functions of wheat (Triticumaestivum L.) under abiotic stresses in central and south-western Punjab

A field experiment was conducted in two agroclimatic zones of the Punjab (viz., Ludhiana representing central plain zone and Bathinda representing south-western arid zone) to study the growth, yield and water use efficiency of wheat under abiotic stresses. The wheat variety HD-2967 was evaluated under five thermal environments (D1 - 20th October, D2 - 05th November, D3 - 20th November, D4 - 5th December and D5 - 20th December) to expose the crop to different thermal environments and two nitrogen levels (N1- Recommended dose of N and N2 - 25 per cent less than recommended N) in main plots and two irrigation levels (I1-Optimal (recommended) irrigation (Irrigation at CRI, Jointing, Flowering and Soft dough stage) and I2-Sub-optimal irrigation (one irrigation less than recommended) (Irrigation at CRI, Flag leaf emergence and Soft dough stage) in sub-plots during two consecutive rabi seasons of 2017-18 and 2018-19. At 45 DAS; number of tillers/m2, plant height, dry matter accumulation and leaf area index in 20th October sown crop was significantly higher than other dates of sowing at both the stations during both the years. But at the time of harvesting, tiller count and plant height was highest under 5th November sown crop, whereas dry matter accumulation and leaf area index was significantly highest under 20th October sown crop. Yield and yield attributes were significantly highest under 5th November and significantly lowest under 20th December sown crop. Wheat crop exhibited significantly highest WUE w.r.t. straw and grain yield in 5th November sowing (D2) which was at par with that under 20th October sowing and significantly lowest water use efficiency was observed under 20th December (D5) sown crop at both the locations during both crop seasons. Recommended dose of nitrogen and optimal irrigation also produced significantly higher WUE at both the locations during both the years. The study concluded that earlier sowing of wheat along with recommended nitrogen and optimal irrigation can significantly improve growth and yield attributes as well as water use efficiency in both the agroclimatic regions.

Improving heat use efficiency of wheat (Triticumaestivum L.) under abiotic stresses in semi-arid and arid agroclimatic conditions of Punjab

A field experiment was conducted in two agroclimatic zones of the Punjab (viz., Ludhiana representing semi-arid and Bathinda representing arid zone) to study the phenologicalbehaviour and heat use efficiency of wheat under abiotic stresses. The wheat variety HD-2967 was evaluated under five thermal environments (D1- 20th October, D2-5th November, D3- 20th November, D4- 5th December and D5- 20th December) to expose the crop to different thermal environments and two nitrogen levels (N1- Recommended dose of N and N2- 25 per cent less than recommended N) in main plots and two irrigation levels (I1 - Optimal (recommended) irrigation (Irrigation at CRI, Jointing, Flowering and Soft dough stage) and I2 - Sub-optimal irrigation (one irrigation less than recommended) (Irrigation at CRI, Flag leaf emergence and Soft dough stage) in sub-plots during two consecutive rabi seasons of 2017-18 and 2018-19. It was found that the wheat crop sown in semi-arid zone i.e., Ludhiana took more number of days to reach physiological maturity. The number of days required to attain different phenological stages decreased with delayed sowing at both the locations. The crop utilized heat more efficiently in the arid zone i.e., Bathinda. At Ludhiana, highest HUE was observed in the crop sown on 20th November (3.08 kg/ha/°C/day) and 5th November (3.18 kg/ha/°C/day) during 2017-18 and 2018-19, respectively; whereas at Bathinda, HUE was highest in the crop sown on 5th November (3.31 and 3.32 kg/ha/°C/day) during both the years. Recommended dose of nitrogen and optimal irrigation also produced significantly higher HUE at both the locations during both the years. The study concluded that timely sowing of the crop along with recommended nitrogen and optimal irrigation can significantly improve efficiency of heat utilisation both in semi-arid and arid agroclimatic conditions.

Comparative analysis of the efficacy of selected gametocide agents in sorghum (Sorghum bicolor [L.] Moench)

A new generation of chemical hybridization agents (CHAs) or gametocides has shown potential to induce male sterility in predominantly self-fertilizing crops, including sorghum (Sorghum bicolor [L.] Moench). There is a lack of information on the relative efficacy of the various available CHAs for large-scale application in plant breeding programs. Therefore, the objective of the present study was to compare the relative effectiveness of three selected CHAs to induce male sterility in sorghum under a controlled environment for hybridization. Foliar applications of three CHAs and a control (ethrel, trifluoromethanesulfonamide [TFMSA], ethyl 4-fluorooxanilate [E4FO] and distilled water [control]) were tested using three grain sorghum genotypes (ICS-1, ICS-2 and ICS-3) in two seasons. The 24 treatment combinations consisting of 4 levels of CHAs, 3 sorghum varieties and two seasons were laid out using a randomized complete block design with three replications. Data on pollen sterility, pollen diameter, plant height, and panicle height were collected and analyzed. Results showed that the CHAs had significant (p<0.05) differences for efficacy of inducing male sterility in sorghum. Ethrel at a dose of 1 gl-1 induced the highest pollen sterility (98% in both seasons) but was highly phytotoxic with at least 60% mortality in the test population in both seasons, making it unsuitable for practical application. TFMSA (2 mg per plant) and E4FO (1 gl-1) d induced 93% male sterility with minimal phytotoxic effects (20 to 30%). Application of either TFMSA at 2mg per plant after flag leaf emergence or 1gl-1 of E4FO at panicle initiation can be used to successfully induce male sterility in sorghum under greenhouse conditions

Winter Crop Growth Monitoring using Multi-Temporal NDVI Profiles in Kapadvanj Taluka, Gujarat State

In the present study on winter crop growth monitoring in different villages in Kapadvanj Taluka of Kheda district was carried out using multi-temporal Sentinel-2 multi-spectral data (spatial resolution 10-m). Multi-temporal Sentinel-2 data covering study area for the winter crop period from November-2018 to March-2019 was downloaded from https://earthexplorer.usgs.gov/. The major objective of this study was to monitor site-specific crop growth in different villages of Kapadvanj Taluka by generating Normalized Difference Vegetation Index (NDVI) profiles of major winter crops. The spectral behavior of wheat, potato, bajara and castor crops during active growth stages was studied and it was observed that the spectral response of wheat and potato crops have quite distinct spectral behavior. However, castor and bajara crops do not show distinct spectral behavior. In this study, from the NDVI profiles of different crops it was observed that very distinct growth stages like early growth stage to flag leaf emergence which correspondence to rising of NDVI, followed by flag leaf emergence to flowering and grain filling stages which corresponds to maximum NDVI and finally physiological maturity stages corresponding to declining of NDVI of all the winter crops.

Selenium effect on wheat grain yield and quality applied in different growth stages

Small field plot experiments were carried out at the testing station of the Central Control and Testing Institute in Agriculture in Veľký Meder (Slovakia) in the experimental years 2014/2015, 2015/2016 and 2016/2017. Selenium salts in the form of sodium selenite and sodium selenate were applied in growth phases: end of tillering (BBCH 29) and flag leaf ligule and collar visible (BBCH 39). The effect of experimental years 2014/2015, 2015/2016 and 2016/2017 on the yield of wheat grain was not statistically significant within the observed variants. The achieved mean yields were in the range from 10.06 ± 0.81 to 11.07 ± 0.29 t/ha in 2014/2015, from 9.82 ± 0.54 to 10.32 ± 0.10 t/hain 2015/2016 and from 11.23 ± 0.76 to 11.64 ± 0.51 t/ha in 2016/2017. Selenate in comparison with selenite influenced the selenium accumulation in wheat grains more positively. However, a significant difference was recorded in variants with selenite application in the flag leaf growth phase in comparison with the end of tillering phase. The influence on the content of macroelements P, K, Ca and microelements Cu and Fe was observed in sodium selenite only; its application decreased the element content in comparison with the control variant. Statistically significantly higher values of fiber and fat were achieved after application of selenium in the flag leaf growth stage in comparison with the end of tillering.

Spectral Response of Winter Crops Using Multi-temporal Sentinel-2 MSI Data in Visnagar Taluka, Gujarat State

Developing Countries like India has more than half of the population engaged in fishery, agriculture etc. and agriculture drives the economy of the Nation. Traditional survey methods are tedious and time consuming, however, with advancement in Remote Sensing Technology data for Agriculture monitoring can be obtained at local and regional scale. The present study demonstrates the use of multi-year multi-date Sentinel-2 MSI data for winter crop monitoring in in Visnagar taluka Mahesansa district of Gujarat state. Multi-temporal Sentinel-2 data covering study area for the winter crop period from November-2018 to March-2019 was downloaded from https://earthexplorer.usgs.gov/ .The major objective of this study was to monitor site-specific crop growth in different villages of Visnagar Taluka by generating Normalized Difference Vegetation Index (NDVI) profiles of major winter crops. The spectral behavior of wheat, mustard, Fennel and castor crops during active growth stages was studied. The results indicated that different winter crops can be discriminated using the data during the early growth phases like flag-leaf emergence to flowering stages of these crops. Even it was observed that the spectral response of normal-sown and late-sown wheat crop have quite distinct spectral behavior as compared to other winter crops. In this study, the NDVI profiles of different winter crops indicated that Last week of January to first week of February, when all the winter crops were at grand growth stages of grain filling and grain-milk, pod formation (mustard & castor) stages have similar NDVI values, therefore during this period major winter crops in this region may not be possible to discriminate using single date satellite data.