Tillering Stage Research Articles

Productivity and nitrogen use efficiency of rice under conventional and organic nutrition

The current study demonstrates the influence of conventional and organic nutrient management practices on nitrogen use efficiency, growth, yield, and physiological and biochemical parameters in four rice varieties, namely, Jaiva, Ezhome 2, Jyothi and Uma. Growth parameters, grain yield per hill, and physiological and biochemical parameters were higher under conventional management for all rice varieties. Although the nitrogen use efficiency of each variety varied significantly with nutrient management practices, the variation was least in Jaiva (23.8%), which is the organic rice variety released by Kerala Agricultural University. The rice varieties Jaiva and Ezhome 2 showed consistency in the grain weight per panicle under both conventional (Jaiva- 4.57 g, Ezhome 2- 5.86 g) and organic (Jaiva, 4.24 g, Ezhome 2, 4.54 g) management. The soil nitrogen content at the tillering stage (0.66**) showed a significantly higher positive correlation with nitrogen use efficiency under organic management. The results of the study provide a better understanding of factors that can lead to a sustained yield in organic rice production in terms of nitrogen use efficiency.

Enhancing wheat production and quality in alkaline soil: a study on the effectiveness of foliar and soil applied zinc

Cultivation of high-yield varieties and unbalanced fertilization have induced micronutrient deficiency in soils worldwide. Zinc (Zn) is an essential nutrient for plant growth and its deficiency is most common in alkaline and calcareous soils. Therefore, this study aimed to evaluate the effect of Zn applied either alone or in combination with foliar application on the quality and production of wheat grown in alkaline soils. Zn was applied in the form of zinc sulfate (ZnSo4) to the soil and as a foliar spray during the sowing and tillering stages, respectively. Results showed that Zn fertilization of wheat, irrespective of modes of application, significantly increased grain and biological yield, grain per spike, and 1,000 grains weight over control; however, its effect was more noticeable when applied as 7.5 kg ha−1of soil Zn combined with foliar Zn at 2.5 kg ha−1. Zn application significantly increased the grain protein content from 9.40% in the control to a maximum of 11.83% at soil Zn of 10 kg ha−1. Similarly, Zn application improved Zn, phosphorus (P), and potassium (K) concentrations in wheat grains. Moreover, correlation analysis showed that the grain Zn concentration was positively correlated with the grain P concentration. The correlation between P concentration in wheat grains and 1,000 grain weight was not significant. A total of 1,000 grains weight was positively correlated with tillers per plant, grain yield, and biological yield. There were positive correlations between protein content, biological yield, grain yield, and tillers per plant. Therefore, soil-applied Zn + foliar application in alkaline soils with limited Zn availability is crucial for improving wheat yield and grain quality.

Mapping crop yield spatial variability using Sentinel-2 vegetation indices in Ethiopia

Crop yield prediction before harvest is a key issue in managing agricultural policies and making the best decisions for the future. Using remote sensing techniques in yield estimation studies is one of the important steps for many countries to reach their agricultural targets. However, crop yield estimates rely on labor-intensive surveys in Ethiopia. To solve this, we used Sentinel-2, crop canopy analyzer, and ground-truthing data to estimate grain yield (GY) and aboveground biomass (AGB) of two major crops, teff and finger millet, in 2020 and 2021 in Ethiopia’s Aba Gerima catchment. We performed a supervised classification of October Sentinel-2 images at the tillering stage. Among vegetation indices and leaf area index (LAI) used to predict teff and finger millet GY and AGB, the enhanced vegetation index (EVI) and normalized-difference VI (NDVI) provided the best fit to the data. NDVI and EVI most influenced teff AGB (R2 = 0.87; RMSE = 0.50 ton/ha) and GY (R2 = 0.84; RMSE = 0.14 ton/ha), and NDVI most influenced finger millet AGB (R2 = 0.87; RMSE = 0.98 ton/ha) and GY (R2 = 0.87; RMSE = 0.22 ton/ha). We found a close association between GY and AGB and the satellite EVI and NDVI. This demonstrates that satellite images can be employed in yield prediction studies. Our results show that satellite and crop canopy analyzer-based monitoring can facilitate the management of teff and finger millet to achieve high yields and more sustainable food production and environmental quality in the area. The results could be reproducible under similar study catchment conditions and boost crop yield. Extrapolation of the models to other areas requires local validation. To improve crop monitoring for farmers and reduce expenses, we suggest integrating time series Sentinel-2 images along with LAI obtained from crop canopy analyzers collected during the cropping season.

OPTIMIZATION OF WINTER WHEAT NUTRITION WITH ZERO TILLAGE TECHNOLOGY IN THE RAINFED ZONES OF SOUTHERN KAZAKHSTAN

The promising research showcased the results of herbicides’ uses, considering the quantitative composition of weeds with zero tillage technology of winter wheat cultivation. It revealed that when treating wheat seeds with the growth stimulator Vimpel (0.5 l/t) and micro-fertilization with Oracle (1.0 l/t) simultaneously etching with the fungicide Bunker (0.4 l/t), as well as, early spring treatment of crops in the tillering phase of winter wheat with the same stimulator (Vimpel, 0.5 l/ha) and micro-fertilization (Oracle multicomplex, 2.0 l/ha) simultaneous with the herbicide “Ballerina” (0.5 l/ha) application, the number of preserved plants before harvesting was 286.1 pcs./m2, reaching a height of 88.9 cm, with a productive bushiness of 1.15 pcs., grains per spike (22.2), 1000-grain weight (34.8 g), and collected dry grains at a standard humidity (22.1 c/ha). It was also evident that the competitive productivity of winter wheat also emerged when treating wheat seeds with biological fertilizer Biobars–M (1.0 l/t), the crop at the tillering stage with Biobars–M (0.5 l/ha), and the earring phase (0.7 l/ha). Similarly, using growth stimulants Vimpel and micronutrient Oracle multicomplex enhanced the grain yield with reduced cost of production (USD 61.3–66.0/kg) compared with the control version (USD 78.6 /kg). On one hectare of winter wheat crop, the net income ranged from USD 289.55 to 443.56.

Effect of Mowing on Wheat Growth at Seeding Stage.

Winter wheat is used as forage at the tillering stage in many countries; however, the regrowth pattern of wheat after mowing remains unclear. In this study, the growth patterns of wheat were revealed through cytological and physiological assessments as well as transcriptome sequencing. The results of agronomic traits and paraffin sections showed that the shoot growth rate increased, but root growth was inhibited after mowing. The submicroscopic structure revealed a decrease in heterochromatin in the tillering node cell and a change in mitochondrial shape in the tillering node and secondary root. Analysis of the transcriptome showed the number of differentially expressed genes (DEGs) involved in biological processes, cellular components, and molecular functions; 2492 upregulated DEGs and 1534 downregulated DEGs were identified. The results of the experimental study showed that mowing induced expression of DEGs in the phenylpropanoid biosynthesis pathway and increased the activity of PAL and 4CL. The upregulated DEGs in the starch and sucrose metabolism pathways and related enzyme activity alterations indicated that the sugar degradation rate increased. The DEGs in the nitrogen metabolism pathway biosynthesis of the amino acids, phenylpropanoid biosynthesis metabolism, and in the TCA pathway also changed after mowing. Hormone content and related gene expression was also altered in the tillering and secondary roots after mowing. When jasmonic acid and ethylene were used to treat the wheat after mowing, the regeneration rate increased, whereas abscisic acid inhibited regrowth. This study revealed the wheat growth patterns after mowing, which could lead to a better understanding of the development of dual-purpose wheat.

Identification of key responsive leaf physiochemical traits for ozone sensitivity in 16 Italian cultivars of Triticum durum subjected to peak concentrations

AbstractPlants of 16 Italian cultivars of durum wheat at the tillering stage were exposed to a single pulse of ozone (O3, 200 ppb, 5 h) to reveal the mechanisms explaining their O3 tolerance/sensitivity by considering some leaf physiochemical traits [e.g., stomatal conductance, photosystem II (PSII) efficiency, antioxidant enzyme activity, and phytohormone synthesis]. At the end of the recovery period (48 h from the beginning of the exposure), all cultivars showed visible foliar injury in the form of widespread chlorosis which developed in bifacial ivory necrotic lesions scattered among the leaf veins of completely expanded leaves. Mongibello leaves showed not only the highest severity of visible injury (McKinney index = 62%), but also a reduction of PSII performance (Fv/Fm ratio: −22% compared with controls) together with an activation of the dissipation of the excess excitation energy as heat (qNP: +35%). The photosynthetic impairment observed throughout the whole experiment, was likely due to stomatal limitations (gs: −36% as average) and indicated that this cultivar was very sensitive to a pulse of O3. Similar results were obtained for Latino and Meridiano. Conversely, Iride, Orobel, and Portorico showed the lowest severity of visible injury (McKinney index around 13%) suggesting that they could be considered tolerant to a pulse of O3. These cultivars showed none or only transient changes due to O3 in terms of photosynthetic activity (e.g., A values), while the slight decrease of Fv/Fm ratio did not determine the photoinhibition of the PSII activity, since mechanisms for dissipating excess excitation energy were being activated. Ozone treatment induced a significant reduction of CO2 assimilation rate (−34%) in Orobel and this is not attributable to stomatal and non‐stomatal limitations. The remaining cultivars were considered moderately sensitive to O3, with McKinney index in the range of 20–43%. The measured biochemical traits are not decisive in determining the O3 sensitivity. In particular, the activity of phenylalanine ammonia lyase increased only in seven cultivars; among them, only in Latino, Vetrodur, and Simeto, this enhancement reflected in an accumulation of phenolic compounds suggesting potential higher protection against reactive oxygen species. This work highlights the relevance of identifying O3‐sensitive cultivars, in the optic to develop sustainable strategies to mitigate the impact of peak O3 episodes on wheat production.

Effect of Foliar Application of Nutrients on Yield and Nutrient Uptake by Rice Crop

A field experiment was conducted during 2018 and 2019 at the Agronomy Research farm of A.N.D. University of Agriculture and Technology, Kumarganj, Ayodhya, UP to evaluate the effect of foliar application of macro and micronutrients on yield and nutrient uptake of rice (Oryza sativa L.). The experiment consists of 10 treatment combinations with some foliar application macro and micronutrients two foliar spray tillering stages and a panicle initiation stage which were laid out in randomized block design with three replications. The results revealed maximum grain yield (38.50 and 40.40 q ha-1), straw (51.90 and 54.60 q ha-1), and harvest index (42.64 and 42.53 %) with treatment T10-75% RDF + WSCF @ 0.5 % (19:19:19) + ZnSO4 @ 0.5 % + Boron @ 0.25 % which was statistically at par with T3- 125 % RDF and significantly superior over rest of the treatments during both the years ., was recorded Similarly significant improvement in nutrient uptake (N, P, K, S, Zn, and B) by rice was observed in T10. Thus, it can be concluded that the application of 75% RDF + WSCF @ 0.5 % (19:19:19) + ZnSO4 @ 0.5 % + Boron @ 0.25 % can improve the yield and nutrient uptake.

Performance of Integrated Nutrient Management and Foliar Spray of Micronutrients on Growth, Yield Attribute and Yield of Wheat (Triticum aestivum L.)

A field experiment was conducted during two rabi seasons of 2021-2022 and 2022-23 at Students’ Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology Kanpur, (U.P.) The experiment was caried out in SPD (Split Plot Design) with fifteen treatment combination were replication thrice. fifteen treatment treatments combination consisted of three organic manure + RDF nutrient source (Control (100% RDF), 100 % RDF + Vermicompost @ 2.5t/ha, and 100 % RDF + FYM @ 5t/ha) put under main plot and five foliar spray of micronutrient control (No spray),Foliar spray of ZnSO4 @ 0.25% at tillering and booting stages, Foliar spray of Nano Zinc @ 0.5% at tillering and booting stages, Foliar spray of FeSO4 @ 0.25% at tillering and booting stages and M5- Foliar spray of ZnSO4 @ 0.25% + FeSO4 @ 0.25% at tillering and booting stages) allotted under sub plot. The study on yield attribute and yield of wheat. The result showed that the maximum increase growth parameters, yield attribute and yield of wheat viz plant height (cm), number of tillers/m2, and leaf area index and number of grain/spike, number spike/m2, total grain weight spike (g) and test weight (1000 grain weight) (g) and grain yield (t/ha) and straw yield (t/ha) recorded significantly higher with F2- 100 % RDF + Vermicompost @ 2.5t/ha treatments. Among the sub plot, M5- foliar spray of ZnSO4 @ 0.25% + FeSO4 @ 0.25% at tillering and booting stages produced significantly maximum highest grain yield (5.95 t/ha) and straw yield (7.94 t/ha)

Effect of Integrated Nutrient Management and Agronomic Biofortification on Growth and Yield of Wheat (Triticum aestivum. L.)

A field experiment was conducted at Students’ Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology Kanpur, (U.P.) to assess the effect of organic source with foliar application of micronutrients on growth and yield of wheat for two consecutive years (2021-22) and (2022-23).The experiment comprises three treatment under main plot viz: F1- Control (100% RDF), F2- 100 % RDF + Vermicompost @ 2.5t/ha, and F3- 100 % RDF + FYM @ 5t/ha, and five treatments foliar spray of micronutrient in sub plot viz: M1- control (No spray), M2- Foliar spray of ZnSO4 @ 0.25% at tillering and booting stages, M3- Foliar spray of Nano Zinc @ 0.5% spray at tillering and booting stages, M4- Foliar spray of FeSO4 @ 0.25% at tillering and booting stages and M5- Foliar spray of ZnSO4 @ 0.25% + FeSO4 @ 0.25% at tillering and booting stages. Fifteen treatment combination were assigned under Split Plot Design (SPD) and replicated thrice. Wheat variety (K- 1006) was grown with the recommended agronomic practices. Results showed that maximum increase in growth parameters and yield and yield attribute of wheat viz: plant height (cm), number of tillers/m2, leaf area index and spike length (cm), number of spikelets /spike and harvest index (%) and biological yield (ton ha-) recorded significantly higher with F2- 100 % RDF + Vermicompost @ 2.5t/ha treatments Among the sub-plot , M5- Foliar spray of ZnSO4 @ 0.25% + FeSO4 @ 0.25% at tillering and booting stages, produced significant maximum highest harvest index (42.77 %) and biological yield (13.88 ton /ha) as compared to all other treatments.

Canopy Structure, Light Intensity, Temperature and Photosynthetic Performance of Winter Wheat under Different Irrigation Conditions.

A high-quality canopy architecture is central to obtaining high crop yields. A field experiment was carried out at the Wuqiao Experimental Station from 2015 to 2019 under four irrigation schemes (W0, no irrigation after sowing; W1, 75 mm irrigation at jointing stage; W2, 75 mm irrigation at jointing and anthesis stages, respectively; W3, 75 mm irrigation at tillering, jointing and anthesis stages, respectively) to investigate the canopy structure, canopy apparent photosynthesis (CAP), canopy temperature (CT), yield and water use efficiency (WUE). The results showed that increasing irrigation times improved the leaf area index (LAI), non-leaf area index (NLAI) and light interception (LI) of the spike and total canopy but decreased the canopy temperature (CT) after anthesis. The CAP in the W3 treatment was consistently lower than that in the W1 treatment, suggesting lower effective utilization of light energy under the W3 treatment. Increasing irrigation times improved wheat yield, but the W2 treatment had no significant difference in yield compared to the W3 treatment. In addition, the W1 and W2 treatments had higher WUEs. The CT, organ temperature and LI were closely positively associated with each other, but they were all strongly negatively related to the yield. Overall, the W2 treatment was the best irrigation scheme for constructing a reasonable canopy architecture for winter wheat, obtaining more efficient water use and yield in the North China Plain (NCP). CT and organ temperature can be used as proxy parameters to estimate the canopy structure.

Barley (Hordeum vulgare L.) photosynthetic and water use efficiency response to dairy‐amended biochar

AbstractBarley (Hordeum vulgare L.) was grown in a greenhouse under a combination of treatments that tested the effects of two types of biochar amended with fermentation solids and dairy lagoon effluent at high and low levels of phosphorus fertilization. We hypothesized that a modified biochar dosed with iron in combination with a dairy amendment would yield the greatest photosynthetic assimilation rates of CO2 and water use efficiency. Furthermore, we hypothesized that these rates may differ between photosynthate demand represented by plant developmental stages, specifically the tillering, stem elongation, and heading stages. We found that photosynthetic assimilation was greatest at the tillering stage. Plant water use efficiency increased with commercially available fertilizer. Plant biomass at harvest was greatest among the chemical fertilizer (high and low levels of phosphorus fertilization) and low‐level fertilization of dairy lagoon, fermentation solid, and an iron dosed biochar. The results suggest that while the dairy‐amended biochar can maintain plant growth, it is not necessarily achieved through improved photosynthesis or water use.

Synthetic auxin herbicides do not injure intermediate wheatgrass or affect grain yield

AbstractIntermediate wheatgrass (IWG) is a cool-season perennial grass developed as a dual-purpose grain and forage crop. One barrier to adopting this crop is a lack of information on the effects of herbicides on IWG for grain production. An experiment was conducted to evaluate herbicide effects on IWG grain yield, crop injury, and weed control over 2 yr (2019 to 2021) at sites in Wisconsin, Minnesota, New York, and North Dakota. This evaluation included broadleaf herbicides registered for use on wheat: 2,4-D amine, clopyralid, MCPA, and a mixture of clopyralid + MCPA (all are categorized as Group 4 herbicides by the Weed Science Society of America). Each herbicide or mixture was applied at 1× and 2× the labeled wheat application rate to newly planted and established (1- to 5-yr-old) IWG stands in the fall or spring. Herbicides were applied during IWG tillering or jointing stages in the fall or during the jointing stage in the spring. Across site years, application timing, herbicide, and application rate showed no effect on IWG grain yield or plant injury. Broadleaf weed control ranged from 71% to 92% across herbicide treatments relative to the nontreated check at the Wisconsin site, whereas weed control at the Minnesota site was variable among treatments. At the New York site, herbicides were equally effective for broadleaf weed suppression, whereas weed pressure was very low at the North Dakota site and treatments did not affect weed cover. The results show that newly planted and established stands of IWG are tolerant to the synthetic auxin herbicides 2,4-D amine, clopyralid, and MCPA when applied during tillering or jointing in the fall or during jointing in the spring. Synthetic auxins represent a potentially useful tool for weed control in IWG cropping systems, especially for problematic broadleaf weed species.

Assessing the yield difference of double-cropping rice in South China driven by radiation use efficiency

Double-cropping rice in South China continues to break the total yield record, but the yield potential of single-cropping rice is not being realized. Radiation use efficiency (RUE) has been singled out as an important determinant of grain yield in many cereal species. However, there is no information on whether the yield gaps in double-cropping rice involve differences in RUE. Field experiments were performed over two years to evaluate the effects of intercepted radiation (IP) and RUE on the above-ground biomass production, crop growth rate (CGR), and harvest index (HI), in four representative rice varieties, i.e., Xiangyaxiangzhan (XYXZ), Meixiangzhan 2 (MXZ2), Nanjingxiangzhan (NJXZ), and Ruanhuayoujinsi (RHYJS), during the early and late seasons of rice cultivation in South China. The results revealed that grain yield in the early season was 8.2% higher than in the late season. The yield advantage in the early season was primarily due to higher spikelets per panicle and above-ground biomass resulting from a higher RUE. The spikelets per panicle in the early season were 6.5, 8.3, 6.9, and 8.5% higher in XYXZ, MXZ2, NJXZ, and RHYJS, respectively, than in the late season. The higher early season grain yield was more closely related to RUE in the middle tillering stage (R2=0.34), panicle initiation (R2=0.16), and maturation stage (R2=0.28), and the intercepted photosynthetically active radiation (IPAR) in the maturation stage (R2=0.28), while the late season grain yield was more dependent on IPAR in the middle tillering stage (R2=0.31) and IPAR at panicle initiation (R2=0.23). The results of this study conclusively show that higher RUE contributes to the yield progress of early season rice, while the yield improvement of late season rice is attributed to higher radiation during the early reproductive stage. Rationally allocating the RUE of double-cropping rice with high RUE varieties or adjustments of the sowing period merits further study.

Impact of foliar applied nano-urea on growth, productivity and profitability of hybrid rice (Oryza sativa L.)

In lowland rice cultivation, the application of conventional urea fertilizer provides low N to rice plants and exhibits low N use efficiency (~ 30%) due to greater loss of N. Hence the present study hypothesized that nano-urea spray could fulfil N requirement of rice plants and thereby produce high yields. So, a field experiment was conducted on hybrid rice (cv. Arize-6444 Gold) at Regional Research Sub-Station, BCKV, Chakdaha, Nadia under new alluvial zone (NAZ) of West Bengal during winter (rabi) season of 2021-22 to assess the effect of nano-urea on growth attributes, yield components, yield, nutrient uptake and economics of hybrid rice.The experiment was laid out in randomized complete block design with six treatments [T1:100% RDN i.e. 150 kg ha-1 through urea, T2:100% N(Urea) + 2 foliar spray of nano-urea, T3:75% N (Urea) + 2 foliar spray of nano-urea, T4:50% N(Urea) + 2 foliar spray of nano-urea, T5:125% N (Urea) + 2 foliar spray of nano-urea, T6:Control], each replicated four times. All the treatments were consisted of a uniform recommended dose of 100% P and K (each of 80 kg ha-1) supplied through SSP and MOP, respectively, except for T6 (control). In each treatment, foliar spray was done with IFFCO nano-urea @ 4ml litre-1 of water twice at active tillering stage and panicle initiation stage. Results of the present experiment revealed that growth parameters of tested hybrid rice namely plant height, LAI, dry matter accumulation and crop growth rate registered better result under treatment T2 than other treatments. As expected, the above-mentioned growth attributes were lowest on receiving T6 treatment at almost all dates of observation. Among yield attributes of hybrid rice, number of panicles m-2(392), panicle length (32.46 cm) and panicle weight (5.58 g) were highest with treatment T5, while filled grains panicle-1(194) and 1000-grain weight (24.18 g) were maximum for T2 treatment. Highest grain yield (7.15 t ha-1) and HI (50.71%) of hybrid rice were obtained with T2 treatment, while the highest straw yield (7.20 t ha-1) was obtained with T5 treatment. The treatment T2 resulted in highest grain N (1.48%) and K (0.21%) content. Total cost of cultivation was highest in T5 (Rs. 77712 ha-1), but net return (Rs. 43720 ha-1) as well as B:C ratio (1.57) was highest for T2 treatment. Hence, the application of 100% RDN in conjunction with nano-urea spray twice at 25 and 50 DAT has been effective for higher productivity and profitability of hybrid rice cultivation.

Phenotypic Analysis and Gene Cloning of a New Allelic Mutant of SPL5 in Rice

This study was conducted on the lesion-mimic mutant lm5, which was produced by mutagenesis of WYJ21 (WT) using ethyl methane sulfonate (EMS). The mutant lm5 was short in the seedling stage and displayed yellowish-brown disease-like spots on leaves that were yellowish-brown when the plant was at the tillering stage. The disease-like spots gradually grew larger as the plant grew until it reached maturity. Compared to WT, lm5 had considerably reduced the plant height, ear panicle length, tiller number, and 1000-grain weight. A single recessive gene was found to be in control of lm5, according to a genetic study. It was physically located 245 kb apart between the RM21160 and RM180 markers on chromosome 7. Using RiceData and other websites, analyze and sequence potential gene candidates. Exon 7 of LOC_Os07g10390 (OsLM5) was identified to have a mutation that changed the 1560 base from G to A, changing the 788 amino acids from Arg to Lys. The OsLM5 gene was found to be a new allele of the SPL5 gene, encoding the protein shear factor SF3b3. Studies showed that OsLM5 was localized in the nucleus, and OsLM5 was significantly expressed in leaves. Reactive oxygen species (ROS) accumulation occurred in the leaves and roots of mutant lm5, and qPCR results showed abnormal expression of genes related to chloroplast development as well as significantly increased expression of genes related to aging and disease course. The OsLM5 gene may have a significant impact on the regulation of apoptosis in rice cells.

Interactive Effect of Elevated Carbon Dioxide, Temperature and Nitrogen on the Growth Parameters of Rice at Active Tillering Stage

Ever since industrialization began, carbon dioxide [CO2] concentration in the atmosphere got increased and it consecutively raised the temperature. This change in climate would affect the agricultural production and crop growth. A pot culture experiment was conducted during the Kuruvai season (June - September) of the year 2023 at Anbil Dharmalingam Agricultural College & Research Institute, Tiruchirappalli to assess the rice growth up to active tillering stage under elevated [CO2] and temperature conditions at different doses of nitrogen (N) fertilization. Rice seedlings were grown inside the four Open Top Chambers (OTC) at ambient (422 ppm) and elevated CO2 (550 ppm) conditions as well as chamber controlled and elevated temperature (+2°C) with four different doses of N (control, 100% recommended dose of N (RDN), 150% RDN and 200% RDN). Plant growth parameters like plant height, number of tillers, leaf area, root length and root volume, root and shoot dry matter were increased significantly under elevated [CO2] (eCO2) conditions. Whereas, all the growth parameters were severely influenced by increased temperature. Increasing N concentration increased the plant growth irrespective of the treatments and the effect was more pronounced in eCO2 treatment due to the fertilization effect of [CO2] as it directly necessitates photosynthesis which improves overall growth of rice plants. Under the future changing climatic conditions suitable N doses should be optimized for the better crop production.

Large-scale RNAseq analysis provide a new insight into the critical genes and regulatory networks of tiller development mediated by gibberellin in sugarcane

Tillering plays a key role in sugarcane growth, development, and cane yield. Gibberellin (GA) and its biosynthesis inhibitor, paclobutrazol, have been used to manipulate the tiller production in sugarcane planting. However, the key genes and regulatory networks of sugarcane tiller development remain unclear. In this study, we applied GA3 and paclobutrazol to soak the sugarcane seeds for generating samples with varying tiller numbers. A total of 54 samples from multiple tissues of three tillering stages were employed for transcriptome sequencing using two full-length transcript isoform sequences datasets as reference. We observed significant downregulation of two genes within the GA metabolism pathway in response to the GA synthesis inhibitor. Additionally, we noted a substantial enrichment of genes associated with photosynthesis following treatment with GA3 or paclobutrazol. Using all the differentially expressed genes (DEGs) between each sample group, 41 gene modules were generated in the coexpression network. The associations between modules and traits were performed. The Gene Ontology (GO) enrichment, KEGG pathway enrichment, and hub genes analysis were implemented in the modules correlated with traits, especially, the modules correlated with GA3 content and tiller number were emphasized. Notably, the pathway of ubiquitin-mediated proteolysis were enriched in both the GA3 content positive correlated module and the tiller number negative correlated module, while an E3 ubiquitin ligase gene, RZFP34, was the top hub gene in these two modules, indicating the vital role of ubiquitin-mediated proteasomal degradation system in tillering regulation in sugarcane. Our study provides a comprehensive insight into regulatory networks involved in GA-mediated regulation of tiller development in sugarcane, which would lay the foundation of hormone regulation to promote sugarcane production.

Mycoinsecticides applied in late afternoon to avoid solar UV damage are more efficacious against rice leaf-rolling insect pests than those applied in the morning

Beauveria bassiana ZJU435 (Bb-ZJU435) and Metarhizium anisopliae CQ421 (Ma-CQ421) registered as mycoinsecticides in China were tested for control efficacies against the rice leaf-rolling pests Cnaphalocrocis medialis and Parnara guttata, which migrated to the tillering stage of rice crop in three rice-shrimp rotation paddy fields, where chemical control is prohibited. Either mycoinsecticide was sprayed twice at a recommended rate after 5:00 pm to avoid solar UV avoidance (UVavo) or before 10:00 am to increase solar UV exposure (UVexp). The first spray, although followed by two-week harsh weather, reduced significantly leaf roll densities (damages) in the fungal treatments compared to blank control. The UVavo and UVexp treatments resulted in control efficacies of 63 % and 35 % for Ma-CQ421 and 28 % and 16 % for Bb-ZJU435 on day 14. The second spray was followed by two weeks of weather favorable for fungal action. Consequently, Bb-ZJU435 and Ma-CQ421 showed significantly higher efficacies in their UVavo treatments (60 % and 55 % on day 21; 66 % and 64 % on day 28) than in corresponding UVexp treatments (47 % and 43 % on day 21; 53 % and 50 % on day 28). The UVavo versus UVexp efficacies after the second spray were corrected to ∼95 % versus ∼85 % for Bb-ZJU435, and 75–84 % versus 54–68 % for Ma-CQ421 by verifying whether the leaf rolls were empty (damage-transferred) or occupied by a living or mycosis-killed larva in all treatments. The corrected efficacies of Bb-ZJU435 were significantly higher than those of Ma-CQ421. Conclusively, either mycoinsecticide was more efficacious against the rice leaf rollers when applied in late afternoon to avoid solar UV damage.

Differential modulation of metabolites induced by salt stress in rice plants

Salinity is one of the abiotic stresses that most limit the growth and development of several crops, such as rice (Oryza sativa L.). According to previous studies, two rice cultivars, São Francisco (SF) and BRS Esmeralda (ES), exhibit contrasting salt stress tolerance in which the SF cultivar is more tolerant to salt stress than the ES cultivar at the pre-tillering stage. However, metabolic adjustments induced by differential tolerance remain to be explored. Hence, this study aimed to evaluate these cultivars under 80 mM NaCl assessing primary metabolism and physiological traits in the tillering stage in a not oxygenated nutrient solution. Salinity caused a significant increase of toxic ions negatively affecting plants' growth and photosynthesis parameters in both cultivars. Salinity reduced the total chlorophyll content, chlorophyll a fluorescence paraments, CO2 assimilation, stomatal conductance, and transpiration of both cultivars. On the other hand, carboxylation efficiency was increased only in SF cultivar. Overall, the physiological traits did not show differential tolerance to salinity in the tillering phase. Nevertheless, the metabolites modulation and activation of the GABA shunt in the SF leaves by salt stress were evident. Besides, 26 metabolites were differentially expressed in leaves and five in roots of the cultivars under salinity. Most of them were amino acids and key-sugars. In addition, glucopyranoside, lysine, ornithine, 2-aminoisobutyric, glutamine, arabitol, and 2-oxoglutaric acid were defined as potential biomarkers of salt stress in rice plants.

Design and Experiment of a Biomimetic Duckbill-like Vibration Chain for Physical Weed Control during the Rice Tillering Stage.

The widespread use of chemical herbicides has jeopardized concerns about food safety and ecological consequences. To address these issues and reduce reliance on chemical herbicides, a physical weed control device was developed for the tillering stage in paddy fields. This device features a biomimetic duckbill-like vibration chain that effectively controls weed outbreaks. The chain penetrates the soft surface soil of the paddy field under gravity and rapidly stirs the soil through vibration, leading to the detachment of the weed roots anchored in the surface layer. Simultaneously, the device avoids mechanical damage to rice seedlings rooted in deeper soil. This study aimed to investigate the effects of chain structural parameters (the number of chain rows, vibration amplitude, and length of chains) and operational parameters (vibration frequency and working velocity) on weed control efficiency and rice seedling damage. Through a central composite regression field test, the optimal device structure and operational parameters were determined. The optimization results demonstrated that a vibration amplitude of 78.8 mm, a chain length of 93.47 cm, and 3.4 rows of chains, along with a vibration frequency and working velocity ranging from 0.5 to 1.25 m/s, achieved an optimal weeding effect. Under the optimal parameter combination, field test results demonstrated that approximately 80% of the weeds in the field were effectively cleared. This indicates that the design of the biomimetic duckbill-like vibration chain weeding device exhibits a relatively superior weeding performance, offering a practical solution for the management of weeds in rice fields.