Panicle Stage Research Articles

Nanosized-Selenium-Application-Mediated Cadmium Toxicity in Aromatic Rice at Different Stages.

Cadmium (Cd) pollution restricts the rice growth and poses a threat to human health. Nanosized selenium (NanoSe) is a new nano material. However, the effects of NanoSe application on aromatic rice performances under Cd pollution have not been reported. In this study, a pot experiment was conducted with two aromatic rice varieties and a soil Cd concentration of 30 mg/kg. Five NanoSe treatments were applied at distinct growth stages: (T1) at the initial panicle stage, (T2) at the heading stage, (T3) at the grain-filling stage, (T1+2) at both the panicle initial and heading stages, and (T1+3) at both the panicle initial and grain-filling stages. A control group (CK) was maintained without any application of Se. The results showed that, compared with CK, the T1+2 and T1+3 treatments significantly reduced the grain Cd content. All NanoSe treatments increased the grain Se content. The grain number per panicle, 1000-grain weight, and grain yield significantly increased due to NanoSe application under Cd pollution. The highest yield was recorded in T3 and T1+3 treatments. Compared with CK, all NanoSe treatments increased the grain 2-acetyl-1-pyrroline (2-AP) content and impacted the content of pyrroline-5-carboxylic acid and 1-pyrroline which are the precursors in 2-AP biosynthesis. In conclusion, the foliar application of NanoSe significantly reduced the Cd content, increased the Se content, and improved the grain yield and 2-AP content of aromatic rice. The best amendment was applying NanoSe at both the panicle initial and grain-filling stages.

Transcriptome and differential expression analysis revealed the pathogenic-related genes in Magnaporthe oryzae during leaf and panicle infection

Magnaporthe oryzae is one of the most destructive pathogens that threaten rice production around the world. Previous studies mainly focus on pathogenic mechanism of M. oryzae during infection on rice at leaf stage. However, the pathogenic mechanism of M. oryzae infection on panicle tissue is not well understood. In the present study, we performed RNA sequencing (RNA-seq) to study gene expression patterns of M. oryzae during infection at leaf stage and at panicle stage, respectively. The differentially expressed genes (DEGs) of M. oryzae in the infected leaf and panicle tissues were analyzed. Gene ontology (GO) enrichment analysis of DEGs revealed that M. oryzae genes involved in the biological processes were different at leaf and panicle stages. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of DEGs indicates that genes related to individual and important pathways may function at different infection stages. In particular, CAZymes carbohydrate esterases (CEs), carbohydrate-binding modules (CBMs), and glycoside hydrolases (GHs) may play important roles during M. oryzae infection on rice leaves, while glycosyltransferases (GTs) and GHs may play important roles during infection at rice panicle stage. Further analysis of effectors (BAS3, BAS113, BAS162, MoCDIP4, and MoHEG13) and their homologous genes suggest that they are involved in host defense suppression. Our findings provide insights into understanding the infection mechanisms of M. oryzae for rice leaf blast and panicle blast disease.

ПРИМЕНЕНИЕ ОРГАНОМИНЕРАЛЬНОГО КОМПЛЕКСА ГУМИТОН ПРИ ВОЗДЕЛЫВАНИИ ОВСА НА ДЕРНОВО-ПОДЗОЛИСТОЙ ПОЧВЕ

Based on the data of a field experiment on sod-podzolic sandy loam soil in the Kaluga Region, it was shown that the use of the organo-mineral complex Gumiton had a positive effect on the biometric indicators of growth and development of oat plants, yield and quality of vegetative mass. When oats were treated with Gumiton in the boot-up phase, the vegetative mass yield increased by 13 %, in the earing phase - by 46 %, and with a double treatment of plants in both these phases - by 48 %. A single treatment with Gumiton in the boot-up phase did not lead to an increase in grain yield, but increased the straw mass by 21.5 % in relation to the control; when treated in the earing phase of oats, the grain yield increased by 17 %, and the straw mass - 23.5 %. Treatment of crops with Gumiton in the oat boot phase contributed to an increase in the ash content in grain by 12 %, double treatment – by 18 %. The content of crude protein in grain did not change either with a single application of Gumiton in different phases of plant development or with double spraying. The fiber content in grain increased with the use of Gumiton in the boot phase of oats by 21.5, at the panicle stage – by 13, and with double treatment – by 31 %. Double spraying of oat crops with Gumiton led to a 17 % decrease in the fat content in the grain.

Transcriptome-wide association analyses reveal the impact of regulatory variants on rice panicle architecture and causal gene regulatory networks

Panicle architecture is a key determinant of rice grain yield and is mainly determined at the 1-2 mm young panicle stage. Here, we investigated the transcriptome of the 1-2 mm young panicles from 275 rice varieties and identified thousands of genes whose expression levels were associated with panicle traits. Multimodel association studies suggested that many small-effect genetic loci determine spikelet per panicle (SPP) by regulating the expression of genes associated with panicle traits. We found that alleles at cis-expression quantitative trait loci of SPP-associated genes underwent positive selection, with a strong preference for alleles increasing SPP. We further developed a method that integrates the associations of cis- and trans-expression components of genes with traits to identify causal genes at even small-effect loci and construct regulatory networks. We identified 36 putative causal genes of SPP, including SDT (MIR156j) and OsMADS17, and inferred that OsMADS17 regulates SDT expression, which was experimentally validated. Our study reveals the impact of regulatory variants on rice panicle architecture and provides new insights into the gene regulatory networks of panicle traits.

Pijx confers broad-spectrum seedling and panicle blast resistance by promoting the degradation of ATP β subunit and OsRbohC-mediated ROS burst in rice

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most important diseases of rice. Utilization of blast-resistance genes is the most economical, effective, and environmentally friendly way to control the disease. However, genetic resources with broad-spectrum resistance (BSR) that is effective throughout the rice growth period are rare. In this work, using a genome-wide association study, we identify a new blast-resistance gene, Pijx, which encodes a typical CC-NBS-LRR protein. Pijx is derived from a wild rice species and confers BSR to M. oryzae at both the seedling and panicle stages. The functions of the resistant haplotypes of Pijx are confirmed by gene knockout and overexpression experiments. Mechanistically, the LRR domain in Pijx interacts with and promotes the degradation of the ATP synthase β subunit (ATPb) via the 26S proteasome pathway. ATPb acts as a negative regulator of Pijx-mediated panicle blast resistance, and interacts with OsRbohC to promote its degradation. Consistently, loss of ATPb function causes an increase in NAPDH content and ROS burst. Remarkably, when Pijx is introgressed into two japonica rice varieties, the introgression lines show BSR and increased yields that are approximately 51.59% and 79.31% higher compared with those of their parents in a natural blast disease nursery. In addition, we generate PPLPijx Pigm and PPLPijx Piz-t pyramided lines and these lines also have higher BSR to panicle blast compared with Pigm- or Piz-t-containing rice plants. Collectively, this study demonstrates that Pijx not only confers BSR to M. oryzae but also maintains high and stable rice yield, providing new genetic resources and molecular targets for breeding rice varieties with broad-spectrum blast resistance.

DETERMINATION OF YIELD AND QUALITY CHARACTERISTICS OF COMMON REED (Phragmites australis (Cav.) Trin. Ex Steud) HARVESTED AT DIFFERENT GROWTH STAGES

Common Reed (Phragmites australis (Cav.) Trin. Ex Steud, which is remained inactive and grown in saline
 drainage channels, has been seen as an important potential to reduce the roughage deficit needed in animal nutrition. For this purpose, some yield, fermantation, chemical and nutritional characteristics of P.australis herbage and silage obtained from the end of the vegetative stage (EVS), the beginning of panicle (BP) and the full panicle stage (FPS) were determined. The study was carried out in 2021-2022 in Igdir, which is located in the North-East of Turkey. The results showed that the forage yield characteristics increased as the development period progressed and also that high lactic acid, low pH, acetic, propionic and butyric acid contents desired in silo feeds were obtained from the cuttings at FPS. In addition, ammonia production was low in silages at BP and FPS, but high the fleig score. It was observed that the dry matter digestibility, metabolic energy and relative feed value were higher while dry matter and crude protein ratio, acid detergent fibre and crude ash content of herbage according to silage were lower. On the other hand, the desired chemical and nutritional values in both herbage and silage were determined during the most suitable BP. As a result, it was determined that the common reed was appropriate to harvest in FPS for a silo feed with high yield and fermentation properties. In addition, it was concluded that the herbage and silage harvested at BP produced a higher quality feed material in terms of nutritional and chemical composition, respectively.

Effect of sowing dates on the vegetative growth and yield parameters of two quinoa (Chenopodium quinoa Willd.) genotypes

The aim of the present study was to select the best sowing time for two quinoa genotypes (Chenopodium quinoa Willd) grown in Ouargla, located in the Saharan region of Algeria. The adopted experimental device is of the random block type, comparing the effect of three sowing dates in 2018: October 16th, October 31st, and November 15th, on some vegetative growth parameters (number of seedlings raised, total number of plants, total fresh weight of plants, height of plants at panicle stage, number of branches per plant, average weight per plant), and yield parameters (number of panicles per plant, weight of the main panicle, weight of 1000 grains, and total weight of grains per square meter) of two quinoa genotypes: "Q102" Amarilla saccaca and "Giza". The obtained results show that the best sowing date for the "Q102" genotype is the first date (October 16th), which ranked first for most of the parameters studied. On the other hand, the best grain yield was observed by the second sowing date (October 31st). As for the "Giza1" genotype, no yield was observed for the first and second sowing dates, while a very low grain yield was observed only by the third sowing date. The results obtained make it possible to conclude the strong capacity of adaptation of genotype "Q102" to the edapho-climatic conditions of the south of Algeria compared to genotype "Giza1". In fact, this study shows that the production potential of quinoa in the Saharan regions is linked to both the genotype and the sowing date.

Determination of physiological maturity and methods for breaking dormancy of rice seeds of IPB 3S variety

Seeds reach maximum quality at physiological maturity, but rice seeds do not germinate readily after harvest because of the after-ripening phenomenon. This study aimed to determine the physiological maturity of rice cv. IPB 3S, and to obtain the method for breaking seed dormancy. An experiment to determine the physiological maturity was conducted in a one-factor complete randomized design with five levels of maturity (½ yellow panicles, ¾ yellow panicles, full yellow panicles, dry yellow panicles, and beyond the harvest time). Heat units were measured from planting to harvesting. An experiment to break seed dormancy was arranged in a two-factor nested complete randomized design, breaking dormancy method (0.2% KNO3 and control) was nested in the after-ripening period (0, 1, and 2 weeks). Seed physiological maturity was reached at the dry yellow panicle stage 34 days after anthesis, and the heat unit needed was 2204.4 °Cd. The harvested seeds were dried to 8-10% moisture content. The seeds had not broken dormancy even after 2-week storage periods at 18-20 °C. Soaking the seeds in 0.2% KNO3 for 36 hours at 28-30 °C broke dormancy before storage with 94.3% germination, and the after-ripening period (1-2 weeks) increased seed viability and vigor.

Photosynthetic efficiency of sorghum (Sorghum bicolor) under the effect of elements of cultivation technology

Purpose. To determine photosynthetic efficiency of Sorghum bicolor hybrids under the foliar application of microfertilizers and plant growth regulators.
 Methods. The research was carried out in 2019–2021 in the experimental site of the Scientific Research Center of the Bila Tserkva National Agrarian University (Kyiv region). Sorghum hybrids 'Brigga' and 'Yutami' wereused in the study. The sowings were treated during the growing season with microfertilizers Alfa-Grow-Extra, 2 l/ha (1st treatment in the 5-leaf stage, 2nd treatment in the 9-leaf stage, 3rd treatment in the emergence of panicle stage) and Intermag-Corn, 2 l/ha (1st treatment in the 5-leaf stage, 2nd and 3rd treatments with an interval of 7 days) and plant growth regulators Regoplant, 50 ml/la and Stimpo, 20 ml/ha in the in the 5-leaf stage.
 Results. It was established that in the panicle emergence stage, the best indicators of the leaf area in the hybrid 'Brigga' were obtained with foliar application of the microfertilizer Intermag-Corn in combination with the growth regulator Regoplant – 49.1 thousand m2/ha, in 'Yutami' – with the application of Intermag-Corn in the composition with Regoplant or Stimpo – 52.9 thousand m2/ha, while in the control this figure was 48.1 thousand m2/ha. At the time of full grain maturity, 14.49 and 16.68 t/ha of dry matter were formed by the hybrids 'Brigga' and 'Yutami' in the treatment with Alpha-Grow-Extra with Stimpo growth regulator. In the interstage period from panicle emergence to flowering, the photosynthetic potential of the hybrid 'Brigga' was on average 0.44 thousand m2/ha × days, in 'Yutami' – 0.52 thousand m2/ha × days. In the interstage period from flowering to full maturity, in the hybrid 'Brigga' when treated with microfertilizer Alpha-Grow-Extra in combination with growth regulator Stimpo, the net productivity of photosynthesis was 3.33 g/m2 of dry matter per day, and in the case of using microfertilizer Intermag-Corn in combination with Stimpo growth regulator – 3.14 g/m2 per day. In the case of growing the 'Yutami' hybrid under foliar application of Alpha-Grow-Extra or Intermag-Corn, the best indicators of net photosynthesis productivity were obtained in the combination with Stimpo growth regulator – 3.19 and 3.19 g/m2 per day of dry matter, respectively.
 Conclusions. The studied elements of the technology, especially foliar application of microfertilizers, effectively influenced the course of photosynthesis processes and, accordingly, ensured the formation better indicators of sorghum productivity.

Integrated Pest Management of Brown Plant Hopper (Nilaparvata lugens (Stal)) in rice of Mancherial District, Telangana State, India

The present study on Integrated Pest Management (IPM) of brown plant hopper, Nilaparvata lugens (Stal) in rice has been conducted as a Front Line Demonstration (FLD) in the adopted villages of KVK, Bellampalli, Mancherial district of Telangana state during the kharif (June – December), season of 2018‒19, 2019‒20 and 2020‒21 respectively to create awareness among the farming community on the IPM practices to manage the pest. The adoption of IPM practices includes formation of alleyways, recommended dose of nitrogen fertilizer, alternate wetting and drying, spraying of need based insecticides like Dinotefuran 20 SG @ 0.4 g or Pymetrozine 50 WDG @ 0.6 g l-1 of water were carried out. The study reveals that the lowest hoppers incidence was witnessed in the demonstrated plot with 1.84, 12.18 and 19.0 adults hill-1 in tillering stage and 7.76, 24.95 and 52.38 adults hill-1 in panicle stage over farmers practice (3.33, 35.40 and 25.42 adults hill-1 in tillering stage and 19.84, 50.30 and 63.47 adults hill-1). The average yields of IPM module demonstrated plot was 7130, 5513 and 5065 kg ha-1 whereas in farmer practice the yield was 6733, 4851 and 4768 kg ha-1 during Kharif (June–December), 2018‒19, 2019‒20 and 2020‒21 respectively with an increased yield of 5.88%, 13.64% and 6.22% during corresponding Kharif (June–December), 2018‒19, 2019‒20 and 2020‒21. Further the Cost-Benefit ratio of 1.88, 2.68 and 1.78 in the technology demonstrated plots whereas in farmers practice the recorded Cost-Benefit ratio of 1.43, 1.94 and 1.48 during corresponding Kharif (June–December), 2018‒19, 2019‒20 and 2020‒21 respectively.

Nitrogen optimization coupled with alternate wetting and drying practice enhances rhizospheric nitrifier and denitrifier abundance and rice productivity.

Optimizing nitrogen (N) fertilization without sacrificing grain yield is a major concern of rice production system because most of the applied N has been depleted from the soil and creating environmental consequences. Hence, limited information is available about nutrient management (NM) performance at a specific site under alternate wetting and drying (AWD) irrigation compared to conventional permanent flooding (PF). We aimed to inquire about the performance of NM practices compared to the farmer’s fertilizer practice (FFP) under PF and AWD on rhizospheric nitrifier and denitrifier abundance, rice yield, plant growth, and photosynthetic parameters. Two improved NM practices; nutrient management by pig manure (NMPM); 40% chemical N replaced by pig manure (organic N), and nutrient management by organic slow-release fertilizer (NMSR); 40% chemical N replaced by organic slow-release N were compared. The results showed an increased total grain yield (16.06%) during AWD compared to PF. Compared to conventional FFP, NMPM, and NMSR significantly increased the yields by 53.84 and 29.67%, respectively, during AWD. Meanwhile, PF prompted a yield increase of 45.07 and 28.75% for NMPM and NMSR, respectively, (p < 0.05) compared to FFP. Besides, a significant correlation was observed between grain yield and nitrogen content during AWD (R2 = 0.58, p < 0.01), but no significant correlation was observed during PF. The NMPM contributed to photosynthetic attributes and the relative chlorophyll content under both watering events. Moreover, relatively higher abundances of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) were observed during AWD, and the highest value was found after the late panicle stage. Our results suggest that the AWD–NMPM model is the best option to stimulate nitrifier and denitrifier gene abundance and promote rice production.

Field-scale rice yield estimation based on UAV-based MiniSAR data with Ku band and modified water-cloud model of panicle layer at panicle stage.

Scientific and accurate estimation of rice yield is of great significance to food security protection and agricultural economic development. Due to the weak penetration of high frequency microwave band, most of the backscattering comes from the rice canopy, and the backscattering coefficient is highly correlated with panicle weight, which provides a basis for inversion of wet biomass of rice ear. To solve the problem of rice yield estimation at the field scale, based on the traditional water cloud model, a modified water-cloud model based on panicle layer and the radar data with Ku band was constructed to estimate rice yield at panicle stage. The wet weight of rice ear scattering model and grain number per rice ear scattering model were constructed at field scale for rice yield estimation. In this paper, the functional area of grain production in Xiashe Village, Xin'an Town, Deqing County, Zhejiang Province, China was taken as the study area. For the first time, the MiniSAR radar system carried by DJI M600 UAV was used in September 2019 to obtain the SAR data with Ku band under polarization HH of the study area as the data source. Then the rice yield was estimated by using the newly constructed modified water-cloud model based on panicle layer. The field investigation was carried out simultaneously for verification. The study results show: the accuracies of the inversion results of wet weight of rice ear scattering model and grain number per rice ear scattering model in parcel B were 95.03% and 94.15%; and the accuracies of wet weight of rice ear scattering model and grain number per rice ear scattering model in parcel C+D+E were over 91.8%. In addition, different growth stages had effects on yield estimation accuracy. For rice at fully mature, the yield estimation accuracies of wet weight of ear and grain number per ear were basically similar, both exceeding 94%. For rice at grouting stage, the yield estimation accuracy of wet weight of ear was 92.7%, better than that of grain number per ear. It was proved that it can effectively estimate rice yield using the modified water-cloud model based on panicle layer constructed in this paper at panicle stage at field scale.

The Starch Physicochemical Properties between Superior and Inferior Grains of Japonica Rice under Panicle Nitrogen Fertilizer Determine the Difference in Eating Quality.

Nitrogen fertilizer is essential for rice growth and development, and topdressing nitrogen fertilizer at panicle stage has a huge impact on rice grain quality. However, the effect of panicle nitrogen fertilizer (PNF) on starch physicochemical properties and fine structure remain unclear. In this study, four PNF levels (0, 60, 120, 180 kg N ha−1) were grown with the same basal and tiller fertilizer (150 kg N ha−1). The starch physicochemical properties, fine structure, texture properties and eating quality of two japonica rice were determined. We found that the content of total protein, crude fat and amylose between superior and inferior grains were significantly different. Compared with inferior grains, superior grains had low relative crystallinity, good pasting characteristics and outstanding eating quality. With the increase of nitrogen application rates, the starch volume mean diameter was lower; the average chain length of amylopectin was longer; and the relative crystallinity of starch was higher. The changes above in starch structure resulted in an increase in starch solubility, swelling power and gelatinization enthalpy, and led to a decrease in retrogradation enthalpy, retrogradation percentage and pasting viscosity, consequently contributing to the increase in hardness and stickiness of rice and the deterioration of taste value. These results indicated that topdressing PNF lengthened the amylopectin chain, decreased starch granule size, enhanced crystallization stability and increased gelatinization enthalpy, which were the direct reasons for the deterioration of cooking and eating quality.

Effects of Precise K Fertilizer Application on the Yield and Quality of Rice under the Mode of Light, Simple, and High-Efficiency N Fertilizer Application during the Panicle Stage

Light, simple, and high-efficiency fertilization is currently an effective method used to improve quality and increase yield. Most research has only focused on the yield or quality of rice, and no effective or in-depth studies exist on the key stage of panicle, which is essential for these two aspects. This study aimed to determine the effect of applying Nitrogen (N) and Potassium (K) fertilizers on the yield and quality at different leaf ages. The rice cultivar, Shennong 265, was grown in the field-tube condition at the 5-leaf age with K fertilizer at different panicle stages. Five K fertilizer and four N fertilizer levels were applied simultaneously during two growing seasons in 2020–2021. The application of K fertilizer at different panicle stages significantly affected the yield and quality. The application of K and N fertilizers at the 12th-leaf-age increased the number of panicles and grains per panicle, thereby increasing the yield with an average increase of 23.20% over local farmer’s fertilization model (CK) in two years. Application at the 10th-leaf age reduced the starch and protein content of the rice and improved the nutritional quality and taste, with an average increase of 11.08 points compared to CK in two years. The processing quality was the best at the panicle K fertilizer application rate of 47.81–64.69 kg ha−1, and the starch and protein contents were the lowest at the panicle K fertilizer application rate of 56.25 kg ha−1. Under different panicle K fertilizer application rates, N fertilizers had great differences in processing quality but had slight differences in nutritional quality; that is, the starch and protein content (total protein and four protein components) significantly increased. The application of panicle N fertilizer mainly affected starch pasting viscosity (RVA profile characteristics). When panicle K fertilizer was applied after panicle N fertilizer, the yield and quality showed a trend of synergistic improvement. Although this improvement was a low-level synergy, it can still be a direction used to explore the synergistic improvement of output and quality.

Sole and combined effect of foliar zinc and arbuscular mycorrhizae inoculation on basmati rice growth, productivity and grains nutrient.

Mismanagement in foliar fertilizer application at different crop stages decreases the productivity of the crop. Likewise, higher application of phosphorus (P) beyond recommended application rates not only decrease zinc (Zn) uptake in rice but also increase fertilizer use cost. Inoculation of arbuscular mycorrhizae (AMF) may optimize the uptake of P and improve crops production via organic secretions. That’s why the current study was conducted to examine the individual and coordinated effects of 0.5% Zn (0.5Zn) foliar spray (tillering (T) and/or panicle (P) initiation stage) and AMF application. Application of foliar 0.5Zn at tillering+panicle stage remained significantly better for significant enhancement in plant height, spike length, gas exchange attributes and total chlorophyll contents than control. A significant decrease in electrolyte leakage Also validated the effectiveness of treatment 0.5ZnT+P compared to control. Compared to control, the maximum increase in N (14.5 and 25.7%), P (42.1 and 33.3%), K (22.2 and 30.0%) and Zn (19.3 and 27.8%) accumulation was also found in 0.5ZnT+P, with and without AMF, respectively. In conclusion, 0.5ZnT+P with AMF is a better approach than sole application of Zn at tillering or panicle initiation stages. Nevertheless, more investigations are suggested at field level under variable climatic zones to confirm the effectiveness of 0.5ZnT+P with AMF for improvement in rice growth and production.

Suitable varieties and high-yielding population characteristics of late season rice in the northern margin area of double-cropping rice along the Yangtze River

<p id="C2">To clarify the suitable types of rice varieties and the mechanism of high yield formation, we mainly analyzed the yield difference between<italic> indica</italic> and <italic>japonica</italic> rice in late season in the northern margin of the double-cropping rice along the Yangtze River. The experiment was conducted from 2018 to 2019 in Lujiang, Anhui province. The differences of yield and yield components, dry matter accumulation, and growth period between <italic>indica</italic> and <italic>japonica</italic> rice were compared and analyzed through 17 <italic>indica</italic> rice and 17 <italic>japonica</italic> rice varieties (strains) which were cultivated in this local area. The results showed that the overall yield level of <italic>japonical</italic> rice was similar to that of <italic>indica</italic> rice. However, compared with <italic>indica</italic> rice, the<italic> japonica</italic> rice had the characteristics of fewer yield-limiting factors, superior safety of panicle fullness, higher yield stability, and ecological safety. High-yield <italic>japonica</italic> rice mainly increased the total dry matter accumulation from transplanting to heading stage so as to improve total spikelets and yield. The effects of dry matter accumulation at different stage with different panicle types on total spikelets were quite different. Among them, the dominance period of dry matter accumulation of medium-large panicle (102.3-112.0 grains per panicle) and small panicle <italic>japonica</italic> rice (52.0-99.7 grains per panicle) are transplanting to panicle differentiation and panicle differentiation to heading stage respectively and the correlation coefficients with total spikelets were 0.709 and 0.829, respectively. Further analysis revealed that dry matter accumulation during transplanting to panicle differentiation stage of large panicle <italic>japonica</italic> rice was significantly affected by the number of tillers at tillering stage, while the dry matter accumulation during panicle differentiation to heading stage of small panicle <italic>japonica</italic> rice was affected by the number of tillers and dry weight of single stem at heading stage. In summary, this study suggested that <italic>japonica</italic> rice was a suitable late season rice variety in the northern margin area of double-cropping rice along the Yangtze River. The number of spikelets in the high-yielding <italic>japonica</italic> rice was 33.8×10³-41.0×10³ m^-2, the dry matter accumulation at maturity was 15.2-16.6 t hm^-2, and the daily yield was 58.9-64.3 kg hm^-2 d^-1. Regarding the selection of varieties, high-yield large-panicle <italic>japonica</italic> rice, such as Jia 58, Wuyujing 6571, and Changyou 5, should have strong tillering ability; while small-panicle rice varieties, such as Ningjing 7, Wuyujing 5745 and Huxiangjing 151, should have a suitable number of tillers at heading stage and dry weight of single stem. In addition, it was necessary to study the optimized cultivation techniques for high-yielding <italic>japonica</italic> rice varieties with different panicle types in order to further develop the yield potential.

An insight into the sensitivity of fully polarimetric SAR data to biomass of pearl millet crop

The development of polarimetric decomposition techniques improves the capability to understand the complex scattering mechanisms occurring in the dryland crops. The present study is focused on assessing the sensitivity of coherent, incoherent, model and Eigen vector-based decomposition techniques from multitemporal Radarsat-2 polarimetric dataset to scattering mechanisms occurring in the critical growth stages of pearl millet crop. Yamaguchi volume component along with its temporal response was observed to be sensitive and reliable due to its dynamic biomass characterization. Overestimation of volume component and earlier saturation of biomass from 4 kgm−2 were observed limitations in Freeman 2 & 3 component decomposition when dealing with higher vegetation crops. The decrease in volume scattering over increasing biomass proved Van Zyl response contrary to the established understanding. Panicle stage was identified as the critical stage for discriminating pearl millet from similar structured maize and sorghum crops. In this stage, alpha angle generated from Cloude-Pottier decomposition almost reached 550 indicating the increase in contribution of dihedral scattering due to vertical prominent panicles in the pearl millet fields. The various Touzi parameters (α1, Ψ1, φ1 and τ1) were observed to have sensitivity towards changes in crop canopy structures, which will require further research to verify. The proposed Δ(F3-Y4) was the most suitable Volume Difference Index (VDI) for characterizing biomass of erectophile crops as the dynamic biomass response was found even beyond 8 kgm−2.

Nitrogen application practices to reduce cadmium concentration in rice (Oryza sativa L.) grains.

Cadmium (Cd) pollution in paddy soils creates challenges in rice grain production, thereby threatening food security. The effectiveness of different base-tillering-panicle urea application ratios and the combined basal application of urea and Chinese milk vetch (CMV, Astragalus sinicus L.) in minimizing Cd accumulation in rice grains was explored in a Cd-contaminated acidic soil via a field experiment. The results indicated that under similar nitrogen (N) application rates, an appropriate amount of urea applied at the panicle stage or the combined basal application of urea and CMV decreased Cd absorption by rice roots and its accumulation in rice grains, as compared with that of conventional N application (control). Furthermore, under a 3:4:3 base-tillering-panicle urea application ratio or under a high basal application of CMV (37,500kg hm-2), Cd concentrations in brown rice were significantly lower (40.7% and 34.1%, respectively) than that of control. Cadmium transport coefficient from root to straw was significantly higher than that of control when an appropriate amount of urea was applied at the panicle stage or when urea and CMV were applied basally, whereas the Cd transport coefficient from straw to brown rice was relatively lower. Moreover, soil pH, or the CEC and CaCl2-Cd concentrations under different N fertilizer treatment was not significantly different. However, the rice grain yield increased by 29.4% with basal application of a high CMV amount compared with that of control. An appropriate amount of urea applied at the panicle stage or the combined basal application of urea and CMV decreased Cd absorption by rice roots and inhibited its transport from straw to brown rice, thus reducing Cd concentration in brown rice. Therefore, combined with the key phase of Cd accumulation in rice, a reasonable urea application ratio or a basal application of high CMV amounts could effectively reduce Cd concentration in brown rice.

A rice R2R3‐MYB (OsC1) transcriptional regulator improves oxidative stress tolerance by modulating anthocyanin biosynthesis

The R2R3 type MYB transcription factors participate in controlling flavonoid production in plants, including anthocyanin and proanthocyanin. Black rice with high anthocyanin content is an important candidate for understanding R2R3-MYB-based regulation of the anthocyanin biosynthesis pathway (ABP). This study was undertaken to draw the functional relationship of an R2R3-MYB protein with anthocyanin biosynthesis and oxidative stress tolerance in plants. The expression levels of the late ABP genes in the panicle stage of black rice were in good agreement with the accumulation of anthocyanin, especially cyanidin 3-glucoside. Among all MYB genes present in rice, an R2R3 type (C1) regulates anthocyanin biosynthesis and was studied further. The positive correlation between the expression of ABP genes and OsC1 along with the nuclear localization of OsC1 are in line with its possible involvement as a transcriptional regulator of ABP genes. Interestingly, OsC1 overexpressed in white rice plants triggered anthocyanin production through augmentation of the transcript level of late ABP genes. Moreover, OsC1-transformed plants exhibited a lower amount of reactive oxygen species upon exposure to oxidative stress. The increased anthocyanin content in white rice seedlings resulted in higher photosynthetic efficiency, less membrane damage and consequently lower oxidative stress. The OsC1 transcriptional regulator helps to ameliorate oxidative stresses in plants owing to its anthocyanin modulating ability.

Effect of ZnO nanoparticles on the productivity, Zn biofortification, and nutritional quality of rice in a life cycle study

Zinc oxide nanoparticles (ZnO NPs), have been commonly used in agriculture, and have attracted more attention for researchers. In this study, a 2-year experiment was conducted involving two Zn types (ZnO NPs and ZnSO4), two concentrations of Zn (25 and 100 mg kg−1), and three Zn application stages (basal stage, tillering stage, and panicle stage). This study comprehensively evaluated the effects of ZnO NPs on rice yield, nutrient uptake, Zn biofortification and grain nutritional quality. Our results showed that both ZnO NPs and Zn salt increased grain yield, NPK uptake, and grain Zn concentration. ZnO NPs application enhanced NPK content in rice, with subsequence increasing panicle number (3.8–10.3%), spikelet number per panicle (2.2–4.7%), and total biomass (6.8–7.6%), thereby promoting the rice yield. Compared with conventional fertilization, ZnO NPs enhanced Zn concentration of brown rice by 13.5–39.4%, this had no negative impact on human health. ZnO NPs application at panicle stage have a higher effectiveness in improving Zn concentration of brown rice than at basal and tillering stage. Furthermore, the application of ZnO NPs at panicle stage was more efficient in increasing Zn concentration of brown rice than for Zn salt. ZnO NPs application slightly altered the amino acids content of rice grains, but had no significant impact on total amino acids content. This study highlights that ZnO NPs could be used as a high performance and safe Zn fertilizer in rice production ecosystem.