Optimizing nitrogen management can improve stem lodging resistance and stabilize the grain yield of japonica rice in rice-crayfish coculture systems

Nitrogen(N)significantly affects rice yield and lodging resistance.Previous studies have primarily investigated the impact of N management on rice lodging in conventional rice monoculture(RM);however,few studies have performed such investigations in rice-crayfish coculture(RC).We hypothesized that RC would increase rice lodging risk and that optimizing N application practices would improve rice lodging resistance without affecting food security.We conducted a two-factor(rice farming mode and N management practice)field experiment from2021 to 2022 to test our hypothesis.The rice farming modes included RM and RC,and the N management practices included no nitrogen fertilizer,conventional N application,and optimized N treatment.The rice yield and lodging resistance characteristics,such as morphology,mechanical and chemical characteristics,anatomic structure,and gene expression levels,were analyzed and compared among the treatments.Under the same N application practice,RC decreased the rice yield by 11.1-24.4% and increased the lodging index by 19.6-45.6% compared with the values yielded in RM.In RC,optimized N application decreased the plant height,panicle neck node height,center of gravity height,bending stress,and lodging index by 4.0-4.8%,5.2-7.8%,0.5-4.5%,5.5-10.5%,and 1.8-19.5%,respectively,compared with those in the conventional N application practice.Furthermore,it increased the culm diameter,culm wall thickness,breaking strength,and non-structural and structural carbohydrate content by 0.8-4.9%,2.2-53.1%,13.5-19.2%,2.2-24.7%,and 31.3-87.2%,respectively.Optimized N application increased sclerenchymal and parenchymal tissue areas of the vascular bundle at the culm wall of the base second internode.Furthermore,optimized N application upregulated genes involved in lignin and cellulose synthesis,thereby promoting lower internodes on the rice stem and enhancing lodging resistance.Optimized N application in RC significantly reduced the lodging index by 1.8-19.5%and stabilized the rice yield(>8,570 kg ha~(-1)on average).This study systematically analyzed and compared the differences in lodging characteristics between RM and RC.The findings will aid in the development of more efficient practices for RC that will reduce N fertilizer application.

Effects of Applying Organic Fertilizer on Rice Lodging Resistance and Yield

[Objective]The aim was to provide a scientific basis for the reasonable application of organic fertilizer to improve lodging resistance and yield of rice.[Method]The application of four different kinds of organic fertilizer was applied to study their effects on rice lodging resistance and yield of late rice Yuzhengxiang that with high quality.[Result] The effect of applying organic fertilizer for improving rice lodging resistance capability was:biogas residues> chicken manure > rapeseed cake> tobac...

Effects of Film-mulched and Dry-farming on Lodging Resistance of Medium Hybrid Rice

Effects of film-mulched and dry-farming on lodging resistance of medium hybrid rice 88S/1128 at late growth stage was studied in this study. The result suggested that the increasing of lodging resistance of rice showed a trend of no film-mulched and water-farmingfilm-mulched and water-farmingno film-mulched and dry-farmingfilm-mulched and dry-faming. The lodging index of water-farming treatment decreased by 9.47%-24.10% compared to that of dry-farming treatment,while the lodging index of no film-mulched decreased by 14.68%-17.09% compared to that of film-mulched treatment; lodging index was significant or extremely significant negative related to resistant press per plant,transpiration rate,intercellular CO2 concentration and photosynthetic rate but extremely significant positive related to biomass per plant; the largest contributed factor in lodging was the plant biomass,while the factors had greatest contribution to lodging resistance showed an order of resistant press per planttranspiration rateintercellular CO2 concentrationphotosynthetic ratestomatal conductance.

Stem Morphological Structure of Super Hybrid Rice and Its Relationship with Lodging Resistance

The stem morphology and anatomical structure of rice, as well as their relationship with lodging resistance, were studied with six super hybrid rice varieties as the tested materials. The results showed that the rice varieties with stronger lodging resistance were characterized by shorter basal elongated internodes and thicker stem base. The lodging index of hybrid rice was positively correlated with the lengths of the first, second and third basal elongated internodes （P〈0.01） and was negatively correlated with the thickness of basal stem wall and the number and area of small vascular bundles, the area of large vascular bundles and the total area of vascular bundles of the second basal elongated internode （P〈0.05）. The correlations between lodging index and plant height, maximum culm diameter of stem base and minimum culm diameter of stem base were not significant. It indi- cates that the lodging resistance of super hybrid rice can be improved by shorten- ing the length of basal elongated internodes, thickening the wall of stem base and increasing the number and area of vascular bundles of basal elongated internodes.

Principal Component Analysis on Traits Related to Lodging Resistance of Plateau Japonica Rice

Objective] This study was conducted to investigate the main factors affect-ing the lodging resistance of plateau japonica rice. [Method] Twenty agronomic traits related to lodging resistance of plateau japonica rice were analyzed by principal component analysis and correlation analysis among 26 varieties/lines of plateau japonica rice. [Result] The lodging resistance of the 26 varieties/lines had great dif-ference among different agronomic traits. Plant height, and wal thickness of the 4th, 3rd and 2nd internodes under the panicle had the most important influence on lodging resistance, while the diameter of the 3rd, 2nd, 4th, 1st nodes under the panicle, length of the 4th and 3rd internodes under the panicle, wal thickness of the 1st internode under the panicle had less influence. The other nine agronomic traits of rice culm did not affect or indirectly affected lodging resistance through above-mentioned agro-nomic traits. Lodging resistance had significant correlations with plant height, length of the 4th and 3rd internodes under the panicle, wal thickness of the 1st, 2nd, 3rd and 4th internodes under the panicle and diameter of the 1st, 2nd, 3rd and 4th node sunder the panicle, had insignificant correlations with panicle length, panicle weight, length of the 1st and 2nd internodes under the panicle, diameter of the 1st, 2nd, 3rd and 4th internodes under the panicle, diameter of the 5th node under the panicle. [Conclu-sion] More attention should be paid to the main factors affecting lodging resistance in breeding to improve lodging resistance of plateau japonica rice.

Effects of Four Kinds of Plant Growth Regulators on Maize Yield and Lodging Resistance

The research reviewed use effects of Yuhuangjin, Xishibao, Zhuangfengling and Jianzhuangsu on Jinhai No. 5. The results showed plant height and ear height declined in varying degrees, as well as empty-stalk rate and lodging rate, with the plant growth regulators applied. Economic characters all improved, including ear length and diameter, barren-tip length and hundred-seed weight, and corn yield went up significantly on average. For example, the increased yield can be as high as 17.43% when Yuhuangjin was applied at 30 ml/hm^2.

Effects of Nitrogen Application Rate and Ratio on Lodging Resistance of Super Rice with Different Genotypes

The objective of this study was to determine the morphology mechanism of nitrogen （N） fertilizer rates and ratio on lodging resistance through analying its effects among lodging index （LI）, lodging-related morphological traits and physical strength in basal intemodes by comparing japonica and indica super rice cultivars. Field experiments, with three nitrogen levels （0, 150 and 300 kg ha-L） and two ratios of basal to topdressing （8：2 and 5：5） with two super rice cultivars （Yliangyou 2 and Wuyunjing 23）, were conducted in the Baolin Farm, Danyang Country, Jiangsu Province, China, in 2011 and 2012. Effects of N fertilizer rates and ratios on morphology of whole plant, morphology traits in basal intemodes and culm＇s physical strength parameters were investigated at 20 d after full heading stage. LI of Yliangyou 2 was significant greater than that of Wuyunjing 23 due to larger bending moment by whole plant （WP） with higher plant height and gravity center height. With higher volume of N fertilizer, LI of two super rice cultivars was increased conspicuously. However, no significant effect was detected with increase of panicle fertilizer ratio. The size of breaking strength （M） in basal intemodes was the key factor determining LI among N fertilizer treatments. Correlation analysis revealed that M value was positively related bending stress （BS） of Wuyunjing 23 and section modulus （Z） of Yliangyou 2, respectively. The higher N fertilizer levels induced reduction ofBS of Wuyunjing 23 due to weak culm and leaf sheath plumpness status and reduced Z of Yliangyou 2 owning to small diameter and culm wall thickness, consequently, influencing their M indirectly. These results suggested that breaking strength was the key factor influencing LI with increase of N fertilizer levels. However, the lodging-related morphology mechanism was different with genotypes. Culm wall thickness and diameter in basal internodes of indica super rice and culm and leaf sheath plumpness status of japonica super rice influenced breaking strength, as well as lodging index, respectively.

Key indicators affecting maize stalk lodging resistance of different growth periods under different sowing dates

The accurate evaluation of maize stalk lodging resistance in different growth periods enables timely management of lodging risks and ensures stable and high maize yields.Here,we established five diferent sowing dates to create diferent conditions for maize growth.We evaluated the effects of the different growth conditions on lodging resistance by determining stalk morphology,moisture content,mechanical strength and dry matter,and the relationship between stalk breaking force and these indicators during the silking stage(R1),milk stage(R3),physiological maturity stage(R6),and 20 days after R6.Plant height at R1 positively affected stalk breaking force.At R3,the cofficient of ear height and the dry weight per unit length of basal internodes were key indicators of stalk lodging resistance.At R6,the key indicators were the coefficient of the center of gravity height and plant fresh weight.After R6,the key indicator was the coefficient of the center of gravity height.The crushing strength of the fourth internode correlated significanty and positively with the stalk breaking force from R1 to R6,which indicates that crushing strength is a reliable indicator of stalk mechanical strength.These results suggest that high stalk strength and low ear height beneft lodging resistance prior to R6.During and after R6,the cofficient of the center of gravity height and the mechanical strength of basal internodes can be used to evaluate plant lodging resistance and the appropriate time for harvesting in fields with a high lodging risk.

Effects of uniconazole with or without micronutrient on the lignin biosynthesis,lodging resistance,and winter wheat production in semiarid regions

Lodging stress results in grain yield and quality reduction in wheat. Uniconazole, a potential plant growth regulator significantly enhances lignin biosynthesis and thus provides mechanical strength to plants in order to cope with lodging stress. A field study was conducted during the 2015–2016 and 2016–2017 growing seasons, to investigate the effects of uniconazole sole application or with micronutrient on the lignin biosynthesis, lodging resistance, and production of winter wheat. In the first experiment, uniconazole at concentrations of 0(CK), 15(US1), 30(US2), and 45(US3) mg L^-1 was applied as sole seed soaking, while in the second experiment with manganese(Mn) at concentration of 0.06 g L^-1 Mn, 0.06 g L^-1 Mn+ 15 mg L^-1 uniconazole(UMS1), 0.06 g L^-1 Mn+30 mg L^-1 uniconazole(UMS2), and 0.06 g L^-1 Mn+45 mg L^-1 uniconazole(UMS3), respectively. Uniconazole sole application or with micronutrient significantly increased the lignin content by improving the lignin-related enzyme activities of phenylalanine ammonia-lyase, cinnamyl alcohol dehydrogenase, tyrosine ammonialyase, and peroxidase, ameliorating basal internode characteristics, and breaking strength. The spike length, spike diameter, spikes/plant, weight/spike, yield/spike, and grain yield increased and then decreased with uniconazole application at a higher concentration, where their maximum values were recorded with UMS2 and US2 treatments. The lignin accumulation was positively correlated with lignin-related enzyme activities and breaking strength while, negatively correlated with lodging rate. Uniconazole significantly improved the lignin biosynthesis, lodging resistance, and grain yield of winter wheat and the treatments which showed the greatest effects were uniconazole seed soaking with micronutrient at a concentration of 30 mg L^-1 and 0.06 g L^-1 , and uniconazole sole seed soaking at a concentration of 30 mg L^-1 .

Genetic progress in stem lodging resistance of the dominant wheat cultivars adapted to Yellow-Huai River Valleys Winter Wheat Zone in China since 1964

Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ)of China during the period of 1964–2015 were evaluated for several lodging-related traits in three cropping seasons.Plant height,height at center of gravity,length of the basal second internode,and lodging index decreased significantly in this period,and the average annual genetic gains for these traits were–0.50 cm or–0.62%,–0.27 cm or–0.60%,–0.06 cm or–0.63%,and–0.01 or–0.94%,respectively.Different from other traits,stem strength showed a significant increasing trend with the breeding period,and the annual genetic gains were 0.03 N or 0.05%.Correlation analysis showed that lodging index was positively correlated with plant height,height at center of gravity,and length of the basal second internode,but negatively correlated with stem strength.Meanwhile,significantly positive correlations were observed between plant height,height at center of gravity,and length of the basal first and second internodes.By comparison with the wild types,dwarfing genes had significant effects on all lodging-related traits studied except for length of the basal first internode and stem strength.Principle component analysis demonstrated that plant height and stem strength were the most important factors influencing lodging resistance.Clustering analysis based on the first two principle components further indicated the targets of wheat lodging-resistant breeding have changed from reducing plant height to strengthening stem strength over the breeding periods.This study indicates that the increase of stem strength is vital to improve lodging resistance in this region under the high-yielding condition when plant height is in an optimal range.

Effects of different mechanical direct seeding methods on grain yield and lodging resistance of early indica rice in South China

Direct seeding of rice has become a main planting method due to the low labor input and high economic benefit in South China.Dry direct seeding(DDS)has been widely used for single-season rice planting establishment.However,few studies have examined the performance of early-season indica rice under mechanical dry direct seeding.A two-year field experiment was conducted with two indica rice cultivars(i.e.,Zhongjiazao 17 and Zhuliangyou 819)to study lodging characteristics and grain yield formation under DDS,flooded direct seeding(FDS)and wet direct seeding(WDS)patterns.The results showed that the annual grain yield in DDS was higher by 14.42–26.34%for cultivar ZLY819 and 6.64–24.58%for cultivar ZJZ17 than in WDS and FDS,respectively,and these increases were mainly attributed to the improvement of the panicles.The DDS pattern significantly increased the seedling emergence rate of early indica rice cultivars,and increased total dry weight and crop growth rate.Meanwhile,shorter basal internodes,better stem diameter and stem wall thickness and lower lodging index were found in DDS in contrast to FDS and WDS.In particular,DDS improved the stem lodging resistance.Our results suggested that the appropriate direct seeding method was beneficial for improving the grain yield and lodging resistance of early indica rice.

Lignin metabolism regulates lodging resistance of maize hybrids under varying planting density

Hybrids and planting density are the main factors affecting maize lodging resistance.Here,we aimed to elucidate the mechanism of the regulation of maize lodging resistance by comparing two hybrids at various planting densities from the perspective of lignin metabolism.Our results showed that compared to lodging-susceptible hybrid Xundan 20(XD20),lodging-resistant hybrid Denghai 605(DH605)showed a lower center of gravity and culm morphological characteristics that contributed to the higher lodging resistance of this hybrid.Lignin content,activities of key lignin synthesis-related enzymes and G-,S-and H-type monomer contents were significantly higher in hybrid DH605 than in hybrid XD20.Stalk mechanical strength,lignin accumulation and enzyme activity decreased significantly with increasing planting density in the two hybrids.While G-type monomers first decreased with increasing planting density but then remained stable,S-type monomers showed a decreasing trend,and H-type monomers showed an increasing trend.Correlation analysis showed that lodging rate was significantly correlated with plant traits and lignin metabolism.Therefore,maize hybrids characterized by high lignin accumulation,high lignin synthesis-related activities,high S-type monomer content,low center of gravity,high stem puncture strength,high cortical thickness,and small vascular bundle area are more resistant to lodging.High planting densities reduce stalk lignin accumulation,relevant enzyme activities and mechanical strength,thereby,ultimately increasing the lodging rate significantly.

Relationship Between Lodging Resistance and Chemical Contents in Culms and Sheaths of Japonica Rice During Grain Filling

To understand the relationship between lodging resistance and chemical component contents in culms and leaf sheaths of rice, the physical strength and maximum bearing capacity of culm, and the contents and amounts of potassium （K） silicon （Si） and soluble sugars in culms and leaf sheaths were investigated using four japonica rice varieties with different lodging resistance characteristics during grain filling. There were significant differences in the total amounts of K, Si and soluble sugars in culms and leaf sheaths among the tested rice varieties. The difference in the total amount of Si was greater than that of K or soluble sugars. The physical strength and maximum bearing capacity of culm continuously decreased from heading to ripening, with a rapid decrease at the dough stage. However, the contents and total amounts of K and Si in culms and the Si content in leaf sheaths gradually increased and an accumulation of K and Si in culms was exhibited, whereas the content and total amount of K and the total amount of Si in leaf sheaths gradually decreased and an exportation of K and Si in leaf sheaths was presented. The physical strength was positively and significantly correlated with the total amounts of K and Si in culms during grain filling except that at the heading stage, the total amount of soluble sugars in culms at the heading and milky stages, the total amounts of Si and soluble sugars in leaf sheaths at the heading stage, the total amount of K in leaf sheaths at the heading and milky stages, and the maximum bearing capacity during grain filling. It is suggested that the lodging resistance of japonica rice would be improved by increasing the amount of soluble sugars in plants at the early filling stage, and enhancing the amount of Si in plants during grain filling through topdressing Si fertilizer at the early filling stage.

Lodging Resistance Related to Root Traits for Mechanized Wet-Seeding of Two Super Rice Cultivars

Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings.However,there is limited knowledge regarding the effects of the establishment of furrows on growth,lodging and yield,and their relationships with root traits.In this study,field experiments were conducted during 2012 and 2013 using two super rice varieties(hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan)under three furrow establishment treatments(T1,both water and seed furrows were established by the machine;T2,only seed furrows were established by the machine;and T3,neither water nor seed furrows were established by the machine).Lodging index,lodging-related traits,grain yield,above-ground dry weight and root traits were measured.The results showed that the lodging index was significantly affected by the treatments with furrows(T1 and T2).The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment(T1)in both 2012 and 2013.Lodging resistance was strongly related to the breaking resistance.No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice.Therefore,the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance,which was related to root traits.

Nitrogen management improves lodging resistance and production in maize(Zea mays L.)at a high plant density

Lodging in maize leads to yield losses worldwide.In this study,we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics,culm mechanical strength,lignin content,root growth,lodging percentage and production in maize at a high plant density.We compared a traditional nitrogen(N)application rate of 300 kg ha–1(R)and an optimized N application rate of 225 kg ha^(–1)(O)under four N application modes:50%of N applied at sowing and 50%at the 10th-leaf stage(N1);100%of N applied at sowing(N2);40%of N applied at sowing,40%at the 10th-leaf stage and 20%at tasseling stage(N3);and 30%of N applied at sowing,30%at the 10th-leaf stage,20%at the tasseling stage,and 20%at the silking stage(N4).The optimized N rate(225 kg ha^(–1))significantly reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.The optimized N rate significantly increased internode diameters,filling degrees,culm mechanical strength,root growth and lignin content.The application of N in four split doses(N4)significantly improved culm morphological characteristics,culm mechanical strength,lignin content,and root growth,while it reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.Internode diameters,filling degrees,culm mechanical strength,lignin content,number and diameter of brace roots,root volume,root dry weight,bleeding safe and grain yield were significantly negatively correlated with plant height,ear height,center of gravity height,internode lengths and lodging percentage.In conclusion,treatment ON4 significantly reduced the lodging percentage by improving the culm morphological characteristics,culm mechanical strength,lignin content,and root growth,so it improved the production of the maize crop at a high plant density.

Analysis of combining ability for stem-related traits and its correlations with lodging resistance heterosis in hybrid wheat

With the application of hybrid wheat, lodging is becoming one of the major factors limiting high yield in its production. However,few studies have focused on combining ability and heterosis analysis of stem-related traits. In this study, 24 crosses were made according to NCII genetic design, using the three(photo-sensitive male sterile lines)×eight(restorer lines) incomplete diallel crosses. The length of basal second internode(LBSI) and breaking strength of basal second internode(BSBSI)as well as other stem-related traits were used to perform the principal component analysis(PCA), combining ability and heterosis analysis. The PCA results showed that the variables could be classified into two main factors, which were named as the positive factor(factor 1) and the negative factor(factor 2), and accounted for 52.3 and 33.2%, respectively, of the total variance in different variables, combined with the analysis for index weight indicated that the factor 1-related traits play positive roles in lodging resistance formation of hybrids. Combining ability variance analysis indicated that its genetic performance was mainly dominated by additive gene effects, and the hybrid combinations with higher lodging resistance can be selected by using of 14 GF6085(R1), 14 GF6343-2(R4), 14 GF6937(R6), 14 GF7433-1(R7), and BS1086(M3),which are with the features with lower general combining ability(GCA) effects of factor 2-related traits whereas higher GCA effects of factor 1-related traits. The heterosis analysis showed that the wide range of heterosis varied with the traits and combinations, and GCA or specific combining ability(SCA) effects of factor 1-related traits except wall thickness of basal second internode(WTBSI) were positively and closely related to the heterosis of lodging resistance. Generally, the correlation coefficients of heterosis to GCA effects of sterile lines(GCAm) of factor 1-related traits are significantly higher than that to GCA of restorer lines(GCAr) and SCA, combined with the higher GCAm variance values of factor 1-related traits compared to GCAr, the GCAm of factor 1-related traits should be particularly considered when breeding hybrid combinations.The heritability analysis showed that the narrow-sense heritability of the diameter of basal second internode(DBSI) and the center of gravity height(TCGH) were obviously lower(<60%) than other traits, suggesting that these two traits were suitable for selection in higher generation for parental breeding. These could provide a theoretical basis for parental breeding and heterosis utilization of lodging resistance.

Characteristics of lodging resistance of high-yield winter wheat as affected by nitrogen rate and irrigation managements

High yields of wheat are mainly obtained through a high level of nitrogen and irrigation supplementation.However,excessive nitrogen and irrigation supplication increase the risk of lodging.The main objectives of this work were to clarify the capacity of lodging resistance of wheat in response to nitrogen and irrigation,as well as to explore the effective ways of improving lodging resistance in a high-yield wheat cultivar.In this study,field experiments were conducted in the 2015-2016 and 2016-2017 growing seasons.A wheat cultivar Jimai 22(JM22),which is widely planted in the northern of Huang-Huai winter wheat region,was grown at Tai’an,Shandong Province,under three nitrogen rates and four irrigation treatments.The lodging risk was increased with increased nitrogen rate,as indicated by increasing lodging index(LI)and lodging rate across both growing seasons.With nitrogen increasing,the plant height,the basal internode length and the center of gravity height,which were positively correlated with LI,increased significantly.While the density of the basal 2nd internode(for culm and leaf sheath)and cell wall component contents,which were negatively correlated with LI,decreased conspicuous along with nitrogen increased.Increasing irrigation supplementation increased the 2nd internode culm wall thickness,breaking strength and leaf sheath density within limits which increased stem strength.Among the treatments,nitrogen application at a rate of 240 kg ha^(-1) and irrigation application at 600 m^(3)ha^(-1) at both the jointing and anthesis stages resulted in the highest yield and strongest stem.A suitable plant height ensures suffcient biomass for high yield,and higher stem stiffness,which was primarily attributed to thicker culm wall,greater density of the culm and leaf sheaths and higher cell wall component contents are the characteristics that should be taken into account to improving wheat lodging resistance.

Contrasting Characteristics of Lodging Resistance in Two Super-Rice Hybrids Differing in Harvest Index

The“super rice”breeding program in China has been successful in developing high-yielding hybrids,including few with high harvest index values.However,there is limited information on the relationship between lodging resistance and harvest index,and the mechanisms underlying the relationship in super-rice hybrids.In this study,a two-year field experiment was conducted to compare lodging resistance and its related traits between two superrice hybrids differing in harvest index,i.e.,Guiliangyou 2(G2)with a high harvest index and Y-liangyou 1(Y1)with a typical harvest index of modern high-yielding rice varieties.Results showed that compared to Y1,G2 was lower in plant height due to its lower aboveground N uptake,and its higher stem breaking resistance(i.e.,lower stem breaking index)resulted from a lower stem height at its center of gravity.Consequently,G2 had a higher lodging resistance(i.e.,lower plant lodging index)than Y1.This study suggests that developing super-rice hybrids with high harvest index values is a possible way to achieve both high grain yield and strong lodging resistance in rice.

Effects of paclobutrazol application on plant architecture,lodging resistance,photosynthetic characteristics,and peanut yield at different single-seed precise sowing densities

The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective practices that increase peanut yield by improving plant architecture,lodging resistance,and photosynthetic characteristics.Therefore,we conducted a two-factor field optimization experiment for the sowing density(D1:1.95×10^(5)plants ha^(-1),D52:2.40×10plants ha^(-1),D3:2.85×10^(5)plants ha^(-1),and D4:3.30×10^(5)plants ha^(-1))and Pbzapplication concentration(P0:0 mg L^(-1)and P1:100 mg L^(-1)).The objective was to optimize agricultural production practices and provide a theoretical basis for highyielding peanut cultivation by evaluating the effects of sowing density and Pbzapplication on plant architecture,lodging resistance,photosynthetic characteristics,and yield.The results showed that at the same Pbzapplication concentration,increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity.At the same sowing density,Pbzapplication reduced lodging percentage by decreasing plant height(PH),improving lignin biosynthesis-related enzyme activities,and enhancing stem puncture strength(SPS)and breaking strength(SBS).The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata,resulting in the increase in relative chlorophyll content and net photosynthetic rate(Pn)of leaves.Furthermore,D3P1treatment had the highest peanut yield among all treatments.In summary,the production strategy combining the sowing density of 2.85×10^(5)plants ha^(-1)with the application of100 mg L^(-1)Pbzwas found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.

Lodging Resistance of Stems in Rice(Oryza sativa L.)

[ Objective ] The paper was to explore the relationship between character of rice stem and compressive strength. [ Method] The morphological and anatomical characters of stems of 10 rice varieties （including 3 internedes） were systematically studied by paraffin sectioning technology; the digital force tester was used to measure the compressive strengths of various varieties; the correlation between various characters and stem compressive strengths was analyzed. [ Result ] Correlation analysis showed that the outer diameter and cress-sectional area of stem had clese relation with longing resistance of stem, which could be adopted as the important factors for stem lodging resistance. The outer diameter and cross-sectional area of 63 Liangyou 636 was significantly higher than other tested varieties, 3 intemedes all had high comoressive strength, and the vleld was also high. [Conclusion] 63 Liangyou 636 could be used as the rice cultivar with super yield.