Tiller Growth Research Articles

Characterization of full-length transcriptome in Saccharum officinarum and molecular insights into tiller development

BackgroundAlthough extensive breeding efforts are ongoing in sugarcane (Saccharum officinarum L.), the average yield is far below the theoretical potential. Tillering is an important component of sugarcane yield, however, the molecular mechanism underlying tiller development is still elusive. The limited genomic data in sugarcane, particularly due to its complex and large genome, has hindered in-depth molecular studies.ResultsHerein, we generated full-length (FL) transcriptome from developing leaf and tiller bud samples based on PacBio Iso-Seq. In addition, we performed RNA-seq from tiller bud samples at three developmental stages (T0, T1 and T2) to uncover key genes and biological pathways involved in sugarcane tiller development. In total, 30,360 and 20,088 high-quality non-redundant isoforms were identified in leaf and tiller bud samples, respectively, representing 41,109 unique isoforms in sugarcane. Likewise, we identified 1063 and 1037 alternative splicing events identified in leaf and tiller bud samples, respectively. We predicted the presence of coding sequence for 40,343 isoforms, 98% of which was successfully annotated. Comparison with previous FL transcriptomes in sugarcane revealed 2963 unreported isoforms. In addition, we characterized 14,946 SSRs from 11,700 transcripts and 310 lncRNAs. By integrating RNA-seq with the FL transcriptome, 468 and 57 differentially expressed genes (DEG) were identified in T1vsT0 and T2vsT0, respectively. Strong up-regulation of several pyruvate phosphate dikinase and phosphoenolpyruvate carboxylase genes suggests enhanced carbon fixation and protein synthesis to facilitate tiller growth. Similarly, up-regulation of linoleate 9S-lipoxygenase and lipoxygenase genes in the linoleic acid metabolism pathway suggests high synthesis of key oxylipins involved in tiller growth and development.ConclusionsCollectively, we have enriched the genomic data available in sugarcane and provided candidate genes for manipulating tiller formation and development, towards productivity enhancement in sugarcane.

Pengaruh Konsentrasi Benziladenin (BA) pada Pertumbuhan Spatifilum (Spathyphyllum wallisii)

Spatifilum (Spathiphyllum wallisii) is a popular ornamental plant that can be used as indoor decoration, so its appearance should be attractive. Apart from flowering, an interesting criteria for the appearance of the spatula is to have many tillers so that it looks lush. One of the efforts to obtain this appearance is the provision of a growth regulator capable of accelerating shoot growth, namely Benzyladenine (BA). The purpose of this study was to determine the concentration of BA which produced the best effect on spatifylum growth. This research was conducted in the greenhouse of the Horticulture Building, Faculty of Agriculture, University of Lampung from July 2019 to January 2020. This research was arranged in a structured single factor treatment design consisting of six BA concentration treatments, namely 0 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, and 50 ppm with six repetitions. Data analysis used standard deviation which is presented in the form of a histogram by taking the average value of each treatment. The results showed that the administration of benzyladenine with concentrations 10-50 ppm tended to increase spatifylum growth in the variable leaf area, leaf greenness, tiller emergence, number of tillers, flower emergence time, and number of flowers, but had no effect on the addition of plant height and number of leaves. Giving benzyladenine with a concentration of 20 ppm was quite efficient in optimizing the vegetatif growth of spatilum, which was shown by the increase in plant height, increased number of leaves, time to emergence of tillers, and number of tillers. On the other hand, the effect of benziladenine on the generative phase requires a higher concentration, namely at a concentration of 50 ppm, the time for which the flower buds appear is the fastest and the number of flowers is the most. Keywords: Benzyladenine, Concentration, and Spatifillum.

Impacts of vegetative and reproductive plasticity associated with tillering in maize crops in low-yielding environments: A physiological framework

• Modern maize hybrids sown at low densities tiller in non-restrictive environments. • Light quality and plant growth rate at early stages govern tiller emission. • Tiller fertility would be determined by shoot growth rate around flowering. • Reproductive plasticity is needed to stabilize yields in ultra-low density settings. • The impact of tillering on crop water and nitrogen economies is hypothesized. Selection for maize ( Zea mays L.) grain yield in high-yielding environments at high population densities has favored a compact phenotype tolerant to crowding stress, bearing a single, well-grained ear. However, by contributing to vegetative and reproductive plasticity (i.e., multiple shoots and ears per plant, respectively), tillering may be adaptive in environments with low and variable availability of resources, chiefly water and nutrients, where crops are sown at low plant population density. In this work we present a robust, new conceptual framework for vegetative and reproductive plasticity in maize with direct agronomic applications, combining original data from new experiments and data reviewed from the literature. First, we describe production systems where tillering in maize would be relevant in terms of grain yield. Next, we discuss possible masked effects of genetic selection at high plant densities on tillering and present novel experimental results showing genotypic variation of tillering in modern maize hybrids and genotype x environment x management effects (plant density x location x sowing date) on tillering expression. We follow with a two-part framework to analyze tillering and prolificacy. In the first part (from axillary buds to tillers), we integrate the early effects of the light environment (through photomorphogenesis) and carbon balance on tillering emission, and discuss the environmental factors (temperature, photoperiod, radiation, water, nitrogen) that modulate tiller emission and tiller growth. In the second part (from tillers to kernels), we summarize the functional relationships governing kernel set on the ears of main shoot (apical and sub-apical ears) and tillers, focusing on the growth rate of shoot cohorts, rather than the whole plant. We then provide examples of the diverse patterns of contribution of multiple shoots to crop grain yield for maize husbandry in low-yielding environments. Finally, we address the effect of tillering on resource capture and use efficiency of maize crops by discussing its relationship with biomass and grain yield and provide supportive experimental data. We conclude with identification of knowledge gaps leading to testable hypotheses.

Tillage and nitrogen managements increased wheat yield through promoting vigor growth and production of tillers

AbstractAdopting suitable tillage and fertilization technologies for wheat (Triticum aestivum L.) can address poor soil conditions and high residual nitrogen following rice (Oryza sativa L.) harvest to improve the sustainability of rice–wheat rotation systems. A field experiment was conducted in 2016–2018 to investigate the influence of tillage methods and nitrogen rates on wheat seedling growth (at the beginning of over‐wintering stage), tillering characteristics, and grain yield. The tillage methods included no‐tillage (NT), rotary tillage twice (RR), and plow tillage followed by rotary tillage (PR). The nitrogen rates were 270 (N270), 240 (N240), and 210 kg ha−1 (N210). In 2016–2017 (higher soil moisture during tillage), NT improved early growth (i.e., leaf area and biomass per stem), single spike yield, and grain yield compared with PR and RR. In 2017–2018 (lower soil moisture during tillage), PR and RR resulted in stronger seedlings (greater tiller number and leaf area and biomass per stem), more fertile tillers, and higher grain yield than NT. In both years, grain yield under RR was between that of PR and NT. With reduced nitrogen application, seedling growth, tiller number, single spike yield, and grain yield showed a declining tendency. We found that more tillers at seedling growth stage (the five‐leaf stage in both years) could boost fertile tiller number, and at this time greater leaf area and biomass per stem were correlated with higher single spike yield. This study demonstrates that suitable tillage and fertilizer applications can facilitate yield formation through improved number and vigor of the early‐produced tillers.

Effects of Biochar Addition on Rice Growth and Yield under Water-Saving Irrigation

To reveal the effect of biochar addition on rice growth and yield under water-saving irrigation, a 2-year field experiment was carried out to clarify the variations of rice tiller number, plant height, yield components, and irrigation water use efficiency with different biochar application amounts (0, 20, 40 t/ha) and irrigation management (flooding irrigation and water-saving irrigation). The results showed that the rice yield with biochar addition (20 and 40 t/ha) was 15.53% and 24.43% higher than that of non-biochar addition paddy fields under water-saving irrigation. The addition of biochar promoted the growth of tillers and plant height, improved the filled grain number, productive panicle number, and seed setting rate, thus affecting rice yield. Rice yield was raised with the increase in the biochar application amount. Under the condition of water-saving irrigation, water deficit had a certain negative effect on the rice growth indexes, resulting in a slight decrease in yield. However, irrigation water input was significantly decreased with water-saving irrigation compare to flooding irrigation. Under the comprehensive effect of water-saving irrigation and biochar application, the irrigation water use efficiency of a rice paddy field with high biochar application (40 t/ha) under water-saving irrigation was the highest, with an average increase of 91.05% compared to a paddy field with flooding irrigation. Therefore, the application of biochar in paddy fields with water-saving irrigation can substantially save irrigation water input, stably increase rice yield, and ultimately improve irrigation water productive efficiency.

Variability among Festuca arundinacea cultivars for tolerance to and recovery from waterlogging, salinity and their combination

Frequency and intensity of floods and the extent of salt-affected lands are expected to increase in pastures and grassland ecosystems as a result of global climate change. This study evaluated the effects of waterlogging, salinity (150 mm NaCl, ~15 dS m–1) and their combination over 14 days of treatment on morphological and growth traits of seven cultivars of Festuca arundinacea (tall fescue). Recovery was also assessed after a 14-day growth period under aerated, non-saline conditions (recovery phase). All cultivars survived the imposed stresses, showing greater tolerance to waterlogging than to salinity or the combined stress, evaluated as a response ratio of total dry mass relative to the control. The combined stress provoked growth lower than predicted by a multiplicative model in one cultivar, growth equal to the model in three cultivars and growth higher than the model in three cultivars. High variability among cultivars in response to each stress and phase was observed; this was more evident for relative growth rate of roots than of shoots. Plant morphological traits were affected by treatments in different ways; mature tiller weight was maintained, and tiller number decreased by 79–71% under waterlogging and combined stresses, whereas the opposite responses occurred under salinity. During the recovery phase, plants in all stress treatments had lower tiller numbers than controls and prioritised the growth of pre-existing tillers, which were heavier. Number of dead leaves per plant increased in saline and combined treatments. In general, F. arundinacea proved more tolerant to waterlogging than to salinity or combined treatments, and showed promising variability among cultivars with respect to root relative growth rate under the evaluated stresses, which can be used in future breeding programs. The findings also provide a basis for further research into the tolerance mechanisms involved.

Skrining dan Efektivitas Metabolit Sekunder Mikania micrantha pada Gulma Jajagoan serta Dampaknya terhadap Padi Sawah

<p>Secondary metabolites from <em>Mikania micrantha</em> could be expected to control barnyardgrass (<em>Echinochloa crus-galli</em>) characteristics and have an effect on lowland rice. This research was aimed to screening of secondary metabolites in <em>M. micrantha</em> extract, obtaining the greater extract concentration in suppressing the barnyardgrass growth, and determine the impact on the lowland rice characteristics. This method used was Randomized Completely Block Design in non-factorial within the concentration rates of <em>M. micrantha</em> extract using ethanol 96% (0%; 20%; 40%; 60%; 80%; 100%, and herbicide 2,4-D dimethylamine at the dose of 1 l ha<sup>-1</sup> as a comparison). Lowland rice and barnyardgrass characteristics were analyzed using F-test and followed by DMRT at 5% with SPSS software. The result showed that <em>M. micrantha</em> had secondary metabolites include alkaloids, flavonoids, and tannins. The concentration at 20 to 100% significantly decreased the fresh- and dry-weight of barnyardgrass with the highest suppressing found in 60% concentration by 65.91% and 67.92%, respectively compared to un-sprayed. The concentrations at 20% and 60% were classified as inhibiting the growth biomass of barnyardgrass. The concentrations at 20%, 60%, and 80% can still encourage the tillers growth of lowland rice. An extract concentration of <em>M. micrantha</em> at 20% can be applied to inhibit the growth of barnyardgrass biomass and stimulate the lowland rice tillers.</p>

PENGARUH KOMBINASI MEDIA SAPIH TERHADAP PERTUMBUHAN ANAKAN BALANGERAN (Shorea balangeran Korth. /Burck)

Balangeran (Shorea balangeran Korth. /Burck) is one type of wood that has a relatively fast growth compared to other types of peat swamps and this wood has a high quality of robust wood II. Therefore, the researchers conducted a study with a combination of different weaning media to find out the extent of the potential for the life of balangeran saplings with different treatments. The treatment used is treatment K (Top soil100%), A (Top soil 50% + Beach sand 25% + Rice husk 25%) B (Top soil 25% + Beach sand 50% + Rice husk 25%) and C ( Top soil 25% + Beach sand 25% + Rice husk + 50%).This research was conducted at the Shade House of the Faculty of Forestry, Lambung Mangkurat University, Banjarbaru, South Kalimantan. The research experiment a requires complete randomized design with 4 treatments and 15 replications so that there were 60 experimental units. The results of the study showed that the percentage of life of baldons reached 100%. The combination of weaning media did not significantly affect the increase in the height of balangeran puppies while the increase in diameter of balangeran puppies showed a significant effect. The best effect of the combination of weaning media on the growth of baldy tillers was shown by treatment A for (0.11 cm). Baloman seedling biomass was obtained from the calculation of weights from each of the tillers, namely in treatment B (14.23 grams), then treatment K (12.64 grams), treatment A (11.76 grams), while treatment C (9.98 grams).Keyword: Weak Media; Top Soil; Beach Sand; Rice Husk

Morpho-physiological traits contributing to better yield performance of japonica/indica hybrids over indica hybrids under input-reduced practices

It is widely reported that japonica/indica hybrids (JIH) have superior grain yield over other main varietal groups such as indica hybrids (IH) under sufficient resource inputs. To date, little attention has been paid to yield performance of JIH under input-reduced practices, and whether JIH could have better grain yield performance over IH under input-reduced practices. In this study, three JIH varieties and three IH varieties were compared in grain yield and their related morpho-physiological traits under two cultivation modes, i.e., conventional high-yielding method (CHYM) and double reductions in nitrogen rate and planting density (DRNP). Our results showed that JIH had 8.3 and 13.3% higher grain yield over IH under CHYM and DRNP, respectively. The superior grain yield of JIH over IH under DRNP was mainly attributed to larger sink size and improved sink filling efficiency. Three main morpho-physiological traits were concluded for better yield performance of JIH over IH under DRNP. Firstly, JIH had the reduced unproductive tillers growth, indicated by a higher percentage of productive tillers and the percentage of effective leaf area index (LAI) to total LAI at heading stage. Secondly, a synergistic increase in biomass accumulation and harvest index were achieved of JIH, supported by higher biomass accumulation and leaf area duration during the main growth periods, and improved non-structural carbohydrate (NSC) remobilization after heading. Thirdly, JIH had an improved canopy structure, showing as higher leaf area of upper three leaves and lower light extinction coefficient. Our results suggested that improved morpho-physiological traits of JIH could lead to better grain yield performance over IH under input-reduced practices.

Morphological and phenological adaptation for convergent development of tillers in Widely spaced wheat sown on different dates

ABSTRACT This study analyzes the dynamics of leaf and tiller emergence and development of widely spaced wheat sown on different dates. We used the phyllochron (time interval between the emergence of successive leaves at the same stage), site filling (the relative rate of increase in the number of tillers per phyllochron), and indices associated with ‘the synchronous growth’. Number of productive tillers per plant (including the main shoot, MS) reached 45.7 in early sowing, and significantly decreased by the delay in sowing. The increase in tiller number with the elapse of leaf age (Haun stage) of MS (HSms) was almost the same as that expected from synchronous growth until HSms 8.6 and site filling before this HSms was close to 0.481. The phyllochron was shortest in MS and increased in axillary tillers with increasing tiller order and position, but the differences in phyllochron between MS and axillary tillers within a plant were significant only at higher order and positions of tillers. The time of emergence of tillers was always advanced in comparison with that expected from synchronous growth. A very close negative linear relationship was found between the number of days from emergence to heading of tillers and the time of their emergence expressed as day of year; this relationship was independent of the tiller order, position and sowing date. Although the phyllochron gradually became longer, a progressive decrease of the leaf and spikelet per spike with the increasing tiller order and position may contribute considerably to the convergence to heading time.

Microbial Inoculants Differentially Influence Plant Growth and Biomass Allocation in Wheat Attacked by Gall-Inducing Hessian Fly (Diptera: Cecidomyiidae).

Beneficial root microbes may mitigate negative effects of crop pests by enhancing plant tolerance or resistance. We used a greenhouse experiment to investigate impacts of commercially available microbial root inoculants on growth and biomass allocation of wheat (Triticum aestivum L. [Cyperales: Poaceae]) and on survival and growth of the gall-inducing wheat pest Hessian fly, Mayetiola destructor (Say). A factorial design was used, with two near-isogenic wheat lines (one susceptible to Hessian fly, the other resistant), two levels of insect infestation (present, absent), and four inoculants containing: 1) Azospirillum brasilense Tarrand et al. (Rhodospirillales: Azospirillaceae), a plant growth-promoting bacterium, 2) Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) (Glomerales: Glomeraceae), an arbuscular mycorrhizal fungus, 3) A. brasilense + R. intraradices, and 4) control, no inoculant. Larval feeding stunted susceptible wheat shoots and roots. Plants had heavier roots and allocated a greater proportion of biomass to roots when plants received the inoculant with R. intraradices, regardless of wheat genotype or insect infestation. Plants receiving the inoculant containing A. brasilense (alone or with R. intraradices) had comparable numbers of tillers between infested and noninsect-infested plants and, if plants were susceptible, a greater proportion of aboveground biomass was allocated to tillers. However, inoculants did not impact density or performance of Hessian fly immatures or metrics associated with adult fitness. Larvae survived and grew normally on susceptible plants and mortality was 100% on resistant plants irrespective of inoculants. This initial study suggests that by influencing plant biomass allocation, microbial inoculants may offset negative impacts of Hessian flies, with inoculant identity impacting whether tolerance is related to root or tiller growth.

The Rice Circadian Clock Regulates Tiller Growth and Panicle Development Through Strigolactone Signaling and Sugar Sensing.

Circadian clocks regulate growth and development in plants and animals, but the role of circadian regulation in crop production is poorly understood. Rice (Oryza sativa) grain yield is largely determined by tillering, which is mediated by physiological and genetic factors. Here we report a regulatory loop that involves the circadian clock, sugar, and strigolactone (SL) pathway to regulate rice tiller-bud and panicle development. Rice CIRCADIAN CLOCK ASSOCIATED1 (OsCCA1) positively regulates expression of TEOSINTE BRANCHED1 (OsTB1, also known as FC1), DWARF14 (D14), and IDEAL PLANT ARCHITECTURE1 (IPA1, also known as OsSPL14) to repress tiller-bud outgrowth. Downregulating and overexpressing OsCCA1 increases and reduces tiller numbers, respectively, whereas manipulating PSEUDORESPONSE REGULATOR1 (OsPPR1) expression results in the opposite effects. OsCCA1 also regulates IPA1 expression to mediate panicle and grain development. Genetic analyses using double mutants and overexpression in the mutants show that OsTB1, D14, and IPA1 act downstream of OsCCA1 Sugars repress OsCCA1 expression in roots and tiller buds to promote tiller-bud outgrowth. The circadian clock integrates sugar responses and the SL pathway to regulate tiller and panicle development, providing insights into improving plant architecture and yield in rice and other cereal crops.

Comparative transcriptome analyses reveal different mechanism of high- and low-tillering genotypes controlling tiller growth in orchardgrass (Dactylis glomerata L.)

BackgroundTillering is an important agronomic trait underlying the yields and reproduction of orchardgrass (Dactylis glomerata), an important perennial forage grass. Although some genes affecting tiller initiation have been identified, the tillering regulatory network is still largely unknown, especially in perennial forage grasses. Thus, unraveling the regulatory mechanisms of tillering in orchardgrass could be helpful in developing selective strategies for high-yield perennial grasses. In this study, we generated high-throughput RNA-sequencing data from multiple tissues of tillering stage plants to identify differentially expressed genes (DEGs) between high- and low-tillering orchardgrass genotypes. Gene Ontology and pathway enrichment analyses connecting the DEGs to tillering number diversity were conducted.ResultsIn the present study, approximately 26,282 DEGs were identified between two orchardgrass genotypes, AKZ-NRGR667 (a high-tillering genotype) and D20170203 (a low-tillering genotype), which significantly differed in tiller number. Pathway enrichment analysis indicated that DEGs related to the biosynthesis of three classes of phytohormones, i.e., strigolactones (SLs), abscisic acid (ABA), and gibberellic acid (GA), as well as nitrogen metabolism dominated such differences between the high- and low-tillering genotypes. We also confirmed that under phosphorus deficiency, the expression level of the major SL biosynthesis genes encoding DWARF27 (D27), 9-cis-beta-carotene 9′,10′-cleaving dioxygenase (CCD7), carlactone synthase (CCD8), and more axillary branching1 (MAX1) proteins in the high-tillering orchardgrass genotype increased more slowly relative to the low-tillering genotype.ConclusionsHere, we used transcriptomic data to study the tillering mechanism of perennial forage grasses. We demonstrated that differential expression patterns of genes involved in SL, ABA, and GA biosynthesis may differentiate high- and low-tillering orchardgrass genotypes at the tillering stage. Furthermore, the core SL biosynthesis-associated genes in high-tillering orchardgrass were more insensitive than the low-tillering genotype to phosphorus deficiency which can lead to increases in SL biosynthesis, raising the possibility that there may be distinct SL biosynthesis way in tillering regulation in orchardgrass. Our research has revealed some candidate genes involved in the regulation of tillering in perennial grasses that is available for establishment of new breeding resources for high-yield perennial grasses and will serve as a new resource for future studies into molecular mechanism of tillering regulation in orchardgrass.

Relationships between yield of winter wheat and bacterial and protozoan fatty acids affected by different green manure amendments

ABSTRACT Soil microorganisms play important roles in crop growth and nutrient cycling. This study investigated the influence of the temporal changes in soil fatty acids (FAs) mainly derived from microorganisms by the incorporation of different green manures on the subsequent crop yield of winter wheat. Plants (Sesbania rostrata or Sorghum bicolor) as green manure were cultivated as the preceding crop, followed by the cultivation of winter wheat. Soil FA structure was characterized by the analysis of the relative abundance of FA methyl esters (FAMEs). Principal component (PC) analysis of the abundance of FAME signatures indicated that the composition of soil FAs was clearly altered by different soil management regimes. The amount of soil FAMEs increased with the incorporation of green manure, and this increase was maintained during wheat cultivation. A positive correlation was observed between wheat yield and the ratio of FAMEs derived from Gram-positive and Gram-negative bacteria at stages of tiller emergence and heading. FAMEs from Gram-positive bacteria and protozoa also positively correlated with one of the wheat yield components, 1,000 grain weight. These results may suggest that the amount of bacterial and protozoan FAs at tiller and heading stage following green manure incorporation is useful to predict the winter wheat productivity.

Optimizing The Fertility Rate of Sugarcane Crops at Precision Agriculture Using The Fuzzy Logic Method

Soil fertility has a significant role in the sugarcane plantation industry to maintain plant fertility so that optimal yield productivity is obtained. The management system that has been used by farmers only based on practices and estimation, so that it can not determine the exact needs of water, lime and fertilizers in each area of the plant. Therefore, we need a system that are able to provide a reference for giving water volume, lime content and fertilization according to the level of nutritional needs of sugarcane plants. This study aims to design a system that is able to provide recommendations for sugarcane needs, based on soil nutrient content using the fuzzy logic method. The first step in this method is the fuzzification process carried out on four types of data used as input parameters, namely soil moisture, soil pH, plant phase, and nutrient content. The next step is choosing the relevant criteria from each assessment to get best alternative. The next stage, a membership function is created to estimate the next process and defuzzification process. According to the result of the study found the value of cost efficiency, optimization of growth in stem height and plant tillers. The resulting cost efficiency is 30.05% compared to the factory method. While the level of optimization of plant growth compared to the factory method, tillering growth increased 8% but the growth of primary stem height was higher by the factory method of 3%.

Rescheduling fertilizer nitrogen topdressing timings for improving productivity and mitigating N2O emissions in timely and late sown irrigated wheat (Triticum aestivum L.)

ABSTRACT Three-year multi-location field experiments were conducted in soils of varying inherent nitrogen (N) supply in diverse agro-climatic zones for improving productivity and mitigating N2O emissions in timely sown and late sown wheat. The biomass, total N uptake (TNU) and spectral properties were monitored at different growth stages. Biomass production and TNU statistics of only 0.76% and 3.4%, respectively, till Zadoks 14 growth stage (four leaves stage) revealed that applying all fertilizer N dose by Zadoks 14 is not an appropriate strategy to assure fertilizer N supply throughout the growth stages. Rescheduled fertilizer N topdressings with moderate N (25 kg ha−1) at sowing and remaining N dose in two equal splits at Zadoks 14 and Zadoks 29 (main shoot and 9 more tillers) growth stages reduced N2O and GHG emissions, respectively, by 32.4% and 30.6%. Sustained N supply till grain filling produced an average of 5.1% to 10.5% higher grain yield and 2.1% to 10.5% higher grain protein content. The spectral properties recorded with PAU-LCC and SPAD meter at Zadoks 29 growth stage governed the grain yield response to fertilizer N application and can be used to fine-tune fertilizer N topdressing decisions over a wide range of varieties, locations, sowing timings and environments.

Interactions Between Exogenous Cytokinin and Nitrogen Application Regulate Tiller Bud Growth via Sucrose and Nitrogen Allocation in Winter Wheat

In this study, we assessed the effects of exogenous cytokinin and nitrogen levels on sucrose and nitrogen allocation and tiller bud growth. Results showed that low nitrogen (1.25 mmol L−1, LN) inhibited tiller bud growth and decreased tiller occurrence rate, compared with high nitrogen (7.5 mmol L−1, HN). SPAD readings and leaf photosynthesis rate was decreased by LN, which resulted in the decrease of sucrose content in the tiller bud. Furthermore, LN promoted the primary and lateral root growth, which may compete with the tiller bud for sucrose and nitrogen. Application of 6-BA (30 mg L−1) increased tiller bud length and the occurrence rate. Compared with LN, leaf photosynthesis and root activity was improved by application of 6-BA under LN condition (LN + 6-BA), which caused the increase of sucrose and nitrogen accumulation in tiller bud. Moreover, LN + 6-BA significantly increased endogenous zeatin (Zt) contents and decreased abscisic acid (ABA) levels in the tiller node. Correlation analysis indicated that tiller bud growth was positively correlated with sucrose and nitrogen accumulation. The latter two were positively correlated with endogenous Zt but negatively correlated with ABA and auxin (IAA):Zt, gibberellin (GA3):Zt, and ABA:Zt. Application of 6-BA with reduced nitrogen fertilizer (240 kg N ha−1, N1 + 6-BA) increased both grain yield and the partial factor productivity of applied N. Therefore, an appropriate combination of exogenous cytokinin with reduced N application could regulate tiller growth to enhance yield by endogenous hormones balance and sucrose and nitrogen allocation in the plant.

Tiller development affected by nitrogen fertilization in a high‐yielding wheat production system

AbstractQuantitative understanding of how fertilizer N affects tiller development is essential for simultaneously achieving high yield and high N use efficiency in wheat (Triticum aestivum L.) production. A 3‐yr field experiment was conducted on the North China Plain during 2015–2017, with winter wheat grown at five fertilizer N rates (0–300 kg ha−1). The highest grain yield (∼9 Mg ha−1) was obtained at the optimized N rate (on average 160 kg ha−1, determined by subtracting the soil NO3− content from estimated N target values) and attributed to the high spike number, which was further contributed by the main stem (MS) and the fertile first tiller (T1). Greater N application than the optimized rate did not further increase grain yield but increased the biomass and N concentration of other tillers that were unproductive. The critical plant aboveground N concentrations (2.81% at stem elongation stage [Zadoks Growth Stage, GS 31] and 1.95% at anthesis (GS 64) and critical root‐zone soil mineral N content (Nmin) (74 kg ha−1 at GS 31 and 129 kg ha−1 at GS 64) for the attainable maximum stem number (1578 m−2 at GS 31 and 944 m−2 at GS 64) were quantified in this high‐yielding system. The critical plant aboveground N concentrations for achieving the maximal biomass of stem were also established to be 2.72% at GS 31 and 1.53% at GS 64, respectively. At these critical levels, the maximal biomass of MS and T1 were obtained without increasing the growth of the other tillers that were unproductive. Our results showed that high yield of winter wheat can be achieved by increasing the number of productive stems and the biomass per productive stem through optimizing the root‐zone Nmin and plant N concentrations.

The Study of Silviculture System for Selective Cutting and Line Planting (TPTJ) and Indonesian Selective Cutting and Planting (TPTI) Application at PT Intracawood Manufacturing Bulungan Regency, North Kalimantan

Selective Cutting and Line Planting (TPTJ) silvicultural systems and Indonesian Selective Cutting and Planting (TPTI) are two of the five silvicultural systems that have been determined by the Ministry of Forestry Regulation No. P.11 / Menhut-II / 2009 juncto P.65 / Menhut-II / 2014 concerning silvicultural systems in the area of timber forest product utilization permits (IUPHHK) in production forests. Three other silvicultural systems based on the regulation are the Gap Logging silviculture system, the Fully Made Rejuvenation System, and the Multi Silviculture System. This study aims to examine the implementation of the TPTJ and TPTI systems in the PT Intracawood Manufacturing (PT Intraca) area, Bulungan Regency, North Kalimantan. The methodology of this research is through the approach of growth analysis, comparison of stand increment, observation of environmental conditions, interviews and literature study. Based on the field research, it was found that the diameter increments of Shorea leprosula, Shorea dasyphila, and Shorea parvifolia were greater in the TPTJ system compared to TPTI. However, the TPTI silviculture system at PT Intraca is easier to apply in the field than the TPTJ silviculture system. The TPTJ system has become less effective because planting in the TPTJ system has been carried out by making a 3-meter wide track with a length of approximately 1 km in a plot and if there is potential for the wood to become ineffective. In the area of PT Intraca, to improve the effectiveness of the TPTJ system a mosaic system is used where the planting path is made only in areas with less potential and representative for planting. The types of plants planted in the TPTJ system are far superior, perspective, and are faster than the types of plants in the TPTI system. Planting/enrichment in the TPTI system is easier because it does not need to make a planting path. Planting with seedlings from the extraction is only a transfer from the growth of tillers from areas with an excessive potential for tillers.

Effect of foliar application of humic acid on fodder and grain yield of oat (Avena sativa L.)

An experiment was carried out at the farm of Field Crops Department, Agriculture College, University of Basrah, Iraq during two winter seasons of 2016–17 and 2017–18 to study the effect of spraying humic acids (0, 3, 6 and 9 g/l) at two growth stages (Tillering and 50% flowering stage) on the fodder and grain yield of oat cv. Shaffaa. Split plot design arranged by RCBD was used with three replications, stage of spraying was placed in the main plots, while foliar humic acid concentrations in the sub-plots. The best concentration of humic acid was 6 g/l which achieved the highest green fodder yield (50.6 and 54.4 t/ha), dry fodder yield (16.9 and 18.6 t/ha) and grain yield (6.19 and 5.97 t/ha) for both the growing seasons. Spraying at tillering stage was more efficient for increasing fodder and grain yield as compared to spraying at 50% flowering stage. The interaction was significant, plants that sprayed at tillering stage with concentration of 6 g/l of the humic acid were more potential for most studied characteristics. Therefore, humic acid @ 6 g/l during tillering growth stage proved most suitable for obtaining optimum yield of oat.