Tiller Growth Research Articles

Experimental analysis of genetic and environmental interactions on leaf elongation and reproductive development in Lolium perenne.

Perennial grasses' reproductive phenology profoundly impacts plant morphogenesis, biomass production, and perenniality in natural ecosystems and cultivated grasslands. Complex interactions between vegetative and reproductive development complicate grass phenology prediction for various environments and genotypes. This work aims to analyse genetic × environment interactions effects on tiller growth and reproductive development in Lolium perenne. Three perennial ryegrass cultivars, Bronsyn, Carvalis, and Tryskal, were grown from seedling to heading under four inductive conditions. T0 plants were continuously exposed to high temperatures and long days (HT-LD). T1, T2, and T3, plants were initially exposed to low temperatures and short days (LT-SD) for 9 weeks. Then, T1 plants were immediately transferred to high temperatures and long days (HT-LD). Before their exposure to HT-LD, T2, and T3 plants were first transferred to high temperatures and short days (HT-SD) for 3 and 6 weeks, respectively. Leaf length, leaf emergence, and heading were regularly monitored. Floral transition and heading only occurred in T1, T2, and T3, i.e. after successive exposure to low temperature and long photoperiod. Bronsyn had higher heading earliness and proportion of reproductive tillers than Carvalis and Tryskal. The duration of HT-SD exposure affected the final number of leaves and spikelets. The rate of leaf and spikelet production significantly increased once plants were exposed to LD. Our results suggest an additive effect of the photoperiod and floral transition on leaf elongation rate. These findings enhance our understanding of the genetic × environment interactions on the vegetative and reproductive development in perennial ryegrass.

A favorable natural variation in CCD7 from orchardgrass confers enhanced tiller number.

Tiller number is a crucial determinant that significantly influences the productivity and reproductive capacity of forage. The regeneration potential, biomass production, and seed yield of perennial forage species are highly reliant on the development of tillering. Strigolactones (SLs) are recently discovered carotenoid-derived phytohormones that play a crucial role in the regulation of tillering in annual crops. However, the modulation of tiller growth in perennial forage by SLs remains insufficiently investigated. In this study, we identified two alleles of the SLs biosynthesis gene, DgCCD7A and DgCCD7D, which encode CAROTENOID CLEAVAGE DIOXYGENASE 7 (CCD7), from two distinct subspecies of orchardgrass (Dactylis glomerata) exhibiting contrasting tillering phenotype and SLs content. The functionality of the DgCCD7A allele derived from high-tillering phenotypic orchardgrass was found to be diminished compared to that of DgCCD7D from the low-tillering type in rescuing the increased branching phenotype of CCD7-defective mutants in Arabidopsis and rice (Oryza sativa). Notably, the introduction of DgCCD7A in rice resulted in an increase in tiller number without significantly compromising grain yield. Moreover, we demonstrated that the L309P variation in DgCCD7A is a rare natural variant exclusively found in orchardgrass. Our findings revealed that DgCCD7A, a rare favorable natural variation of CCD7 in orchardgrass, holds significant potential for breeding application in improving the plant architecture of perennial forage and crops.

Yield Loss Quantification Due to Stalk-Eyed Fly (Diopsidae) Infestations on Rice Crops (Oryza Sativa) in Fogera Plain

Stalk-Eyed Flies (Diopsidae) pose a significant threat to rice crops (Oryza sativa), causing yield loss and affecting crop development. This study aims to quantify yield loss due to Stalk-Eyed Fly infestations and identify susceptible growth stages of rice crops to this insect. Field experiments were conducted to assess the yield loss of rice due to stalk eyed fly at Fogera, in 2021 and 2022. With the treatments Both Thiamethoxam seed treatment and Chlorpyrifos systemic foliar insecticide were applied to combat the infestation, with untreated varieties serving as controls. And the pot experiment was conducted to assess susceptibility of rice growth stage to the stalk eye fly artistically analyses, were employed to evaluate treatment impacts. With the treatments of different crop stages, Seedling Stage, Tillering Stage, Stem Elongation Stage, Panicle Initiation Stage, Booting, Heading, Flowering. The effect of rice growth stage on stalk eyed fly infestation showed that there is statistically significant difference among the different growth stage, tillering stage appears to be the most susceptible to Stalk-Eyed Fly infestations in terms of the impact on tiller growth in rice crops. During this stage, the mean percentage change of tillers is the highest at 59.3%, indicating a substantial impact of infestations on tiller growth. This suggests that rice crops are particularly vulnerable to stalked fly infestations during the tillering stage, highlighting the importance of effective pest management strategies during this critical growth phase to mitigate potential yield losses. In the field experiment, significant variations in yield loss were observed across treatments. The presence of dead hearts, indicative of infestation, varied notably between treated and untreated rice. Rice varieties incorporating pesticide applications demonstrated lower dead heart percentages, suggesting there is rice yield loss if the stalk-eyed fly is not controlled. Notably, treatments influenced grain yield, with insect protection measures resulting in higher yields and lower yield loss compared to controls. In conclusion, stalk-eyed fly infestation impacts rice crop productivity, particularly during vulnerable growth stages. Pesticide applications show promise in reducing infestation severity and mitigating yield loss. We recommend implementing targeted treatment strategies, focusing on susceptible growth stages, to effectively manage infestations and optimize rice crop yields.

An automated phenotyping method for Chinese Cymbidium seedlings based on 3D point cloud

Aiming at the problems of low efficiency and high cost in determining the phenotypic parameters of Cymbidium seedlings by artificial approaches, this study proposed a fully automated measurement scheme for some phenotypic parameters based on point cloud. The key point or difficulty is to design a segmentation method for individual tillers according to the morphology-specific structure. After determining the branch points, two rounds of segmentation schemes were designed. The non-overlapping part of each tiller and the overlapping parts of each ramet are separated in the first round based on the edge point cloud-based segmentation, while in the second round, the overlapping part was sliced along the horizontal direction according to the weight ratio of the tillers above, to obtain the complete point cloud of all tillers. The core superiority of the algorithm is that the segmentation fits the tiller growth direction well, and the extracted skeleton points of tillers are close to the actual growth direction, significantly improving the prediction accuracy of the subsequent phenotypic parameters. Five phenotypic parameters, plant height, leaf number, leaf length, leaf width and leaf area, were automatically calculated. Through experiments, the accuracy of the five parameters reached 98.6%, 100%, 92.2%, 89.1%, and 82.3%, respectively, which reach the needs of various phenotypic applications.

Effect of crop burning and harvest timing on growth of plant cane and ratoon cane tillers

Effect of crop burning and harvest timing on growth of plant cane and ratoon cane tillers

Effects of Compound Fertilizer and Branch Fertilizer on Population Construction and Yield of Machine-Transplanted Rice.

In order to study the effects of combined application of compound fertilizer and branch fertilizer on the growth and yield of machine-transplanted rice, four hybrid rice varieties were used as experimental materials, and four fertilization treatments were set up by completely random design: compound fertilizer (T0), compound fertilizer + conventional branch fertilizer (T1), compound fertilizer + (branch fertilizer - 20%) (T2), compound fertilizer + (branch fertilizer + 20%) (T3). The results showed that the branch fertilizer could effectively promote the early growth and rapid development of tillers, and increase the agronomic traits such as chlorophyll content, LAI and dry matter accumulation. Among the four varieties, the yield of the V4 variety was the highest under T3 treatment, which was 11,471.15 kg·hm-2, which was 37.34% higher than that of the control, and the yield increase effect was the most significant. The correlations showed that dry matter accumulation and LAI were significantly or highly significantly positively correlated with the number of effective spikes and yield, and the number of effective spikes was highly significantly positively correlated with the yield. In general, the application of pitchfork fertiliser increased the effective number of spikes and the number of grains per spike of each variety to different degrees, which effectively promoted the improvement of the rice yield.

The dual role of casein kinase 1, DTG1, in regulating tillering and grain size in rice

Tiller number and grain size are important agronomic traits that determine grain yield in rice. Here, we demonstrate that DEFECTIVE TILLER GROWTH 1 (DTG1), a member of the casein kinase 1 protein family, exerts a co-regulatory effect on tiller number and grain size. We identified a single amino acid substitution in DTG1 (I357K) that caused a decrease in tiller number and an increase in grain size in NIL-dtg1. Genetic analyses revealed that DTG1 plays a pivotal role in regulation of tillering and grain size. The DTG1I357K allelic variant exhibited robust functionality in suppressing tillering. We show that DTG1 is preferentially expressed in tiller buds and young panicles, and negatively regulates grain size by restricting cell proliferation in spikelet hulls. We further confirm that DTG1 functioned in grain size regulation by directly interacting with Grain Width 2 (GW2), a critical grain size regulator in rice. The CRISPR/Cas9-mediated elimination of DTG1 significantly enhanced tiller number and grain size, thereby increasing rice grain yield under field conditions, thus highlighting potential value of DTG1 in rice breeding.

Cytokinin catabolism and transport are involved in strigolactone-modulated rice tiller bud elongation fueled by phosphate and nitrogen supply

Phosphate (P) and nitrogen (N) fertilization affect rice tillering, indicating that P- and N-regulated tiller growth has a crucial effect on grain yield. Cytokinins and strigolactones (SLs) promote and inhibit tiller bud outgrowth, respectively; however, the underlying mechanisms are unclear. In this study, tiller bud outgrowth and cytokinin fractions were evaluated in rice plants fertilized at different levels of P and N. Low phosphate or nitrogen (LP or LN) reduced rice tiller numbers and bud elongation, in line with low cytokinin levels in tiller buds and xylem sap as well as low TCSn:GUS expression, a sensitive cytokinin signal reporter, in the stem base. Furthermore, exogenous cytokinin (6-benzylaminopurin, 6-BA) administration restored bud length and TCSn:GUS activity in LP- and LN-treated plants to similar levels as control plants. The TCSn:GUS activity and tiller bud outgrowth were less affected by LP and LN supplies in SL-synthetic and SL-signaling mutants (d17 and d53) compared to LP- and LN-treated wild-type (WT) plants, indicating that SL modulate tiller bud elongation under LP and LN supplies by reducing the cytokinin levels in tiller buds. OsCKX9 (a cytokinin catabolism gene) transcription in buds and roots was induced by LP, LN supplies and by adding the SL analog GR24. A reduced response of cytokinin fractions to LP and LN supplies was observed in tiller buds and xylem sap of the d53 mutant compared to WT plants. These results suggest that cytokinin catabolism and transport are involved in SL-modulated rice tillering fueled by P and N fertilization.

Photosynthesis regulates tillering bud elongation and nitrogen-use efficiency via sugar-induced NGR5 in rice.

Rice tillering is one of the most important agronomical traits largely determining grain yield. Photosynthesis and nitrogen availability are two important factors affecting rice tiller bud elongation; however, underlying mechanism and their cross-talk is poorly understood. Here, we used map-based cloning, transcriptome profiling, phenotypic analysis, and molecular genetics to understand the roles of the Decreased Tiller Number 1 (DTN1) gene that encodes the fructose-1,6-bisphosphate aldolase and involvesin photosynthesis required for light-induced axillary bud elongation in rice. Deficiency of DTN1 results in the reduced photosynthetic rate and decreased contents of sucrose and other sugars in both leaves and axillary buds, and the reduced tiller number in dtn1 mutant could be partially rescued by exogenous sucrose treatment. Furthermore, we found that the expression of nitrogen-mediated tiller growth response 5 (NGR5) was remarkably decreased in shoot base of dtn1-2, which can be activated by sucrose treatment. Overexpression of NGR5 in the dtn1-2 could partially rescue the reduced tiller number, and the tiller number of dtn1-2 was insensitive to nitrogen supply. This work demonstrated that the sugar level regulated by photosynthesis and DTN1 could positively regulate NGR5 expression, which coordinates the cross-talk between carbon and nitrate to control tiller bud outgrowth in rice.

Efficacy of Essential Oil Formulations in Rice Seed Treatment Against <i>Magnaporthe oryzae </i>B.C Couch, a Rice Blast Pathogen

Rice is one of the most widely produced cereals in Burkina Faso. However, the fungi transmitted by rice seeds, <i>Oryza sativa</i> L, cause enormous production losses in rice fields. The aim of this study was to assess the efficacy of powdery formulations of essential oils against <i>Magnaporthe oryzae </i>in rice. Thus, rice seeds of the FKR64 variety were disinfected with 15% sodium hypochlorite for 10 minutes and soaked in the suspension of 10<sup>4</sup> conidia/ml for 24 hours. These contaminated rice seeds were coated into powdery formulations of essential oils of <i>L. multiflora,</i> <i>C. schoenanthus</i> and their combination at a dose of 10g/kg of seed. A contaminated control was used. The experimental set-up was a completely randomised block with four treatments in three replicates, one of which was an absolute control. These treatments were carried out on <i>L. multiflora </i>essential oil, <i>C. schoenanthus essential oil</i> and their combination at a proportion of 50%. The results showed that the essential oil of <i>L. multiflora</i> recorded the highest percentage emergence, average height and average number of tillers of the plants, with values of 97.33%, 47.67 cm and 7.89 tillers respectively. This same formulation recorded the lowest percentage of seedling melt and foliar incidence, at 1.33% and 11.67% respectively. These essential oil formulations can be recommended for seed treatment against <i>Magnaporthe oryzae</i>.

Transcriptome-Based Weighted Gene Co-Expression Network Analysis Reveals the Photosynthesis Pathway and Hub Genes Involved in Promoting Tiller Growth under Repeated Drought–Rewatering Cycles in Perennial Ryegrass

Drought stress, which often occurs repeatedly across the world, can cause multiple and long-term effects on plant growth. However, the repeated drought–rewatering effects on plant growth remain uncertain. This study was conducted to determine the effects of drought–rewatering cycles on aboveground growth and explore the underlying mechanisms. Perennial ryegrass plants were subjected to three watering regimes: well-watered control (W), two cycles of drought–rewatering (D2R), and one cycle of drought–rewatering (D1R). The results indicated that the D2R treatment increased the tiller number by 40.9% and accumulated 28.3% more aboveground biomass compared with W; whereas the D1R treatment reduced the tiller number by 23.9% and biomass by 42.2% compared to the W treatment. A time-course transcriptome analysis was performed using crown tissues obtained from plants under D2R and W treatments at 14, 17, 30, and 33 days (d). A total number of 2272 differentially expressed genes (DEGs) were identified. In addition, an in-depth weighted gene co-expression network analysis (WGCNA) was carried out to investigate the relationship between RNA-seq data and tiller number. The results indicated that DEGs were enriched in photosynthesis-related pathways and were further supported by chlorophyll content measurements. Moreover, tiller-development-related hub genes were identified in the D2R treatment, including F-box/LRR-repeat MAX2 homolog (D3), homeobox-leucine zipper protein HOX12-like (HOX12), and putative laccase-17 (LAC17). The consistency of RNA-seq and qRT-PCR data were validated by high Pearson’s correlation coefficients ranging from 0.899 to 0.998. This study can provide a new irrigation management strategy that might increase plant biomass with less water consumption. In addition, candidate photosynthesis and hub genes in regulating tiller growth may provide new insights for drought-resistant breeding.

Maintaining grain yield of Th. intermedium across stand age through constant spike fertility and spike density: Understanding its response to various agronomic managements

Thinopyrum intermedium subsp. intermedium (Host) Barkworth & D.R. Dewey is a perennial grass proposed as a dual-use crop for both forage and grain. Being in the nascent stage of domestication, its grain yield potential is still low compared to annual counterparts. The understanding of Th. intermedium development and the resulting grain yield in field is limited along with its response to agronomic management. To identify the interrelations between development traits and their influence on grain yield, various crop measurements were evaluated during four growing seasons in field grown Th. intermedium conducted under various autumn defoliation operations and nitrogen (N) fertilizations. Under sufficient N treatments (i.e., 100 kg N ha−1), grain yield remained constant over the four years of the experiment with a mean of 1 t ha−1 resulting from a constant spike fertility and a spike density level above 400 spikes m−2. However, significant mortality and inhibition of reproductive growth of tillers can occur when number of tillers is too high and/or resources too scarce (e.g., unfertilized plots or water deficiencies). In addition, excessive aboveground production at the beginning of the reproductive phase can be detrimental to the final grain yield through the negative influence of tiller density and aboveground biomass (DM) on the yield per spike. The highest aboveground production was observed during the second year with 1415 tillers m−2 at the beginning of the reproductive phase and 16 t of DM ha−1 at grain harvest. Although grain yield response to N fertilization was positively associated to spike density, excessive aboveground biomass could be enhanced by N fertilization. The fertilization of 50 kg ha−1 in autumn combined with a fertilization of 50 kg ha−1 in early-spring could sustain tiller fertility without hampering grain production. In autumn, plant regrowth was low with the highest value of 1.3 t of DM ha−1 observed in the first year. Autumn defoliation could be used to maintain the yield per spike in case of excessive biomass production by the reduction of the DM and the final tiller density coupled with the increase of the grain weight the next year. Finally, shredding post-harvest crop residues at ground level to promote light penetration at the bases of plants may have a positive influence on the tiller fertility. Therefore, under fertile soil conditions (i.e., deep soils and sufficient N fertilization) combined with an optimal stand establishment (i.e., from 500 to 1000 tillers m−2 at the beginning of the growing season) we demonstrated that grain yield potential can be maintained as the crop ages. In the future, breeding should raise resource allocation to the grain by increasing yield per spike and avoid overproduction of new tillers through tillering or rhizome propagation without compromising the vigor of regrowth and its environmental performance.

Pengaruh Kompos Blotong untuk Pertumbuhan Tebu Varietas Bululawang Fase Anakan pada Tanah Areal Pantai Firdaus Kecamatan Asembagus

Sugarcane (Saccharum officinarum L.) is one of Indonesia's white sugar producers. Sugar production which continues to soar needs to be balanced with the right cultivation pattern, one of which is by optimizing the growth phase of the sugarcane plant. In the growth phase of the sugarcane plant there is a tiller phase, the tiller phase itself results in the growth of tillers around the mother cane itself. This study examined the soil in the coastal area. In the coastal area there are obstacles to plant growth, such as a lack of nutrients in the soil so that the soil is easily leached which causes the soil to lack nitrogen. The addition of filter cake compost is expected to help maximize the elements in the soil of the coastal area. This study aims to determine the impact of the tillering phase of sugarcane growth from the application of beach area soil with filter cake compost and to determine the appropriate dose of bagasse compost in order to get the best sugarcane crop yields. This study used a non-factorial randomized block design (RBD) with 5 treatments, 4 plant units, and 4 replications. The results of the final project research that has been carried out can be concluded that the effect of filter cake compost on the soil in the coastal area for sugarcane tillering phase showed significantly different results on the parameters of plant height at 14 HST and 42 DAP, while plants aged 70 HST showed highly significant different results. The parameter of the number of tillers showed significantly different results at 42 HST observations. The most influential dose of filter cake compost on the beach area soil was 50% for the Firdaus Beach soil treatment and 50% for the filter cake compost, namely in the third treatment (P2) as evidenced by the results of the highest average plant height parameter compared to other treatments

Optimasi Level Benzyl Amino Purin (BAP) terhadap Pertumbuhan Tanaman Kembang Telang (Clitoria ternatea) melalui Teknik Kultur Jaringan

The research objective was to measure the optimum level of BAP for supporting the growth of butterfly pea flowers through tissue culture techniques. The study used a completely randomized design (CRD) with 5 treatments based on BAP media levels (BAP 0 ppm, BAP 0.5 ppm, BAP 1 ppm, BAP 1.5 ppm, and BAP 2 ppm) and 20 replications. Parameters measured were plant height, plant height increase, number of leaves, number of branches, number of tillers, percentage of tiller growth, plant weight, and leaf color. The results showed that the use of BAP levels 0, 0.5, 1, 1.5, and 2 ppm in butterfly pea flower plants through tissue culture techniques was not effective in increasing plant height, number of leaves, number of branches, number of tillers, and percentage of tillers at the end of the research (27 DAP). Using an optimum BAP level of 0.5 ppm resulted in higher biomass production and the dominance of green leaf color visualization.
 Key words: BAP (Benzyl Amino Purine), butterfly pea, Clitoria ternatea, tissue culture

Modelling the dynamics and phenotypic consequences of tiller outgrowth and cessation in sorghum

Abstract Tillering affects canopy leaf area, and hence crop growth via capture of light, water and nutrients. Depending on the season, variation in tillering can result in increased or decreased yield. Reduced tillering has been associated with water-saving and enhanced yield in water-limited conditions. The objective of this study was to develop a generic model of the dynamics of tillering in sorghum incorporating key genetic and environmental controls. The dynamic of tillering was defined in four key phases—pre-tillering, tiller emergence, cessation of tiller emergence and cessation of tiller growth. Tillering commenced at full expansion of leaf four and thereafter was synchronized with leaf appearance. The potential total number of tillers (TTN) was dependent on a genetic propensity to tiller and an index of assimilate availability dependent on the shoot source–sink balance. Cessation of tiller emergence could occur before TTN depending on extent of competition from neighbours. Subsequent cessation of growth of emerged tillers was related to the extent of internal competition for assimilate among plant organs, resulting in prediction of final fertile tiller number (FTN). The model predicted tillering dynamics well in an experiment with a range in plant density. Plausibility simulations of FTN conducted for diverse field conditions in the Australian sorghum belt reflected expectations. The model is able to predict FTN as an emergent property. Its utility to explore GxMxE crop adaptation landscapes, guide molecular discovery, provide a generic template for other cereals and link to advanced methods for enhancing genetic gain in crops were discussed.

Growth of tandem long-mat rice seedlings using controlled release fertilizers: Mechanical transplantation can be more economical and high yielding

The traditional soil-based rice seedling production methods for mechanical transplanting are resource-intensive, time consuming and laborious. The improvement and optimization of nutrient management in soil-less nursery raising methods like tandem long-mat seedlings (TLMS) are necessary for the resource-efficient cultivation of rice. In the present study, a controlled-release fertilizer (CRF)-polymer-coated compound fertilizer with 3 months release period (PCCF-3M) was applied as seedling fertilizer (SF), and five different dosages of SF (SF-0, SF-10, SF-20, SF-30, and SF-40) were compared with an organic substrate as the control (CK). Among all SF treatments, the best results were obtained with the application of 20 g/tray of SF (SF-20), as the seedling quality and machine transplanting quality were comparable to those of CK. In contrast, the lower dosages (SF-0 and SF-10) resulted in low nitrogen content and reduced shoot growth, while the higher dosages (SF-30 and SF-40) resulted in toxicity (increased malondialdehyde accumulation) and inhibited the root growth. Similarly, SF-20 increased panicle number (5.6–7.0%) and yield (4.3–5.3%) compared with CK, which might be related to the remaining SF entangled in the roots supporting the tiller growth of rice seedlings in the field. Moreover, SF-20 reduced the seedling block weight (53.1%) and cost of seedling production (23.5%) but increased the gross margin, indicating that it was easy to handle and economical. Taken together, our results indicate that SF-20 is a cost-effective way to promote the growth and transplanting efficiency of rice seedlings. To our knowledge, this study is the first to determine the optimum dosage of CRF for the soil-less production of rice seedlings.

Apu Wood (Pistia stratiotes) as Phytoremediation Agent of Screen-printing Wastewater

Abstract. The screen-printing process produces wastewater like organic compounds that are difficult to degrade and heavy metals such as chromium, copper, manganese, and lead, which are toxic and can accumulate in the human body through the food chain. Phytoremediation is one method that utilizes plants' ability to reduce organic and inorganic pollutants, including heavy metals. Objective: This study aimed to describe the concentration of screen-printing waste that can be tolerated by apu wood plants and analyze the effectiveness of apu wood as a heavy metal remediator. Technology or Method: The method used in this research is a combination of filtration and phytoremediation using apu wood to reduce heavy metals such as Pb and Cr,6+ and a preliminary test of Pb and Cr6+ contained in the screen-printing wastewater was carried out. Results: Apu wood lives and thrives on screen-printing wastewater, with an average of 34 new individuals' tillers growth within 15 days. The propagation of apu wood in screen-printing wastewater produced total biomass with an average of 145 grams per reactor. The effectiveness of apu wood as a remediator of Pb was 13.65%, and accumulated in the leaves was 0.0911 mg/L. The accumulation of Cr6+ in the leaves was 0.6635 mg/L. The Cr6+ component in the waste during 15 days of treatment did not show a positive effect on metal removal because the higher chromium element oxidation reaction occurred in the wastewater during the research process.
 Keywords Apu wood; chromium (VI); filtration; phytoremediation.

Analysis of the Dynamics and Characteristics of Rice Stem Tillers via Water Level Management

Based on theoretical analysis and numerical calculations, this study systematically investigated the changes in rice tillering dynamics and the simulation of stem tiller growth during the tillering stage using the farm water level as a regulation index for rice irrigation and drainage. Based on pit testing, the results of this study show that both flooding and drought in the tillering stage suppress the tiller output of rice and have a certain compensating effect following rehydration. Heavy drought during the tillering period reduced the effective tiller rate, while flooding and light drought had little effect on the effective tiller rate. Flooding and maintaining a high infiltration rate also increased the effective tiller rate. The primary kinetic model of tiller elongation (DMOR) was a good fit for the tiller elongation process (coefficients of determination of 0.99 or higher). In addition, the growth and extinction rates of the stem tiller extinction curves were fitted. The maximum growth rate of the stem tiller growth segment was ranked as CK > L1 > H1 > L2 > H2, and the maximum extinction rate of the stem tiller extinction segment was ranked as CK > H2 > H1 > L2 > L1, indicating that both flooding and drought during the tillering stage could reduce the growth and extinction rates of the stem tiller. This shows that both flooding and drought can reduce the growth and extinction rates of tillers.

Study of ‘Red Torch’ and ‘Pink Torch’ Cultivars of Torch Ginger in Brazilian Cerrado

Aims: To characterize the development, yield, and morphological characteristics of the ‘Red torch’ and ‘Pink torch’ cultivars of torch ginger cultivated in the Brazilian Cerrado.
 Study design: The experiment was performed using two cultivars (‘Red torch’ and ‘Pink torch’) with three replications of three ginger torch clumps per plot.
 Place and Duration of Study: Germplasm Active Bank of Ornamental Tropical Plants of the State University of Mato Grosso (14°08′38′′S, 57°03′45′′W; altitude of 488 m), Brazil, from August 2015 to July 2018.
 Methodology: At monthly intervals during the first 10 months after planting, we assessed clump development, based on the measurement of the area occupied by the clump, and number of tillers emerging from the clump. The monthly yield per hectare was estimated from August 2016 to July 2018. During this period, the average number of floral stems produced per clump was determined, and the floral stems were characterized during the second year, for stem length, stem diameter, inflorescence length, inflorescence diameter, and fresh stem mass. Evaluations were based on the measurements obtained from 10 stems per clump.
 Results: First-year clump expansion rates for 'Red torch' and 'Pink torch' were 4.00 and 7.90 cm2, respectively. 'Pink torch' presented a higher monthly average of tiller emergence than 'Red torch', and consequently higher productivity. The cultivars produced floral stems of commercial standard in the second year of growth, with stem lengths and diameters greater than 60.00 cm and 10.00 mm, respectively. In this study, we found that ‘Red torch’ and ‘Pink torch’ showed high yields and produce inflorescences with characteristics suitable for commercialization.
 Conclusion: The basis of this study, we can conclude that cultivation of torch ginger in the Brazilian Cerrado would be viable.

Effect of Rhizome Fragment Length and Burial Depth on the Emergence of a Tropical Invasive Weed Cyperus aromaticus (Navua Sedge)

Cyperus aromaticus (Navua sedge) is a problematic perennial weed in pastures and crops including sugarcane, banana, rice, and fruits and vegetables in tropical climates. It reproduces both via rhizomes and seeds. As a regenerative and storage organ, these rhizomes play an important part in the invasion, establishment, and persistence of this weed. To eliminate their regenerative ability, it is important to understand the regrowth potential with respect to rhizome fragment size and burial depth. This study evaluated the emergence of C. aromaticus from rhizomes in a controlled condition. Three different sizes of rhizome fragments were buried at seven depths of up to 20 cm in two soil types. The experimental measurements included (i) the time for tillers to emerge, (ii) the cumulative emergence of tillers, recorded weekly, and (iii) the number of underground emerging tillers. The cumulative shoot emergence and the number of underground tillers produced were found to be positively correlated with the initial length of the rhizome fragments and negatively correlated with the burial depth. The time for the emergence of the tillers was negatively correlated with the burial depth, and soil type had no significant effect on any of the parameters recorded. There was no emergence recorded from rhizomes buried at 15 cm depth and deeper, irrespective of their size. Our results indicate that the combination of the fragmentation of rhizomes into small pieces and a deep burial, below 15 cm, is an important aspect to control the regeneration of C. aromaticus from rhizomes, if tillage is carried out, and can therefore form a part of an integrated weed management strategy for this troublesome weed.