Tiller Dynamics Research Articles

Tillering Capacity of Brachiaria Cultivars in the Brazilian Semi-Arid Region During the Dry Season

Identifying forage species that are responsive in regions with marked water deficits is one of the greatest challenges for the sustainable development of agriculture. However, information is still lacking about the persistence response of those pastures and their abilities to produce new tissues at the times of water scarcity. We hypothesized that Brachiaria grass has a tillering capacity during water-stress periods. This study thus examined the tillering capacity and structural characteristics of four Brachiaria brizantha cultivars (Xaraes, Piata, Marandu, and Paiaguas) and one Brachiaria decumbens cultivar (Basilisk) in the Brazilian semi-arid region during the dry season (September to March). The experiment was laid out in a randomized block design with repeated measures over time in which five treatments were tested in four replicates. Tillering parameters, pasture production, and structural variables were evaluated. There was no interaction effect of cultivar × evaluation period on the tiller appearance (p= 0.1774), mortality (p= 0.1952) or survival (p= 0.4469) rates. The highest tiller appearance and mortality rates were observed in Marandu, while the highest survival rates were found in Marandu and Paiaguas. The index of tiller population stability was higher than or equal to 1.0 in all cultivars. Cultivar Basilisk showed the highest herbage mass yield (4448.0 kg DM ha-1), whereas Basilisk exhibited the highest yields of leaf (1845.9 kg DM ha-1), stem (1676.9 kg DM ha-1), and dead material (925.2 kg DM ha-1). The highest leaf:stem ratio (1.8) was found in Marandu. Cultivar Xaraes had the highest canopy (70.8 cm). The B. brizantha and B. decumbens cultivars evaluated in this study have the potential for cultivation in areas with marked water deficits, as is the case of the Brazilian semi-arid region. Cultivars Marandu, Basilisk, and Paiaguas exhibited the greatest tillering dynamics as well as the highest herbage-mass yield.

Population Dynamics in Mixed Canopies Composed of Kikuyu-Grass and Tall Fescue

The current work was based on the central hypothesis that grazing management strategies modulate tillering dynamics of mixed canopies composed of kikuyu-grass (C4 perennial grass) and tall fescue (C3 perennial grass). Among the five grazing management conditions evaluated, three (7, 12, and 17 cm) represented the heights up to which the grasses were kept by mimicking a continuous stocking method throughout the experimental period (from May 2016 to October 2017), and the other two consisted of the heights 12 and 17 cm with a single grazing to 7 cm in mid-autumn. Nitrogen fertilization was applied only during winter–spring. The results showed that under severe grazing (7 cm), kikuyu-grass predominated in the area and that tall fescue population predominated in the moderately lenient (12 cm) and lenient (17 cm) grazed pastures, regardless of an occasional autumn grazing to 7 cm. After two years of evaluation, kikuyu-grass tillers were reduced to 6% of the total population in those pastures managed at the heights of 12 and 17 cm. Grazing management strategies modulate species proportions in a mixed canopy composed of kikuyu and tall fescue. Moreover, our data also suggest that it seems unlikely that there is a stable association of tall fescue and kikuyu-grass when no nitrogen fertilization is applied during summer.

Tillering and characterisation of tillers on marandu palisadegrass deferred and fertilised with nitrogen

Evaluations of tillering dynamics and characteristics of the individual tillers allow the changes that occur in the growth and structure of the deferred and nitrogen (N) fertilised pasture to be understood. This work was carried out to evaluate the tillering and morphological characteristics of basal tillers in deferred canopies of Brachiaria brizantha syn. Urochloa brizantha cv. Marandu (marandu palisadegrass) submitted to two N doses (50 and 200 kg ha-1). The evaluations were carried out at the beginning, middle and end of the deferment period. The experimental design was completely randomised in split-plot design with four replications. Tiller appearance rate (TAR) was higher at the beginning than in the middle and at the end of the deferment period, contrary to that observed for the number and weight of the tiller. Tiller mortality rate (TMR) was higher at the end than at the beginning and in the middle of the deferment period. The tiller population stability index (SI) was similar at the beginning and middle, but lower at the end of the deferment period. The leaf area of the tiller was higher in the middle compared to at the beginning and end of deferment. N dose did not influence TAR, TMR and SI. The canopy fertilised with 200 kg ha-1 of N presented a higher number and weight of tiller compared to the canopy fertilised with 50 kg ha-1 of N. The N increases the number and weight of tillers, but does not change tillering dynamics during the deferment period for marandu palisadegrass. The tillering decreases and the morphological composition of the tiller worsens with the increase in the deferment period in marandu palisadegrass.

Tillering dynamics of ‘Mulato II’ brachiariagrass under continuous stocking

AbstractLong‐term stand persistence is a desirable characteristic of sustainable grassland ecosystems, and tillering dynamics is an important determinant of persistence. Grazing intensity and nutrient supply affect tiller density, weight, and survival. Understanding the relationships among these factors can help optimize performance of grazed pastures. The objective of this research was to determine the effects of canopy height (10, 25, and 40 cm; maintained under mimicked continuous stocking) and N fertilization (50 and 250 kg ha−1 yr−1) on the tiller dynamics and canopy stability index (SI) of ‘Mulato II’ hybrid brachiariagrass (Brachiariaspp. syn.Urochloaspp.) during two growing seasons. Tiller population density (TPD) increased by 9% with greater N fertilization and decreased linearly from 1,130 to 900 tillers m−2as canopy height increased from 10 to 40 cm. Tiller weight (TW) increased from 0.39 to 1.46 g as canopy height increased from 10 to 40 cm, but TW decreased by 9% with a greater N rate. Tiller appearance rate increased by 30% and tiller survival rate (TSR) decreased by 13.5% as N rate increased. The TSR was greater for 25‐ and 40‐cm than for 10‐cm canopies (81, 82, and 74 tillers per 100 tillers per 30 d, respectively). The SI increased from 0.91 to 1.0 with increasing canopy height from 10 to 40 cm. Mulato II canopies followed the tiller size–density compensation mechanism, displaying phenotypic plasticity in response to canopy height, but these results suggest a 25‐cm canopy height is near optimal for continuously stocked Mulato II brachiariagrass pastures.

Population density and tillering of andropogon grass submitted to different cutting heights

ABTRACT The objective of this study was to evaluate the tillering dynamics and population density of Andropogon gayanus cv. Planaltina, submitted to different cutting heights during the dry and rainy season. A randomized block design was adopted in a split plot scheme. In the main plot, the three cutting heights (10, 20, and 30 cm) were allocated, while the subplots included the following periods: dry (October, November, and December) and rainy (April, May, and June). During the dry period at the height of 10 cm, there was a higher population density of tillers, with 1298.44 tillers m-2. The appearance rate was higher in October for heights of 10 and 30 cm and in December for 20 cm. The 10-cm height provided a higher mortality rate. The survival rate and the stability index were higher in October, with 88.47% and 1.38, respectively. In the rainy season, specifically June, the pasture had a higher height (130.06 cm). The rate of appearance and the stability index were higher in April and during June there was greater mortality, while at the 20-cm height, there was less mortality and greater survival (85.71%) of the tillers. The 20-cm cut height provides a higher survival rate and lower mortality rate of andropogon grass in the dry and rainy season.

Plate meter calibrations for forage mass follow a continuum of sward basal density

AbstractThe ability to quantify forage mass (FM) is needed when budgeting pasture supply. Calibrated sward height is an indirect measure of FM. In a previous study, it was observed that the regression intercept and slope of forage density vs. height (FDint and FDslope, respectively) had a strong linear relation, giving rise to the hypothesis that there is a calibration continuum across pastures. This hypothesis was tested using 121 plate meter calibrations conducted across a range of plant species, defoliation managements, land resource areas, latitude, and elevation. Sward compressed height (CHt) was measured using a resting plate meter. Within calibrations, 30 to 60 paired CHt and FM samples were collected: half pre‐grazing and half post‐grazing. Within calibrations, the linear relation between CHt and forage density (FD) was calculated. Across calibrations, the linear relation between FDint and FDslope was calculated. Forage mass available for grazing (FMAG) was predicted using individual calibrations and the continuum calibration and compared with forage mass grazed (FMG) measured using pre‐ and post‐grazing clipped samples. Across calibrations, there was a strong linear relation between FDint and FDslope (R2 = 0.83). Within calibrations, predicted FMAG vs. FMG was accurate and precise. Across events, predicted FMAG using the continuum was accurate but less precise. Using the continuum to estimate FMAG provided estimates within 10% for recommended grazing heights. Factors that determine the relation between FDint and FDslope include morphology of the dominate grass, species composition, tiller size/density compensation, sward growth to optimize light interception, and tiller dynamics relative to time of year.

Tillering dynamics of Alexandergrass pasture under nitrogen fertilization

ABSTRACT This study was carried out to evaluate the effect of nitrogen fertilization on tillering dynamics of Alexandergrass (Urochloa plantaginea (Link) Hitch) grazed by beef heifers in a rotational stocking grazing method. The experiment was conducted in a completely randomized design following a repeated measure arrangement, three levels of nitrogen (Zero, 150 and 300kg ha-1) and two area repetition. The classification of tillers into categories (basal and axillary) showed a greater number of basal tillers, due to their higher appearance rate, in the absence of nitrogen fertilization. Nitrogen fertilization promoted higher axillary tiller density. The use of nitrogen promotes the renewal of axillary tillers of Alexandergrass, without compromising the stability of the tiller population.

Dynamics and stability of Marandu grass tillers in monocrop systems and babassu palm silvopastoral systems

This study aimed to evaluate the dynamics, population density of tillers and stability index of Urochloa brizantha in silvopastoral systems composed of babassu palm trees in the Pre-Amazon region. Four systems consisting of different densities of palm trees (80, 131, and 160 palms ha-1) and a monocrop were evaluated. The rates at which the basal tillers appeared in systems with 131 and 160 palms ha-1 were similar to each other and were slower compared to the monocrop pasture and the system with 80 palms ha-1. Despite the variations, the stability index was always higher than 1.0, which infers a compensatory mechanism between tiller appearance and mortality rate, since monocrop pastures and systems with 80 palms ha-1 have a higher rate of tissue turnover with high rates of tiller appearance and mortality; in contrast, the system with 160 palms ha-1 presents high tiller survival rates. Both the 160 and 131 palms ha-1 systems indicate impaired canopy renewal, as seen in the low appearance rate of basal tillers due to shading. As such, the tillering dynamics of the systems vary according to the density of palm trees, and the smaller tree densities favor the tiller turnover in the first generations evaluated.

Effects of Nitrogen Fertilization and Seed Piece Applied Fungicides on Establishment, Tiller Dynamics, and Sucrose Yields in Successively Planted Sugarcane

Sugarcane (Saccharum spp.) successive planting causes 25–30% yield reduction in comparison to fallow or rice rotation planting in a three-year production cycle on Florida Histosols. Field experiments were established to manage the yield losses associated with successive planting through nitrogen fertilization and seed piece application of fungicides in plant and first ratoon crops each at two sites. Nitrogen fertilization treatments included 0 (N0), 50 (N50), and 100 (N100) kg ha−1 applied in furrows at the time of planting, and one split application (N50+50) with 50 kg ha−1 applied at planting and 50 kg ha−1 applied at 90 days after planting as side-dress. Fungicides treatments were mancozeb at 2.5 kg a.i. (active ingredient) ha−1, mefenoxam at 0.57 kg a.i. ha−1, and azoxystrobin at 0.30 kg a.i. ha−1 applied to seed cane pieces laid in the furrows at planting. Nitrogen fertilization showed increasing trends of the tiller and millable stalks production in plant and ratoon crops. N response varied with the time of ratooning. Overall, N50+50 produced greater tons of cane per hectare (TCH) and tons of sucrose per hectare (TSH) compared to other N treatments in plant crop and late season ratoon crop (ratooned in March). N100 treatment enhanced tillering and TCH in December ratooned crop. In 2016 plant crop, mefenoxam produced higher TCH than others, but no carryover effects were observed in ratoon crops. Both nitrogen fertilization and fungicides seem to be promising cultural practices to minimize yield losses in successive sugarcane planting in Histosols.

Tiller dynamics in Piatã palisade grass submitted to nitrogen fertilization

The objective of this study was to determine the residual effect of nitrogen fertilization applied at the time of the waters on the demography of tillers of Urochloa brizantha cv. Piata kept under cut simulating manning continues in the dry season. The experiment was installed in the farm Capim Branco da Universidade Federal de Uberlândia (UFU), located in the city of Uberlândia, Minas Gerais. It was established the Piata grass (Urochloa brizantha cv BRS Piata) in September 2011 in an area of 9 m 2 plot -1 . The experimental design was a completely randomized block design, with four replications, with treatments distributed in a 4 x 5 factorial scheme, in which the first factor doses of urea (0, 100, 200, 400 kg ha-1 of N), demarcated in four applications always performed after the demotion of experimental units and the second factor was the time of evaluation (May, June, July, August and September). Performed the evaluations of the tillering dynamics during five months, assessing rate of appearance, mortality and survival, as well as the stability index of the population and population density, analyzing data by the method of Student-Newman-Keuls (SNK). The use of N doses did not affect the tillering of Piata grass in the dry season, due to the implementation of this have occurred with low water availability in the soil. The development of the plant is linked to the amount of water present in the soil, reducing your energy expenditure, consequently decreasing your development and production.

Effect of nitrogen fertilization on structure and tillering dynamics of Piata palisade grass during the deferment period

Nitrogen fertilization can increase the appearance of new tillers, which can improve the structure of deferred sward, since the deferral period is not long. Thus, the objective of this study was to estimate the effects of nitrogen fertilization on structure and tillering dynamics of Piata palisade grass (Brachiaria brizantha cv. Piata) during deferment. We evaluated three nitrogen fertilization levels (none - 0 kg ha -1; medium - 75 kg ha -1; and high - 150 kg ha -1) associated with deferment periods (1, 30, 60, 90, and 120 days). The experimental design was set in completely randomised blocks in a split-plot arrangement, with three replications. The deferment period influenced foliage area index quadratically (p < 0.01) at all fertilization levels. The improvement in nitrogen fertilization levels increased light interception and reduced the foliage angle, but it did not affect tillering dynamics of Piata palisade grass during the deferment period. Appearance and mortality rates, the balance between tiller appearance and mortality and the stability index of the population of aerial and basal tillers of Piata palisade grass were higher at the beginning of the pasture deferment period. Nitrogen fertilization does not stimulate appearance of tillers on deferred Piata palisade grass. Tiller population stability, however, is only high at the beginning of deferment, decreasing after this initial period.

WALTer: a three-dimensional wheat model to study competition for light through the prediction of tillering dynamics.

Branching is a main morphogenetic process involved in the adaptation of plants to the environment. In grasses, tillering is divided into three phases: tiller emergence, cessation of tillering and tiller regression. Understanding and prediction of the tillering process is a major challenge to better control cereal yields. In this paper, we present and evaluate WALTer, an individual-based model of wheat built on simple self-adaptive rules for predicting the tillering dynamics at contrasting sowing densities. WALTer simulates the three-dimensional (3-D) development of the aerial architecture of winter wheat. Tillering was modelled using two main hypotheses: (H1) a plant ceases to initiate new tillers when a critical Green Area Index (GAIc) is reached, and (H2) the regression of a tiller occurs if its interception of light is below a threshold (PARt). The development of vegetative organs follows descriptive rules adapted from the literature. A sensitivity analysis was performed to evaluate the impact of each parameter on tillering and GAI dynamics. WALTer was parameterized and evaluated using an initial dataset providing an extensive description of GAI dynamics, and another dataset describing tillering dynamics under a wide range of sowing densities. Sensitivity analysis indicated the predominant importance of GAIc and PARt. Tillering and GAI dynamics of expt 1 were well fit by WALTer. Once calibrated based on the agronomic density of expt 2, tillering parameters allowed an adequate prediction of tillering dynamics at contrasting sowing densities. Using simple rules and a small number of parameters, WALTer efficiently simulated the wheat tillering dynamics observed at contrasting densities in experimental data. These results show that the definition of a critical GAI and a threshold of PAR is a relevant way to represent, respectively, cessation of tillering and tiller regression under competition for light.

Tillering dynamics of digit grass subjected to different defoliation frequencies

Abstract: The objective of this work was to evaluate the tillering dynamics of 'Suvernola' digit grass (Digitaria eriantha) when subjected to different defoliation frequencies. Four defoliation frequencies (interval among harvests) were evaluated - very high, when the grass reached 25 cm in height; high, 35 cm; medium, 45 cm; and low, 55 cm - in two seasons of the year, with higher and lower insolation, from January 2015 to January 2016. A randomized complete block design with four replicates was used. The increase in defoliation frequency increased the number of generations and the appearance, mortality, and density rates of tillers, besides decreasing their survival rate, without changing population stability. At the time of lower insolation, tiller appearance and mortality rates were higher, while tiller survival rate, balance, and density were lower. The evaluated defoliation frequencies and seasons of the year do not change the persistence of digit grass when irrigated. Higher defoliation frequencies result in a greater renewal of digit grass tillers.

Grazing height management does not change the persistence pathway of Andropogon lateralis in a natural pasture

Abstract: The objective of this work was to evaluate tiller dynamics and population stability of Andropogon lateralis in a natural pasture subjected to grazing height management under intermittent stocking method. The experiment was carried out in a randomized complete block design with four treatments and four replicates, in 16 experimental units of 875 m2 each. The treatments consisted of four pre-grazing heights of A. lateralis (12, 20, 28, and 36 cm), which was grazed until its initial height was reduced by 40%. Dynamics of tiller birth and death were evaluated using the marked tiller technique over a period of 18 months, from October 2015 to March 2017. The results indicate that the use of different heights for the management of natural pastures does not affect the stability of the tiller population of A. lateralis and that, regardless of the management strategy, the persistent pathway of this species is mainly based on the maintenance of high-tiller survival rates.

Parameterising wheat leaf and tiller dynamics for faithful reconstruction of wheat plants by structural plant models

Structural 3D plant models aim at mimicking the dynamics of plant and crop structure based on experimental data. Such models can be interfaced with physical models to investigate plant-environment interactions. This work aimed at defining functions that represent the leaf and tiller development of individual wheat plants, and that could be fitted to the specific traits produced in a broad range of situations.A dataset of the dynamics of wheat plant (Triticum aestivum) architecture was collected for 55 experimental situations, including 11 growing seasons, three sowing densities, three sowing dates, and 13 commercial cultivars. Data were analysed to identify conserved patterns in the dynamics of leaf emergence and of tiller emergence and senescence.The broad range of conditions tested allowed us to evaluate the robustness of relationships proposed in previous studies and to identify novel patterns. Amongst them, we observed: (i) that leaf emergence dynamics may follow either a linear or a bilinear pattern for the same genotype. When a change in phyllochron occurred, it coincided with the initiation of the flag leaf; (ii) the delay between leaf and tiller emergence was not constant, but increased very regularly for successive phytomers; (iii) the number of leaves emerged at tillering cessation decreased with plant density but depended also on the final number of leaves on the main stem (MS) and marked differences existed between cultivars. Finally, we defined functions representing leaf and tiller dynamics with parameters that have a simple botanical interpretation and are easy to derive from field measurements. Assessing plant density, crop leaf stage at 5–6 dates and tiller population at 2 dates during the cycle provide the required data.This study defines a rationale to analyse and represent the dynamics of the architecture of individual wheat plants. The method can be used to determine the dynamics of architecture in 3D models and should be transposable to a wide range of cereal species.

CHANGES IN TILLERING DYNAMICS OF INTERCROPPED BLACK OAT AND ANNUAL RYEGRASS ENSURE A STABLE SWARD

SUMMARYMixing species with different tillering peaks may enhance pasture stability, but intercropping may also alter the plants’ tillering patterns. This study aimed to evaluate tillering dynamics in black oat (Avena strigosa Schreb.) and annual ryegrass (Lolium multiflorum Lam.) pastures grown as monocultures or intercropped. Three following treatments are established: black oat and annual ryegrass pastures grown as monocultures and an intercrop composed of these two species. Tillering dynamics were measured for black oat and annual ryegrass populations separately. When intercropped, tiller birth rates of black oat decreased (20.0 vs. 28.9 tillers 100 tillers−1) and those of annual ryegrass increased (30.5 vs. 14.3 tillers 100 tillers−1), compared to their monocultures. Tiller death rates for annual ryegrass did not differ between monoculture and intercropping (23.9 tillers 100 tillers−1), but black oat presented higher mortality in monocultures (48.8 vs. 36.4 tillers 100 tillers−1). The black oat monoculture had the lowest population stability index (0.80), whereas annual ryegrass in monoculture and intercropped pastures exhibited greater values (on average, 0.92). Our results indicated that black oat and annual ryegrass present distinct tillering dynamics whether grown as monoculture or intercropped, and suggest that intercropping species with elevated death rates (black oat) with later species (annual ryegrass) could be an important tool for maintaining pasture stability throughout the growing season.

Temporal tillering behavior of Sri Lankan elite rice varieties in response to phosphorus availability

Tillering is closely related to environmental conditions including the accessibility to nutrients. Phosphorus (P) availability affects tillering dynamics in rice. A hydroponic experiment was conducted to identify the tillering dynamics of forty eight elite rice varieties in response to optimum (50 μM) and deprived (10 μM) P status in the growing medium. Results showed that there was a significant delay in tillering in P deprived condition. Days taken to tillering, shoot dry weight, root dry weight, growth rate, shoot P concentration, P uptake rate, P utilization efficiency and shoot : root dry weight ratio at the time of tillering were affected by the variety and level of P supply. There was no relationship between the time to initiate tillering and the age for maturity of a rice variety. The variety Bg 94-1showed least delay in tillering followed by Bg 454 and At 353 and they were identified as tolerant varieties while most of elite rice varieties were identified as susceptible rice varieties for P deficiency tolerance. Furthermore, days taken for tillering can be used as a nondestructive criterion in selecting plants in segregating populations at early growth stages for P deficiency tolerance.

Effects of soilless substrates on seedling quality and the growth of transplanted super japonica rice

This study was conducted to investigate the effects of soilless substrates of hydroponically grown long-mat seedlings (HLMS) on seedling quality and field growth characteristics of transplanted super japonica rice. A widely grown conventional super japonica rice cultivar (Wuyunjing 23) was selected as the test material. The effect of HLMS on seedling quality, mechanical transplantation quality, field growth characteristics, yield, and benefit-cost ratio were compared with seedlings grown in organic substrates and traditional nutritive soil, which was selected as the control. Root number, root twisting power and root activity of seedlings cultivated by HLMS were decreased compared to that of the organic substrates and control. However, seedling root length as well as aboveground growth were increased compared to the organic substrates and control seedlings. In the HLMS, the content of gibberellin acid (GA3) decreased while abscisic acid (ABA) content increased compared to that of the organic substrates and control seedlings. During the early stages after transplanting, the re-greening of HLMS was delayed compared to that of the organic substrates and control seedlings. Nevertheless, there were no significant differences in tiller dynamics and crop yield among the HLMS, organic substrates and control treatments. The effects of HLMS on seedling production were similar to those of the organic substrates and traditional nutritive soil in the present study, suggesting that HLMS have the potential to replace traditional nutritive soil in seedling production without decreasing crop yield. Finally, it is important to reduce organic substrates and topsoil dependence during rice seedling production and worthwhile to consider HLMS popularization and its application on a larger scale.

Effect of Plant Growth Regulators on Tiller Dynamics and Yield of Sugarcane (Saccharum officinarum L.)

Effect of Plant Growth Regulators on Tiller Dynamics and Yield of Sugarcane (Saccharum officinarum L.)

Reduction of sward height in the fall/winter as strategy to optimize tillering in Urochloa brizantha syn. Brachiaria brizantha

The evaluation of tillering dynamics is important to understand the effects of defoliation strategies and climate on forage production and perenniality of the sward. Therefore, the objective of this study was to identify defoliation strategies that optimize the tillering of marandu palisadegrass through the year. Three defoliation strategies were evaluated: sward with 15 cm in fall/winter and 30 cm in spring/summer; 45 cm in fall/winter and 30 cm in spring/summer; and 30 cm during the entire experimental period. Tiller appearance (TAR), mortality (TMR), and survival (TSR) rates; the balance (BAL) between TAR and TMR; stability index (SI); and tiller density (TD) were evaluated monthly and grouped into the seasons: winter, early spring, late spring, and summer. A completely randomized design with four replicates was adopted. In summer and early spring, TAR, SI, and TD were higher than in winter and late spring. Winter was characterized by unfavorable climatic conditions to plant growth, such as low precipitation and temperature, and in summer there was a short period of rainfall scarcity. The defoliation strategies in fall/winter did not influence tillering dynamics. The marandu palisadegrass with 15 cm in fall/winter showed a greater TD than that with 45 cm. To increase TD, marandu palisadegrass can be maintained at 15 cm in fall/winter, and at 30 cm in summer.