Basal Tillers Research Articles

Structure of differed Marandu palisade grass with variables nitrogen doses and heights

This study aims to evaluate the effects of height (15 and 30 cm)and nitrogen dose (N, 40, 80, and 120 kg ha-1) at the beginning of thestockpiling period on the structural characteristics of the Urochloabrizantha cv. Marandu (Marandu palisade grass) during winter. Thefalling index of the plant did not vary with the factors under scrutiny(P>0,10). The number of basal tillers was higher (P<0,10) in the 15-cmdeferred canopy than in the 30-cm canopy only when the highest N dosewas used. Under conditions of application of 0 or 80 kg ha-1 of N, the 30-cmstockpiled canopies showed a higher (P<0,10) forage mass than the 15-cmones. Associated with reduced canopy height at the beginning ofstockpiling period, nitrogen fertilization improves the morphologicalcomposition of Marandu palisade grass. To maximize the forage mass inthe dry season, the canopies of Marandu palisade grass can be deferredeither at 15 cm (fertilized with about 100 kg ha-1 of N) or at 30 cm (with nonitrogen fertilization) at the beginning of the stockpiling period.

Studies on correlation and path coefficient analysis in foxtail millet [Setaria italica (L.) BEAUV

The present investigation consists of 40 genotypes of Foxtail Millet, which were grown in the Field Experimentation Centre of the Department of Genetics and Plant breeding, SHUATS, Prayagraj during Kharif 2019 following RBD with three with three replications. The data were recorded on 13 characters to study the analysis of variance, heritability, genetic advance, coefficient of variation, correlation coefficient and path analysis. Based on the mean performance genotype ISE1419, were identified as best genotypes for grain yield per plant. Highly significant variation was obtained for all characters studies. The values of PCV were higher than that of GCV for all the characters. High heritability estimates coupled with high genetic advance as percent mean were observed for Harvest index(%) followed by test weight, Grain yield, No. of basal tillers, Inflorescence width. Thus these traits are predominantly under the control of additive gene action and these Charecters can be improved by selection. Moderately high genetic advance observed for Days to 50% flowering, leaf width, flag leaf length Biological yield and No. of days to maturity. These traits appear to be under the control of both additive and non additive gene actions. The present study revealed that grain yield per plant was positively and significantly correlated with Days to 50% flowering, No. of Days to maturity, Plant height, Panicle length, Inflorescence width, Biological yield, Harvest index, Test weight. Path analysis studies revealed that Days to 50% flowering, Panicle length, Peduncle length, Biological yield, Harvest index and Test weight had true relationship with grain yield per plant by establishing significant positive association and positive direct effect at phenotypic level. Considering the nature and magnitude of character associations and direct and indirect effects, it can be inferred that days to 50% flowering, Panicle length, Peduncle length Biological yield, Harvest index and test weight could serve as important traits in any selection programme for developing high yielding foxtail millet genotypes.

ζ-Carotene Isomerase Suppresses Tillering in Rice through the Coordinated Biosynthesis of Strigolactone and Abscisic Acid

Rice tillering is an important agronomic trait affecting grain yield. Here, we identified a high-tillering mutant tillering20 (t20), which could be restored to the wild type by treatment with the strigolactone (SL) analog rac-GR24. T20 encodes a chloroplast ζ-carotene isomerase (Z-ISO), which is involved in the biosynthesis of carotenoids and their metabolites, SL and abscisic acid (ABA). The t20 mutant has reduced SL and ABA, raising the question of how SL and ABA biosynthesis is coordinated, and whether they have overlapping functions in tillering. We discovered that rac-GR24 stimulated T20 expression and enhanced all-trans-β-carotene biosynthesis. Importantly, rac-GR24 also stimulated expression of Oryza sativa 9-CIS-EPOXYCAROTENOID DIOXYGENASE 1 (OsNCED1) through induction of Oryza sativa HOMEOBOX12 (OsHOX12), promoting ABA biosynthesis in shoot base. On the other hand, ABA treatment significantly repressed SL biosynthesis and the ABA biosynthetic mutants displayed elevated SL biosynthesis. ABA treatment reduced the number of basal tillers in both t20 and wild-type plants. Furthermore, while ABA-deficient mutants aba1 and aba2 had the same number of basal tillers as wild type, they had more unproductive upper tillers at maturity. This work demonstrates complex interactions in the biosynthesis of carotenoid, SLs and ABA, and reveals a role for ABA in the regulation of rice tillering.

What is the productive potential of digit grass in response to nitrogen fertilization?

The digit grass is a highly cultivated species in Northeast Brazil, especially in Sergipe and Alagoas. However, research related to the management of fertilization of this specie is incipient. This experiment was carried out to examine the productive potential of digit grass and its morphological changes in response to nitrogen fertilization. The experimental period was from August 2014 to July 2015. Treatments consisted of five levels of nitrogen fertilization (0, 50, 100, 300 and 600 kg ha-1) arranged in a randomized-block design with four replicates. Urea was used as a source of nitrogen. Height, light interception (LI), leaf area index (LAI), total tiller density (TTD), basal tiller density (BTD) and total (TDM), leaf (LDM) and stem dry matter (SDM) accumulations were influenced (P<0.05) by the nitrogen doses, fitting a positive quadratic equation. Nitrogen fertilization did not influence (P>0.05) dead material accumulation rate or aerial tiller density. Overall, the increasing nitrogen doses culminated in increased canopy height, LI and LAI as a result of the increase in TTD and BTD, which in turn elevated TDM, LDM and SDM. The herbage yield potential of digit grass can be increased with the application of 478 kg N ha-1, enabling its use as an alternative in intensive animal production systems.

Enumeration of genetic diversity of wild rice through phenotypic trait analysis

Nine species of wild rice viz. Oryza alta, O. australiensis, O. barthii, O. longistaminata, O. punctata, O. officinalis, O. brachyantha, O. rhizomatis and O. rufipogon were used for morphological trait analysis. Analyzed traits were number of node and internodes, flag leaf length and breadth, leaf blade length and width, leaf blade area, ligule length, height of tiller, tiller base thickness, auricle length, awn length, culm length, panicle length, length of primary branches, spikelet length and width, grain length and width, spikelet per panicle, peduncle length, thickness of awn, anther length and days of flower initiation. A significant variation was found for all qualitative and quantitative parameters among all the nine species of wild rice.

Diversity study using principal component analysis in barnyard millet (Echinochloa frumentacea (Roxb.) Link)

Among nutri-cereals, now-a-days, barnyard millet getting popular among the public for its rich nutritional and cooking qualities. A total of forty genotypes were evaluated in three different environments to study the genetic diversity using Principal Component Analysis. Foremost three components contributed 85.65% of the total multivariable differences. Germplasm projection delivered four main groups on first two canonical components. Genotypes splitting were on the basis of trait performance. Majority of the traits had explained low to moderate values with negative loadings to PC1, PC2 and PC3 except few traits like thousand grain weight and number of basal tillers, which had positive loadings with high values. Loadings bi-plots of PC1-PC2 and PC1-PC3, classified the groups into two major categories, consisting of late matured -high yielding genotypes on left side and early matured -low to medium yielding genotypes on right side of scattering.

Genetic variability and association analysis in barnyard millet mutants

The present study was carried out using 40 mutants along with two check varieties CO(Kv)2 and MDU1 during Kharif 2019. Sixteen characters were studied and out of which only 11 traits showed significant variation. Correlation and path analysis were done for 11 traits viz., number of basal tillers, days to fifty percent flowering, flag leaf length, panicle length, plant height, number of raceme, number of productive tillers, number of leaves in main tiller, average leaves in side tiller, single ear head weight and single plant yield. Among the eleven biometrical traits, high heritability was recorded by traits such as number of basal tillers, days to fifty percent flowering, flag leaf length, plant height, number of racemes, number of productive tillers, number of leaves in main tiller, single ear head weight and single plant yield. Correlation studies showed that number of productive tillers, single ear head weight and plant height possess significant positive correlation with yield at both genotypic and phenotypic level. Path analysis showed that traits like number of basal tillers, single ear head weight and panicle length had high direct effect on yield. Thus, selection of these traits would be rewarding for yield improvement in barnyard millet.

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.

Growth dynamics and senescence of digit grass as a response to several canopy heights

The purpose of this study was to examine the growth and senescence dynamics of Digitaria eriantha cv. Survenola as a response to several canopy heights (25, 35, 45, and 55 cm) of harvests in two seasons of the year (rainy and dry). The experiment was established at the Federal University of Sergipe, in São Cristóvão - SE, Brazil, from 03/26/2015 to 03/28/2016, under a randomized-complete-block design with four replicates. Plots were irrigated, and upon reaching the pre-established canopy heights, they were cut to a 10 cm-residual height. Increasing canopy heights in the dry season led to lower tiller density, for basal and aerial tillers. However, irrespective of tiller type and season, this variable increased after the rest period. Light interception rose with canopy heights (P<0.05) in the dry period and it showed a quadratic response in the rainy season. Greater canopy heights led to a higher (P<0.05) daily leaf senescence rates and daily stem growth rates. Regardless of the season, the total accumulation and net herbage accumulation rates of basal tillers increased as canopy heights did. The greatest canopy height promoted the daily stem production, whereas the lowest height did not allow the grass to express its production potential. The defoliation-height range of 35 to 45 cm is the most recommended, as it favors the control of stem growth and leaf senescence.

Phenotypic Diversity and Molecular diversity of Finger Millet Composite Collection and Identification of Trait Specific Germplasm for Use in Crop Improvement

A composite collection of finger millet consisting of 1000 accessions representing the diversity of the entire germplasm at ICRISAT gene bank was developed, including 622 accessions of ICRISAT core collection. Phenotyping of the composite collection for 15 quantitative traits and 20 SSR markers genotyping data resulted in the identification of promising traitspecific accessions. Principal component analysis with seven components indicated relative importance of the traits (days to 50 % flowering, plant height, peduncle length, ear head length, and panicle exertion) to total divergence. Clustering analysis grouped biological races into three clusters wherein cultivated races vulgaris, plana, elongata, and compacta were grouped in Cluster I and wild races spontanea in Cluster II and africana in Cluster III. Accessions were identified as useful for important traits such as early flowering (34), high grain yield (38), fodder yield (19); more fingers (29); basal tiller number (25) and ear head length (28).

Morphogenetic and structural characteristics of Urochloa species under inoculation with plant-growth-promoting bacteria and nitrogen fertilisation

Ineffective management of pastures still constitutes the main problem in the Brazilian livestock industry, in which recovery of soil fertility is a determinant for soil restoration. In this context and in combination with the adoption of sustainable technologies, the use of plant-growth-promoting bacteria (PGPB) may represent an alternative to the use of chemical fertilisers that would reduce costs and environmental impacts. In this study, morphogenetic and structural characteristics were evaluated in three Urochloa (syn. Brachiaria) varieties. Urochloa is a genus that is present in the most degraded pastures in Brazil. The three varieties were inoculated with five PGPB (Azospirillum brasilense Ab-V5 and Ab-V6, Pseudomonas fluorescens CCTB 03 and ET76, and Pantoea ananatis AMG521) and treated with different doses of nitrogen (N) fertiliser (0, 50 and 100 kg N ha–1) in pots filled with sandy soil under greenhouse conditions. In general, for Marandu grass U. brizantha cvv. BRS Paiaguás and Xaraés, the best performances for leaf and stem elongation rates and number of basal tillers were obtained with strains CCTB 03 and AMG521. For U. ruziziensis, the best performance in the duration and rate of renewal of leaves and leaf senescence was observed with strains AMG521, Ab-V5 and Ab-V6. This result indicated the specificity of the effects of bacterial strains on different genotypes of Urochloa. Differences in the interactions between PGPB and N fertilisation were also verified. In U. brizantha, interaction effects were additive, whereas in U. ruziziensis, they were competitive. The results indicate the feasibility of inoculation of Urochloa with elite strains of PGPB that positively affect the production of forage biomass and allow reductions in N fertiliser usage.

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.

Natural Variations at TIG1 Encoding a TCP Transcription Factor Contribute to Plant Architecture Domestication in Rice

The modification of plant architecture is a crucial target in rice domestication and modern genetic improvement. Although several genes regulating rice plant architecture have been characterized, the molecular mechanisms underlying rice plant architecture domestication remain largely unclear. Here we show that the inclined tiller growth in wild rice is controlled by a single dominant gene, TILLER INCLINED GROWTH 1 (TIG1), which is located on chromosome 8 and encodes a TCP transcriptional activator. TIG1 is primarily expressed in the adaxial side of the tiller base, promotes cell elongation, and enlarges the tiller angle in wild rice. Variations in the TIG1 promoter of indica cultivars (tig1 allele) resulted in decreased expression of TIG1 in the adaxial side of tiller base and reduced cell length and tiller angle, leading to the transition from inclined tiller growth in wild rice to erect tiller growth during rice domestication. TIG1 positively regulates the expression of EXPA3, EXPB5, and SAUR39 to promote cell elongation and increase the tiller angle. Selective sweep analysis revealed that the tig1 allele was selected in indica cultivars by human beings. The cloning and characterization of TIG1 supports a new scenario of plant architecture evolution in rice.

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.

CARACTERÍSTICAS ESTRUTURAIS E PRODUTIVAS EM HÍBRIDOS INTRAESPECÍFICOS E INTERESPECÍFICOS DE CAPIM-ELEFANTE

Resumo Objetivou-se avaliar a estrutura e a produção de forragem em híbridos de capim-elefante manejados sob corte. Utilizaram-se como tratamentos 24 clones de capim-elefante provenientes da Embrapa Gado de Leite e o Cameroom como testemunha. Os capins foram cortados rentes ao solo, a cada 60 dias. Os parâmetros avaliados foram: produção e teor de matéria seca, número de perfilhos basais, número de folhas por perfilho, altura da planta, diâmetro do colmo. A maior altura das plantas foi observada no clone CNPGL 00-103-1. O grupo com maior número de perfilhos teve três clones e média de 39,38 perfilhos m-2. No grupo dos clones CNPGL 00-103-1, CNPGL 93-25-3, CNPGL 00-16-1 e CNPGL 00-90-3 foram observados os maiores teores de matéria seca (22,7% de MS). As maiores massas de forragem, de lâmina foliar e de colmo foram observadas no clone CNPGL 00-214, 15852 e 6195 kg ha-1 de MS respectivamente. A maior relação lâmina foliar/colmo foi do clone CNPGL 00-201-1 e apenas neste a massa de lâmina foliar foi superior à de colmo. O clone CNPGL 00-214 mostrou-se mais produtivo, com alta capacidade de perfilhamento e de acúmulo de forragem.

Grazing intensity modulates carbohydrate storage pattern in five grass species from temperate grasslands

Regrowth after defoliation is an essential mechanism of plant tolerance to grazing. In grasses, non-structural carbohydrates (NSC) contained in tiller bases constitute a major substrate for regrowth after defoliation. Using a multi-specific approach, the present study aimed at testing the effect of grazing intensity on NSC concentration in tiller bases. We selected five grazing-tolerant grass species (Agrostis stolonifera, Cynosurus cristatus, Hordeum secalinum, Lolium perenne and Poa trivialis) and collected plants in a grassland subjected to two cattle grazing intensities (intensive versus moderate) for years. We measured NSC concentrations (starch, fructans, sucrose, glucose and fructose) in tiller bases. We found that fructan and sucrose concentrations before the grazing season (April) were higher under intensive than moderate grazing. By contrast, no significant effect of the grazing intensity on these NSC concentrations in tiller bases remained at the end of the grazing season (October). These results suggest that the level of reserves available before the onset of disturbance caused by grazing as well as the reserve replenishment capacity during the grazing season are modified by the intensity of grazing.

Non-dormant Axillary Bud 1 regulates axillary bud outgrowth in sorghum.

Tillering contributes to grain yield and plant architecture and therefore is an agronomically important trait in sorghum (Sorghum bicolor). Here, we identified and functionally characterized a mutant of the Non-dormant Axillary Bud 1 (NAB1) gene from an ethyl methanesulfonate-mutagenized sorghum population. The nab1 mutants have increased tillering and reduced plant height. Map-based cloning revealed that NAB1 encodes a carotenoid-cleavage dioxygenase 7 (CCD7) orthologous to rice (Oryza sativa) HIGH-TILLERING DWARF1/DWARF17 and Arabidopsis thaliana MORE AXILLARY BRANCHING 3. NAB1 is primarily expressed in axillary nodes and tiller bases and NAB1 localizes to chloroplasts. The nab1 mutation causes outgrowth of basal axillary buds; removing these non-dormant basal axillary buds restored the wild-type phenotype. The tillering of nab1 plants was completely suppressed by exogenous application of the synthetic strigolactone analog GR24. Moreover, the nab1 plants had no detectable strigolactones and displayed stronger polar auxin transport than wild-type plants. Finally, RNA-seq showed that the expression of genes involved in multiple processes, including auxin-related genes, was significantly altered in nab1. These results suggest that NAB1 functions in strigolactone biosynthesis and the regulation of shoot branching via an interaction with auxin transport.

Tiller population dynamics in eight cultivars of elephant grass during undisturbed growth

The aim of the study was to assess tiller population dynamics of aerial and basal tillers in eight cultivars of Pennisetum purpureum (Schumach.), syn. Cenchrus purpureus (Schumach.) Morrone, in a warm humid climate in Veracruz, Mexico. This is a pioneer study on tiller population dynamics in elephant grass under conditions of undisturbed growth. The tiller population assays included data from 14 days after cutting until 154 and 182 days after cutting for the dry and wet seasons, respectively. On each sampling date, a distinctive ring was placed on every new tiller, and rings were removed from dead tillers. Tiller density, mortality and appearance were determined. In wet seasons, copious tillering occurred on initial regrowth (by day 42, mostly aerial tillers, with a ratio of 2:1 to 4:1 for aerial to basal tiller appearance), and on day 98 (a higher proportion of basal tillers, with an aerial to basal tiller ratio of 1.5:1). Aerial tillers showed a higher overall mortality rate than basal tillers (29.0 vs 14.4). Younger basal tillers showed higher mortality than older tillers. Higher tiller density occurred during the dry season, where it increased gradually until day 70 and then declined. The cultivars ‘Cameroon‘, ‘CT115‘ and ‘OM22‘ showed remarkably high tillering ability. The findings indicate that harvesting a forage bank is possible from day 70 during a dry season.

Key factors that influence for seasonal production of Guinea grass

Climate, soil and management are the main drives for growth and production of tropical pastures. Thus, a better understanding of the effects of these factors and their interactions under climate conditions is required to obtain effective management options. Here, we used data from two field trials to research on climate and management interactions on the production seasonality of Panicum maximum Jacq. Treatments included four sampling times (250, 500, 750, and 1000 °C accumulated) during eight regrowth period, under irrigated and rainfed conditions and, cuts were made to simulate grazing intensity. All treatments were arranged in a completely randomized block design with four replications. At each sampling time, basal tillers were sampled to observe meristematic differentiation and were linked with the respective daylength. Soil moisture was determined, and the water availability index (WAI) was calculated. The dry matter production (DMP) was taken and relative productivity was calculated. Soil moisture was the key seasonal drive in spring-summer and the WAI could be used to adjust the maximum production for that season. The major drive for DMP in fall was the daylength, which was found at 11.81 h. For all seasons, DMP correlated better with the residues in early regrowth phase (r = 0.82 and p < 0.0001) and with degree-days at final regrowth phase (r = 0.73 p < 0.01). Applying these critical values to management guidelines should make Guinea grass DMP more efficient on tropical farms.