Sugarcane Roots Research Articles

<b>Effect of <i>Anacardium humile</i> St. Hill (Anacardiaceae) Aqueous Extract on <i>Mahanarva fimbriolata</i> (Stal, 1854) (Hemiptera: Cercopidae)</b> - doi: 10.4025/actasciagron.v35i4.16597

The study of plant-derived substances for the control of insect pests is desirable in the attempt to discover less toxic insecticides that are safe for the environment. Indeed, extracts from the cashew of the savannah, Anacardium humile, have shown insecticidal activities against certain insects. The sugarcane root spittlebug Mahanarva fimbriolata is considered an important pest of sugarcane, causing severe damage and significant yield reductions. The aim of this study was to evaluate the effect of the aqueous extract of A. humile (0.05, 0.4 and 1.0%) on M. fimbriolata. The application of the aqueous extract of Anacardium humile resulted in 53.1% nymphal mortality at a concentration of 1.0%, which was significantly higher than that observed in the negative control. The nymphal period and longevity of M. fimbriolata, however, were not affected by the aqueous A. humile extract.

Weedy Host Plants of the Sugarcane Root Weevil (Coleoptera: Curculionidae) in Florida Sugarcane

A greenhouse study was conducted to evaluate adult sugarcane root weevil (Diaprepes abbreviatus (L.)) residence (location), feeding damage, and oviposition choice on 4 sugarcane varieties and 5 weed species found in Florida sugarcane. Sugarcane varieties were CP 89 - 2143, CP 88 - 1762, CP 80 - 1743, and CP 78 - 1628. Weed species were common lambsquarters (Chenopodium album L.), spiny amaranth (Amaranthus spinosus L.), common purslane (Portulaca oleracea L.), sicklepod (Senna obtusifolia (L.) H.S. Irwin & Barneby), and coffee senna (Senna occidentalis (L.) Link). Adult residence was highest on coffee senna followed by spiny amaranth, sicklepod, and common purslane. Few adults were observed on sugarcane varieties and common lambsquarters. Adults caused feeding damage on all weed species. Coffee senna, spiny amaranth, and sicklepod had the highest feeding damage whereas common lambsquarters had the least damage. Little feeding damage was observed on sugarcane varieties. Oviposition of D. abbreviatus was observed on all sugarcane varieties and weed species with exception of common lambsquarters and sicklepod. Significantly more egg masses were found on sugarcane varieties compared with weed species. Weed surveys conducted in 3 locations in Florida sugarcane showed common lambsquarters, spiny amaranth, common purslane, and sicklepod as common broadleaf weeds in sugarcane fields. These results show that several weed species found in Florida sugarcane are suitable as food sources and oviposition sites for D. abbreviatus. However, sugarcane is generally more preferred for oviposition by D. abbreviatus. Preventing or removing weed hosts of D. abbreviatus from sugarcane fields will be an important defense against the weevil.

Expression Analysis of Sugarcane Aquaporin Genes under Water Deficit

The present work is a pioneer study specifically addressing the aquaporin transcripts in sugarcane transcriptomes. Representatives of the four aquaporin subfamilies (PIP, TIP, SIP, and NIP), already described for higher plants, were identified. Forty-two distinct aquaporin isoforms were expressed in four HT-SuperSAGE libraries from sugarcane roots of drought-tolerant and -sensitive genotypes, respectively. At least 10 different potential aquaporin isoform targets and their respective unitags were considered to be promising for future studies and especially for the development of molecular markers for plant breeding. From those 10 isoforms, four (SoPIP2-4, SoPIP2-6, OsPIP2-4, and SsPIP1-1) showed distinct responses towards drought, with divergent expressions between the bulks from tolerant and sensitive genotypes, when they were compared under normal and stress conditions. Two targets (SsPIP1-1 and SoPIP1-3/PIP1-4) were selected for validation via RT-qPCR and their expression patterns as detected by HT-SuperSAGE were confirmed. The employed validation strategy revealed that different genotypes share the same tolerant or sensitive phenotype, respectively, but may use different routes for stress acclimation, indicating the aquaporin transcription in sugarcane to be potentially genotype-specific.

RNA Interference of Endochitinases in the Sugarcane Endophyte Trichoderma virens 223 Reduces Its Fitness as a Biocontrol Agent of Pineapple Disease

The sugarcane root endophyte Trichoderma virens 223 holds enormous potential as a sustainable alternative to chemical pesticides in the control of sugarcane diseases. Its efficacy as a biocontrol agent is thought to be associated with its production of chitinase enzymes, including N-acetyl-ß-D-glucosaminidases, chitobiosidases and endochitinases. We used targeted gene deletion and RNA-dependent gene silencing strategies to disrupt N-acetyl-ß-D-glucosaminidase and endochitinase activities of the fungus, and to determine their roles in the biocontrol of soil-borne plant pathogens. The loss of N-acetyl-ß-D-glucosaminidase activities was dispensable for biocontrol of the plurivorous damping-off pathogens Rhizoctonia solani and Sclerotinia sclerotiorum, and of the sugarcane pathogen Ceratocystis paradoxa, the causal agent of pineapple disease. Similarly, suppression of endochitinase activities had no effect on R. solani and S. sclerotiorum disease control, but had a pronounced effect on the ability of T. virens 223 to control pineapple disease. Our work demonstrates a critical requirement for T. virens 223 endochitinase activity in the biocontrol of C. paradoxa sugarcane disease, but not for general antagonism of other soil pathogens. This may reflect its lifestyle as a sugarcane root endophyte.

Thiamethoxam on the histological characteristics of sugarcane young roots

Thiamethoxam is a systemic insecticide from the neonicotinoid group, nitroguanidin family which affects the nicotinic receptor acetyl choline in the insect membrane, wounding the nervous system and causing the death of the insect. It was used with success in the control of initial pests of several crops. It was considered that thiamethoxam has a bioactivator effect, because in the absence of insects promoted increase in vigor, development and productivity of crops. This work was carried out to verify if thiamethoxam causes histological changes in sugarcane roots. In this work, it was used optical microscopy, images arrest, tissue biometrics and statistical analysis, in young roots of sugarcane RB 83 5486 after the treatments with different thiamethoxam concentrations. It was determined changes in histological structure of tissues 7, 14, 21 and 28 days after the treatments, establishing its effects on root plant anatomy. It was verified that thiamethoxam increased root cortex width, increasing the vascular cylinder and the metaxylem vessel elements number in the vascular tissue until 21 days after application.

Soil physical properties and sugarcane root growth in a red oxiso

Sugarcane, which involves the use of agricultural machinery in all crop stages, from soil preparation to harvest, is currently one of the most relevant crops for agribusiness in Brazil. The purpose of this study was to investigate soil physical properties and root growth in a eutroferric red Oxisol (Latossolo Vermelho eutroférrico) after different periods under sugarcane. The study was carried out in a cane plantation in Rolândia, Paraná State, where treatments consisted of a number of cuts (1, 3, 8, 10 and 16), harvested as green and burned sugarcane, at which soil bulk density, macro and microporosity, penetration resistance, as well as root length, density and area were determined. Results showed that sugarcane management practices lead to alterations in soil penetration resistance, bulk density and porosity, compared to native forest soil. These alterations in soil physical characteristics impede the full growth of the sugarcane root system beneath 10 cm, in all growing seasons analyzed.

Trocas gasosas e balanço de carboidratos em plantas de cana-de-açúcar sob condições de estresses radiculares

Embora a resposta da fotossíntese de plantas de cana-de-açúcar a estresses ambientais seja conhecida, o acúmulo de fitomassa e a dinâmica de carboidratos de reserva diante da exposição simultânea ao frio e à seca são pouco conhecidos. Este trabalho objetiva investigar o efeito do déficit hídrico e da baixa temperatura radicular, isolados e simultaneamente, no genótipo de cana-de-açúcar IACSP94-2094, considerado tolerante à seca. Como hipótese, consideramos que este genótipo também é tolerante à baixa temperatura radicular, já que baixas temperaturas e déficit hídrico ocorrem simultaneamente no campo. A imposição da restrição hídrica de forma isolada ou simultaneamente à baixa temperatura radicular causou redução do potencial da água na folha e da assimilação de CO2, o que não foi observado nas plantas submetidas apenas à baixa temperatura do substrato. Os teores foliares de carboidratos não estruturais, de sacarose e de amido aumentaram nas plantas sob frio radicular. Nos tratamentos com déficit hídrico, apenas o teor de amido foliar diminuiu. Os estresses radiculares causaram aumento nos teores de açúcares solúveis totais e diminuição no teor de amido nas raízes. Como o acúmulo de fitomassa das plantas não foi afetado, mesmo com a restrição no crescimento radicular nos tratamentos com baixa temperatura do substrato, conclui-se que o genótipo de cana-de-açúcar IACSP94-2094 contém indícios de tolerância à baixa temperatura radicular. A manutenção do crescimento da planta deve estar associada à degradação das reservas de amido foliares e radiculares.

High soil penetration resistance reduces sugarcane root system development

Although mechanized harvesting of sugarcane can benefit the soil–environment system, successive harvests can compromise the physical soil quality. Information on the growth and distribution of the sugarcane root system and its relationship with physical soil properties are scarce in the literature. The objective of this study was to analyze the relationships between the spatial distribution of physical soil properties and sugarcane root density in a mechanically harvested area. The study was carried out in Jaboticabal, SP, Brazil in a Typic Kandiudox and with the SP81 3250 cultivar. Sugarcane plots were established in April 2005, and samples were taken from four trenches in July 2008 after three successive harvests. In each trench, 15 undisturbed soil samples were collected to evaluate bulk density ( Ds), penetration resistance ( Pr), total porosity ( Tp) and moisture at field capacity ( θ fc ), and 15 monoliths were collected to evaluate the root density ( Rd), root length ( Rl), root area ( Ra) and root moisture ( Rm) at different depths and plant locations. Soil moisture was balanced to the field capacity before Pr determination. The hypothesis that the sugarcane root system varied vertically and horizontally relative to the central axis of the plant and in relation to physical soil parameters was validated. Soil physical parameters varied significantly in the vertical direction, but sugarcane root system varied both vertically and horizontally. Ds values were 1.57, 1.55 and 1.39 g cm −3 for layers between 0 and 0.2 m, 0.2 and 0.4 m and 0.4 and 0.6 m, respectively. For the same layers, the Pr was 1.42, 1.20 and 0.87 MPa. The largest Pr value (1.93 MPa) was obtained near the surface in the space between rows. As Ds increased, Tp decreased and Pr increased. A consistent relationship was observed between Ds and Pr in all layers, and restrictions on root growth ( Pr > 2.0 MPa) may occur when Ds ≥ 1.78 g cm −3. The multivariate boundary line approach, in combination with nonlinear multiple regression analysis, successfully quantified the effects of Pr on Rd, Rl and Ra. Sugarcane root growth was not affected below Pr values of 0.75 MPa, but decreased significantly between 0.75 and 2.0 MPa. Root growth was severely restricted when Pr > 2.0 MPa.

Atividade da enzima redutase do nitrato e teores de prolina livre em raízes de cana-de-açúcar sob os estresses hídrico e ácido no solo

The aim of this work was evaluate the physiological indicators of association between water deficiency and soil acidity, by determining the nitrate reductase activity, the levels of free proline and initial growth of the root system of seedlings of sugarcane cv. IAC91-5155. After 30 days, the seedlings were transferred to plastic pots with 12 dm 3 of dystrophic alic Red Latosol (Oxisol) and submitted to association of three treatments of water availability: no stress (70%), moderate stress (55%) and severe stress (40%), in according with field capacity and three acidity treatments: no stress (55%), moderate stress (33%) and severe stress (23%), considering the base saturation. The experimental design was that of random blocks under factorial scheme of 3x3, with four replicates. After 60 days under the stress association, the levels of free proline, the nitrate reductase activity and the growth of the sugarcane roots system were evaluated in seedlings of sugarcane. The nitrate reductase enzyme activity can be considered a physiological indicator of the effect of the association of acid and water stress in moderate conditions in soil, while the free proline can be considered physiological indicator to both stress in severe conditions. Water deficiency increasing reduced growth of sugarcane roots.

Bionomic data and larval density of Scarabaeidae (Pleurosticti) in sugarcane in the central region of Mato Grosso do Sul, Brazil

Bionomic data and larval density of Scarabaeidae (Pleurosticti) in sugarcane in the central region of Mato Grosso do Sul, Brazil. Phytophagous larvae of Scarabaeidae cause damage to diverse crops. Information on these pests is scarce; therefore, the objective of this study was to determine biological aspects and larval density of species occurring in an area of sugarcane. The studies were developed in Sidrolândia from April 2009 to March 2010. Scarab beetle larvae were collected in sugarcane roots every fifteen days, taken to the laboratory and reared to obtain the adults and determine biological parameters. A total of 2,656 larvae were collected, being 162 Liogenys fuscus, 120 Cyclocephala verticalis, 37 Cyclocephala forsteri, and 2337 Anomonyx sp. In January, 53.65 larvae m-2 were obtained, and the most abundant species was Anomonyx sp, representing 87.99% of the total larvae collected. From November to March, the greatest densities of Anomonyx were observed in the field. The adults of this species occurred from May to September, and egg laying from September to November. Eggs measured 1.1 x 1.7 mm, and incubation period last 15.4 days. First instar larvae were observed mainly in October; second instar larvae from November to April; and third instar from January to July. Pupae were observed from May to August. The most abundant scarab beetle, Anomonyx sp. in roots of sugarcane presents one generation per year in Sidrolândia, MS.

Interaction of Azospirillum brasilense and Glomus intrarradix in Sugar Cane Roots

Fifteen-day-old variety NA 56-79 sugar cane seedlings were inoculated with Azospirillum brasilense and Glomus intrarradix. This article aims at examining changes in sugar cane root seedlings inoculated with Glomus intrarradix and Azospirillum brasilense, the increase in microbial biomass and the acetylene reduction process as well. The internal root colonization was studied 20days after inoculation using scanning and a transmission electron microscope. Both microorganisms entered the sugar cane root through the emergent lateral roots. The microorganisms were capable of coexisting both intra and intercellularly, producing changes in the cell wall, thus allowing colonization and interaction between the organisms. These changes increased the number of microorganisms inside the root as well as acetylene nitrogen reduction. Sugar cane plant biomass increased with joint-inoculation. The number of endophytic microorganisms and nitrogen fixing activity increased when they were colonized by Azospirillum and Glomus together.

Differential pathogenicity of Metarhizium anisopliae and the control of the sugarcane root spittlebug Mahanarva fimbriolata

In order to assess the effectiveness of Metarhizium anisopliae var. anisopliae (Metschnikoff) Sorokin isolates in controlling the sugarcane root spittlebug Mahanarva fimbriolata (Stal) (Hemiptera: Cercopidae), nine isolates obtained from a single geographical region were studied. 'Confirmed cumulative' and 'corrected cumulative' spittlebug mortality rates were measured for each of the isolates. Based on the confirmed mortality curve, the isolates URM5946, URM5951 and URM6033 were considered to be potentially the most effective in a biological control program for M. fimbriolata.

Molecular characterisation of the diazotrophic bacterial community in uninoculated and inoculated field-grown sugarcane (Saccharum sp.)

To identify active diazotrophs in sugarcane, 16S rRNA and nifH transcript analyses were applied. This should help to better understand the basis of the biological nitrogen fixation (BNF) activity of a high nitrogen fixing sugarcane variety. A field experiment using the sugarcane variety RB 867515 was conducted in Seropedica, RJ, Brazil, receiving the following treatments: unfertilised and fertilised controls without inoculation, unfertilised with inoculation. The five-strain mixture developed by EMBRAPA-CNPAB was used as inoculum. Root and leaf sheath samples were harvested in the third year of cultivation to analyse the 16S rRNA and nifH transcript diversity. In addition to nifH expression from Gluconacetobacter spp. and Burkholderia spp., a wide diversity of nifH sequences from previously uncharacterised Ideonella/Herbaspirillum related phylotypes in sugarcane shoots as well as Bradyrhizobium sp. and Rhizobium sp. in roots was found. These results were confirmed using 16S cDNA analysis. From the inoculated bacteria, only nifH transcripts from G. diazotrophicus and B. tropica were detected in leaf sheaths and roots. Known as well as yet uncultivated diazotrophs were found active in sugarcane roots and stems using molecular analyses. Two strains of the inoculum mix were identified at the late summer harvest.

Induction of insect plant resistance to the spittlebug Mahanarva fimbriolata Stål (Hemiptera: Cercopidae) in sugarcane by silicon application

Changes in the agroecosystem with the increase of green cane harvesting in Brazil affected the insect populations associated to this crop, and secondary pests like the spittlebug Mahanarva fimbriolata Stål, became much more important. Many studies have demonstrated the active role played by silicon in plant defense against herbivory. The objective of this study was to evaluate the effects of silicon applications on the biology of the spittlebug reared on two resistant (SP79-1011 and SP80-1816) and one susceptible (SP81-3250) sugarcane cultivars. Sugarcane plants were grown under greenhouse conditions and submitted to different treatments: with and without silicon fertilizer in two different soil type (sandy and clay soil). The newly hatched nymphs were transferred to sugarcane roots and placed into boxes with lids, to keep a moistened and dark environment favoring their growth and maintenance of the root system, providing food access to the developing nymphs. After emergence, adult males and females were placed in cages for mating and oviposition. The silicon absorbed and accumulated in the plant caused an increase in nymphal mortality, and depending on the sugarcane cultivar tested this element also provided an increase in the duration of the nymphal stage and a decrease in the longevity of males and females. 'SP79-1011' presented the highest silicon content in leaves, and M. fimbriolata had the highest nymph mortality and the shortest female longevity. The pre-oviposition period, fecundity and egg viability were not affected by the silicon content in plants or the cultivar used.

Sugarcane Underground Organs: Going Deep for Sustainable Production

Sugarcane breeding has greatly advanced in recent decades, but many aspects of sugarcane physiology are still poorly understood, including the root-shoot relationships that ultimately affect yield. Traditional methods for studying root systems are imprecise due to methodological difficulties of in situ assessment and sampling; this seems especially true for the sugarcane root system. Studies on sugarcane roots lag well behind those on other crops, in part due to the large plant stature and long crop cycle. Commercial sugarcane cultivars are hybrids from crosses mostly between Saccharum officinarum and S. spontaneum made by breeders at the beginning of the last century. These hybrids have a genomic structure composed of 80% S. officinarum, 10% S. spontaneum and 10% recombinants of these two species. S. spontaneum is included in large part for the robustness of its underground organs (root and rhizome). The S. spontaneum genes controlling these characteristics may be lost during recurrent backcrosses with S. officinarum to increase sugar content and yield. Thus, ratooning ability is one of the most desired traits. Ratooning ability comes mainly from the rhizomatousness of S. spontaneum, but this trait has been diluted during the selection process so that the stubble of hybrids does not have rhizomes sensu stricto. In this review, we revisit some basic aspects of the sugarcane root system, mainly from an ecophysiological view, and point out considerations for breeders to consider in designing the architecture of a new sugarcane cultivar that can meet the need for sustainable agricultural production.

Recovery of Nitrogen (15N) by Sugarcane from Previous Crop Residues and Urea Fertilisation Under a Minimum Tillage System

Residues of green-harvested sugarcane contribute to nutrient recycling in production systems. Therefore, better understanding of trash decomposition dynamics can help crop fertilisation management. This study was conducted during the 2006–2008 seasons in Jaboticabal, north-eastern Sao Paulo State, Brazil and aimed to evaluate the nitrogen recovery rates from the previous crop residues or from urea applied on sugarcane planting in a minimum tillage system, thus without trash and rhizome incorporation in crop renewal. Previous crop residues consisted of 9 and 3 t/ha of sugarcane trash (dry tops + leaves) and root system (roots + rhizomes) enriched with 1.07 and 0.81% 15N isotope, respectively. These contributed 51 and 33 kg/ha of N. 15N labelled trash laid on the soil surface and buried 15N-root system attempted to simulate the original field residues disposal. The SP81-3250 variety was planted with 80 kg N/ha of a 5.17% 15N-labelled urea. Recovery of sugarcane residues-N (trash-N and root system-N) or urea-N incorporated to the soil at planting were evaluated in distinct plant parts (stem, tops and dry leaves) during three consecutive harvest seasons. Recovery of urea-N was higher in the first harvest season (31% of initial N rate) and its uptake decreased in the second and third to 5 and 4%, respectively. In later harvested seasons, urea-N had probably been turned-over as soil organic matter and/or microbial biomass but remained in the soil N pool and available for plant recovery. Trash-N uptake closely resembled urea-N uptake, and only 13% of its N content was recovered in the first year, followed by 7 and 3% in the second and third seasons. Root system-N recovery was different since the second cut uptake was higher than the first followed by the third, 9, 6 and 2% respectively. Three year cumulative recovery of urea-N, trash-N and root system-N was 39, 23 and 17%, respectively. Most recovered N was found in stems followed by tops and dry leaves.

Sugarcane root length density and distribution from root intersection counting on a trench-profile

Root length density (RLD) is a critical feature in determining crops potential to uptake water and nutrients, but it is difficult to be measured. No standard method is currently available for assessing RLD in the soil. In this study, an in situ method used for other crops for studying root length density and distribution was tested for sugarcane (Saccharum spp.). This method involved root intersection counting (RIC) on a Rhodic Eutrudox profile using grids with 0.05 x 0.05 m and modeling RLD from RIC. The results were compared to a conventional soil core-sampled method (COR) (volume 0.00043 m³). At four dates of the cropping season in three tillage treatments (plowing soil, minimum tillage and direct planting), with eight soil depths divided in 0.1 m soil layer (between 0-0.6 and 1.6-1.8 m) and three horizontal distances from the row (0-0.23, 0.23-0.46 and 0.46-0.69 m), COR and RIC methods presented similar RLD results. A positive relationship between COR and RIC was found (R² = 0.76). The RLD profiles considering the average of the three row distances per depth obtained using COR and RIC (mean of four dates and 12 replications) were close and did not differ at each depth of 0.1 m within a total depth of 0.6 m. Total RLD between 0 and 0.6 m was 7.300 and 7.100 m m-2 for COR and RIC respectively. For time consumption, the RIC method was tenfold less time-consuming than COR and RIC can be carried out in the field with no need to remove soil samples. The RLD distribution in depth and row distance (2-D variability) by RIC can be assessed in relation to the soil properties in the same soil profiles. The RIC method was suitable for studying these 2-D (depth and row distance in the soil profile) relationships between soil, tillage and root distribution in the field.

Predominant nifH transcript phylotypes related to Rhizobium rosettiformans in field‐grown sugarcane plants and in Norway spruce

Although some sugarcane cultivars may benefit substantially from biological nitrogen fixation (BNF), the responsible bacteria have been not identified yet. Here, we examined the active diazotrophic bacterial community in sugarcane roots from Africa and America by reverse transcription (RT)-PCR using broad-range nifH-specific primers. Denaturing gradient gel electrophoresis (DGGE) profiles obtained from sugarcane showed a low diversity at all sample locations with one phylotype amounting up to 100% of the nifH transcripts. This major phylotype has 93.9-99.6% DNA identity to the partial nifH sequence from a strain affiliated with Rhizobium rosettiformans. In addition, nifH transcripts of this phylotype were also detected in spruce roots sampled in Germany, where they made up 91% of nifH transcripts detected. In contrast, in control soil or shoot samples two distinct nifH transcript sequences distantly related to nifH from Sulfurospirillum multivorans or Bradyrhizobium elkanii, respectively, were predominant. These results suggest that R. rosettiformans is involved in root-associated nitrogen fixation with sugarcane and spruce, plants that do not form root-nodule symbioses.

Specific plant induced biofilm formation in Methylobacterium species

Two endophytic strains of Methylobacterium spp. were used to evaluate biofilm formation on sugarcane roots and on inert wooden sticks. Results show that biofilm formation is variable and that plant surface and possibly root exudates have a role in Methylobacterium spp. host recognition, biofilm formation and successful colonization as endophytes.

Functional Relationship Between Sugarcane Root Biomass and Length for Cropping System Applications

Sugarcane root length density (RLD, m/m3) and root biomass are key characteristics for respectively determining: (i) the crop nutrient and water uptake capacity, and (ii) carbon partitioning in plants and balance in soil. In previous studies, often only one of these parameters was measured. It is therefore useful to link the RLD and root biomass density (RBD, g/m3) to evaluate one parameter in relation to the other. Relationships between RLD and RBD and specific root length (SRL, m/g) were studied in Cote d’Ivoire and Reunion. Mean SRLs of fine roots were independent of the root location in the soil profile and plant age but higher in Cote d’Ivoire (68 m/g, SD = 19) than in Reunion (35 m/g, SD = 10). The best fit between the RBD and RLD of thick roots was a power function (RLD = 21.3 RBD0.745; R 2 = 0.85). Mean SRL was 7 m/g. When all roots were studied together, the best fit between RBD and RLD was also a power function, with little variation between the two sites or between plant and ratoon sugarcane. The fits calculated with all data except those obtained very close to the plant stem were: RLD = 85.5 RBD0.742 (R 2 = 0.88) and mean SRL = 27 m/g (SD = 13). Relationships between root length and biomass were neither fixed nor fully random. Due to SRL variability, it was hard to pinpoint any mechanistic links between root length and biomass. Conversely, for simple field evaluations, a rough and ready RLD estimate can be made on the basis of RBD, and vice versa.