Sugarcane Setts Research Articles

Enhancing Rooting and Biomass of Sugarcane Setts with Bio-Stimulant at Germination Stage

The study aims to determine the effect of the application of bio-stimulant to one-eyed and two-eyed sugarcane setts as planting materials in enhancing the rooting and biomass. The study was conducted at UNO-R School of Agriculture, Philippines from November to December 2023. Phil 2006-2289 variety was used as planting materials. The study was laid out in a two-way factorial Completely Randomized Design with the kind of materials as the main plot and the four (4) levels of concentration of bio-stimulant solutions (BSS) plus the control as the sub-plots replicated 4 times. Cane setts preparation was done a day before the planting operations. Leaf sheaths were remove and only those setts with good and viable eye buds were selected for planting. Soaking was done for 24 hours. Bio-stimulants (BSS) were diluted in water and used as a soaking solution and succeeding application was done 15 days after planting. Statistical analysis revealed highly significant differences among treatments on the germination, biomass accumulation, weight and length of roots, number, weight, and height of tillers applied with 500ml of BSS. There was a high significant difference on the root length and biomass as influence by type of cane setts and the levels of concentration of BSS. Two-eyed cane setts applied with 500ml of BSS got the heaviest root weight and biomass. The study recommends the use of 500ml of BSS and two-eyed cane setts in enhancing the rooting and biomass of sugarcane plants during the germination phase.

Influence of Bio-Stimulant to Rooting and Biomass of Sugarcane Setts at Pre-Tillering Stage

Sugarcane is an important crop in the Philippines planted throughout the country but is most abundant in the Visayas and particularly on Negros Island. This study aims to determine the effect of the application of different concentrations of bio-stimulant on enhancing root and biomass accumulations at the pre-tillering stage of the sugarcane plant. The study was conducted at the University of Negros Occidental – Recoletos School of Agriculture, Philippines last December 6, 2023, to February 6, 2024. One hundred pieces of two-eyed cane points of RC-88 were used as planting materials. Soaking the cane points in water was done for 24 hours. Thereafter they were removed from water and air-dried for 30 minutes. The bio-stimulant was prepared before the application based on the study protocol. The bio-stimulant was diluted in distilled water and applied at the base of the plant using a measuring cup for even distribution. Regular monitoring for the presence of pests/diseases was done including watering. There were five (5) treatments, replicated four (4) times using Complete Randomized Design (CRD). Statistical analysis revealed that most of the characteristics of sugarcane plants significantly correlated with roots and biomass accumulation when applied with different levels of concentrations of bio-stimulant concentration at the pre-tillering stage of sugarcane. The use of 500ml Bio-stimulant significantly influenced the germination, tiller height, weight of tillers, weight of roots, length of roots, and biomass. This study recommends the use of 500ml bio-stimulant in enhancing the rooting and biomass accumulation of sugarcane setts at pre-tillering stage.

Response of Sugarcane Setts to Bio-Stimulant Solutions at Tillering Stage

Response of Sugarcane Setts to Bio-Stimulant Solutions at Tillering Stage

Entomopathogenic fungi, Metarhizium anisopliae as a chemical substitute for termite pest management in sugarcane

Aim: The present research study was undertaken to assess the efficacy of microbial and natural origin bio-pesticides in comparison to chemical control against termites infesting sugarcane. Methodology: Field trials were executed for a period of three successive seasons i.e., 2019-20, 2020-21 and 2021-22 at Sugarcane Research Station, Vuyyuru, Krishna district, Andhra Pradesh. The experiment was laid out in randomized block design with seven treatments replicated thrice and imposed the treatments as per protocol. A set of four bio-pesticides (Beauveria bassiana, Metarhizium anisopliae, Bacillus thuringiensis and Azadirachtin) and two insecticides (Imidacloprid and Bifenthrin) were evaluated for their efficacy against termite infestation in terms of both mean number of sugarcane setts infested and mean portion of setts infested by termites. Results: The chemicals imidacloprid and bifenthrin had registered highest per cent reduction of termite infestation over control. However, the biopesticides, Metarhizium anisopliae had registered least per cent reduction of mean number of setts infested with 59.95 at 60 DAP, 62.85 at 90 DAP and 56.03 at 120 DAP and mean portion of setts infested with termite was 56.20 per cent. With respect to yield also the chemical treatments viz., imidacloprid and bifenthrin had recorded higher yields with pooled mean of 77.33 and 76.78 t ha-1, followed by M. anisopliae with 73.94 t ha-1. Interpretation: Even though the chemical based treatments were found superior in reducing termite infestation, entomopathogenic fungi, M. anisopliae as biopesticide also attributed better results with regard to suppression of termite infestation and can be suggested as alternative or substitution to chemical based management. Key words: Chemical control, Entomopathogenic fungi, Metarhizium, Sugarcane, Termites

Factors affecting the germination of teliospores of Sporisorium scitamineum and the development of sugarcane smut in the field

AbstractTemperature and water potential are critical factors influencing the germination of Sporisorium scitamineum teliospores and subsequent crop infection. This paper reports on the effect of temperature, water potential and incubation time on S. scitamineum teliospore germination. A field trial was conducted to determine the influence of temperature and length of exposure to teliospores on smut incidence. A 200 μL aliquot of teliospore (1.5 × 106 teliospores/mL) was cultured on water agar (WA) amended by potassium chloride (KCl) or sucrose. The plates were incubated across a range of temperatures and incubation times. For the field trial, sugarcane setts were inoculated and incubated at different temperatures and for varying incubation periods. The results demonstrated that germination decreased with declining water potential with either KCl or sucrose. The greatest germination (95.8%) occurred on unamended WA incubated at 30°C for 6 h. Even at the lowest water potential of −45 bars and 30°C, 50% teliospores were still able to germinate. These results indicate that 30°C is the optimum temperature for teliospore germination and that S. scitamineum may still germinate in fairly dry conditions. However, high temperatures (40°C), greatly reduce S. scitamineum germination. These results are consistent with field trial outcomes, which showed that the highest disease incidence (40.4%) occurred when temperature of inoculation was maintained at 30°C. On the other hand, the incidence was significantly reduced to 5.7% at 35°C. The results suggested consistent conditions for teliospore germination and sugarcane bud infection, with a temperature of 30°C being optimal for both.

Protein hydrolysates enhance germination and early growth of maize and sugarcane

Protein hydrolysates have been reported as a plant biostimulant due to their activity like phytohormones. This research aimed to study protein hydrolysate’s effect on the germination and growth of maize and sugarcane. Chicken feather meal (TB) and trash fish meal (TI) based protein hydrolysates were tested their ability to promote rooting and shooting in the early growth of maize and sugarcane, following an adequately dipping. In the maize bioassay, seeds were soaked for 1 hour in aquadest and 10 ppm of TB and TI hydrolysates in three replicates. Shoots and roots length were measured 5 days after germination. In the sugarcane assay, setts having a single bud on top and bottom stalk of PSJT-941 were grown in a polybag. The experiment was performed in eight treatments and 10 replicates, comprising setts from top and bottom, followed by 5, 10, and 30 minutes dipping in 20 ppm of TB hydrolysate. The setts soaked in aquadest was the negative control. Maize treated with TB hydrolysate had the highest shoots and roots length, while sugarcane setts from the top stalk soaked for 30 minutes in the TB hydrolysates showed germination in all replications besides the best in rooting and number of shoots.

Problem confrontation of sugarcane farmers in Natore district of Bangladesh

The present study was conducted to explore the problems of sugarcane farmers in the selected areas of Natore district in Bangladesh. A total of 100 farmers were selected from Lalpur upazila of Natore district by using a simple random sampling technique. Data were collected through individual interviews during October to November, 2019 by using a structured interview schedule. Both descriptive and inferential statistics were used to analyze data. The majority of the sugarcane farmers (80%) had medium problems in sugarcane cultivation. Among twenty problems, difficulty in getting sugarcane setts was identified as the most critical one, followed by low market price of sugarcane. The least important problem faced by the farmers was lack of labour for sugarcane cultivation. Correlation analysis revealed that credit received, input availability, and extension media contact were significantly associated with the problems of sugarcane farmers. The study indicated some opportunities for the policymakers to address the dominant factors i.e. credit received, input availability, and extension media contact for increasing sugarcane production. Moreover, credit facilities, supply of inputs, proper training and access to extension services could play a vital role in lessening problems in sugarcane cultivation.
 Int. J. Agril. Res. Innov. Tech. 11(1): 101-108, June 2021

Enhancing cane and sugar productivity applying variable modes of plant growth regulators in sugarcane (Saccharum sp. complex) cultivation under coastal climatic conditions of India

A field experiment was carried out for three crop seasons at Sugarcane Research Station, Nayagarh (Odisha) during spring seasons of 2015-16, 2016-17 and 2017-18 to assess the effect of ethrel and gibberellic acid on growth, yield attributing characters, yield and quality of sugarcane (Saccharum sp. complex). Pooled data of three years study indicated that different treatments with plant growth regulators had significant effect on growth, yield and quality parameters of sugarcane. Germination percent of cane buds was the highest in the treatment involving planting of sugarcane setts after overnight soaking in 100 ppm ethrel solution followed by foliar application of gibberellic acid @35 ppm at 90,120 and 150 days after planting (DAP). Other sugarcane growth parameters, viz. number of tillers and plant heights were significantly higher with the application of growth regulators which produced higher number of millable canes (at harvest) than that of other treatments in the test. Overnight soaking of cane setts in 100 ppm ethrel solution followed by foliar application of gibberellic acid @35 ppm at 90,120 and 150 days after planting also produced significantly higher yield parameters, viz. number of millable cane (84.26’ 000 ha-1), cane length (313.6 cm), cane girth (2.94 cm) and single cane weight (1.64 kg) as compared to conventionally planted sugarcane crop. There was no significant influence on juice quality parameters due to various treatments in this study. However, overnight soaking of setts with 100 ppm ethrel solution followed by foliar application of gibberellic acid @ 35 ppm at 90, 120 and 150 days after planting showed comparatively higher values in all the juice quality parameters. Significantly higher cane and sugar yields of 116.14 t/ha and 12.82 t/ha, respectively were obtained with planting of sugarcane after overnight soaking in 100 ppm ethrel solution followed by gibberellic acid spray @ 35 ppm at 90, 120 and 150 days after planting. The above higher yields were attributed mainly to marked improvement in growth and yield attributes in response to application of plant growth regulators. Therefore, it can be concluded that combined application of ethrel and gibberellic acid had the positive effect to improve the growth parameters, yield and quality of sugarcane.

Bifenthrin in the tropical sugarcane ecosystem: persistence and environmental risk assessment.

Termites are one of the major pests of sugarcane. Bifenthrin has label claim for use against sugarcane termites and is applied at the time of planting over the cane setts in the furrows. A thorough knowledge on the dissipation kinetics of bifenthrin in the soil and cane setts provides an insight into its dynamic behavior in the soil-plant-environment continuum, and hence, was studied in detail. The recoveries of the method adopted to determine the residues of bifenthrin in the soil, sugarcane setts, stem, and leaf were in the range of 92.78-98.19% at three levels of fortification ranged between 0.01 and 0.1 μg/g of matrix. At the recommended dose (100 g a.i./ha), bifenthrin was found to persist in the soil and cane setts up to 60 and 75 days after treatment (DAT) with the half-lives of 16.4 and 25.0 days, respectively. The dissipation kinetics of bifenthrin followed the biphasic model. At double the recommended dose, the residues persisted up to 75 DAT and reached below the detectable limit (< 0.01 μg/g) on 90 DAT both in the soil and setts. The half-life of bifenthrin was 22.0 days in the sandy clay loam soil and 17.6 days in/on the sugarcane setts. In the present study, dissipation by photolysis has been ruled out, as the treated setts were not exposed to sunlight. This could be one of the reasons for longer persistence of bifenthrin in the sugarcane setts up to 75 DAT with the half-life of more than2 weeks. The bifenthrin residues were not detected in the leaf and stem of sugarcane plant throughout the experimental period. There could be harmful effects to earthworms (risk quotient > 1.0) due to the presence of bifenthrin residues in the soil of tropical sugarcane ecosystem.

Evaluation of Insecticide-treated Sugarcane Setts against Subterranean Termites at Sargodha

Termites contribute significantly to most of world's ecosystems. They are of great importance in recycling woody and other plant materials and their tunnelling efforts help to aerate the soil. The present study was done to evaluate the efficacy of insecticides against the termites in a sugarcane field. The dipping of setts in insecticides solution @ 1%, 0.50%, 0.25% was carried out and the planted setts was observed for damage/infestation. In order to select a site for an experiment in village Dhero Sial of Sargodha District. Five samples were taken from field at 4 different places. Area of sample was one sq. meter and population of termites was noted. Later on, poplar stakes were erected to confirm the population of termites after 10-15 days. As the chemical treatment is the only remedy for the crops attacked by subterranean termites available to the farmers in Pakistan the evaluation of these six insecticides showed that most effective is the Fipronil both in reducing the population density and damage on the cones.

ANALYSIS OF SUSTAINABILITY OF SUGARCANE FARMING IN NIGERIA

The study was conducted to analyze sustainability of sugarcane farming in Nigeria. Kano State was purposively selected with a sample size of 54 sugarcane farmers using randomized sampling procedure. The data were analyzed using descriptive statistics, farm budgeting and regression analysis. The result showed that 94% of the respondents were male, with an average age of 39 years. The mean household of the farmers was 8 persons. The average farm size was 2.3ha; it cost N33,224.22 to produce sugarcane per hectare with revenue of N36,706.17; the gross margin was N3,481.95 and the investment rate of return was 0.10. The findings further disclosed that age, household size, education and labour were significant (P&lt;0.05) and influenced the output of sugarcane farming in Nigeria. The results also reveal that land, sugarcane setts, fertilizer, insecticide and labour had ratios of 2.57, 33.44, 6.55, 1.630, and 0.27, respectively. The study revealed the constraints to sugarcane production in Nigeria to include, small farm holdings, high cost of inputs, inadequate credit, land tenure problem and poor extension services. It was concluded that even though sugarcane production is profitable, land, sugar cane sett, fertilizer and insecticide were underutilized and labour was over utilized. The study recommended that the farmers should increase the use of the underutilized factors and reduce the over utilized inputs; and also, the Government should review land ownership policies and subsidize farming inputs.

Athelia rolfsii causes sett rots and germination failure in sugarcane (Saccharum hybrid): pathogenicity and symptomatology

An unknown sclerotium-forming fungus was observed and isolated in 2016 from sugarcane grown at Sugar Research Australia, Woodford Pathology farm, Woodford, Queensland. The fungus appeared to be causing germination failure of sugarcane setts. The fungus was isolated from infected tissues and mycelia from internal pithy sett tissues. White mycelia and abundant sclerotia were grown on PDA. Morphological observation and molecular analysis confirmed the identification of the fungus as Athelia rolfsii. Significant reductions in sett germination (>70%) were observed in the field when inoculated setts were planted. Reddish and patchy lesions were observed on the external surface of the setts and pale-red to red discolouration in internal tissues (associated with white mycelial growth in the pithy tissues and on the cut end of setts). Symptoms on young plants included water-soaked to light-brown lesions at their base, production of sclerotia / white mycelium in and around the lesions, and death of the young plants. This is the first report demonstrating that A. rolfsii can cause germination failure and young plant death in sugarcane.

The Mo- and Fe-nitrogenases of the endophyte Kosakonia sp. UYSO10 are necessary for growth promotion of sugarcane

Sugarcane is a multipurpose crop primarily used to produce sugar, energy and bioethanol. It requires high amounts of N-fertilization for optimal growth, which increases production costs and environmental degradation. The contribution of biological nitrogen fixation to Uruguayan commercial sugarcane cultivars was demonstrated previously, and diazotrophic bacteria that were isolated from the stems were characterized and identified. From this collection, the isolate UYSO10 related to the Kosakonia genus (formerly Enterobacter) was described as a plant growth-promoting endophyte of sugarcane plants. To evaluate the effect of the inoculation of wild-type and nitrogenase-deficient strains of Kosakonia sp. UYSO10 on sugarcane growth promotion under non-sterile conditions. Kosakonia sp. UYSO10 was inoculated onto sugarcane setts for plant growth promotion greenhouse experiments. Single and double mutants resulting to the nitrogenase-encoding genes (nifH, anfH) were constructed, and the phenotypes were evaluated in vitro and in vivo. Kosakonia sp. UYSO10 is able to promote sugarcane growth under non-sterile conditions, that strain UYSO10 harbors two functional nitrogenases and the inactivation of both nitrogenase-encoding genes diminish its capacity of promoting growth on sugarcane. All together, the results obtained showed that the biological nitrogen fixation ability of Kosakonia sp. UYSO10 is required for sugarcane growth promotion.

Influence of nitrate - ammonium ratio on the growth, nutrition, and metabolism of sugarcane

Although ammonium (NH4+) has been claimed as the preferential N source for sugarcane (Saccharum spp.), the intense uptake of this mineral form by plants can impair metabolic processes and crop yield. We aimed to assess the growth, nutrition, and metabolic responses of sugarcane grown under different amounts of nitrate (NO3−) and NH4+. Sugarcane setts were grown in nutrient solution at a total concentration of 15 mM N using different NO3−/NH4+ ratios (100/0, 75/25, 50/50, 25/75, and 0/100, respectively) for 163 d under controlled conditions. The pH of the medium was daily adjusted to 5.8 ± 0.1, with replacement of the hydroponic solution every 10 d. NH4+–only fed plants showed lower dry biomass yield, nutrient content, leaf surface area, and leaf gas exchange than those under sole NO3− supply, in addition to favoring the development of brown rust (Puccinia melanocephala). However, there was no indication that NH4+ is directly related to oxidative stress in sugarcane. On the other hand, the highest N utilization efficiency was obtained with NO3−–only fed plants, which also resulted in the highest biomass yield, leaf surface area, nutrient content, leaf gas exchange, and root growth. Since NO3− was not stored in plant tissues, we therefore suggested that most of this N form is assimilated following its uptake. Despite the well–known preference of the crop for NH4+, the optimal growth response of sugarcane plants to NO3−/NH4+ ratios was observed under NO3− supply.

Development of a reverse transcription loop-mediated isothermal amplification assay for rapid and visual detection of Sugarcane streak mosaic virus in sugarcane

Sugarcane mosaic disease (SMD) is one of the most destructive sugarcane diseases that occur around the world. Sugarcane streak mosaic virus (SCSMV) belongs to the genus Poacevirus of the family Potyviridae, and is a novel pathogen that causes SMD. The pathogen spreads primarily through infected sugarcane setts, and hence the use of disease-free planting materials is essential to prevent disease development in the field. In the present study, a species-specific reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for the rapid and accurate detection of SCSMV. Based on the conserved polyprotein gene nucleotide sequences of SCSMV isolates that differ from Sugarcane mosaic virus (SCMV) and Sorghum mosaic virus (SrMV), four SCSMV specific primers, namely, P2-F3, P2-B3, P2-FIP, and P2-BIP, were designed and screened, using a panel of sugarcane viruses as controls. After optimization of the reaction conditions, the detection sensitivity of the RT-LAMP assay was 10-fold more sensitive than the conventional RT-PCR. The assay showed a high specificity in discriminating SCSMV from common viral pathogens of sugarcane such as SCMV, SrMV, Sugarcane yellow leaf virus (SCYLV), and sugarcane bacilliform virus (SCBV). The RT-LAMP assay also detected SCSMV in young sugarcane leaves with no visible sugarcane mosaic disease symptoms. The findings of this study provide a visual, simple, highly sensitive, rapid, and reliable technique for the detection of SCSMV, a tool that is useful for sugarcane quarantine and production of SCSMV-free seedcane. This is the first report of a RT-LAMP-based assay for the detection of SCSMV in sugarcane.

Comparison of Leifsonia xyli subsp. xyli molecular detection in heat-treated sugarcane setts1

ABSTRACT The thermotherapy of sugarcane setts is currently the primary management method for Leifsonia xyli subsp. xyli (Lxx), in Brazil. When they are immersed, the enzymes and proteins of the bacterial cell are denatured without harming the setts buds. Due to possible escapes from detection and consequent bacterium survival to thermotherapy, what may result in asymptomatic seedlings, this study aimed to detect the Leifsonia xyli subsp. xyli bacterium in sugarcane setts using molecular techniques and different time and temperature combinations, with or without the addition of antibiotics. The conventional PCR method detected the Lxx bacterial DNA only in the positive control, consisting of a highly susceptible plant with a high bacterial concentration. Using the nested-PCR, the Lxx DNA was detected in all the treatments used. Thus, none of the treatments adopted in the thermotherapy was able to eliminate the Lxx from the setts, and the use of kasugamicin also did not eliminate the bacterium, but reduced the bacterial population in the tested treatments. These results confirm that the nested-PCR is a useful tool to detect the presence of this phytobacterium in setts that will be used as seedlings.

The effect of potassium-rich biostimulant from seaweed Kappaphycus alvarezii on yield and quality of cane and cane juice of sugarcane var. Co 86032 under plantation and ratoon crops

A field experiment was conducted during 2011–2015 to study the effect of potassium-rich biostimulant manufactured from seaweed Kappaphycus alvarezii on growth, yield, and quality of sugarcane var. Co 86032 with plant and three consecutive ratoon crops. The concentrated biostimulant manufactured from K. alvarezii had 17.45% of solid content with majority potash (11.28%) and other macro-micro nutrients and plant growth substances. Sugarcane setts were treated with 0.3% of biostimulant and planted. During crop development, 1% of biostimulant was applied three times, i.e., first dose at the time of germination phase (30 days), second dose at tiller sprouting stage (75th day), and last dose was given at the stage of building of the sugar content (125 days) in both plantation and three consecutive ratoon crops. The higher cane yield obtained from treated plant over control was 24.90, 28.79, 20.47, and 26.16% more in plant crop, 1st, 2nd, and 3rd ratoon crops, respectively, with statistically significant values in commercial cane sugar yield, brix, purity, and polarity. The present research suggests that natural potash from seaweed can be applied on sugarcane to improve yield and quality of cane and cane juice.

Exogenous Application of Ethrel and Gibberellic Acid Stimulates Physiological Growth of Late Planted Sugarcane with Short Growth Period in Sub-tropical India

Physiological growth of late planted sugarcane crop is restricted by high temperature and a short growth period. This causes considerable reduction in crop and sucrose yields. Improving physiological growth within the short period is, therefore, highly desirable. Two field experiments were undertaken to determine the effect of exogenous applications of Ethrel and gibberellic acid (GA3) on sprouting, shoot population and physiological growth. Sugarcane setts were soaked overnight in Ethrel before planting. Foliar application of GA3 was performed at 90, 120 and 150 days after planting (DAP). Ethrel soaking led to 100% sprouting and high settling population at 20 DAP, due to a significant increase in bud moisture and activities of acid invertase (AI), indole acetic acid oxidase (IAAO), adenosine triphosphatase (ATPase), superoxide dismutase (SOD) and nitrate reductase (NR) activity in vivo. Early sprouting increased the growth period to 245 days compared to 220 days in the unsoaked setts. The applications increased leaf area (57%), leaf area index (76%), leaf area ratio (71%), leaf area duration (48%), biomass duration (52%) and net assimilation rate (69.64%) at the grand growth stage. The changes led to increased shoot numbers (26.3%), internodal numbers stalk−1 (40.74%), internodal length (40%), internodal girth (46.15%) and stalk length (42%) at the harvest stage. The stimulated physiological growth augmented dry matter content, oBrix and purity of cane juice by 24.2, 3 and 0.3%, respectively. The study demonstrates that the induction of higher shoot numbers together with increased leaf area index (LAI) and stalk elongation within a short growth period through Ethrel soaking and gibberellic acid applications is positively associated with enhanced dry matter and sucrose contents.

Development of Sugarcane-cum-Potato Planter for Mechanisation of Simultaneous Planting of Sugarcane and Potato

Sugarcane and potato are the two major cash crops cultivated in the Indo-Gangetic plains of South Asia. Growing potato as intercrop with sugarcane has a synergistic effect on sugarcane, resulting in increased economic returns to farmers. In order to mechanise simultaneous planting of sugarcane and potato for intercropping, a new planting machinery named as sugarcane-cum-potato planter was designed and developed at ICAR-Indian Institute of Sugarcane Research, Lucknow, India. It was equipped with furrowers for opening of furrow and ridge making in between furrows, sett cutting unit for cane planting, potato seed tuber metering mechanism for potato planting, covering unit to cover planted sugarcane setts and potato and insecticide application unit. The designed equipment planted two rows of sugarcane in furrows and two rows of potato on ridges simultaneously in single pass. Picking and dropping of seed potato were automatic, whereas sugarcane seed stalk feeding for sett cutting was manual. Field testing of the developed planter was conducted at IISR farm in sandy loam soil. The effective field capacity of planter was 0.127 ha h−1. Average soil cover on sugarcane setts was 45 mm. Average depth of seed potato tuber placement on the ridges was 40 mm, and average tuber to tuber spacing was 192 mm. Developed machine-planted sugarcane at furrow spacing of 750 mm with average overlapping of 68 mm between the setts. The cost of planting operation with developed equipment was rupees 3160 ha−1 as against rupees 13,600 ha−1 in conventional planting. Saving in cost of planting operation was about 76% and labour about 90% with the developed planter as compared to conventional planting. Irrigation water use efficiency, yield attributes and total yield increased significantly in potato–sugarcane intercropping as compared to relay cropping of potato and sugarcane. Benefit/cost ratio in mechanised intercropping of potato and sugarcane with the developed planter was 2.57:1 followed by conventional manual intercropping (2.26:1) and manual potato–sugarcane relay cropping (1.84:1).

Improvement of sugarcane (Saccharum officinarum L. var. Isd. 39) using gamma irradiation and large scale plantlet production from M1 generation through in vitro culture

The present study was aimed to develop mutant sugarcane (Saccharum officinarum L. var. Isd. 39) using gamma radiation followed by regeneration of those mutants through in vitro technique. Five different doses of gamma radiation (10, 20, 30, 40 and 50 Gy) were applied to the sugarcane setts and among these doses 10 Gy irradiated mutant sugarcane showed the best agronomical traits. In addition, 10 Gy irradiated mutant sugarcane also contained higher sugar concentrations (14.25%) compared to control (14.23%). On the other hand, shoot tip and young folded leaf segments from the 10 Gy irradiated plants (M1 generation) were used as explants in in vitro culture. It was evident from the experiment that direct shoot regeneration was better than indirect regeneration. Young leaf segments produced the highest percentage (84%) of shoots when cultured on MS+1.0 mg/l Kin + 0.2 mg/l NAA. The mean number of shoots was recorded as 35 ± 1.12 in the same medium. Moreover, addition of 4% sucrose and 10% coconut water (CW) in the same medium increased the number of shoot up to 45 per culture. Best rooting was obtained from shoots cultured on half-strength of MS fortified with 1.0mg/l NAA and 0.5mg/l IBA. Well-rooted plantlets were transferred to poly bag containing soil and compost (2:1) for hardening. During hardening 70% plantlets survived, which were subsequently transferred to the experimental field.Jahangirnagar University J. Biol. Sci. 5(1): 1-9, 2016 (June)