Paper Towel Method Research Articles

Foliar application of plant defense elicitors on seed crop affects alternaria leaf and pod spots as well as seed quality parameters in Radish

The experiment was conducted in the feld and laboratory of Department of Seed Science and Technology, Dr. YSPUHF, Nauni, Solan (HP) during 2017–18 and 2018–19 to study the effect of foliar application of plant defense elicitors like salicylic acid, methyl jasmonate, amino butyric acid and potassium nitrate on severity of Alternaria leaf and pod spots, seed yield, seed quality, vigour and health of radish seed crop (cv. Japanese white). In all 13 treatments viz., SA @50ppm, 75ppm, 100ppm, MeJA @55 ppm, 110 ppm, 165 ppm, BABA @ 250ppm, 500ppm, 750ppm, KNO3 @1%, 1.5%, 2% and untreated control were there. Disease severity and seed yield were observed in feld while seed quality and health parameters of seeds were observed in the laboratory following blotter paper, roll paper towel method and grow out test. SA @100ppm besides reducing disease severity of Alternaria, was also found effective in increasing seed yield, 1000 seed weight and enhancing various seed quality and seed health parameters.

In vitro antagonistic potential, plant growth-promoting activity and indole-3-acetic acid producing trait of bacterial isolates from spent mushroom substrate of Agaricus bisporus

Spent mushroom substrate (SMS) is widely used as fertilizer and to control plant diseases. The microorganisms surviving in SMS play a crucial role in plant growth promotion and biocontrol properties of SMS. In this study, an effort was made to isolate and characterize the bacterial species present in the SMS of Agaricus bisporus and to study their antagonistic potential, plant growth-promoting ability and indole-3-acetic acid (IAA) producing trait. Six different bacterial isolates exhibiting morphological variabilities were obtained from the SMS by serial dilution technique. On the basis of 16S rRNA gene sequences, these isolates were identified as Staphylococcus epidermidis (Sh1 and Sh3), S. aureus (Sh2), Bacillus albus (Sh4), Delftia lacustris (Sh6) and Comamonas aquatica (Sh7). These bacterial strains were assayed for their antagonism against Pythium aphanidermatum, a phytopathogenic oomycete. The results of in vitro dual culture assay revealed that all the 6 bacterial isolates showed low levels of suppression of P. aphanidermatum and recorded less than 5 mm inhibition zone. Among the bacterial isolates, S. epidermidis Sh3 recorded the maximum inhibition zone of 4.2 mm. Plant growth promotion test using roll paper towel method revealed that C. aquatica Sh7, B. albus Sh4, D. lacustris Sh6 and S. epidermidis Sh3 caused a significant increase in seedling vigour of cucumber compared to control. The seeds treated with the bacterial isolate C. aquatica Sh7 showed the maximum seedling vigor. Assessment of in vitro production of IAA by the bacterial isolates revealed that the bacterial isolates highly varied (ranging from 0.28 to 9.25 mg L-1) in their potential for production of IAA. The maximum amount of IAA was produced by C. aquatica Sh7 (9.25 mg L-1), while the minimum was produced by S. epidermidis Sh1 (0.28 mg L-1).

Evaluation of safflower (Carthamus tinctorius L) genotypes against salinity stress

Safflower genotypes were evaluated for salinity stress using irrigation water with 5 EC levels through paper towel method. Among the 24 genotypes tried, performance of 5 genotypes was prominent in terms of shoot length and weight at 15 days growth. The genotype IC-406052 showed 23% reduction and genotype SSF-733 showed 65% reduction with EC of 10 dS/m against zero salinity. Highest reduction of shoot weight was noticed in SSF-733(54%) and minimum was recorded in IC-406052 (26%) with EC of 10 dS/m compared to zero salinity.

Morphological and molecular characterization of Macrophomina phaseolina isolated from three legume crops and evaluation of mungbean genotypes for resistance to dry root rot

Dry root rot (DRR) is an important emerging disease of mungbean caused by fungus Macrophomina phaseolina. The disease is seed and soil-borne and hence management is difficult. Exploitation of host resistance could be a good option to manage the disease. The objectives of this study were to characterize the isolates of M. phaseolina from three legume crops and to identify resistant sources against DRR of mungbean. Isolates of M. phaseolina from mungbean, urdbean, and vegetable soybean were identified using morphological characteristics and sequencing internal transcribed sequence (ITS) region of 18S rRNA. Isolates of M. phaseolina from urdbean and vegetable soybean were inoculated on susceptible check genotype of mungbean to assess their pathogenicity. Forty three mungbean genotypes were screened against M. phaseolina isolate of mungbean using the paper towel method to identify sources of resistance. Among these genotypes, 9 were resistant in repeated experiment, with disease score ranging from 1.9 to 3.0. Resistant genotypes showing lower disease score, namely IPM99-125, EC693368, and EC693369, were further screened using the sick pot method to confirm their resistance. Among these three genotypes, IPM99-125 showed consistently higher plant survival rate followed by EC693368 and EC693369 as compared to susceptible checks (VC3960-88, KPS1). In addition, these three genotypes were resistant when screened with two strains of M. phaseolina isolated from urdbean and vegetable soybean, with IPM99-125 having lower disease score. The mungbean genotype IPM99-125 could be useful in mungbean breeding programs to develop root rot-resistant varieties.

Uji Deteriorasi Terkontrol (UDT) ‎untuk Memperkirakan Masa Simpan Benih Kedelai (Glycine max (L.) Merr.)

Deterioration of seeds during storage may reduce the supply of high-quality seeds which become the limiting ‎factor of soybean production in tropical countries. Controlled Deterioration Test (CDT) is one of the ‎fastest vigor testing methods. The objective of this study was to achieve the suitable moisture content and ‎duration of CDT treatment in soybean seed, then establish a model that associated with the seed vigor in ‎the field after a certain time of storage. Split-plot with 2 factors, namely seed varieties and the combination of ‎moisture content and heat exposure duration were used to determine the influence of CDT treatment. ‎Another split-plot for 2 factors, namely storage period and seed varieties were used to determine the effect ‎of shelf life. Viability parameters were observed by germination strength (GS) and seedling vigor index (VI), ‎using a rolled paper towel method. The results showed that there was an interaction between soybean seed ‎varieties and the combination of seed moisture content treatment with duration of CDT exposure. Sindoro ‎and Tanggamus varieties had higher viability and storability than other varieties. Combinations of 28% seed ‎moisture content for 24 hours CDT duration were sensitive enough to evaluate the physiological potential of ‎soybean seeds, providing information that was closely related to seed germination after stored for 1 month. ‎

Germination and seedling emergence responses of common bean and cowpea to plant extract seed treatments

SUMMARYThe present study was initiated to investigate the effect of crude plant extracts as seed treatments onPhaseolus vulgaris(common bean) andVigna unguiculata(cowpea) seed germination and emergence in the presence ofColletotrichum lindemuthianumandColletotrichum dematium,respectively. Common bean and cowpea seeds were treated with crude water and acetone extracts ofAgapanthus caulescensSpreng.,Allium sativumL.,Carica papayaL. andSyzygium cordatumHochst.ex Krauss at 5 and 15 mg/ml concentrations. Seeds treated with the synthetic fungicide fludioxonil+mefenoxam (the commercial product Celest®XL) represented the positive control, whereas dimethyl sulphoxide and water-soaked seeds represented negative controls. The rolled paper towel method of the International Seed Testing Association was used to investigate the effect of the treatments on seed germination. Mean emergence time (MET) was determined using seed inoculated with the respective pathogens. The changes in the ultrastructure of embryonic roots and the connecting tissues of embryo-cotyledon of common bean and cowpea treated withSyzygiumacetone extracts andAgapanthuswater extracts were investigated using transmission electron microscopy (TEM). High germination percentages of >90% were observed in bean seeds from two production seasons treated with low concentrations of water extracts ofAllium, SyzygiumandAgapanthusand acetone extracts ofAllium, AgapanthusandCarica. These treatments also recorded high emergence percentages with low MET values, which were similar to the water control. Cowpea seeds treated withCaricawater extract had the highest germination and emergence.Syzygiumacetone was the only extract that gave higher germination and emergence in both IT93K5132 and PAN 311 varieties. Therefore,Caricawater andSyzygiumacetone extracts can be considered as potential bean and cowpea seed treatments. Generally, there were inconsistencies in terms of correlations of germination with emergence percentages in both cowpea and bean seed treated with plant extracts used in the study, which could be due to differences in vigour. The TEM study of embryo-cotyledon tissue of both species revealed thatSyzygiumandAgapanthusextract seed treatment may accelerate metabolic processes as evidenced by the presence of vacuoles, many cristae and few lipid bodies.

Evaluation of hot water treatment on seed germination and seedling infection of artificially inoculated cowpea seeds by Xanthomonas axonopodis pv. Vignicola

Cowpea [ Vigna unguiculata (L.) Walp.] is an important multipurpose pulse crop subjected to various diseases, among them bacterial blight is one of the important diseases caused by Xanthomonas axonopodis pv. vignicola (Burkh. 1944) Vauterin et al., 1995. Which is known to cause severe reduction in grain yield as it is both internally and externally seed borne pathogen. The investigation was undertaken at UAS Dharwad to study the effect of hot water treatment on disease and pathogen to mitigate the problem effectively. Hot water treatment by both roll paper towel method and pot culture experiment revealed that 52 0 C for 10 min., was found effective in eliminating seed borne bacteria Xanthomonas axonopodis pv. vignicola without affecting seed germination to a greater extent.

Using a Centrifuge to Determine Moisture Properties of Lightweight Fine Aggregate for Use in Internal Curing

Abstract Internally cured (IC) concrete is frequently produced using pre-wetted lightweight aggregate (LWA). One important aspect associated with preparing quality IC concrete is being able to determine the absorbed moisture and surface moisture associated with the LWA which enables aggregate moisture corrections to be made for the concrete mixture. ASTM 1761-13b specifies the use of the “paper towel method” to define a surface dry state for pre-wetted LWA; however, this can be time consuming and hard to perform at the batching plant. This paper proposes an alternative method for obtaining a surface dry state of the aggregate based on spinning the pre-wetted LWA in a centrifuge. It is shown that using a centrifuge (with bowl radius of 11.4 cm) for 3 min at 2000 rpm permits a surface dry state to be obtained consistently which enables surface and absorbed moisture to be determined accurately and rapidly. The moisture values obtained using the centrifuge correspond well with those obtained using the paper towel method.

An efficient technique to obtain conidial inoculum of Peronosclerospora sorghi causing downy mildew of sorghum

An effective and simple technique to obtain conidial inoculum of Peronosclerospora sorghi has been devised, which confers many advantages over the conventional method. Systemically infected sorghum leaves were packed into folds of paper-towel. The end of folded paper-towel containing cut-ends of leaves was dipped in 3 cm deep water in a container. The container was exposed to moist field conditions at night and sporulated leaves were harvested with chilled distilled water in the morning to obtain the inoculum. Advantages of the technique include lower cost and effort, rapid harvesting and daily production of inoculum for up to seven consecutive days from same leaves. Though conventional method of plating leaf pieces in Petri plates proves superior in terms of the amount of sporulation, paper-towel method has the edge under working conditions.

Screening of Pseudomonas fluorescens isolates for biological control of Macrophomina phaseolina root-rot of safflower

The aim of this study was to assess the potential bacterial antagonists to control Macrophomina phaseolinaroot-rot of safflower by using screening methods. In total, 38 fluorescent pseudomonads isolated from rhizosphere soil of healthy safflower plants were collected from major safflower growing areas, 13 were initially selected based on dual culture technique on potato dextrose agar media. Furthermore, these13 isolates were screened for reduction of percent incidence of M. phaseolina and to check their efficacy in seed germination and seedling growth in laboratory condition. Most of the isolates showed varying levels of antagonism againstM. phaseolina in both standard blotter method and paper towel method. In addition, few isolates increased percent germination, root-shoot lengths of safflower. Among them, CTPF31 showed the highest ability to reduce the root-rot disease severity in the greenhouse biological control test. The promised fluorescent pseudomonads (CTPF31 and CTPf36) enhanced the defense enzymes, peroxidase, PAL, β 1,3-glucanase, and chitinase after challenge inoculation with the target pathogen. These results indicated that the dual culture technique and seedling assay are more important for selection of promising biocontrol agents against M. phaseolina, besides they also increased the plant growth by controlling the disease as evidenced by induction of defense enzymes. Key words: Plant growth-promoting Rhizobacteria, safflower, root-rot, Macrophomina phaseolina, Pseudomonas fluorescens, biological control.

English

Forty two strains of Trichoderma sp. were isolated from cultivated lands around Bangalore and analyzed for their antagonistic potential against Sclerotium rolfsii and Fusarium ciceri . The potential of biocontrol agents ultimately lies in their capacity to control pathogens i n vivo. Bioefficacy studies were hence conducted using chickpea ( Cicer argentums c.v. Annigeri ) as an experimental plant by the roll paper towel method. Overall the isolates T40, T35, T30 and T25 showed better antagonistic potential in addition to enhancing plant growth. The production of chitinases to break down the mycelial cell walls of fungal plant pathogens has been implicated as a major cause of biocontrol activity (Inbar and Chet, 1995). In order to study the mechanism of biocontrol, ten better performing strains were plated on media, amended with colloidal chitin and Sclerotium rolfsii cell wall extract. All the isolates showed chitinolytic activity on day three as well as day five. Production of endochitinase and exochitinase were assayed in liquid media using colloidal chitin amended broth. Strains T35 and T6 displayed maximum endochitinase and exochitinase activity. Although all strains exhibited cellulase activity, the quantum of enzyme produced was higher in T35 and T6. The results also indicate a positive correlation between enzyme production and bioefficacy. Keywords- biocontrol, bioefficacy, cellulase, chitinase

Response of Dry Bean Genotypes to Fusarium Root Rot, Caused by Fusarium solani f. sp. phaseoli, Under Field and Controlled Conditions.

Fusarium root rot of dry bean (Phaseolus vulgaris), caused by Fusarium solani f. sp. phaseoli, is a major yield-limiting disease in North Dakota and Minnesota. Although a few sources of partial resistance are available, most commercial cultivars grown in this region are susceptible, especially in the red kidney bean market class. This study evaluated three methods of screening for resistance to Fusarium root rot. A sand-cornmeal inoculum layer method, spore suspension method, and paper towel method were used to evaluate 11 dry bean genotypes for resistance to Fusarium root rot under growth-chamber conditions. These same genotypes were also evaluated in field trials at Fargo, ND, and Park Rapids and Perham, MN, in 2005. In all trials, the small red genotype VAX 3 was found to have a consistently high level of resistance to Fusarium root rot and could be used as a source of resistance by dry bean breeders. Correlation analyses between field and growth-chamber root rot ratings indicated that all three growth-chamber methods had significantly (P ≤ 0.05) positive correlations with field results from Perham and Fargo, which suggests that all three methods could be used to screen germplasm efficiently for resistance to Fusarium root rot.

Método do rolo de papel toalha modificado para a detecção de Sclerotinia sclerotiorum em sementes de feijão

O mofo branco do feijoeiro, causado pelo fungo Sclerotinia sclerotiorum (Lib.) de Bary, é uma das principais doenças da cultura. O patógeno pode ser disseminado por sementes infectadas, que têm um importante papel na infestação de novas áreas de plantio e no estabelecimento da doença no início do ciclo da cultura. Este trabalho apresenta uma adaptação do método do rolo de papel toalha, originalmente desenvolvido para a detecção de Colletotrichum lindemuthianum, com o objetivo de detectar a presença de S. sclerotiorum em sementes de feijão. Neste método, as sementes foram incubadas por 7 dias a 20 ºC em rolos de papel toalha para germinação, sendo mantidas sob condições de 100% de umidade relativa. Após esse período, as plântulas infeccionadas e as sementes mortas, circundadas por micélio característico de S. sclerotiorum, foram transportadas para caixas tipo gerbox, sobre duas folhas de papel de filtro umedecido. Após 3 a 4 dias de incubação a 20 ºC e sob regime de 12 horas de luz por 12 horas de escuro, os escleródios foram observados nas sementes e plântulas. O método foi relativamente rápido, simples e barato, além de apresentar a vantagem de possibilitar a detecção simultânea de S. sclerotiorum e de outros importantes patógenos transmitidos por sementes de feijão, como C. lindemuthianum, Macrophomina phaseolina e Rhizoctonia solani.

Growth promotion of maize by phosphate-solubilizing bacteria isolated from composts and macrofauna

Five bacterial strains with phosphate-solubilizing ability and other plant growth promoting traits increased the plant biomass (20-40%) by paper towel method. Glasshouse and field experiments were conducted using two efficient strains Serratia marcescens EB 67 and Pseudomonas sp. CDB 35. Increase in plant biomass (dry weight) was 99% with EB 67 and 94% with CDB 35 under glasshouse conditions. Increase in plant biomass at 48 and 96 days after sowing was 66% and 50% with EB 67 and 51% and 18% with CDB 35 under field conditions. Seed treatment with EB 67 and CDB 35 increased the grain yield of field-grown maize by 85% and 64% compared to the uninoculated control. Population of EB 67 and CDB 35 were traced back from the rhizosphere of maize on buffered rock phosphate (RP) medium and both the strains survived up to 96 days after sowing.

Identification of geneticaly modified soybean seeds resistant to glyphosate

Advances in genetic engineering permit the modification of plants to be tolerant to certain herbicides that are usually not selective. For practical and commercial purposes, it is important to be able to detect the presence or absence of these traits in genotypes. The objective of this research was to develop a procedure for identifying genetically modified soybean (Glycine max L. Merr.) with resistance to the herbicide glyphosate. Two studies were conducted based on germination test. In the first study, soybean seeds were pre-imbibed in paper towel with the herbicide solutions, then transferred to moist paper towel for the germination test. In the second study, seeds were placed directly in herbicide solutions in plastic cups and tested for germination using the paper towel method. Eight soybean genotypes were compared: four Roundup Ready, that contained the gene resistant to the herbicide (G99-G725, Prichard RR, G99-G6682, and H7242 RR) and four non-transgenic parental cultivars (Boggs, Haskell, Benning, and Prichard). In the first study, the seeds were imbibed for 16 hours at 25°C in herbicide concentrations between 0.0 and 1.5% of the glyphosate active ingredient. In the second, seeds were subjected to concentrations between 0.0 and 0.48%, for one hour, at 30°C. The evaluation parameters were: germination, hypocotyl length, root length and total length of the seedlings. Both methods are efficient in identifying glyphosate-resistant soybean genotypes. It is possible to identify the genetically modified soybean genotypes after three days, by imbibing the seed in 0.12% herbicide solution, and after six days if the substrate is pre-imbibed in a 0.6% herbicide solution. The resistance trait was identified in all cultivars, independent of the initial physiological quality of the seed.

Survival of Rhizoctonia bataticola in groundnut seed under different storage conditions

Rhizoctonia bataticola (sclerotial stage of Macrophomina phaseolina), which causes charcoal rot disease of groundnut, is an important pathogen of this crop. Under warm and wet conditions in the field, the pathogen enters the seed and remains inside without any visible symptoms. Groundnut germplasm stored for various durations in the medium term storage (4°C) commonly shows 10-29% infection of this pathogen. To determine the longevity and survival of this pathogen in groundnut seed, a study began on 15 May 1995 with healthy and R. bataticola infected groundnut seed stored at 20, 4 and -18°C. Initial levels of infection and moisture were determined in both the seed lots. Independent samples from the two bulks were drawn every year for determining seed germination and the level of pathogen infection. Agar plate method was used for pathogen detection and paper towel method for seed germination. After five years of storage, the germination of healthy seed was not affected at any of the temperatures. However, a drastic reduction in the germination of infected seed occurred at all temperatures even within three years of storage. This reduction in germination was associated with a significant increase in the incidence of R. bataticola in infected seed stored at all temperatures after 5 years of storage. In the case of healthy seed, there was a little increase in the incidence of infection at 20 and 4°C, but no increase occurred at -18°C. The results show that R. bataticola can survive and its incidence can substantially increase in infected groundnut seed even at -18°C, a temperature recommended for long term storage. The implication of these results is that for maintaining a high level of germination in groundnut seed, only.

Teste de frio para avaliação do potencial fisiológico de sementes de algodão

O teste de frio tem sido usado principalmente para sementes de milho. Porém, seu uso em outras espécies como feijão, soja, algodão e ervilha tem crescido significativamente em todo o mundo. No entanto, ressalta-se a necessidade da padronização de metodologias do teste de frio de acordo com as características de cada espécie a ser testada. Dessa forma, com o objetivo de determinar a eficiência do teste de frio na avaliação do potencial fisiológico de sementes de algodão, cinco lotes do cultivar Delta Pine - Acala 90, deslintados quimicamente, foram submetidos a diferentes procedimentos: caixa com terra, rolo de papel com terra e rolo de papel sem terra, variando-se o período de exposição (três, cinco e sete dias) das sementes à baixa temperatura (10°C). Paralelamente, as sementes foram submetidas aos testes de condutividade elétrica e de envelhecimento acelerado, para comparação com os resultados obtidos nos diferentes procedimentos do teste de frio. A utilização de rolo de papel sem terra, com cinco e sete dias de exposição ao frio, permitiu classificar de maneira mais consistente, os lotes de sementes de algodão, em função do potencial fisiológico, com relação às informações obtidas nos testes de condutividade elétrica e de envelhecimento acelerado. O uso desse procedimento, com cinco dias de exposição a 10°C, pode ser indicado para avaliação do vigor de sementes de algodão.

EFFECTS OF GAS COMPOSITION DURING PRIMING OF sh2 MAIZE SEEDS

Sweet corn with the shrunken-2 (sh2) gene is characterized by poor seed emergence and low seedling vigor. Also, this variety is sensitive to flooded conditions. Our objective was to determine the effects of aeration, during priming treatment, on germination and vigor. Priming consisted of aerating sh2 maize seed during soaking then drying on a lab bench overnight under a fan. Fifty seeds at a time were soaked (25 ± 2C) in 100 ml deionized water. During this time they received either 75% O2: 25% N2, pure N2, pure CO2, or no gas (soak control) for up to 6 hours. The flow rates ranged from 0.35 to 2 standard liters per minute for 75% O2: 25% N2, 0.8 to 2.5 for N2, and 0.5 to 1.3 for CO2. Pressure was held constant at 1 psi. All samples were weighed before soaking, immediately after soaking, and again upon partial drying. Germination was counted after 7 days using the rolled paper towel method (25 ± 1C). Radicle lengths were measured after 72 hours. Oxygen (75%) increased vigor. Also, O2 permitted greater water absorption (P < 0.02). Carbon dioxide and N2 both decreased vigor. Data suggest that aeration conditions (75% O2) during the hydration treatment has beneficial effects.

Elucidation of seed dormancy and phytohormones by germination after exogenous foliage whey application

A study was conducted with an aim of achieving 100% seed germination and to evaluate the rate of dormancy upon exogenous application of the deproteinised leaf juice (DPJ) in various leguminous and non leguminous seeds. DPJ if inducing retardation of dormancy, the activity of enzyme was analysed to prove the presence of phytohormones. DPJ from the three non leguminous foliages of brinjal, radddish and dasheen were prepared by green crop fractionation. The seed germination results obtained by the paper towel method and the activity of enzyme protease in DPJ of radish and Colocasia leaves separately. There was variation in germination rate by different DPJ influence. Some seeds showed fast germination while some germinated late. Few seeds were not germinated by control. In some seeds, DPJ decreased the rate of germination while on the contrary there was rapid growth of seedlings by the potentiality of DPJ. DPJ found mutagenic by its influencing inhibitory expression in seedling growth in some cases. The enzyme protease released by phytohormone gibberellin during the seed germination. Positive glyoxlic test indicated presence of auxins in whey.