Total Plant Weight Research Articles

Rhizobacteria inoculation in maize associated with nitrogen and zinc fertilization at sowing

ABSTRACT Rhizobacteria have a wide range of plant growth-promoting mechanisms of action, making them an alternative and/or complementary biological input for chemical fertilizers. In this respect, the present study aimed to assess growth and nitrogen accumulation in maize plants as a function of Azospirillum brasilense, Bacillus subtilis, zinc and nitrogen application at sowing. The experiment with the ‘AL Bandeirante’ maize variety was conducted in a greenhouse, using a completely randomized design. The treatments were arranged in a 2 x 2 x 2 x 2 factorial scheme, with six repetitions, considering the presence and absence of Azospirillum brasilense (5 g kg-1), Bacillus subtilis (5 mL kg-1) and zinc (20 g kg-1) in the seeds and addition or not of nitrogen (30 kg ha-1) to the soil. The variables assessed were plant height, stem diameter, leaf, stem, shoot, root and total dry weight, and shoot nitrogen content. Nitrogen fertilization in the absence of zinc increased shoot and total dry weight as well as shoot nitrogen content. Zinc applied to the seeds improved the total and stem dry weight of maize plants in the absence of Bacillus subtilis. Inoculation with Azospirillum brasilense and Bacillus subtilis increased the stem diameter and shoot nitrogen content of maize plants when nitrogen fertilization was not performed at sowing. There was no isolated or interaction effect between factors for plant height and root dry weight.

The potential of seaweed used as hydroponic solution on the growth and yields of lettuce (Lactuca sativa L.)

Lettuce (Lactuca Sativa L.) is one the most popular leaf vegetable in Indonesia. Hydroponic systems do not require extensive land cultivation. The advantages of using hydroponic systems is that it has higher production with more efficient land use. Seaweeds have been reported to be used as a fertilizer. This study aims to determine the effect of various nutrient solutions on the growth and yield of lettuce plants with hydroponic system. This study used a randomized block design (RBD), with five treatments: N1=OLF (organic liquid fertilizer) solution, N2=OLF solution + spray, N3=Seaweeds extract solution, N4=Seaweeds extract solution + OLF solution, N5=AB mix (Nutriponik). Each treatment was repeated 4 times, so that there were 20 units of experiment. Each unit of experiment consist of 5 plants so that the total population was 100 plants. The results showed that the AB mix nutrient solution gave the best growth responses. It produced an average plant height, number of leaves, total fresh weight of plant, and total dry weight of plants better than other solutions.

Prevention and Detection of Fungicide Resistance Development in Rhizoctonia zeae from Soybean and Corn in Nebraska

The goal of this research was to advance the foundational knowledge required to quantify and mitigate fungicide resistance in Rhizoctonia zeae, the seedling disease pathogen of soybean and corn. In vitro sensitivity to azoxystrobin, fludioxonil, sedaxane, and/or prothioconazole was determined for 91 R. zeae isolates obtained mostly from soybean and corn fields in Nebraska. Isolates were sensitive to fludioxonil, sedaxane, and prothioconazole (EC50 < 3 µg/ml) and had a positively skewed EC50 distribution. Isolates were not sensitive to azoxystrobin in vitro (EC50 > 100 µg/ml) or in planta. Application of azoxystrobin did not significantly decrease disease severity or improve total dry weight of the soybean plants (P > 0.05). The risk of resistance development in R. zeae was estimated by characterizing its population structure. Eighty-one R. zeae isolates were genotyped using six microsatellite markers. Results showed that the population has a mixed mode of reproduction and is structured according to geographic region, suggesting limited dispersal. These population characteristics suggest that R. zeae has an intermediate risk of resistance development. Overall, this research established the current status of fungicide sensitivity in R. zeae in Nebraska and estimated its risk of resistance development, which can inform fungicide resistance management for R. zeae.

Agro-morphometric Diversity Analysis in Carrot Germplasm from Indian Genebank

Carrot is a nutrient rich and commercially important root vegetable in India. A study was undertaken in rabi seasons of 2015-16 and 2016-17 to assess the agro-morphological diversity in 100 accessions collected from different regions of India and from other countries. Wide variation was observed in accessions for qualitative (root and core colour) and quantitative (plant length, root length and length, shoulder, root, core size, number of leaves per plant, total plant weight root yield etc.) traits. Maximum accessions had red and mixture of light red (45) to light purple roots (38). Only orange accessions had uniformity in root shape and colour. Wide variation was observed in root length (13.6-25.6 cm) and shoot length (25.0 - 88.3 cm). The study revealed wide variation in carrot germplasm maintained by Indian genebank, however, intra-population variation needs to be fixed before use in breeding.

The effect of different compositions of growth media on the development of microplants of the Antonina potato variety

The results of studying the influence of growth media of different compositions on the growth and development of healthy microplants of potato variety Antonina in laboratory conditions in vitro are presented. Six compositions of Murashige and Skoog culture medium were considered: standard according to the recipe modified for micropropagation (control); with a reduced content of mineral components (up to 1/2 and 1/3); with an increased content of agar-agar (10 g/l); with a reduced content of agar-agar (4 g/l), and modified by the addition of 3 mg/l giberrellic acid and 1 mg/l indoleacetic acid. The following parameters of cultivated plants were studied: plant length, root presence, number of internodes, total plant weight, leaf weight, root weight, leaf surface area. The use of growth media with a reduced content of mineral components led to an increase in the length of the plants under study by 8–9%, a decrease in the number of internodes by 0.49–0.85 pcs/plant, an increase in the mass of the root system by 23% and a decrease in the mass of the shoot due to reduced leaf mass by 16–31%, as well as a decrease in the total leaf surface area by 21–30%. When growing plants on a growth medium with an increased content of agar-agar, the following changes were observed: a decrease in the length of plants by 13%, a decrease in the mass of the root system by 8%, a decrease in the shoot mass due to reduced leaf mass by 11% and stem mass by 17%. Plants grown on a growth medium with a low content of agar-agar had a shorter stem length (by 12%), a lower number of internodes (by 0.93 pcs/ plant), a lower mass of root system and leaves by 31% and 11%, respectively, compared to the control. In this variant, the rate of rhizogenesis was also reduced. With the addition of giberrellic and indoleacetic acid to the growth medium, the plants demonstrated a significant increase in length by 32%, a decrease in the root mass by 77%, and a decrease in the shoot mass due to reduced leaf mass by 58% and stem mass by 33%. The total leaf surface area was 34% lower than the control values. In order to accelerate micropropagation of healthy Antonina potato plants and prepare the plants for replanting to an aero-hydroponic system, Murashige and Skoog medium modified for micropropagation proved to be the best option among the tested growth media. In order to keep this variety in the in-vitro collection, it is recommended to use the MS growth medium with a low agar-agar content.

Evaluation of Silicon and irrigation on three Safflower cultivars

This study was performed to evaluation of interaction of silicon application and irrigation on agronomic and physiologic traits of safflower at 2018 and 2019. The experiment was conducted as a split plot factorial based on randomized complete block design with 3 replications. The irrigation was main factor (0, 2 and 4 times during growth) and the sub-factor were silicon foliar application (at three levels: 0, 1 and 2 mM) and three safflower cultivars (Goldasht, Padideh and Golmehr). The studied traits were: number of seeds per boll and 1000-grain weight, number and weight of boll, number of lateral branches and branch diameter, plant weight and total plant weight, floret yield, grain yield, chlorophyll a and b, proline and antioxidant enzymes. According to results, treatments had significant effects on studied traits at 5 or 1% statistically level. 2 and 3 times irrigation led to 7 and 24% the increasing of seed yield in compare to control, respectively. It was obtained that 1 and 2mM silicon led to 25 and 15% the increase of seed yield in compare to control. Interaction between treatments showed that the highest seed yield (500g per m2) was observed by Goldasht cultivar under 4-time irrigation and 2mM silicon. Therefore, it can be suggested that Goldasht with 2 mM silicon be used to reduce the effects of dehydration.

Physiological and molecular comparative analysis of two contrasting rice varieties under jasmonic acid treatment

Rice is one of the most important crops but its productivity is severely threatened by both biotic and abiotic stresses. Jasmonic acid and its derivatives (referred to JA) are the lipid-based plant hormones that were commonly known as regulators of plant growth, development and defense responses. In this study, we compare the physiological and molecular responses of two rice accessions, G38 (Nep_nuong) and G11 (Tam-tron) to JA treatment. G38 plants under JA treatment experienced a reduction in shoot length, root weight, shoot weight and total plant weight which suggested its sensitiveness to JA, whereas G11 plants showed a less reduction in these traits. The expression levels of 12 JA-related genes were investigated in order to better understand how the JA biosynthesis and responses differ in these two contrasting rice accessions. A significantly higher expression level of a set of genes related to JA biosynthesis, signaling and response in G11 compare to G38 was observed. Furthermore, the inorganic phosphorus starvation (Pi) response was also examined in the two varieties G11 and G38. In low Pi condition (40 µM), G11 plants showed more roots, longer root length and shoot length, higher weight compared to the G38 plants which suggest that G11 did not suffer much effect of Pi deficiency. This study highlights the differences in JA growth response in 2 contrasting rice genotypes and also suggests the link between JA developmental response and the tolerance to the Pi starvation condition in rice.

Growth and Yield of Soybean as a Response of the Fertilization of NPK Compound Produced with Spent and Deoiled Bleaching Earth Filler

<span>Spent Bleaching Earth (SBE) is a by-product of the refining of Crude Palm Oil (CPO) into cooking oil which is classified as hazardous and toxic materials waste. SBE has the potential to be used as a filler in the production of NPK fertilizer. This study aims to compare the effect of SBE and Deoiled Bleaching Earth (DBE) as the replacement of clay mineral, which is expected to have the same effect as the control treatment in terms of the leaf area, total dry weight, plant height and yield of plant. </span><span lang="EN-US">This experiment used a one-factor Randomized Complete Block Design (RCBD) with three replicates. The treatments of filler in NPK fertilizer were 10% clay minerals, NPK with 5% clay mineral + 5% SBE filler and NPK with 5% clay mineral + 5% DBE filler. Fertilizer was given twice, ie when the plant was 14 days after planting (DAP) as much as 2 g polybag<sup>-1</sup> and age 35 DAP as much as 3 g polybag<sup>-1</sup> at each treatment. The results showed that the application of NPK fertilization with 5% clay mineral + 5% SBE filler and NPK fertilization with 5% clay mineral + 5% DBE filler had the same effect as NPK fertilization with 10% clay mineral filler on leaf area, total dry weight, plant height and yield of plant. SBE and DBE can be used as substituties for clay mineral in NPK fertilizer production.</span>

Effects of Foliar Application of Liquid Fertilizer on Agronomical and Physiological Traits of Rice (Oryza sativa L.)

Providing rice (<em>Oryza sativa </em>L.) plants with the required nutrients is essential in order to avoid yield reduction. As such, an experiment was performed at the Rice Research Institute of Iran in Amol Township to evaluate the effects of foliar application of nutrients on rice plants. The experiment consisted of a randomized complete block design, with four replications during 2 crop years (2016 and 2017). Experimental treatments included foliar application of nutrients [the chemical composition of liquid fertilizer was as follows: nitrogen (N): 7%, phosphorus (P): 7%, potassium (K): 7%, iron (Fe): 0.05%, boron (B): 0.05%, zinc (Zn): 0.01%, manganese (Mn): 0.01%, and copper (Cu): 0.01%] in the following growth phases: (A) midtillering stage, (B) maximum tillering, (C) panicle initiation, (D) maximum tillering + panicle initiation, (E) all stages, and (F) control treatment (no liquid fertilizer applied). Our results indicate that foliar application of nutrients in different vegetative and generative stages significantly affected plant height, number of tillers per plant, chlorophyll concentration, number of filled grains per panicle, and grain yield. However, our treatments did not significantly affect the 1,000-grain weight. Furthermore, foliar application of nutrients significantly affected physiological traits including leaf area index, growth rate, and total dry weight of plants. Our results indicate that the mean values of the investigated traits were highest in the “maximum tillering + panicle initiation” and “all stages” treatments. In contrast, the lowest mean values of the investigated traits were found in the control treatment. Foliar application of nutrients at the “maximum tillering + panicle initiation” stage resulted in the highest chlorophyll concentrations, leaf area index, and crop growth rate in the flowering stage. Our results indicate that foliar application of nutrients was most effective when applied to Sahel variety rice during two vegetative and reproductive stages.

RESPON PERTUMBUHAN DAN HASIL SELADA (LACTUCA SATIVA L.) TERHADAP INTERVAL WAKTU APLIKASI PEMBERIAN AIR CUCIAN BERAS

Lettuce is one of the most popular vegetables from various groups, because it does not need special preparation to enjoy it immediately. Its cultivation is relatively easy and does not require special techniques, making lettuce can be grown in polybags or hydroponically. Rice washing water, which is usually not utilized, actually has the potential as liquid organic fertilizer. Besides being practical and environmentally friendly, liquid organic fertilizer can be applied easily. This study aims to determine the effect of the appropriate application time interval for giving rice washing water on the growth and yield of lettuce. This research was conducted in August-October 2020 using polybags containing soil: manure: husk (1: 1: 1). The design used was a single factor completely randomized block design (RAKL). The factor is the application time interval for giving rice washing water with 4 levels, namely: W0 = without giving rice washing water (control), W1 = once every 2 days, W2 = once every 4 days and W3 = once every 6 days with a dose of 50 ml polybag-1. The results showed that the time interval treatment with washing rice water had no significant effect on plant height, number of leaves, diameter, fresh root weight, and total fresh weight of lettuce plants. However, the treatment of giving rice washing water at an interval of 6 days (W3) once showed a better value than without treatment, the time interval for giving rice washing water once every 2 days or 4 days.

Genetic diversity in leafy mustard (Brassica juncea var. rugosa) as revealed by agro-morphological traits and SSR markers.

Leafy mustard (B. juncea var. rugosa) constitutes an important group of vegetable mustard crops in India and is mainly cultivated in home-backyard and hilly regions of Uttarakhand and some North-eastern states. In the present study, various agro-morphological traits, physiological and biochemical traits along with SSR markers were used for genetic diversity evaluation in a germplasm collection of leafy mustard. This study revealed a significant variation among 59 accessions of leafy mustard in both qualitative and quantitative agro-morphological traits indicating the accessions' promising potential for consumption purpose and for use in breeding programs. Maximum variability was recorded for leaf area elongation rate (CV = 53.12%), followed by total plant weight (TPW) (CV = 50.63%) and seed yield per plant (CV = 44.33%). In molecular analysis, 155 SSRs evaluated resulted in 482 alleles and the number of alleles varied form 1 to 8 with an average of 3.11 alleles per marker. A total of 122 (78.70%) SSRs resulted into polymorphic amplicons. PIC value varied from 0.32 to 0.77 with an average value of 0.44 per SSR locus. The unweighted neighbour-joining-based dendrogram analysis divided all the 59 accessions into two major groups on the basis of both agro-morphological traits and SSR markers, whereas, three subpopulations/subgroups were predicted by population STRUCTURE analysis. AMOVA indicated the presence of more variability within population than among population. Overall, agro-morphologically better performing and genetically diverse genotypes have been identified which could be further used as donors for leafy mustard improvement programs.

Genetic and epistatic effects for grain quality and yield of three grain-size QTLs identified in brewing rice (Oryza sativa L.).

Rice (Oryza sativa L.) in Japan is not only a food staple but also an important material for the Japanese alcoholic beverage, sake. The grain used in sake brewing has different characters from the cooking rice grain, including a large grain size and high white-core expression rate (WCE). Because large-sized grains often have a heavy grain weight and higher yield, this trait is also important for cooking rice. Chalky grains, such as white-core or white-belly grains, are not ideal as cooking rice. Here, we report that three grain-size quantitative trait loci (QTLs; qGL4-2, qGWh5, qGWh10), derived from the brewing cultivar, Yamadanishiki, affect grain shape, chalky grain rate, and yield, using near isogenic and pyramiding lines in the genetic background of the cooking cultivar, Koshihikari. First, these QTLs influenced multiple components of grain shape, where epistatic effects were detected between qGL4-2 and qGWh5, for grain width and thickness, and between qGL4-2 and qGWh10, for grain length. Therefore, these QTLs may coordinate to control grain shape. Second, lines harboring qGWh5 or qGWh10 at the Yamadanishiki allele exhibited increased WCE, whereas lines with qGL4-2 and qGWh10 exhibited decreased white-belly grain rate (WBR). Thus, grain shape is associated with the occurrence of chalky grain, where the chalky type depends on the QTL. Finally, we used total panicle weight of plants as a simplified rice yield index, and a promising line pyramiding qGL4-2 and qGWh5 emerged. In conclusion, qGL4-2 would be useful for the breeding of cooking rice, to decrease WBR, while qGWh5 and qGWh10 were definitely more beneficial for that of brewing rice, to increase grain weight and WCE.

Foliar application of iron, zinc, and manganese nano-chelates improves physiological indicators and soybean yield under water deficit stress

To investigate the effect of foliar application of nano-chelates of iron, zinc, and manganese subjected to different irrigation conditions on physiological traits, and yield of soybean (cultivar M9), a split plot experiment was conducted in a completely randomized block design with three replications in two crop years (2016–2017). The main plot included four levels of irrigation (I): full irrigation (I 1), irrigation withhold at flowering stage (I 2), irrigation withhold at podding stage (I 3), and irrigation withhold during the grain filling period (I 4). Also, the subplot included eight levels of foliar application with Fe, Zn, Mn, Fe + Zn, Fe + Mn, Zn + Mn, Fe + Zn + Mn nano-chelates, and distilled water (control). The results of combined analysis of variance suggested that the effect of irrigation and foliar application of nano-chelate was significant on all traits. Water deficit stress significantly reduced the grain yield. The minimum numbers of pods per plant, number of grains per plant, 100-seed weight per plant, leaf area index, leaf chlorophyll concentration, total dry weight of plant, and the grain yield were obtained by irrigation withhold at podding stage. Foliar application of combined nano-chelates increased the soybean resistance against water shortage more considerably than the separate consumption of these elements. Under drought stress in podding stage, the application of Fe + Zn led to the highest yield with a mean of 2613.84 kg ha−1 where this increase was 61.1% higher than control.

Leaching potential of the herbicide mixture 2,4-D + picloram

Weed control strategies are fundamental to ensure pasture productivity and quality in Brazil. However, care must be taken in the use of long residual herbicides, which can increase the risk of leaching. From this context, the present study evaluates the leaching potential of the commercial mixture of herbicides 2,4-D + picloram. Leaching columns filled with loam-clay-sandy soil were used. The columns were0.6 m in length and 0.2 m in diameter. The experimental design was randomized blocks with eight replications. Treatments were arranged in a 5x2 factorial scheme, in which factor A corresponds to herbicide doses (0, 1, 2, 3 and, 4 L ha -1 ) and factor B corresponds to the position of herbicides in the columns (0-30 cm and 30-60 cm depth). After herbicide application, weekly rainfall of 60 mm was simulated for four weeks at the top of the columns. The columns were sectioned vertically giving rise to two section, which were separated into two portions (0-30 cm and 30-60 cm). Then, cucumber was sown as a bioindicator in the 0-30 cm and 30-60 cm layers. At 45 days after sowing, the following parameters were deter­mined: chlorophyll a fluorescence transient, shoot length, root length, and total dry weight of plants. Both the chlo­rophyll fluorescence data and the biometric data of the bioindicator plant showed the presence of the commercial mixture only in the first 30 cm of depth. It is concluded that 2,4-D + picloram remained in the 0-30 cm deep layer of the loam--clay-sandy soil after 240 mm rainfall.

Efficiency of Double Vaccine by Azotobacter chroococcum & Pseudomonas chlororaphus on Some Biological characteristics of Hordeum vulgare

This experiment was carried out to investigate the effect of the double agent of Azotobacter chroococcum and Pseudomonas chlororaphus. Pots were used in the experiment by following the RCBD design with five replicates in green clay mixed soil on the barley plant. The following parameters were studied: germination ratio, root length and leaf area, total plant weight, total root weight, and nitrogen and phosphorus concentration. After 45 days of planting, the results showed a significant increase in germination rate which was 90% in the treatment of the vaccine compared to control, which was 73%. There was also a significant increase in leaf area in addition to vegetative and root weight. The treatment of double vaccine yielded a significant increase in nitrogen and phosphorus rates, as nitrogen reached 2.4 Melgm.gm-1 and phosphorus 1.5 Melgm.gm -1.

Tuz Stresi Altındaki Biber Bitkisindeki Kalsiyum Uygulamalarının Antioksidatif Enzim Aktivitelerine Etkisinin Araştırılması

Demre sivri biber çeşidinin kullanıldığı çalışmada, tuz stresi altındaki biber bitkisine farklı dozlarda uygulanan kalsiyumun (Ca) bitki gelişimi ve antioksidant enzim aktiviteleri üzerine etkileri araştırılmıştır. Çalışma kontrollü şartlardaki 16/8 saatlik aydınlık/ karanlık fotoperiyotta, 25 oC de ve %70 nemli iklim odasında yürütülmüştür. Çalışmada toplam bitki ağırlığı ile bitkilerin tuza dayanım skalaları belirlenmiştir. Stres altındaki bitkilerde meydana gelen biyokimyasal değişiklikleri belirlemek amacıyla bitki yapraklarındaki antioksidant enzim aktiviteleri (Katalaz (CAT), Askorbat peroksidaz (APX), Süperoksit dismutaz (SOD)) belirlenmiştir. Tuz stresi altındaki bitkilere uygulanan kalsiyumun dozu arttıkça bitkilerin toplam ağırlıklarında artış olmuştur. Bu sonuçlara paralel olarak, bitkiler strese girmedikleri için ya da çok az stres oluştuğu için her üç enzim aktivitesinde Ca doz artışına bağlı olarak düşüşler olmuştur. Tuz stresi altındaki biber fidelerine artan dozlarda Ca uygulamalarının tuzun olumsuz etkisini azaltmada kısmen de olsa etkili olduğu yapılan ölçüm ve analizler sonucunda söylenebilir.

EFFECT OF CERTAIN PSEUDOMONAS FLUORESCENS ISOLATES ON THE INFECTION OF ROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA IN TOMATO AND EGGPLANT AND THE PLANT GROWTH

Under screen house conditions, two experiments were carried out to evaluate certain bacterium, Pseudomonas fluorescens isolates regarding reproductive potential of root-knot nematode, Meloidogyne incognita, infecting tomato or eggplant. Results on tomato revealed that, on the basis of average total percentages nematode reduction, the over topped results were gained with P. fluorescens (Pf2) which recorded the highest significant (P≤0.05) average nematode reduction (61.3%) and higher percentage reduction of females (77%) per plant. The second rank was obtained by Pf3 which reduced all nematode numbers as an average of 56.9%.On the basis of average total percentages plant growth and weight of fruit increases, four bacterial treatments can be ranked in a descending order as follows: Pf9 > Pf4>Pf1and Pf7, as they achieved the highest average total percentages increases of 96.0, 47.3, 38.2and 29.8%, respectively compared to other treatments and untreated check. Regarding to eggplant, the over topped results observed was achieved by P. fluorescens (Pf10) which recorded the highest average total nematode reduction (66.2%) with higher reduction of (J2s) in roots (89.9%) per plant and in soil (78.8%) per pot. The second rank was obtained by Pf9 and Pf2 where they reduced all nematode numbers as averages of 55.9% and 54.9%, respectively. Also Pseudomonas isolates enhanced the plant growth of eggplant, averages were found in a descending order as follows: Pf1 (20.0%), Pf9 (18.7%) and Pf10 (18.3%) . It is worthy to note that the most distinct growth criteria was fresh weight of roots as it achieved higher percentage increase (58.1%) by using Pf9 followed by Pf1 as it caused 40.6% increase compared to untreated check. The highest average percentage of fresh weight of shoot were recorded for Pf10 (26.4%) and Pf8 (22.1%). Whereas for dry weight Pf3 (29.8%) and Pf2 (19.1%). In conclusion, the tested biocontrol agent was efficient in controlling the root-knot nematode on tested plants.

Bacillus subtilis EA-CB0575 genome reveals clues for plant growth promotion and potential for sustainable agriculture.

Bacillus subtilis is a remarkably diverse bacterial species that displays many ecological functions. Given its genomic diversity, the strain Bacillus subtilis EA-CB0575, isolated from the rhizosphere of a banana plant, was sequenced and assembled to determine the genomic potential associated with its plant growth promotion potential. The genome was sequenced by Illumina technology and assembled using Velvet 1.2.10, resulting in a whole genome of 4.09Mb with 4332 genes. Genes involved in the production of indoles, siderophores, lipopeptides, volatile compounds, phytase, bacilibactin, and nitrogenase were predicted by gene annotation or by metabolic pathway prediction by RAST. These potential traits were determined using in vitro biochemical tests, finding that B. subtilis EA-CB0575 produces two families of lipopeptides (surfactin and fengycin), solubilizes phosphate, fixes nitrogen, and produces indole and siderophores compounds. Finally, strain EA-CB0575 increased 34.60% the total dry weight (TDW) of tomato plants with respect to non-inoculated plants at greenhouse level. These results suggest that the identification of strain-specific genes and predicted metabolic pathways might explain the strain potential to promote plant growth by several mechanisms of action, accelerating the development of plant biostimulants for sustainable agricultural.

USE OF LACTIC ACID BACTERIA IN PEANUT SEED TREATMENT

Three lactic acid bacteria (LAB) strains, Lactobacillus sp. L5, Lactobacillus sp. L3, Lactobacillus sp. L2N, isolated from Vietnamese traditional Nem chua grew well in cabbage broth supplemented with 12 g/L glucose and 15 g/L peptone and showed inhibitory activity ranging from 40% to 44% against Aspergillus sp. CDP isolated from mould contaminated peanuts, while Daconil 75WP – a fungicide compounds – as a positive control showed only 26.9%. LAB strains also displayed Indole-acetic acid (IAA) production, P-solubilization and biofilm formation. Soaking seeds in separate cabbage based culture broth of three LAB strains with/without heat treatment and mixed culture broths at the ratio 1:1:1 with the total bacterial count 108cfu/mL exhibited the antifungal activity of mixed cultures in both cases with or without bacterial culture heat treatment. Soaking seeds in the same mixed bacterial cultures without heat treatment increased seed germination and vigor index, compared to the control seeds without any treatment and those treated with fungicide compounds. After 75 days of sowing the length and total fresh weight of LAB-treated peanut plants increased by 22.4 % and 99.6%, higher than that of Daconil treated ones with only 15.9% and 59.7% increment. Moreover, the fresh yield of peanut pegs increased 2.5 times, compared to those of untreated and Daconil treated seeds. This study suggested that seed treatment with LAB is a novel technology towards organic farming to replace fungicide used in conventional agriculture.

Tritrophic interaction between the Mexican sunflower, the aphid Aphis gossypii and natural enemies in a greenhouse experiment

The establishment of invasive plants negatively affects natural environments. Invasive herbivores that attack weeds can be used as a form of biological control, but natural enemies of herbivores must be associated with this interaction to prevent the invasive phytophagous from become a local pest. We performed a greenhouse experiment to evaluate how the cotton aphid, Aphis gossypii, a ok and invasive herbivore, affects the performance of the weed Tithonia diversifolia, the Mexican sunflower. We also examined the relationship between the aphid and local natural enemies. Seedlings of T. diversifolia were divided in two groups: one infested by the aphid and another not infested. After 22 days, we assessed the relationship between aphid abundance and the presence of natural enemies (Coccinelidae and Aphidius platensis) on infested plants, and compared the vegetative performance of the two seedling groups. Both natural enemies were positively related to high aphid density on infested plants. Plants infested by the aphid presented foliar necrosis and senescence, and a reduction of around 50% in leaf number, foliar area, shoot length and shoot, root and total plant weight compared to non-infested plants. These results indicate potential biological control of Mexican sunflower seedlings by the cotton aphid, and control of this aphid by the studied natural enemies.