ARPN Journal of Agricultural and Biological Science       ISSN 1990-6145
   
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ARPN Journal of Agricultural and Biological Science          October 2014 | Vol. 9 No. 10
 
Title:

In vitro evaluation of some plant extracts against Alternaria alternata causing leaf spot of Aloe vera

Author (s):

Roshan Regmi, Ravi Jha, L .Sobita Simon and Abhilasha A Lal

Abstract:

Aloe Vera (L.) Burn f. is a perennial succulent plant grown worldwide mainly for medicinal and cosmetic uses. During a routine survey a leaf spot disease of Aloe vera having infected plants with large necrotic, sunken, circular to oval, dark brown spots present on both surface of leaves was observed at SHIATS and neighboring areas. Microscopical examination revealed the presence of Alternaria alternata in the infected areas. Pathogen was isolated and cultured on Potato Dextrose Agar medium.  Leaf Extracts of six plants viz, Jatropa curcas, Datura strumarium, Azadirachata indica, Moringa oleifera, Calotropis gigantean and Morus Alba @ 50 % were evaluated In vitro by food poison techniques against the fungus. The results revealed that all plant extracts @ 50 % significantly inhibited the mycelial growth of pathogen. However leaf extract of J. curcas demonstrated maximum mycelial growth inhibition of A. alternata (62.9%) followed by D. strumarium leaf extract (55.6%) and was significantly superior to all other tested extracts. A. indica extract (51.9%) also inhibited its mycelial growth followed by M. oleifera (46.9%), C. gigantea extract (23.45%) and M. Alba (13.6%) as compared to control.

 
 
 
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Title:

Occurrence and abundance of plant parasitic nematodes in cabbage-based cropping systems in Kenya

Author (s):

Mwangi, J. M., J.W. Waceke and G.M. Kariuki

Abstract:

A survey was conducted to determine the incidences of plant parasitic nematodes (PPN) and factors enhancing population build-up in cabbage (Brassica oleracea L. var capitata)-based cropping system in selected agro-ecological zones of Kenya. Samples were collected from sixty cabbage growing farms in Nyandarua and Embu Counties. Nematodes assay was conducted for both root and soil samples. Extraction of PPN from soil and root sample was done using modified extraction tray method and modified maceration extraction technique respectively. Extracted nematodes were enumerated, identified to genus level and their frequencies of occurrence and abundance determined. Nematodes belonging to various genera were found associated with cabbage in six agro-ecological zones. The study revealed that cabbage is a preferable host to lesion nematodes (Pratylenchus) with 87% and 58% frequency of occurrence in soil and roots, respectively. The mean population of this nematode in soil and root samples was significantly different from other nematode general. Meloidogyne was present at low frequency of 42% and 23% in soil and roots and density 6.36/100cm3 of soil and 1.1/10g roots. Helicotylenchus was recovered in significant numbers with 82% frequency of occurrence in rhizosphere and 27% in roots and a density of 26.28/100cm3 in soils and less than 1 nematode per 10g of roots. Tylenchorhynchus occurred in 67% of the soil samples while Paratrichodorus, Trichodorus and Paratylenchus was present in 78%, 57% and 58% frequency of occurrence in the cabbage rhizosphere but at a low population density. Other PPN detected in low frequencies of occurrence and density include; Tylenchus Scutellonema, Xiphinema. among others. The study encourages more research work to establish the economic importance and the management of the reported nematode pests.

 
 
 
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Title:

Virulence of three strains of beauveria bassiana against the banana weevil

Author (s):

C.A. Omukoko, K.N.Maniania, J .M. Wesonga, E.M. Kahangi and L.S. Wamocho

Abstract:

The banana weevil, Cosmopolites sordidus Germar, is the most important insect pest of banana and plantain. Beauveria bassiana is the most researched and commercialized fungal biopesticide effective against a variety of insects. Laboratory studies have revealed a great potential of this entomopathogen for use against the banana weevil, Cosmopolites sordidus in banana. Use of traps for collecting adults or infecting them with biopesticides will most likely capture only those weevils in the immediate vicinity of the traps. The indiscriminate use of chemicals has resulted in the development of resistance in insect pests, adverse ecological events, affecting beneficial fauna, and accumulation of residues in the environment. There is considerable need therefore to develop safe and cheaper biocontrol alternatives that can be used to complement existing control methods. The potential of utilizing the entomopathogen B. bassiana for control of banana weevil was evaluated by testing the virulence of three isolates of Beauveria bassiana (ICIPE 273, M353 and M207) at three concentration (108, 3 x108 and 109). From previous pathogenicity tests these three isolates were the most pathogenic. At higher fungal concentrations of 3 x108 and 109 adult mortality for all the three isolates was between 35%-70%. The highest mortality was achieved using an elevated concentration of 109, causing mortalities varying from 50-70% 40 days after exposure depending on the isolate. ICIPE 273 was the most virulent, killing 70% of adults followed by M353 (65% mortality) and M207 (51% mortality). This was far much greater than when a standard concentration of 108 was used (mortalities ranged between 28%-50%). Differences in virulence among the tested isolates were due to their geographical origins.

 
 
 
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Title:

Allelopathic interactions between two barley cultivars (Hordeum Vulgare L) on weed annual ryegrass (Lolium Multiflorum L) and charlock (Sinapis Arvensis L) using the equal-compartment-agar-method

Author (s):

Mohammad Reza Baziar, Farhad Farahvash, Bahram Mirshekari, and Varahram Rashidi

Abstract:

The use of cultivars with allelopathic potential is one of weed management techniques. Factorial experiment in a completely randomized design with two factors including the density and culture on two barley cultivars namely Valfajer and Reyhaneh were used in laboratory, Fasa branch, Islamic Azad University, Fasa 2013. Actors examined included various densities of barley (0, 8, 16, 24, 32) and culture time (simultaneous and delayed). Ryegrass and Charlock seedling growth features were under investigation. The results showed that increasing barley plant density in both samples, compared to control, leads to the significant decrease in the seedling, radical and plumule lengths, wet and dry seedling weights of both weeds. Compared with plumule length, the radicle lengths of both weeds were more affected by a density which shows its high sensitivity. Considering the culture time of barley revealed that delayed planting has significant effect on the measured characteristics of weeds than simultaneous planting. Compared to simultaneous culture, cut-off interaction of similar densities at both culture times, showed the noticeable influence of delayed culture on weeds of ryegrass and charlock growth features, and also the most effective treatment combination was on the growth habits of weeds density of 32 and delayed culture of both barleys. Also, in order to compare the allelopathic potential of Valfajer and Reyhaneh barleys, using the linear regression model, the changes in the radicle length and plumule length of ryegrass and charlock were determined regarding applied densities. Comparison of modelís parameters based on the confidence interval revealed the same reduction of both cultivars on the mentioned features and there was no noticeable significant difference between them.

 
 
 
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Title:

The response of haricot bean varieties to different rates of phosphorus at Arba Minch, southern Ethiopia

Author (s):

Amare Girma, Assaye Demelash and Tuma Ayele

Abstract:

Field experiment was conducted during 2013 to determine the response of common varieties to phosphorus fertilizer application. The treatment consists of three common bean varieties (Hawassa Dume, Ibbado and Nasir) and three phosphorus rates (0, 20 and 40 kg P2O5 /ha) laid out in Randomized Complete Block Design with three replications. Data was collected on plant height (cm), number of nodule/plant, dry matter, number of pods/plant, number of seeds/pod, 1000 seed weight (g), seed yield (kg/ha), harvest index, crude protein content and phosphorus uptake. The increasing rates of fertilizer showed substantial improvement in nodule number, seed yield, crude protein content, fertilizer recovery, agronomic efficiency and physiological efficiency where the highest values of these parameters were obtained from fertilizer at the rate of 20 kg P2O5/ha. Hawasa dume showed the best performance in most parameters whereas Ibbado gave the lowest performance in contrary. These results can indicate the benefit of phosphorus fertilizer application and variety consideration for yield improvement, nodulation potential and better nutrient use efficiency of common in the study area.

 
 
 
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Title:

Effect of bio-fertilizer and organic manure on growth and nutrients content of pearl millet

Author (s):

Abdullahi R, Sheriff, H.H and Buba A

Abstract:

Field experiment was conducted to study the effect of bio-fertilizer, Arbuscular mycorrhizal fungi (AMF) (Glomus mossea) and Azospirillum brasilense alone or in combination with cow dung (CD) or poultry manure (PM) on growth of pearl millet. The experiment was laid out in randomized complete block design with six treatments and three replications. Treatments were: T1 (Control), T2 (Bio-fertilizer), T3 (Bio-fertilizer + 5 ton ha-1 CD), T4 (Bio-fertilizer + 2.5 ton ha-1 PM), T5 (10 ton ha-1 CD), T6 (5 ton ha-1 PM). Bio-fertilizer and organic manure singly or in combination enhanced plant growth, % root colonization by AM fungi, shoot and root dry biomass and nutrients concentration (N, P and K) compared to control. Bio-fertilizer + PM recorded highest plant performance viz; plant height (72.6 cm), number of tillers/plant (4.1), shoots and root dry biomass (8.8 and 3.9 g) followed by bio-fertilizer alone and poultry manure. Applying 10 ton-1 of cow dung produced plants with the lowest growth attributes although not a par with control. N and P concentrations varied significantly between all treatments. Bio-fertilizer + PM recorded the highest concentration of N and P, and values were significantly higher than all the treatments. There was no definite trend for K concentration among all treatments. Inoculated and un-inoculated plants were colonized by AM fungi. Inoculated plants were significantly colonized compared to un-inoculated plants. Significant difference in % root colonization was observed between inoculated plants. Bio- fertilizer + PM recorded the highest root colonization of 62% followed by bio-fertilizer alone (56.7%). From the findings of this study, it can be concluded that application of bio-fertilizer and organic manure alone or in combination could improve pearl millet production in low-input agriculture. Results also showed that bio-fertilizer tended to reduce by half the application rates of organic manure. Bio-fertilizer in combination with 2.5 ton ha-1 of PM could be recommended for millet production in the study area.

 
 
 
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Title:

Genetic polymorphism and allelic frequency of GHRH gene locus in Iranian Sarabi breed of cattle

Author (s):

Mehdi Amin Afshar, Mehdi Khosravi and Mohammad Chamani

Abstract:

Animal selection based on molecular markers is one of the latest breeding methods that can improve the correctness of predictions and of response to selection. The GHRH (growth hormone-releasing hormone) gene is one of the candidate genes for selection strategies based on markers. According to available reports, gene polymorphism is significantly related to the traits of milk constituents and milk production. Blood samples were taken from 112 head of Sarabi breed cattle to study polymorphism in the GHRH gene locus. The genomic DNA of the blood samples was extracted and a 297-bp fragment of this gene was amplified using the polymerase chain reaction. The amplified fragment was cut by the HaeIII restriction enzyme and electrophoresed on 2% agarose gel. Results showed that the two alleles GHRHA and GHRHB with the respective frequencies of 0.19 and 0.81 in the whole population are in this locus. Three genotypes GHRHA GHRHA, GHRHA GHRHB , GHRHGHRHB) were identified the calculated genotype frequencies of which were 0.0357, 0.3037, and 0.6607. The Chi-square test indicated the Hardy-Weinberg Equilibrium existed in the population. Results of this research show that the genetic variety in the Sarabi breed of cattle can help future selection programs, especially the MAS (marker-assisted selection) programs.

 
 
 
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