Prevalence of Seed-Borne Fungi Associated with Seeds of Some Selected Flowers

The prevalence of fungi associated with seeds of some selected local flowers namely cosmos, marigold, calendula, and periwinkle collected from three different locations (Arboriculture Garden, Ramna Park Garden, and Horticulture Garden) in Dhaka district and four hybrid flower seeds (African marigold, cockscomb, petunia, and Portulaca) collected from Momin Beej Ghar, Dhaka district were recorded. The results showed that the highest percent germination (91.38%) of cosmos was obtained from Horticulture garden’s seed, marigold (95.25%) obtained from Arboriculture garden’s seed, and calendula (65.88%) periwinkle (79.38%) obtained from Ramna park garden’s seeds. But in the case of hybrid seeds, African marigold showed the highest percent seed germination (98.25%). The Horticulture garden’s seed was better than the others considering the incidence of fungi in all local flower seeds tested. But periwinkle was the lowest affected seed (12.58%, 12.20%, 8.07% incidence) and marigold was the highest affected seed (40.31%, 35.33%, 31.33% incidence) collected from Arboriculture Garden, Ramna Park, and Horticulture Garden, respectively. But in hybrid flower seeds, the lowest fungal infection (3.14%) was recorded in Portulaca and petunia seeds whereas the highest (6.20%) was in African marigold seeds.

Post-Harvest Fungi Associated with Cowpea (Vigna unguiculata L. Walp.) Seeds Produced in Burkina Faso

Cowpea is a very popular foodstuff among people in sub-Saharan Africa. In Burkina Faso, it is the main food legume, especially in rural areas. Its production is facing difficulties including post-harvest losses caused by fungi. Therefore, the objective of this study was to isolate and identify fungal strains associated with cowpea seeds produced in Burkina Faso. Thus, a total of 108 seed samples were collected in the three agro-ecological zones of Burkina Faso. The sanitary analysis of the seeds was carried out using the direct contact method. The isolation and purification of the isolates were performed on Potato Dextrose Agar medium while their identification was done through macroscopic and microscopic phenotypical characterization using different culture media (Potato Dextrose Agar (PDA), Malt Extract Agar (MEA) and Czapeck Dox Agar (CZA)) and different identification keys. A total of 10 fungal species were isolated, with predominance of Aspergillus flavus, Aspegillus niger, Macrophomina phaseolina, Fusarium oxysporium and Rhizopus sp. whose infection rates were 70.8% to 100% of seed samples. In addition to being present in all three zones, the infection rates of Aspergillus flavus (56.55%), Aspergillus niger (20.35%) and Rhizopus (32.80%) were higher in the Sahelian zone. In the Sudano-Sahelian zone, Macrophomina (50.66%) and Fusarium (18.88%) presented the highest infection rates, while Penicillium sp. showed the highest infection rate (2.84%) in the Sudanian zone. This finding demonstrated the necessity to improve post-harvest and conservation techniques of cowpea to limit crop losses and preserve the sanitary quality of this important foodstuff.

A LAMP-assay-based specific microbiota analysis reveals community dynamics and potential interactions of 13 major soybean root pathogens

Soybean root diseases are associated with numerous fungal and oomycete pathogens;however,the community dynamics and interactions of these pathogens are largely unknown.We performed 13 loop-mediated isothermal amplification(LAMP)assays that targeted specific soybean root pathogens,and traditional isolation assays.A total of 159 samples were collected from three locations in the Huang-Huai-Hai region of China at three soybean growth stages(30,60,and 90 days after planting)in 2016.In LAMP results,we found that pathogen communities differed slightly among locations,but changed dramatically between soybean growth stages.Phytophthora sojae,Rhizoctonia solani,and Fusarium oxysporum were most frequently detected at the early stage,whereas Phomopsis longicolla,Fusarium equiseti,and Fusarium virguliforme were most common in the later stages.Most samples(86%)contained two to six pathogen species.Interestingly,the less detectable species tended to exist in the samples containing more detected species,and some pathogens preferentially co-occurred in diseased tissue,including P.sojae–R.solani–F.oxysporum and F.virguliforme–Calonectria ilicicola,implying potential interactions during infection.The LAMP detection results were confirmed by traditional isolation methods.The isolated strains exhibited different virulence to soybean,further implying a beneficial interaction among some pathogens.

Control of seed born mycobiota associated with Glycine max L.Merr.seeds by a combination of traditional medicinal plants extracts

Seeds from soybean collected from different commercial markets were surveyed for seed-borne fungi.Ninetyeight fungal colonies were isolated all over three monthly isolations constituting twenty-two fungal species.The isolated fungi were belonging to the genera:Alternaria,Aspergillus,Cephalosporium,Chaetomium,Cladosporium,Colletotrichum,Curvularia,Fusarium,Macrophomina,Mucor,Penicillium,Rhizoctonia,Rhizopus,Sclerotium,Stemphylium,and Verticillium.Assay of the antifungal activity of four ethanolic extracts of clove,cinnamon,garlic,and mint was carried out against the most common fungal species(Aspergillus flavus,A.niger,Fusarium solani,F.oxysporium,and F.moniliforme),which significantly reduced the growth of tested fungi.Clove extract recorded the highest antimicrobial potentiality against the seed-borne fungal species,followed by cinnamon,garlic,and mint.Clove and cinnamon achieved minimum inhibitory concentration(MIC)values less than that of the reference antifungal drug fluconazole.Simultaneously,garlic and mint recorded MIC values equal to or higher than that of control.A combination of clove and cinnamon,clove and garlic,cinnamon and garlic,cinnamon,and mint extracts increased the mean relative activity percentage.They decreased MIC values below their values when used individually;this indicated synergistic interaction between the two extracts.A combination of clove with mint and garlic with mint recorded a decrease in the percentage of mean relative activity and an increase in MIC values than their values when used individually,indicating antagonistic interaction between them.

Fungi associated with wheat seed discolouration and abnormalities in <i>in-vitro</i>study

The main aim of present study is to ascertain the fungal species and their effect on germination associated with wheat seeds. Seeds of three varieties WH896, PBW-373 and HD264 of wheat (Triticum aestivum) were collected from Quarsi Agriculture Farm Aligarh. These three seed samples of wheat showing different forms of discouloration and abnormalities were screened for associated fungi. Microscopic examination of wheat seeds reveals that seeds of all the varieties of wheat possess injuries to varying extent. Detailed examination of the seeds has shown that the seeds can be classified on the basis of extent of injury in the three categories viz., seeds having minor cracks, cracks without exposed embryo and cracks with exposed embryo. Seed soaking and washing techniques were also employed. Fusarium moniliforme and Alternaria alternata were isolated from all the categories of seed tested. Floating mycelial bits and conidia of Alternaria, Fusarium, Drechslera, Curvularia lunata, Mucor were found in all the three varieties of wheat. The seeds were subjected to visual observation and examination under stereoscopic microscope. These findings are to study and detect the phytopathogenic mycoflora which causes damage and loss to our seeds and crops.

Seedling Production from Seeds of a Wild Ecotype of Vetiver Grass (<i>Vetiveria zizanioides</i>L.) in Southern China

Vetiver grass (Vetiveria zizanioides L.) is widely used for soil and water conservation, and land management. In practice, all vetiver seedlings are propagated via ramets or tillers, which cannot meet the market demand and would also destroy the original habitat. Most vetiver genotypes flower but do not produce seeds. A wild ecotype of vetiver grass originated in southern China is fertile, but the rate of seed germination is very low. This study aimed to develop a novel method to improve its seed germination and seedling establishment. In the field, the inflorescences of wild vetiver were wrapped using a transparent plastic bag with a pot containing wet soils. The effects of inflorescence bagging and Tween 80 application on seed germination and seedling growth were examined. The results showed that seed development was characterized by low seed setting rate (19.2%), uneven maturity time, easy shedding (more than 95% of spikelets shed off 20 days after flowering), therefore difficult harvest of viable seeds. Bagging the inflorescence with moist soils in pot ensured the mature seeds falling onto the nursery soil surface and absorbing water for germination while the immature seeds continued to grow on the inflorescence. Bigging not only improved seed development and maturity, saved the procedure of seed collection and storage, but also provided a humid micro-environment for seed germination and seedling growth. Tween 80 as a surfactant promoted seed water absorption, germination and seedling growth. This simple and novel method has integrated the procedures of seed collection, storage, germination and seedling establishment, and enables the production of a large number of healthy seedlings. The possible reasons for the degeneration and disappearance of the original population were also discussed from the perspective of the disadvantages of vetiver propagation.

RAPD marker linked with sbm-1, a gene conferring resistance to pea seed-born mosaic virus

DNA markers linked with trait of disease-resistance offer a very useful tool forselection of putative disease-resistant progeny and cloning disease-resistant genes.Peaseed-born mosaic virus(PSbMV)is spread mainly through planting infected pea seeds andby non-persistent aphid transmission.Three strains of PSbMV have been identified,designated as P-1,L and P-4.Strain P-1 is most widely distributed.Four recessive