Longevity of Bipolaris oryzae on HEERA-2 Hybrid Rice Seed

Seeds of hybrid rice variety Heera-2 was collected from Mymensingh district in Bangladesh. Longevity of Bipolaris oryzae was studied in 2012 to 2016 at Seed Pathology Centre, Bangladesh Agricultural University, Seed processing &preservation center and Seed Pathology Laboratory of Supreme Seed Company Limited. The data collected from the experiments were analyzed for test of significance and compared the treatment means by using DMRT at 5% level of probability following the Statistical tool for Agricultural Research (STAR) 2.1 program.The longevity of B. oryzae was observed till five years by blotter incubation methods, seedling symptom test and growing on test. Both untreated and seeds treated with Vitaflo 200FF (carboxin and thiram) were kept in jute bag and polybag stored for five years under both normal and dehumidified condition. The inocula of B. oryzae on Hybrid Heera 2 seed remained viable up to five years. When the seed samples were stored under dehumidified condition, the highest incidence of B. oryzae was recorded in case of jute bag after five years. After treated with Vitaflo 200FF, there was no any infection of B. oryzae under both storage condition Environ. Sci. & Natural Resources, 12(1&2): 209-213, 2019

Corynespora cassiicola in soybean seeds – incidence and transmission

The fungus Corynespora cassiicola, causal agent of target spot in soybeans, has been considered, from the seed pathology point of view, a seed-borne pathogen of limited importance. Therefore, little importance has been given to the role of the seeds in the transmission of this pathogen. The objectives of this study were to determine the incidence of C. cassiicola in soybean seeds and evaluate the effects of this seed-borne pathogen, inoculated in the seeds, in relation to physiological and epidemiological parameters. The experiments were carried out at TAGRO and Embrapa Western Agriculture under lab (blotter test and seed germination test) and greenhouse conditions (growing on test). The fungus C. cassiicola was detected in 11.3% of the 639 seed samples analyzed, with an average incidence of 0.91% and maximum of 8.5%. The transmission of C. cassiicola from the seeds to above-ground parts of soybean seedlings was demonstrated, by pathogen establishment on the cotyledon, showing circular lesions with concentric rings, reddish-brown in the center and surrounded by a yellowish green halo, as a typical symptoms of target spot. Reddish-brown lesions on the roots and stem of the seedlings were also observed. Considering a sample seed with 66.0% of C. cassiicola incidence, the symptomatic transmission based on cotyledon symptoms was 42.2%, corresponding to a transmission rate of 2.4:1. This is the first report, in a quantified way, about the transmission of C. cassiicola from the seeds to above-ground parts of soybean seedlings. When compared to non-inoculated seeds, seed germination, seedling emergence and seedling initial development were influenced by the presence of the pathogen in the seeds, with the lowest values being observed when the seeds were inoculated.

DETECÇÃO, QUANTIFICAÇÃO E IDENTIFICAÇÃO DE FITOBACTÉRIAS EM SEMENTES DE TRIGO

A qualidade sanitária das sementes merece atenção, considerando os reflexos negativos que a associação de patógenos em sementes pode gerar. Este estudo objetivou detectar, quantificar e identificar bactérias fitopatogênicas em sementes de trigo. A incidência foi avaliada utilizando as sementes diretamente dispostas sobre os meios de cultura 523, WBC e XTS. Dez diferentes métodos de quantificação foram testados, utilizando 100, 500, 1000 e 3000 sementes com e sem incubação; 3000 sementes com centrifugação e 3000 trituradas. Através do meio 523 não foi possível avaliar a incidência devido a presença de contaminantes. Utilizando o meio WBC obtiveram-se incidências de 92, 82 e 78 % para os cultivares Quartzo, Marfin e BRS 331 respectivamente e com o meio XTS 68% de incidência na cultivar BRS 331. Os resultados permitiram observar que o melhor método para quantificação de bactérias em sementes de trigo foi a utilização de 3000 sementes com incubação, com trituração e com centrifugação. Os resultados das avaliações como morfologia colonial, testes bioquímicos e fisiológicos permitem concluir que as bactérias isoladas pertencem às espécies Xanthomonas translucens e Pseudomonas fuscovagine, sendo que, alguns desses isolados a identificação só foi possível ao nível de gênero sendo identificados como Xanthomonas e Pseudomonas.Palavras-chave: bacteriose; patogenicidade; patologia de sementes; triticum aestivum. DETECTION AND QUANTIFICATION OF PHYTOPATHOGENIC BACTERIA IN WHEAT SEED ABSTRACT: The sanitary quality of seeds deserves attention, considering the negative impact that the association of pathogens in seeds can generate. This study aimed detects, quantify and identify phytopathogenic bacteria gifts in wheat seeds. The incidence of bacteria was evaluated using the seeds directly arranged on the culture medium 523, WBC and XTS. Ten different methods of quantification of pathogenic bacteria were tested with 100, 500, 1000 and 3000 seeds with and without incubation; 3000 seeds with crushed and 3000 with centrifugation. Across the middle 523 was not possible to assess the impact due to the presence of contaminants. Using the WBC light yielded incidences of 92, 82 and 78 % for Quartzo, Marfim and BRS 331cultivars respectively. With the environment XTS 68 % incidence BRS 331. Results showed that the best method for quantification of bacteria in wheat seeds was to use incubation with 3000 seeds with milling and centrifuging. The isolates were identified by colony morphology, biochemical and physiological tests showed that the isolated bacteria belonging to the species Pseudomonas fuscovaginae and Xanthomonas translucens and genera Pseudomonas and Xanthomonas.Keywords: bacterial; pathogenicity; seed pathology; triticum aestivum.

Effect of Seed Treatments and Containers on Chilli and Brinjal Seed Viability

An experiment was conducted to investigate the influence of fungicides and packaging materials on longevity of chilli (variety: RCH-1) and brinjal (variety: Hisar Shyamal) seeds. The seeds were treated with 15 fungicides and were kept in three containers viz. Metal box, Cloth bag and Plastic zipling bag up to 12 months under ambient conditions in seed pathology laboratory of Department of Seed Science & Technology, CCSHAU, Hisar, India. The samples were drawn at quarterly intervals for ascertaining the seed quality parameters. The seeds treated with flusilazole and carbendazim (2 g kg-1 seed) in case of chilli and brinjal and stored in metal-box were found better for maintenance of higher seed quality parameters [electrical conductivity and dehydrogenase activity] during the study period. The study suggested that use of appropriate packaging material and seed treatment could be useful to prolong the storage life of chilli and brinjal seeds.

Effect of Seed Treatments and Containers on Chilli Seed Viability

An experiment was conducted to investigate the influence of fungicides and packaging materials on longevity of chilli seed (variety: RCH-1). The seeds were treated with 15 fungicides and were kept in three containers viz. Metal box, Cloth bag and Plastic zipling bag up to 12 months under ambient conditions in seed pathology laboratory of Department of Seed Science & Technology, CCSHAU, Hisar, India. The samples were drawn at quaterly intervals for ascertaining the seed quality parameters. The seeds treated with flusilazole (2 g kg-1 seed) and stored in metal-box were found better for maintenance of higher seed quality parameters [germination, root length, shoot length, mean seedling dry weight, vigour indices] during the study period. The study suggested that use of appropriate packaging material and seed treatment could be useful to prolong the storage life of chilli seeds.

Physiological and Sanitary Quality in Cowpea Seeds Produced in Rio Grande Do Norte, Brazil

The importance of cowpea (Vigna unguiculata (L.) Walp.) to the Northeast region of Brazil is undeniable, it is a major crop in local family agriculture. As a result, the research aimed to evaluate the physiological and sanitary quality of local varieties of cowpea coming from the state of Rio Grande do Norte. The experiment was carried out at the Seed Pathology and Seed Analysis Laboratory, in Federal University of Paraíba, Campus II, Areia, Paraiba, Brazil. Six cowpea varieties (Baeta, Coruja, Sempre Verde, Epace 10, Feijão da Bahia and Pingo de Ouro) from rural Area of the municipality of Apodi, Rio Grande do Norte, Brazil.were evaluated  Seed physiological quality was evaluated by determining the first germination count (FGC), germination percentage (G%), seedling length (SL) and electrical conductivity (EC). The sanitary quality of the seeds was evaluated by the method of incubation in filter paper (blotter test). The experimental design was completely randomized, with 4 replicates. The Pingo de Ouro, Sempre Verde and Coruja varieties had germination percentages greater than the minimum standards required for commercialization, while the lower germination percentage and vigor of the Feijão da Bahia, Epace 10 and Baeta varieties may be associated with the presence of Aspergillus sp. and Penicillium sp.