Phylogenetic Analyses of Phytopathogenic Isolates of Verticillium spp     

Qin QM  Vallad GE  Wu BM  Subbarao KV 《Phytopathology》2006,96(6):582-592

ABSTRACT To better understand the genetic relationships between Verticillium dahliae isolates from lettuce and other phytopathogenic Verticillium spp. isolates from various hosts and geographic locations, the complete intergenic spacer (IGS) region of the nuclear ribosomal RNA gene (rDNA) and the beta-tubulin gene were amplified and sequenced. The sequences of the complete IGS region and the beta-tubulin gene were used alone and in combination to infer genetic relationships among different isolates of Verticillium with the maximum-likelihood distance method. Phylogenetic analyses set sequences into four distinct groups comprising isolates of V. albo-atrum, V. tricorpus, and V. dahliae from cruciferous and noncruciferous hosts. Within the four Verticillium groups, isolates of V. dahliae from cruciferous hosts displayed the closest affinity to V. dahliae from noncruciferous hosts. Isolates of V. dahliae from noncruciferous hosts could be further divided into four subgroups based on sequence similarities within the IGS region. Cross-pathogenicity tests demonstrated that most Verticillium isolates were as virulent on other hosts as on their hosts of origin. A phenogram based on the cross pathogenicity of individual isolates resembled those derived from the IGS and beta-tubulin sequence comparisons. On the basis of the data presented, the potential origin of some isolates of V. dahliae pathogenic on lettuce is proposed.  相似文献   

Community water management to intensify agricultural productivity in the polders of the coastal zone of Bangladesh     

Yadav  Sudhir  Mondal  Manoranjan K.  Shew  Aaron  Jagadish  S. V. Krishna  Khan  Zahirul Haque  Sutradhar  Asish  Bhandari  Humnath  Humphreys  Elizabeth  Bhattacharya  Jayanta  Parvin  Rokhsana  Rahman  Mahabubur  Chandna  Parvesh 《Paddy and Water Environment》2020,18(2):331-343

Paddy and Water Environment - Most of the lands of the southern coastal zone of Bangladesh are protected from tidal flooding and storm surges by embankments constructed during the 1960s and 1970s,...  相似文献   

Adoption and Impact of Modern Rice Varieties on Poverty in Eastern India     

Kwasi Bannor Richard  Amarnath Krishna Kumar Gupta  Oppong-Kyeremeh Helena  Abawiera Wongnaa Camillus 《水稻科学》2020,27(1):56-66

The factors affecting the adoption of modern varieties(MVs) of rice and impact on poverty in Odisha, India were discussed. A total of 363 households from Cuttack and Sambalpur districts of Odisha via multistage sampling technique participated in the survey. The Cragg's Double hurdle model was used to model the determinants of adoption and intensity of adoption of MVs of rice, and the propensity score matching was used to analyze the impact of adoption on poverty. The results showed that age, education, risk aversion, land size, yield, perception of MVs as high yielding, resistant to diseases and availability of MVs positively influenced the decision to adopt. However, variables such as household size, experience of a farmer, off-farm job participation, amount of credit received, cost of seeds, insecticides and fertilizers negatively influenced the adoption of MVs. Intensity of adoption of MVs was negatively influenced by experience of a farmer, cost of fertilizer and marketability of MVs, and positively affected by household size, risk aversion, land size, cost of insecticides, perception of MVs as high yielding and availability of MV seeds. Poverty incidence, gap and severity were high among non-adopters to adopters of MVs. After matching adopters and non-adopters of MV groups using four different algorithms of nearest neighbour matching, stratification matching, radius matching and kernel matching, the impact of MV adoption resulted in higher per capita monthly household expenditure by about US$ 52.82 to US$ 63.17.  相似文献   

Biocontrol potential of Pseudomonas azotoformans,Serratia marcescens and Trichoderma virens against Fusarium wilt of Dalbergia sissoo     

Sabyasachi Banerjee  Seema Singh  Shailesh Pandey  Maneesh S. Bhandari  Amit Pandey  Krishna Giri 《Forest Pathology》2020,50(2)

Wilt disease caused by Fusarium solani is a serious constraint to Dalbergia sissoo (shisham) plantations in northern India. In this study, the antagonistic potential of 40 bacterial isolates recovered from rhizophere soil of healthy shisham trees, and a well‐characterized Trichoderma species (Trichoderma virens) were tested for their possibility as biocontrol agents for F. solani. Two promising isolates (S1 and S15) were identified which inhibited pathogen growth, caused chitin degradation, produced siderophores and solubilized phosphate in vitro. Isolate S15 scored highest for hydrogen cyanide (HCN) production while isolate S1 was a non‐HCN producer. These two isolates were identified as Serratia marcescens (S1) and Pseudomonas azotoformans (S15) following sequence analysis of 16S rDNA. In dual culture assays, T. virens caused 80% inhibition of mycelial growth of the test fungus. The three selected antagonists when tested in planta in the glasshouse completely suppressed production of wilt symptoms on 12‐month‐old shisham plants. Further work is needed to ascertain the potential of these isolates to be used as biocontrol agents to manage shisham wilt under field conditions.  相似文献   

Rice gluten meal as an alternative by-product feed for growing dairy calves     

Rohit Kumar  Sudarshan Singh Thakur  M. S. Mahesh 《Tropical animal health and production》2016,48(3):619-624

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Herd-level risk factors for bovine viral diarrhea infection in cattle of Tamil Nadu     

Subbiah Krishna Kumar  K. M. Palanivel  K. Sukumar  B. Samuel Masilamoni Ronald  G. Selvaraju  G. Ponnudurai 《Tropical animal health and production》2018,50(4):793-799

A cross-sectional study was carried out to identify risk factors for bovine viral diarrhea virus (BVDV) infection in 62 randomly selected dairy herds which were tested for BVD serum antibodies by using an indirect ELISA kit (IDEXX). Results from the chi-square test analysis were interpreted by analyzing by chi-square test. A sum of 500 sera samples were screened and 66 animals (13.20%) showed positive for BVDV antibody. Within herd, BVD seroprevalence was 12–65%. This study concluded that epidemiological risk factors like location, herd size, housing patterns like, tail to tail system, roofing pattern, distance between the manure pit and farm, and distance between farms were significantly associated with BVDV serological status (P?<?0.05).  相似文献   

Inheritance of foliar blast resistance in pearl millet (Pennisetum glaucum)     

Shashi K. Gupta  Rajan Sharma  Kedar N. Rai  Ram P. Thakur 《Plant Breeding》2012,131(1):217-219

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Short term effect of applied nitrate on nitrogen metabilism of Acacia catechu seedlings     

U. Thakur  D. K. Khurana  A. K. Nath 《New Forests》1996,12(1):1-9

Nitrogen metabolism of Acacia catechu seedlings was studied after 5, 10 and 15 days of daily 20 mM nitrate application. Fresh weight of shoots and total nitrogen content of the plants increased significantly with applied nitrate but there was no effect on nodulation. An increase in the nitrate reductase activity, nitrate and nitrite content in nodules and leaves of the treated plants was also observed. However, the total soluble protein content declined and the amino acid content increased in different parts of the treated plants.  相似文献   

Zur Wirkung der Partikelgröße der Imaginalnahrung auf die Eizahl vonTribolium castaneum (Hbst.) (Col., Tenebrionidae)     

R. Narayan Singh  S. S. Krishna 《Journal of pest science》1985,58(1):17-18

Whole and intact wheat grains or those broken into 2 or 8 equal pieces and supplemented with yeast provided as adult food to individuals ofTribolium castaneum considerably reduced the egg output in these beetles although their larvae were reared on finely powdered yeast-supplemented whole wheat flour. However, egg fertility in all the three dietary situations was 100%.  相似文献   

Biology of Termites     

Krishna K. und F. M. Weesner 《Journal of pest science》1969,42(5):79

Ohne Zusammenfassung

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Biology of Termites

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