Experimental infection of pups with Ancylostoma caninum-infected mouse tissues

Migration and distribution of Ancylostoma caninum larvae in the tissues of mice orally infected with 1000 larvae, and establishment of patent infection from the mice to the definitive host, were studied. Larval yield from different organs of mice, after digestion with artificial gastric juice, indicated that the highest recovery was at 4 h post-infection (62.8%), and thereafter a slight decline occurred up until 30 days post-infection (51.5%). Migration of larvae to the lungs occurred within 4 h, to the liver within 12 h and into the heart within 24 h. No larvae were recovered from spleen and kidney tissues. From the 9th day onwards larvae were also recovered from the brain. Migration in the muscles of head and neck occurred within 4 h, in the thoracic and abdominal muscles at 24 h and in lumbosacral and leg muscles at 48 h. The establishment of patent infections in the definitive host was studied by feeding the orally- and percutaneously-infected mice to hookworm-free pups at 10 and 30 days post-infection. The mean necropsy worm burden in the pups fed with the orally-infected mice was comparatively higher than in the pups fed cutaneously-infected mice.     

Effects of inoculation with stress-adapted arbuscular mycorrhizal fungus Glomus deserticola on growth of Solanum melogena L. and Sorghum sudanese Staph. seedlings under salinity and heavy metal stress conditions

The beneficial effects of a Glomus deserticola strain isolated from the rhizosphere of grasses (belonging to Poaceae family) growing along the industrial waste from a distillery were investigated under stress conditions. The study was conducted to assess the efficacy of the arbuscular mycorrhizal (AM) fungal ecotype in salinity and heavy metal (HM) tolerance of eggplant (Solanum melongena L.) in soils amended with various stress levels of NaCl, zinc and cadmium. Mycorrhizal (M) seedlings produced a significantly (p < 0.05) greater growth response and were more tolerant to salt and HM stresses than nonmycorrhizal (NM) seedlings in all treatments. The HM contents in the plant tissues were significantly higher in M than NM eggplants. Furthermore, when the efficacy was compared with other AM isolates in HM-polluted soils with Sudan grass (Sorghum sudanese Staph.) as a test plant, the AM ecotype responded best to these soils, as evident from the significantly greater growth response and its aggressiveness in colonizing roots in all soil types tested. These results suggest that this G. deserticola ecotype can be used as an effective tool to alleviate the adverse effects of excessive salinity and HM toxicity on plant growth. Finally, the isolate may have potential in the bioremediation of polluted soils.     

Effect of Azolla as an Organic Source of Nitrogen in Rice-Wheat Cropping System

Increasing area under high yielding varieties require more quantity of fertilizers and other inputs for higher yield. However, utilization of available biomass could reduce the dependence on costly crop production inputs like fertilizers. In light of this, field experiments were carried out at Agricultural Engineering Department, Indian Institute of Technology, Kharagpur for two years i.e. 1982–83 and 1983–84 to find out the possibilities to meet at least a part of nitrogen requirement through incorporation of Azolla in rice-wheat cropping system. Incorporation of 10 t/ha of fresh Azolla before planting + 30 kg N/ha through fertilizer as basal proved to be the best and recorded maximum land productivity in rice-wheat cropping system. This treatment recorded 117.69 and 103.30 per cent higher grain yield of rice and wheat respectively over control. About 30 kg N could be supplemented through preplanting incorporation of 5 t fresh Azolla. The result indicated that Azolla could be utilized as an alternative source of N-fertilizer for higher production of crops in rice-wheat cropping system.     

Seventh British Insecticide and Fungicide Conference,Brighton, November 1973

Abstract

A field experiment was conducted during the wet seasons of 1980 and 1981 to find out the relative influence of weed control and applied nitrogen on performance of transplanted rice and nutrients uptake by rice and weeds. Propanil and thiobencarb, each at 2.0 kg a.i/ha, were found comparable to two hand weedings in increasing grain yield of rice and minimizing dry matter of weeds. The mean grain yield was increased by 28.06% while dry matter of weeds reduced by 84.04% over unweeded control. Application of nitrogen from 0 to 75 kg N/ha increased grain yield to the tune of 1631 kg/ha. Remarkable increase in grain yield was noticed when weed control treatments were associated with application of nitrogen. Higher uptake of N, P and K by crop and lower removal of same nutrients by weeds were observed in herbicides and hand weedings than unweeded control. N, P and K in the order of 11.49, 1.71 and 12.40 kg/ha respectively could be saved through weed control in transplanted rice.     

Direct and Residual Effect of Slow Release Urea Fertilizers in Rice-Wheat Cropping System

Field experiments were conducted for three consecutive years during 1979—80 to 1981—82 to find out the relative efficiency of different forms of urea fertilizer for rice and their residual effect on the succeeding crop of wheat. In rice crop, root zone placement of nitrogen as urea super granule 1.0 g size (USG) under puddled field condition was proved to be superior to other sources. The relative efficiency of USG, urea in splits and sulphur coated urea (SCU) was 116.92%, 107.71% and 101.41% respectively as compared to ordinary urea at planting. Significant residual effect on succeeding crop of wheat was recorded in case of SCU which was followed by USG, urea in splits and urea at planting.     

Isolation and expression analysis of defensin gene and its promoter from Brassica juncea

Journal of Plant Diseases and Protection - The full-length pathogen-inducible plant defensin gene encoding 80 amino acid sequences of pathogen-related gene PR12 (Bjdefensin) was isolated from...     

Infectivity of Ancylostoma caninum in dogs by different routes of inoculation

Infectivity of A. caninum in dogs inoculated with 500 larvae by different routes (percutaneous, subcutaneous, intravenous, per os, through a stomach tube and foot pad) was studied by ascertaining the worm burden at necropsy 21-27 days post-infection. Infection through foot-pads yielded the maximum number of worms. The percentage of worm establishment using foot-pad inoculation was 73.8%, followed by subcutaneous (49.0%), percutaneous (45.0%) and per os (35.0%) routes. These results show that active penetration of the larvae through skin and particularly foot-pad is the most favourable mode of infection of dogs.     

Growth and Yield of Peanut as Influenced by Degree and Duration of Shading

Peanuts ( Arachis hypogaea L.) which are commonly grown in intercropping systems often suffer from shading caused by the associated crop. Through this study an attempt has been made to estimate the effect of different levels of shade at different growth stages on crop yield. Field experiments were laid out during monsoon and winter seasons of 1985 and 1986 by creating artificial shading up to 25 and 50 per cent of the day/natural light at flowering-pegging, pod filling and maturity stages of a Spanish bunch type peanut. Dry matter production has shown linear response to light intensity and due to 50 per cent shading it was reduced by 55 per cent. Vegetative growth rate during pod filling stage was very poor as a result of increase in shading at this stage. In shaded plants the nodulation was less and some reduction in chlorophyll content was also observed. However, oil content in kernel was not affected by shading. Shading caused significant reduction in pod number and kernel weight and thus there was decrease in pod yield. Flowering to pegging and pod filling stages seemed to be sensitive to shading while increase in shading at maturity stage did not cause any reduction in yield. It could be possible to obtain about 90 per cent pod yield by avoiding shading during flowering to pegging stage (45 DAS).     

Influence of nitrogen and weed management on the productivity of upland rice

Nitrogen and weeds are two important factors that influence the productivity of rainfed upland rice (Oryza sativa L.) in tropical Asia. A low recovery of applied fertilizer N in rainfed uplands is generally associated with high nitrate leaching losses and weed interferences. Field experiments were conducted during the wet seasons of 2002 and 2003 at the research farm of Central Rainfed Upland Rice Research Station, Hazaribag, Jharkhand, India, to determine the response of upland rice to nitrogen applied at 60 kg N ha^–1 as different forms of urea (single pre‐plant application of controlled‐release urea, single pre‐plant application of urea supergranules, and split application of prilled urea with or without basal N) against no N application under three weed‐control regimes (unweeded, pre‐emergence application of butachlor at 1.5 kg a.i. ha^–1 supplemented with one single hand weeding or two hand weedings). The response of rice to applied N varied greatly among the three weed‐control regimes. Across the different N treatments, the application of 60 kg N ha^–1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha^–1 in unweeded treatments, whereas yields increased by 1.07 Mg ha^–1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha^–1 with two hand weedings. Among the weed‐control measures, hand weeding twice produced highest grain yield in both years. The comparison of different forms of urea showed that a single pre‐plant application of controlled‐release urea resulted in average grain yields of 1.57 and 1.87 Mg ha^–1 compared to 1.32 and 1.30 Mg ha^–1 in the case of the recommended practice of split‐applied prilled urea in the years 2002 and 2003, respectively. The highest agronomic N use efficiency of 15–20 kg grain per kg N applied and the highest apparent N recovery of 39%–45% were attained with controlled‐release urea, suggesting that this N form is particularly beneficial for upland‐rice cultivation under variable rainfall conditions, provided weeds are controlled.