Comparative efficiency of phosphate-solubilizing bacteria under greenhouse conditions for promoting growth and aloin-A content of Aloe barbadensis

This study was conducted with Aloe barbadensis in order to investigate the efficacy of four phosphate-solubilizing bacteria (PSB), Pseudomonas synxantha 10223, Burkholderia gladioli 10242, Enterobacter hormaechei 10240 and Serratia marcescens 10241 to solubilize Mussorie rock phosphate (MRP) and to evaluate its effects on growth, soluble P content and P uptake compared with control, i.e. uninoculated plants. Pot experiments were conducted in a greenhouse, in soil supplemented with MRP. Each PSB treatment showed different effects on different plant growth parameters. The maximum increase in leaf length (23.7%), total number of leaves (33.33%) and dry rind weight (69.10%) was observed in plants treated with P. synxantha 10223 compared with control. Whereas, maximum increase in root length (23.43%), fresh leaves weight (79.03%), dry gel weight (113.08%) and total gel volume (112.10%), was observed in plants treated with S. marcescens 10241 compared with uninoculated plants. Maximum increase in aloin-A content [114.92% (per g dry gel weight) and 322.32% (per plant dry gel weight)] was observed in plants treated with P. synxantha 10223 compared with control plants. Root colonization by inoculated PSB as estimated by RAPD technique showed that all PSB were able to survive in the rhizosphere of Aloe plants.     

An evaluation of furrows for managing soil and water loss from a shallow Alfisol under simulated rainfall

Furrows are widely used in rainfed areas of semi-arid India for soil and water conservation. The orientation of furrows, either down or across slope, and their spacing influence the effectiveness of furrows as soil and water conservation measures. We evaluated treatments with furrows aligned down and across 3% sloping land at spacings of 90, 60 and 30 cm under simulated rainfall intensities of 80 and 100 mm/h on a shallow Alfisol. A bare plot without any furrows was considered as a control. A large (24 m × 3 m) rainfall simulator developed at the Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad, was used for this controlled study. Run-off was measured by a calibrated tipping bucket run-off recorder. The effects of the treatments on peak flow rate (L/s), sediment loss with run-off water (kg/ha/mm), peak sediment concentration (g/L), run-off (per cent rainfall) and time to peak (min) were investigated. When compared with the control (no furrows), across slope furrowing with 60- and 30-cm spacing reduced sediment yields by 19.9 and 21.3 kg/ha/mm of run-off, respectively, under a rainfall intensity of 80 mm/h and 24 and 25.3 kg/ha/mm of run-off, respectively, under a rainfall intensity of 100 mm/h. For the control, sediment loss was 50.72 kg/ha/mm run-off and 56.68 kg/ha/mm run-off for rainfall intensities of 80 and 100 mm/h, respectively. Similar trends were recorded from observations of peak flow, time to peak and peak sediment concentration. Run-off hydrographs demonstrated the conservation value of across slope furrowing by delaying run-off initiation, reducing run-off and slowly releasing the run-off after the cessation of rainfall. The results show that furrow orientation has major effects on reducing run-off, whereas furrow spacing has insignificant effects.     

Suppression of cell-mediated immunity by purified aflatoxin B1 in broiler chicks

The effect of purified aflatoxin B1 on cell-mediated immunity (CMI) in broiler chicks was assessed using doses of 0.3 and 1 mg/kg feed from hatching to 6 weeks of age. Total lymphocyte and T lymphocyte counts and the 2,4-dinitrofluorobenzene skin sensitivity test, graft-versus-host reaction and nitroblue tetrazolium salt reduction tests were used to evaluate CMI. Both doses of aflatoxin B1, including the apparently nontoxic dose of 0.3 mg/kg feed, caused a significant (P less than 0.05) decline in CMI. The functional activity of splenic macrophages was decreased significantly (P less than 0.05) by both doses of the toxin.     

Effect of Growth Regulators on the Productivity of Some Major Oilseed Crops

A number of field experiments were conducted at the Viswavidyalaya Research Farm during 1984–85 to 1986–87 to study the effects of five growth regulators viz. Miraculan (a triacontanol based growth stimulant), Nutron (1-triacontanol growth stimulant), Planofix ( α -napthylacetic acid), Paras or Mixtalol (Higher alcoholic carbon compounds) and N-triacontanol on productivity of five different major oilseed crops viz. rapeseed ( Brassica campestris L. var. yellow sarson), mustard ( Brassica juncea L. Czern and Coss), sesame ( Sesamum indicum L.), linseed ( Linum usitatissimum L.) and safflower ( Carthemus tinctorius L.). Results showed the positive influence of growth regulators on the productivity of crops (10–40 % increase in yield); however the influence was not consistent over the years. N-triacontanol when tried on mustard only improved the grain yield significantly, more so when applied with paras or planofix, sesame was most influenced by spraying planofix and paras. Nutron favourably influenced safflower and linseed. The test weight of grains followed by the number of pods/plant were influenced most by the application of growth regulators. Inconsistency in results over the years, however, need further investigations on the timing of spraying.     

Comparative sequence analysis of 16S rRNA gene of Pasteurella multocida serogroup B isolates from different animal species

The phylogenetic relationships of five isolates of Pasteurella multocida serotype B:2 belonging to buffalo, cattle, pig, sheep and goat were investigated by comparative sequence analysis of 16S rRNA gene. The 1468bp fragment of 16S rRNA gene sequence comparison showed that the isolates of cattle (PM75), pig (PM49) and sheep (PM82) shared 99.9% homology with the buffalo isolate (vaccine strain P52) whereas, the goat isolate (PM86) shared 99.8% homology with the vaccine strain. The 16S rRNA gene sequences of these isolates were also found monophyletic with type B reference strain NCTC 10323 of P. multocida subsp. multocida. The present study indicated the close relationships of haemorrhagic septicaemia causing P. multocida serotype B:2 isolates of buffalo and cattle with other uncommon hosts (pig, sheep and goat).     

Tillage Effects on Crop Yield and Physicochemical Properties of Sodic Soils

Tillage modifies soil structure and has been suggested as a practice to improve physical, hydrological and chemical properties of compacted soils. But little is known about effect of long‐term tillage on physicochemical soil properties and crop yield on sodic soils in India. Our objective was to investigate the effect of different tillage regimes on crop yield (wheat and paddy rice) and physicochemical properties of sodic soils. Two sodic sites under conventional tillage for 5 (5‐YT; 5‐year tillage) and 9 (9‐YT; 9‐year tillage) years were selected for this study. Changes in crop yield and physicochemical soil properties were compared with a control, sodic land without any till history, that is, 0‐year tillage/untilled (0‐YT). Five replicated samples at 0‐ to 10‐cm and 10‐ to 20‐cm soils depths were analysed from each site. In the top, 0‐ to 10‐cm soil depth 5‐YT and 9‐YT sites had higher particle density (Pd), porosity, water holding capacity, hydraulic conductivity, organic carbon, total nitrogen (N_t), available nitrogen (N_avail), phosphorus (P_avail) and exchangeable calcium (Exch. Ca⁺⁺) than 0‐YT, whereas bulk density (Bd), C : N ratio and CaCO₃ were significantly lower. Bd, pH, EC and CaCO₃ increased significantly with depth in all the lands, whereas Pd, porosity, water holding capacity, hydraulic conductivity, organic carbon, N_t, N_avail, P_avail and Exch. Ca⁺⁺ decreased. We conclude that continuous tillage and cropping can be useful for physical and chemical restoration of sodic soils. Copyright © 2014 John Wiley & Sons, Ltd.     

Genetic improvement of legumes using somatic cell and molecular techniques

Summary The merits and limitations of somatic cell techniques involving Agrobacterium-mediated transformation, direct gene transfer and protoplast fusion, are discussed in relation to the genetic improvement of forage and grain legumes. Whilst progress with legumes is limited compared to that with plants of other families such as the Solanaceae, the fact that many legumes are readily amenable to tissue culture now permits somatic cell techniques to be targetted to these species. Future development of the subject will necessitate close collaboration between molecular biologists and plant breeders to enable novel plants generated by in vitro technologies to be incorporated into conventional breeding programmes.     

The Influence of Plant Developmental Stage on Expression of Resistance to leaf Rust (Puccinia recondita) in Two Near Isogenic Lines of Wheat

Cultivar ‘Thatcher’, and ‘Thatcher’ lines with Lr 21 and Lr 22 were studied against a number of races of Puccinia recondita for seedling and adult plant reaction. The study has established that Lr 21 and Lr 22 are genes effective against P. recondita at adult plant stage. It has also shown that these genes confer resistance against all races when plants are inoculated at boot leaf stage.