Season-specific varietal management as an option to increase rainfed lowland rice production in East African high altitude cropping systems

Due to land expansion and an increase in productivity, rice production in sub-Saharan Africa has been growing at a rate of 6% in the past decade. Rainfed rice production systems have accounted for a large share of this expansion. In these systems, the potential growing period not only depends on the length of the rainy season and thus water availability, but is often, especially in the highlands of East Africa, bordered by the onset of the cool period of the year, when low minimum temperatures compromise rice yields. The objective of this study was to investigate the yield potential of 30 rice varieties contrasting in crop duration and cold tolerance in the highlands of East Africa, with its limited length of growing period. A field trial was conducted in the cropping seasons in 2016 and 2017 at the Fogera rice research station, Ethiopia. As a function of the onset of rains, rice was sown mid-July in 2016 and early July in 2017. Early sowing in 2017 led to an extended crop duration and significantly lower yields of the short-duration varieties, and to a shortened duration and significantly higher yields of the medium- and long-duration varieties, when compared to late sowing in 2016. Late sowing compromised yield of the medium- and long-duration varieties because of low temperatures during booting stage, which led to high spikelet sterility. Early sowing resulted in low yields of the short-duration varieties, probably due to low solar radiation during the cloudy rainy season, which coincided with the vegetative stage. Therefore, choice of variety should be a function of the variable onset of the rainy season and related sowing date. However, crop models precisely calibrated for potential varieties and the respective environmental conditions could fully support the selection of a suitable variety, depending on the date of sowing, for example with the help of online tools or smartphone applications.     

Diagnosis of paratuberculosis in goats by cell mediated immune response,conventional and molecular diagnostic techniques

In the present study efficacy of single intradermal Johnin test, acid fast staining of faecal smear and IS 900 faecal polymerase chain reaction tests was evaluated in 200 goats for detection of Mycobacterium avium subsp paratuberculosis. Two hundred goats comprising 150 goats from an organised farm in Trichur district and 50 goats reared under field condition at farmers premise from Malappuram district of Kerala state formed the study population. Faecal smear from all the 200 goats was stained by Ziehl–Neelsen acid fast stain and faecal polymerase chain reaction (PCR) specific for M. avium subsp paratuberculosis (MAP); IS 900 was performed on all samples. All the animals were subjected to single intradermal Johnin test. Out of 200 goats screened for paratuberculosis, six goats (3%), 11 goats (5.5%) and 42 goats (21%) were found positive by Ziehl–Neelsen acid fast staining of faecal smear, single intradermal Johnin test and IS 900 PCR respectively. Results of the present study indicate that amplification of IS 900 insertion element was the most specific and sensitive diagnostic detection method. Single intradermal Johnin test and Ziehl–Neelsen acid fast staining did not show any significant difference.     

Nipah virus: epidemiology,pathology, immunobiology and advances in diagnosis,vaccine designing and control strategies – a comprehensive review

Nipah (Nee-pa) viral disease is a zoonotic infection caused by Nipah virus (NiV), a paramyxovirus belonging to the genus Henipavirus of the family Paramyxoviridae. It is a biosafety level-4 pathogen, which is transmitted by specific types of fruit bats, mainly Pteropus spp. which are natural reservoir host. The disease was reported for the first time from the Kampung Sungai Nipah village of Malaysia in 1998. Human-to-human transmission also occurs. Outbreaks have been reported also from other countries in South and Southeast Asia. Phylogenetic analysis affirmed the circulation of two major clades of NiV as based on currently available complete N and G gene sequences. NiV isolates from Malaysia and Cambodia clustered together in NiV-MY clade, whereas isolates from Bangladesh and India clusterered within NiV-BD clade. NiV isolates from Thailand harboured mixed population of sequences. In humans, the virus is responsible for causing rapidly progressing severe illness which might be characterized by severe respiratory illness and/or deadly encephalitis. In pigs below six months of age, respiratory illness along with nervous symptoms may develop. Different types of enzyme-linked immunosorbent assays along with molecular methods based on polymerase chain reaction have been developed for diagnostic purposes. Due to the expensive nature of the antibody drugs, identification of broad-spectrum antivirals is essential along with focusing on small interfering RNAs (siRNAs). High pathogenicity of NiV in humans, and lack of vaccines or therapeutics to counter this disease have attracted attention of researchers worldwide for developing effective NiV vaccine and treatment regimens.     

Effect of different level and source of copper supplementation on immune response and copper dependent enzyme activity in lambs

An experiment was conducted on 30 male Nellore lambs with average body weight (BW) of 15.45 +/- 0.06 kg to determine the level of the copper (Cu) supplementation in diet from inorganic and organic sources required for optimum immunity and its effect on copper dependent enzymes by allotting them randomly to five groups in completely randomized design. The dietary treatments were viz., basal diet (no Cu supplementation, BD), other four groups were offered BD supplemented with 7 or 14 ppm Cu from copper sulphate (CuSO(4)) and Cu-proteinate, respectively. The lambs were fed the respective diets at 3.5 per cent BW to meet the requirements except Cu for 180 days. The humoral immune response against Brucella abortus and chicken RBC was assessed after 90 days of feeding. The in vivo delayed type hyper sensitivity reaction against PHA-P and in vitro lymphocyte proliferation against Con A indicative of cell mediated immune response (CMI) was assayed at 180 days of feeding. At the end of experiment four lambs from each group were slaughtered for estimation of liver superoxide dismutase activity (SOD). The ceruloplasmin and RBC-SOD activities were higher (P < 0.05) in 14 ppm Cu supplemented lambs from Cu-proteinate at 90 and 180 days, while the liver SOD activity was higher (P < 0.05) in lambs fed 14 ppm Cu from CuSO(4). The STAT titres against B. abortus were higher in Cu supplemented lambs, with no effect of dose of supplementation. Lambs supplemented with Cu-proteinate had higher titers than CuSO(4) on 7 and 14 days of post sensitization. The total immunoglobulin concentration and the CMI response against PHA-P and Con-A was higher (P < 0.05) in lambs fed 14 ppm Cu-proteinae diet. The IgM level was though high in Cu supplemented lambs, no dose or source effect were observed. The study indicated that Cu dependent enzymes activity and immune response were highest and respond better against stress in lambs on 14 ppm supplemented Cu from Cu-proteinate.     

Restriction Enzyme Analysis of Indian Isolates of Egg Drop Syndrome 1976 Virus Recovered from Chicken,Duck and Quail

Egg drop syndrome 1976 (EDS-76) is caused by a haemagglutinating adenovirus belonging to group III of the genus Aviadenovirus in the family Adenoviridae. All isolates are serologically identical, but have been divided into three groups based on restriction endonuclease (RE) analysis. In this study the viral DNA of various Indian EDS-76 viral isolates (CEDS-A, CEDS-B, EDS-M, EDS-ML, EDS-1/AD/86, EDS-KC and QEDS) obtained from different avian species and different geographical regions were digested with restriction endonucleases viz., EcoRI, BamHI, HindIII and PstI. The results showed that one Indian isolate obtained from duck (DEDS-KC) was different from all other chicken and quail counterparts. All other isolates were identical to the reference viral strain BC-14, which belong to group I of EDS-76 viruses. The duck isolate EDS-KC could not be placed in any of the three groups reported earlier.     

Modified rice cultivation in Tamil Nadu,India: Yield gains and farmers’ (lack of) acceptance

The looming water crisis and water-intensive nature of rice cultivation are driving the search for alternative management methods to increase water productivity in rice cultivation. Experiments were conducted under on-station and on-farm conditions to compare rice production using modified methods of irrigation, planting, weeding and nutrient management with conventional methods of cultivation. Farm surveys were used to evaluate adoption of modified rice cultivation method. On-station experiments showed that, a combination of water-saving irrigation, young seedling or direct seeding, mechanical weeding and green manure application increased the rice water productivity though the largest yields were obtained for a combination of conventional irrigation, young seedling or direct seeding, mechanical weeding and green manure application. On-farm experiments demonstrated a yield advantage of 1.5 t ha⁻¹ for the modified method over conventional method. We found, however, that yield advantages were not the sole factor driving adoption. Associated changes required in management, including the increased labour demand for modified planting, unwillingness of agricultural labourers to change practices, difficulties with modified nursery preparation and the need to replace cheaper women’s labour for hand weeding with more costly men’s labour for mechanical weeding, all reduced the chance of adopting the modified rice cultivation method. Risks associated with water-saving irrigation, such as uncertainty about the timing and amount of water release for irrigation affect adoption adversely as well. There was no incentive for farmers to adopt water-saving irrigation as water from reservoirs and electricity for pumping well-water are both free of charge. To date farmers continue to experiment with the modified cultivation method on a small part of their farms, but are unlikely to adopt the modified method on a large-scale unless policies governing water management are changed.     

Collection of plant genetic resources from Andaman and Nicobar Islands

The Andaman and Nicobar (A&N) group of islands is immensely rich in plant biodiversity. Andaman’s native tribes are hunter-gatherers, sustaining on wild or marine food and practically do not have any cultivation. Diversity in cultivated crops is presently maintained in home gardens by settlers from the mainland and other adjoining countries. The National Bureau of Plant Genetic Resources (NBPGR) through explorations either alone or in association with CARI or with other ICAR institutes has collected 1234 accessions in 48 exploration and collection missions. Variability was collected in rice, cowpea, black gram, green gram, okra, Chinese spinach, ash gourd, taro, cucumber, pumpkin, bottle gourd, ridge gourd, bitter gourd, chilli, greater yam and coconut. Indigenous landraces are absent. The in situ conservation of the wild relatives of crops is well taken care of by a large number of protected forest reserves.     

PCR-RFLP analysis of chloroplast gene regions in Cajanus (Leguminosae) and allied genera

Twenty-eight species belonging to five genera of the sub tribe Cajaninae; viz., Cajanus(15 species), Rhynchosia (10 species), Dunbaria, Flemingia and Paracalyx were analysed for variations in four chloroplast generegions, rbcL, trnS-psbC, 16S and trnL-UAA. The four chloroplast gene regions were amplified with specific primers and subsequently digested with 15 restriction enzymes. Rhynchosia did not show any inter-specific differences in the four gene regions for any of the enzymes used. In Cajanus, the inter-specific PCR-RFLP profile of the four gene regions for all the enzymes were similar except for the Pst I digests of trnS-psbC gene region. At inter-generic level, rbcL gene region did not show polymorphism with any of the enzymes used; while in trnS-psbC gene region polymorphism was observed only with Pst I and Hae III digestions. Inter-generic PCR-RFLP of 16S did not reveal any variation. The trnL-UAA gene region had restriction site only forEcoR I in which Cajanus and Rhynchosia showed similar profiles while Dunbaria showed a different profile. The trnL-UAA gene region in Paracalyx and Flemingia did not have restriction site for this enzyme. Despite the analyses of four gene regions using 15 restriction enzymes, differentiation at genus level could not be obtained. These observations indicated limited divergence of the chloroplast genome among the four genera of the sub-tribe Cajaninae suggesting close relationships of the taxa. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antibacterial activity of Cuscuta reflexa stem and Corchorus olitorius seed

The methanol extracts of Cuscuta reflexa stem and Corchorus olitorius seed showed a broad spectrum of antibacterial activity.     

Development of rapid flow-through-based dot-immunoassay for serodiagnosis of leptospirosis in dogs

An IgG-ELISA used recombinant antigen and a rapid flow-through enzyme immunoassay were developed for rapid screening of leptospiral antibodies in dogs using recombinant LipL41, which is one of the conserved outer membrane proteins in pathogenic leptospires as the coating antigen. Results from this study were compared with the standard microscopic agglutination test and found that the sensitivity and specificity of the enzyme-linked immunosorbent assay were 75.46% and 93.29% and whereas that of flow-through-based dot-immunobinding assay were 87.73% and 89.63%, respectively. Relative merits of these tests were also assessed. The flow-through-based dot-immunobinding assay was thus proved to be a valid screening test for canine leptospirosis.