Effects of social network factors on information acquisition and adoption of improved groundnut varieties: the case of Uganda and Kenya

Social networks play a significant role in learning and thus in farmers’ adoption of new agricultural technologies. This study examined the effects of social network factors on information acquisition and adoption of new seed varieties among groundnut farmers in Uganda and Kenya. The data were generated through face-to-face interviews from a random sample of 461 farmers, 232 in Uganda and 229 in Kenya. To assess these effects two alternative econometric models were used: a seemingly unrelated bivariate probit (SUBP) model and a recursive bivariate probit (RBP) model. The statistical evaluation of the SUBP shows that information acquisition and adoption decisions are interrelated while tests for the RBP do not support this latter model. Therefore, the analysis is based on the results obtained from the SUBP. These results reveal that social network factors, particularly weak ties with external support (e.g., researchers, extension agents, etc.), partially influence information acquisition, but do not influence adoption. In Uganda, external support, gender, farm size, and geographic location have an impact on information acquisition. In Kenya, external support and geographic location also have an impact on information acquisition. With regard to adoption, gender, household size, and geographic location play the most important roles for Ugandan farmers, while in Kenya information from external sources, education, and farm size affect adoption choice. The study provides insight on the importance of external weak ties in groundnut farming, and a need to understand regional differences along gender lines while developing agricultural strategies. This study further illustrates the importance of farmer participation in applied technology research and the impact of social interactions among farmers and external agents.     

Effects of different neem preparations in comparison to synthetic insecticides on the whitefly parasitoid Encarsia sophia (Hymenoptera: Aphelinidae) and the predator Chrysoperla carnea (Neuroptera: Chrysopidae) on cotton under laboratory conditions

The contact and feeding toxicity of NeemAzal T/S (EID Parry, Chennai, India) to the parasitoid Encarsia sophia (Girault & Dodd) was compared with three synthetic insecticides (chlorpyriphos, endosulfan and triazophos) against immatures and adult emergence. NeemAzal T/S (1.0%) at lower dose (200 mg/l) did not cause any effect on the emergence of E. sophia adults, but there was a significant reduction in emergence at higher doses (800 mg/l). Also, it did not show contact toxicity to adults of E. sophia, but there was a significantly high feeding mortality in a dosage dependant manner, whereas chlorpyriphos, endosulfan and triazophos showed high toxicity both by contact and feeding method. Three neem preparations registered in India, NeemAzal T/S, Nimbecidine (T. Stains, Coimbatore) and Godrej Achook (Godrej Agrovet, Mumbai) were tested against egg and larval stages of Chrysoperla carnea (Stephens) at three dosages, using a synthetic insecticide, triazophos 40 EC (200 mg/l), for comparison under laboratory conditions. The three biorationals did not induce any adverse effect on the hatchability of C. carnea eggs. The mortality of the first instars of C. carnea was not affected by any of the azadirachtin enriched formulations; however, at higher dosage of 800 mg/l these neem based products resulted in increased mortality of the first and second instar larvae of C. carnea relative to the untreated controls. Whereas, triazophos induced very high mortality rates (85.0, 89.0 and 81.5%) of all the three larval instars. The neem based insecticides showed a dosage-dependant effect on the larval instars of C. carnea. Thus, these biorationals show that there is a potential to use them in an IPM system, being safe for natural enemies of B. tabaci in cotton.     

AFLP analysis of introgression in coffee cultivars (Coffea arabica L.) derived from a natural interspecific hybrid

S.288 an offspring of a putative spontaneous interspecific hybrid between tetraploid Coffea Arabica (2n = 4x = 44) and diploid C. liberica(2n = 2x = 22) and 17 arabica coffee introgression lines (representing F₂ and F₄) derived from the cross S.288 x Kent arabica were evaluated for introgression of C. liberica genetic material. In all, 36 AFLP primer combinations were used in the analysis. The AFLP profiles of introgressed lines were compared to five accessions each of C. arabica and C. liberica. A total of 137 polymorphic bands were scored among the 29 accessions analysed. The introgressed genotypes exhibited 102 marker bands consisting of 65 additional bands and 37missing bands associated with introgression of C. liberica genetic material. C. liberica accessions of EA group (C. liberica var liberica of Guinean origin) seemed to be the likely progenitor in the origin of natural hybrid. Analysis of genetic relationships in the introgressed lines suggested that introgression was limited to few fragments. Segregation and wide variation in number of marker fragments in the F₂ and F₄progenies were attributed to chromosome recombinations. The differences in the level of introgression between introgressed parent, F₂ and F₄ groups was not pronounced. Therefore the alien genetic material appeared to be fixed and there was no elimination or counter-selection over generations, from introgressed parent to F₄.In C. arabica accessions, only 35 polymorphic bands were seen confirming the low genetic diversity. On the contrary, although representing a small amount of alien genome introgression, the Liberica-introgressed genotypes provided notable genetic diversity. Considering the fact that the diploid species of Coffea constitute a valuable source of genetic diversity, the potential implications of variability generated by Liberica-introgressed genotypes in C. arabica breeding are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Analysis of genetic diversity in Indian robusta coffee genepool (<Emphasis Type="Italic">Coffea canephora</Emphasis>) in comparison with a representative core collection using SSRs and AFLPs

Genetic diversity among 40 accessions (Coffea canephora) of robusta coffee genepool available in India was determined in comparison with 14 representative samples from a C. canephora core collection and three accessions of C. congensis, using amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSR) markers. Both these molecular approaches were able to generate unique fingerprints for each of the accessions analysed. All the 12 SSR primers used in the present study were found polymorphic, with an average of six alleles per primer pair. Comparative analysis revealed the higher amount of diversity in representatives from a core collection than in the Indian genepool. Moreover, a total of 205 polymorphic AFLP bands were scored in all the 57 accessions analysed. The genetic relationship among 57 accessions was compared on the basis of SSR and AFLP polymorphisms. Genetic similarity dendrograms showed high correlation between the two marker systems. This study clearly established the high amount of diversity present in core samples, which is not represented in Indian genepool. Furthermore, the three accessions of C. congensis did not exhibit any significant diversity from other robusta accessions supporting the school of thought that C. congensis forms a biotype of C. canephora. The potential use of SSRs and AFLP markers in genetic diversity analysis for better ex situ management and also for exploitation of diversity in breeding programmes is discussed.     

Effect of curcumin on inflammation and oxidative stress in cisplatin-induced experimental nephrotoxicity

Nephrotoxicity is a major complication and a dose limiting factor for cisplatin therapy. Recent evidence suggests that inflammation and oxidative stress may contribute to the pathogenesis of cisplatin-induced acute renal failure. Curcumin is claimed to be a potent anti-inflammatory and antioxidant agent. The present study was performed to explore the effect of curcumin against cisplatin-induced experimental nephrotoxicity. Curcumin in the dosages of 15, 30, and 60 mg kg(-1) was administered 2 days before and 3 days after cisplatin administration. Renal injury was assessed by measuring serum creatinine, blood urea nitrogen, creatinine, urea clearance, and serum nitrite levels. Renal oxidative stress was assessed by determining renal malondialdehyde levels, reduced glutathione levels and enzymatic activities of superoxide dismutase and catalase. Systemic inflammation was assessed by tumor necrosis factor-alpha (TNF-alpha) levels. A single dose of cisplatin resulted in marked inflammation (486% rise in TNF-alpha level) and oxidative stress and significantly deranged renal functions as well as renal morphology. The serum TNF-alpha level was markedly reduced in curcumin-treated rats. Curcumin treatment significantly and dose-dependently restored renal function, reduced lipid peroxidation, and enhanced the levels of reduced glutathione and activities of superoxide dismutase and catalase. The present study demonstrates that curcumin has a protective effect on cisplatin-induced experimental nephrotoxicity, and this effect is attributed to its direct anti-inflammatory and strong antioxidant profile. Hence, curcumin has a strong potential to be used as a therapeutic adjuvant in cisplatin nephrotoxicity.     

Predicting Phytoplankton Growth and Dynamics in Relation to Physico-chemical Characteristics of Water Body

Water, Air, & Soil Pollution - Cryptosporidium parvum oocysts may reach soil through direct deposition of human or animal fecal material, irrigation with raw wastewater or untreated effluents,...     

Screening of water-efficient rice genotypes for dry direct seeding in South Asia

Rice genotypes having high crop water productivity in dry direct-seeded rice (DDSR) need to be assessed while promoting labor- and water-saving technology. The objective of this study was to evaluate the ability of several selection indices to identify genotypes with high crop water productivity in DDSR. A set of 16 genotypes [13 recombinant inbred lines (RILs) and three genotypes as check for control] were evaluated under DDSR for two consecutive years (2013 and 2014) using two irrigation regimes [-10 kPa (non-stress) and -20 kPa (stress)]. Grain yield varied from 5.3 to 8.4 t ha^-1 and 5.9 to 8.7 t ha^-1 for irrigation regimes of -20 and -10 kPa, respectively. Yield reductions caused by water stress ranged from 2.9 to 25.1%; being lowest in RIL1649 and highest in hybrid SVH-127. The genotypes with high stress-tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP) and harmonic mean productivity (HAR) were identified as the most productive genotypes for high crop water productivity in DDSR. The results implied that selection based on stress tolerance indices likes STI, MP, GMP and HAR was useful in identifying genotypes with high crop water productivity under DDSR and RIL 1649 and SVH-127 were identified as superior genotypes in this regard.     

Duck virus enteritis (duck plague) – a comprehensive update

Duck virus enteritis (DVE), also called duck plague, is one of the major contagious and fatal diseases of ducks, geese and swan. It is caused by duck enteritis virus (DEV)/Anatid herpesvirus-1 of the genus Mardivirus, family Herpesviridae, and subfamily Alpha-herpesvirinae. Of note, DVE has worldwide distribution, wherein migratory waterfowl plays a crucial role in its transmission within and between continents. Furthermore, horizontal and/ or vertical transmission plays a significant role in disease spread through oral-fecal discharges. Either of sexes from varying age groups of ducks is vulnerable to DVE. The disease is characterized by sudden death, vascular damage and subsequent internal hemorrhage, lesions in lymphoid organs, digestive mucosal eruptions, severe diarrhea and degenerative lesions in parenchymatous organs. Huge economic losses are connected with acute nature of the disease, increased morbidity and mortality (5%–100%), condemnations of carcasses, decreased egg production and hatchability. Although clinical manifestations and histopathology can provide preliminary diagnosis, the confirmatory diagnosis involves virus isolation and detection using serological and molecular tests. For prophylaxis, both live-attenuated and killed vaccines are being used in broiler and breeder ducks above 2 weeks of age. Since DEV is capable of becoming latent as well as shed intermittently, recombinant subunit and DNA vaccines either alone or in combination (polyvalent) are being targeted for its benign prevention. This review describes DEV, epidemiology, transmission, the disease (DVE), pathogenesis, and advances in diagnosis, vaccination and antiviral agents/therapies along with appropriate prevention and control strategies.     

The infestation of Vicia faba L. (Fabaceae) by Aphis fabae (Scop.) (Homoptera: Aphididae) under the influence of Lamiaceae (Ocimum basilicum L. and Satureja hortensis L.)

Abtract The system Vicia faba–Aphis fabae fabae was studied under the influence of Ocimum basilicum (basil) and Satureja hortensis, in a wind tunnel, in the greenhouse and in field experiments. In the wind tunnel at 20°C both Lamiaceae were deterrent for A. fabae, and S. hortensis proved to be more deterrent than O. basilicum. In experiments in the greenhouse at low temperatures (average minimum 14.6°C, average maximum 24.1°C), A. fabae colonised first and significantly more intense Vicia fabae (field beans) not surrounded by O. basilicum or S. hortensis. At high temperatures (average minimum 18.0°C, average maximum 38.5°C) this relation was inverted: Vicia faba surrounded by the two Lamiaceae were preferred for colonisation (Ocimum basilicum significantly). It showed that pots with Lamiaceae were no obstacle for the aphids to reach Vicia faba. In strip cropping in the field, the repellent effect of Ocimum basilicum proved to be stronger than of Satureja hortensis. In 2002 there was observed only a tendency of lower aphid attack of field beans intercropped with Lamiaceae, while in 2004 and 2005 the infestation of Vicia faba by Aphis fabae was significantly lower in plots intercropped with basil. In plots with Satureja hortensis as intercrop, Vicia faba were significantly lower infested, after 3 weeks. The differences between the results of the wind tunnel/greenhouse at low temperatures, and the field experiments concerning the deterrence by Satureja hortensis cannot be explained. But basing on our results with Ocimum basilicum and those published by other authors, it is recommended to follow up intercropping, after a sincere analysis in every case, in favour of agronomists.     

Allergenicity assessment of osmotin, a pathogenesis-related protein, used for transgenic crops

Genetic engineering can enhance abiotic stress tolerance of plants, thereby increasing productivity. The present study investigates allergenicity of osmotin protein used for developing transgenic crops. Bioinformatic analysis of osmotin was performed using SDAP and Farrp allergen databases. Osmotin was cloned in pET22b+ vector, purified to homogeneity, and analyzed for digestibility, heat stability, and IgE binding using atopic patients' sera. Osmotin showed 40-92% and 48-75% homology with allergens in SDAP and Farrp databases, respectively. These cross-reactive allergens were from apple, tomato, peach, capsicum, kiwi fruit, and cypress. Osmotin was resistant to pepsin digestion and heat treatment at 90 °C for 1 h. Osmotin protein showed dose-dependent inhibition with pooled patients' sera. It showed significant IgE binding with 22 of 117 patients' sera who were sensitized to tomato and apple, thus indicating cross-reactivity among tomato, apple, and osmotin allergens. In conclusion, osmotin was identified as a potential allergen and showed cross-reactivity with tomato and apple allergens.