Extending the horizons of agricultural research and extension: Methodological challenges

The recent enthusiasm for “participation” in agricultural development has fueled the development of new approaches to research and extension. The rhetoric of “participation” extends the horizons of agricultural research and extension beyond technical problem-solving. Yet in practice few of the personal, political, and experiential aspects of this process are addressed. This paper aims to draw attention to these elements of practice and to locate research and extension within wider social processes. Through a critique of conventional methodological strategies, this paper considers the possibilities offered by “participatory” alternatives. Considering the scope and objectives of agricultural development raises a series of methodological questions: What counts as knowledge? Who defines and represents this knowledge? Whose knowledge counts? Knowledge for what? Knowledge for whom? The paper goes on to assess a number of these “new” methodologies, within and beyond agricultural development. Through a consideration of their strengths and weaknesses, a series of further issues are highlighted for future methodological development. It is argued that for agricultural research and extension to acknowledge process, closer attention needs to be paid to context. The activities of research and extension need to be set in time. Strategies are needed to explore and address diversity and difference in communities. Situating the actors and agencies involved in development within relations of power involves addressing—and redressing—the nature of interactions between these actors. These changes require not an ever increasing array of methods, it is argued, but new approaches to learning.     

Structure Activity Relationship of Brevenal Hydrazide Derivatives

Brevenal is a ladder frame polyether produced by the dinoflagellate Karenia brevis. This organism is also responsible for the production of the neurotoxic compounds known as brevetoxins. Ingestion or inhalation of the brevetoxins leads to adverse effects such as gastrointestinal maladies and bronchoconstriction. Brevenal shows antagonistic behavior to the brevetoxins and shows beneficial attributes when administered alone. For example, in an asthmatic sheep model, brevenal has been shown to increase tracheal mucosal velocity, an attribute which has led to its development as a potential treatment for Cystic Fibrosis. The mechanism of action of brevenal is poorly understood and the exact binding site has not been elucidated. In an attempt to further understand the mechanism of action of brevenal and potentially develop a second generation drug candidate, a series of brevenal derivatives were prepared through modification of the aldehyde moiety. These derivatives include aliphatic, aromatic and heteroaromatic hydrazide derivatives. The brevenal derivatives were tested using in vitro synaptosome binding assays to determine the ability of the compounds to displace brevetoxin and brevenal from their native receptors. A sheep inhalation model was used to determine if instillation of the brevenal derivatives resulted in bronchoconstriction. Only small modifications were tolerated, with larger moieties leading to loss of affinity for the brevenal receptor and bronchoconstriction in the sheep model.     

Survey of tuberculin testing in Swedish zoos.

Tuberculin test results from 214 animals in three Swedish zoos, tested between the years 1993 and 2000, were compiled from a questionnaire sent out to zoo veterinarians. Comparative testing with bovine and avian tuberculin was used on various sites of injection. A total of five skin test reactors were found: three cotton-top tamarins (Saguinus oedipus) in one zoo and two tapirs (Tapirus terrestris) in another zoo. Postmortem culture from one of the tapirs revealed growth of Mycobacterium tuberculosis, and a stamping out policy was adopted in the herd. Tuberculosis in the primates was ruled out by further investigations. Zoo veterinarians should try to adopt a common scheme for the regular testing of zoo animals to improve the diagnostic ability and comparison of results between institutions.     

Occurrence and frequency of putatively Y chromosome linked DNA markers in Cannabis sativa L.

DNA from female and male hemp (Cannabis sativa L.) plants belonging to nine different varieties were screened with180 RAPD primers in a search for sex-associated DNA markers. About 1500bands were produced in total, nine primers were found yielding one or two DNA bands amplified in all nine male DNA bulks and absent in all female DNA bulks. These putatively male-associated markers were then scored in three different F1progenies, deriving from a cross between a common male parent and three different female plants. The sex of the progeny was accurately scored on the basis of the floral phenotype, and the presence of the nine male-associated markers was verified by RAPD analysis. In all three progenies examined, all the male plants showed the DNA markers previously identified by bulk segregant analysis (BSA) on the hemp varieties, while all the female plants lacked them. The fact that the association between these markers and the staminate phenotype is found when examining male plants of distantly related varieties, and that such linkage is never broken when different progenies are examined, strongly supports the hypothesis that the markers found are physically located on the Y chromosome, in a region excluded from recombination during meiosis. Another marker was shown to be present in the male parent, in all the male plants of each progeny, and in 50% of the female progenies, while it was absent in the female parent; the possible occurrence of markers deriving from multiple amplification sites of the genome is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Pattern of variation for seed size traits and molecular markers in Italian germplasm of Phaseolus coccineus L.

Variation in Italian germplasm of Phaseolus coccineus L. was assessed for seed traits and molecular markers. A total of 130 seeds and seedlings, five for each of 21 Italian landraces, an Italian commercial cultivar and four Mesoamerican landraces of P. coccineus, were analysed using seven selected PCR markers: three RAPDs, two ISSRs and two ETs. Seed weight of the Mesoamerican landraces was ≤1 g, whereas that of the Italian landraces varied from 1 g to 2.5 g and was related to their origin. Oval shape was more frequent, with round shape observed only in Mesoamerican landraces. Three seed coat colours were observed: white, violet mottled or spotted black and buff spotted brown, also this trait was related to the origin. The level of polymorphism detected by molecular markers was low but with significant discriminant power. ISSRs were the most effective markers prone to unravel molecular polymorphism. The within accession component of variation exceeded that among accessions, as expected for an allogamous species. However correct classification of the individuals was achieved performing either discriminant analysis of the seed phenotypic traits or cluster analysis of seedling similarity measure based on the whole banding patterns obtained by the three marker types. Our data suggest that the Italian farmers, starting with ancestral Mesoamerican runner bean introductions in Europe, bred their own landraces through selection for seed size and seed coat colour, but occasional gene flow maintained variability within landraces bred by different farmers in the same Italian Region. Selection favored molecular and seed trait uniformity within several landraces making them suitable for certification.