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Agricultural Trade Reform and the Doha Development AgendaAgriculture is yet again causing
 contention in international trade negotiations. It caused
 long delays to the Uruguay round in the late 1980s and
 1990s, and it is again proving to be the major stumbling
 block in the World Trade Organization's (WTO) Doha
 round of multilateral trade negotiations (formally known as
 the Doha Development Agenda, or DDA). This study builds on
 numerous recent analyses of the Doha Development Agenda and
 agricultural trade, including five very helpful books that
 appeared in 2004. One, edited by Aksoy and Beghin (2004),
 provides details of trends in global agricultural markets
 and policies, especially as they affect nine commodities of
 interest to developing countries. Another, edited by Ingco
 and Winters (2004), includes a wide range of analyses based
 on papers revised following a conference held just before
 the aborted WTO trade ministerial meeting in Seattle in
 1999. The third, edited by Ingco and Nash (2004), provides a
 follow-up to the broad global perspective of the Ingco and
 winters volume: it explores a wide range of key issues and
 options in agricultural trade reform from a
 developing-country perspective. The fourth, edited by
 Anania, Bowman, Carter, and McCalla (2004), is a
 comprehensive, tenth-anniversary retrospective on the
 Uruguay Round Agreement on Agriculture and numerous
 unilateral trade and subsidy reforms in developed,
 transition, and developing economies. And the fifth, edited
 by Jank (2004), focuses on implications for Latin America.
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Características de aislamientos de Rhizoctonia solani Huhn y su importancia como patógenos de Stylosanthes guianensis (Aubl.) Sw.Se encontró considerable variación en el crecimiento, color, zonificación, esclerocios, textura del micelio y en la virulencia de siete aislamientos de R. solani. Como seis aislamientos fueron multinucleados y uno binucleado, se demostró que es indispensable determinar ésta característica en ensayos con R. solani. Los aislamientos se ubicaron en los grupos de anastomosis AG -1, AG-2, AG-4; pero en los ensayos con electroforesis de isoenzirnas los modelos de bandas para los a islamientos probadores de los AG y los probados en éste estudio fueron diferentes, lo que llevó a cuestionar la importancia de los AG. Los ecotípos de Centrosema spp y P. phaseoloides fueron más afectados que los de S. guianensis, D. ovalifolium y S. capitata. La reacción al daño de R. solani fue diferencial en los ecotipos CIAT 1283 (tardío) y 184 (común) y tuvo mucha relación con la edad; en general, la enfermedad se incrementó con la edad en el eco tipo tardío y disminuyó con ésta o fue independiente en el ecotipo común; el ecotipo más fectado fue el tardío; las pérdidas de forraje no fueron considerables, pero el efecto en la digestibilidad fue notorio; la capacidad de rebrote fue buena en 184. Se observó un estímulo en el crecimiento de las plantas de S.guianensis y D. ovalifolium.<br>Considerable variation was found in the growth, color, zonation, sclerotia, mycelial texture and virulence of seven isolates of R. solani. Six multinuclease and one binuclease isolates were determined, demonstrating that it is indispensable to determine this characteristic in trials with this pathogen. The isolates were placed in three anastomosis group AG -1, AG -2 and AG -4; but with electrophoresis of isoenzymes it was found that the band models were different for the known rest AG iso lates and those isolates proven in this study which questions the importance of anastomosis qroups. Ecotypes of Centrosema spp. and P. phaseoloides were more affected than those of S. guianensis, D. ovalifolium and S. capitata. The reaction on damage by R. solani was differencial for ecotypes C IAT 1283 (tardío) and 184 (comrno n) and was related to age. In general, the disease increased with age in the tardio and decreased or was independent of age in the cornrnon: the tardio was more affected; forage losses were not cosiderable but the effect on the digestibility was noted; the regrowth capacity was good in the cornrnon. A stimulus in the growth of plants of S. guianensis and D. ovalifolium was observed.
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Effect of salinity stress on proline content, membrane stability and water relations in two sugar beet cultivarsIn order to study the effects of salinity stress on some physiological characteristics of sugar beet (beta vulgaris L.) a factorial experiment was conducted with two factors: salinity at six levels (0.6, 4.2, 6.8, 9.7, 14.2 and 19 (ds/m)) and two varieties of sugar beet (sbsi004 polymeric and Dorotea) in a completely randomized design with four replications. The experiment was carried out in a research greenhouse of the Islamic Azad University branch of Mahabad, Faculty of Agriculture. Results indicated significant effects of treatments on membrane permeability, relative water content and proline content. Effect of salinity was significant for all factors, but effects of variety were non-significant for membrane permeability, leaf water potential, and relative water content. Effects of salinity and variety were significant on membrane permeability and proline content. Salinity decreased relative water content and leaf water potential while increased membrane permeability and proline content. Results indicate that these parameters can be used as an appropriate measure to determine tolerance to salinity stress.