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Contents & Foreword, Characterizing And ... - IRRI books

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the Green Revolution, the coverage of HYV rice area is merely 60%, which is aheadof only Assam (50%).This chapter has two main parts. The first section briefly reviews some of therelevant past work. Because the volume of such published research is overwhelming,we have attempted simply to review some representative work rather than to presentan exhaustive discussion of all work. The second section attempts to identify andanalyze constraints to the adoption of MVs and other component technologies in therainfed lowland ecosystem of Bihar.To summarize the vast amount of empirical literature on adoption constraintssystematically, we organized the review of this work according to the key constraintsto adoption.Biophysical constraintsThe bulk of rice in the rainfed ecosystem is grown in the rainy (kharif) season, inwhich the vagaries of the monsoon, characterized by drought or floods, as well as thereoccurrence of other biotic and abiotic constraints are remarkable. The hot and humidclimate supports the outbreak of several harmful pests and diseases. Since it isnot possible to manipulate nature (climate), we need to incorporate sufficient toleranceand adaptability into the rice varieties to be developed for the rainfed ecosystem.The lack of tolerance in rice varieties for abiotic constraints such as flash floods andfrequent drought as well as biotic constraints such as gall midge, brown planthopper,tungro, sheath blight, and bacterial blight seems to affect the adoption of modern ricevarieties and their component technologies in the rainfed rice ecosystem. Tripathi(1977) identified susceptibility of HYVs to diseases and pests, low germination, ineffectivenessof dry seed treatment, nonavailability of irrigation water in summer forthe nursery, and serious waterlogging in the wet nursery as important constraints incoastal Orissa, whereas Gowda and Jolihal (1969) have reported the unsuitability ofMVs for late planting as an important constraint. The lack of irrigation is also one ofthe most limiting factors affecting the adoption of MVs and their associated technologies.Roy (1976) found inappropriate irrigation facilities as the most important constraintto the adoption of HYVs in the kharif season besides disease incidence and thelack of suitable varieties in West Bengal. Shakya and Flinn (1985) examined factorsinfluencing the adoption of MVs and fertilizer in the Tarai of southeastern Nepal andstated that adoption of MVs is highest where irrigation exists. Because rice lands ineastern India will remain rainfed in the foreseeable future, a greater spread of MVsinto these adverse environments will probably depend on new varieties being bredthat are specifically adapted to these environments.Constraints to the adoption of modern varieties of rice . . . 307

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