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110 Kochi University Review, No. 97or exchange new varieties from co-farmers who are in irrigated areas, where there iswidespread promotion of the use of certified seeds through the national rice prog....

110 Kochi University Review, No. 97or exchange new varieties from co-farmers who are in irrigated areas, where there iswidespread promotion of the use of certified seeds through the national rice program.Using the weighted average age of varieties as an index of the adoption rate ofnew varieties revealed higher adoption during the DS in irrigated ecosystems. Theweighted average age of varieties planted in the country ranged from around 8 to 11years, with the average age in the irrigated areas during the DS at 8 to 9 years. Thisrelatively consistent trend based on the three sets of cross-section data implies thatvarieties in farmers’ fields in general are replaced every 8 to 11 years, faster in theirrigated areas during the DS. In the 1997 survey, the average age of varieties planted ina majority of the provinces were less than 10 years in both seasons, while in the 2002survey, it was 10 years or more. This confirms the above observation that althoughsome farmers planted new varieties, most of the rice areas in 2002 were planted withvarieties released prior to 1997.The information on the oldest and newest varieties used show two things. First,some farmers still plant varieties released more than 20 years ago. In 1997, a fewfarmers in various provinces still planted IR20, an early modern variety bred for insectand disease resistance released in 1969. It was reported not only by farmers in Luzon,but also in provinces in the Visayas and Mindanao which are far from the primarysource of seed materials. In 2002, some farmers still planted varieties released in1975 such as IR29 and IR32, and many farmers planted IR42 released in 1977. TheIR42 variety endures generally because of its good grain quality and it still commandspremium price in the market.Second, the information on the newest variety planted shows that farmers douse new varieties suggesting that the current extension system (use of seed network,tri-media and technology-demonstration farms) for varieties is apparently functioning.For example, in the 1992 WS, 5% of farmers in the major rice-growing provincesalready planted the varieties PSB Rc2 and PSB Rc4, which were released only in Nov.1991. This is only one season after their release. In the case of PSB Rc10, PSB Rc12and PSB Rc14, all of which were released in May, 1992, almost 2% of farmers wereplanting these varieties by the 1993 DS including PSB Rc6 and PSB Rc8 varieties. InNovember 1997, several newly released varieties were already used by some farmers inthe 1996 WS and 1997 DS. This is possible because there were varieties recommendedand submitted for seed increase although their official approval was delayed. In the