097号 page 113/212

このページは 097号 の電子ブックに掲載されている113ページの概要です。
秒後に電子ブックの対象ページへ移動します。
「電子ブックを開く」をクリックすると今すぐ対象ページへ移動します。

概要：
103　ARTICLESRecent Adoption and Spatial Diversityof Modern Rice Varieties in the PhilippinesCheryll C. Launio1, 2, Guadalupe O. Redondo2 and Jesusa C. Beltran2AbstractThis paper provides updated info....

103　ARTICLESRecent Adoption and Spatial Diversityof Modern Rice Varieties in the PhilippinesCheryll C. Launio1, 2, Guadalupe O. Redondo2 and Jesusa C. Beltran2AbstractThis paper provides updated information on rice (Oryza sativa L.) variety adoption trendsin the Philippines using three sets of surveys of nationwide rice farm households. It alsopresents some assessments of the adoption rates of newly released varieties and calculatedspatial diversity indices for rice. In 2003, the area planted with modern varieties was almost100% in both the irrigated and rainfed areas. The aggregate measure of the replacementperiod for rice varieties in the farmers’ fields is around 8 to 11 years, with the fastestadoption rate during the dry season in irrigated areas. The spatial diversity indices showno clear trend across periods except for a relative increase in the coefficient of variationof the indices, and greater variability across provinces in richness, relative abundanceand evenness. There are some indications, however, of relatively increasing richness andlowering dominance especially during the dry season when farmers try more new varieties.Key words: rice, variety adoption, spatial diversity, genetic diversity, PhilippinesIntroductionAlthough the Philippines was one of the earliest adopters of “green revolution”seeds and fertilizer technologies, and in 2003, the area of the country planted tomodern varieties (MVs) was almost 100% in both irrigated and rainfed areas, thecountry is still not self-sufficient in rice. From 1990 to 2005, yield grew by only 1.6%per year leading to slow production growth, while the population growth rate continuesto grow by more than 2% yearly (PhilRice, 2005: Figure 1). Thus, rice researchersKochi University Review of Social Science No. 97 March 20101 Kochi Univeriversity (Monobe, Nankoku, Kochi, Japan)2 Philippine Rice Research Institute (PhilRice, Munoz, Nueva Ecija, Philippines)