Transitions in the Diversity of Sugarcane Varieties and Its Components in Nansei Islands

• TAKARAGAWA Hiroo

  Faculty of Agriculture, University of the Ryukyus

• KAWAMITSU Yoshinobu

  Faculty of Agriculture, University of the Ryukyus

Bibliographic Information

Other Title

• 南西諸島におけるサトウキビ品種の多様性および構成要素の変遷

Abstract

Sugarcane is grown under adverse conditions. Planting several varieties with different geo-ecological types is suggested to enhance risk diversification against such condition, which could result in stable production. The importance of varietal diversity has been paid attention from the early era of breeding in Japan. However, its quantitative evaluation considering both number and area ratio of cultivated varieties has never been attempted, which prevents further discussion concerning optimum variety composition. The present study attempted to quantify varietal diversity using ecological means with the objective to discuss the current status and perspective of the diversity. Varietal diversities were different between two administrative divisions (Okinawa and Kagoshima prefectures) and between two milling regions in Okinawa (Centrifugal and non-centrifugal) with different policies and preferences. Variety evenness was suggested to contribute to the increased diversity in Kagoshima and non-centrifugal region in Okinawa, while variety richness did in centrifugal region in Okinawa. In addition, multiplicative beta diversity indicated that variety composition tended to be similar between regions despite of increased number of varieties in Okinawa. These results suggested that update of the extension strategies would accelerate an effective variety choice and utilization. Because there is a limitation to improve varietal diversity only by increasing number of varieties, an additional approach to manage evenness, namely variety composition is also required. A new administrative system such as control of propagation and public awareness for optimum variety use should be considered.

Journal

• Research for Tropical Agriculture

  Research for Tropical Agriculture 13 (1), 20-26, 2020

  Japanese Society for Tropical Agriculture

Keywords

• Distribution of varieties
• Diversity index
• Evenness index
• Variety composition

Details

• CRID: 1390287783176543488
• NII Article ID: 130008028980
• DOI: 10.11248/nettai.13.20
• ISSN: 21872414
• ISSN: 18828434
• Text Lang: ja
• Data Source:
  • JaLC
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed