Exploration and Collection of Wild Rice in Northwestern and Southeastern Regions of Myanmar, 2005

Myanmar has been known as a part of the center of genetic diversity of wild rice as well as cultivated rice. In 2005, northwestern and southeastern regions of Myanmar were investigated in collaboration between Myanmar and Japan under the NIAS Genebank Project, since few samples of wild rice have been reported in the regions based on the information collected in 2004, when we have explored wild rice in the northern and western regions of the country. A total of 54 wild rice samples consisting of 40 O. rufipogon and 14 O. officinalis were collected. Regarding features of O. rufipogon, many wild rice plants were growing in swamps and canals that were near paddy fields along roads and disturbed by people and livestock. Wild rice plants growing in deep water showed floating ability, while others growing in shallow water did not. These ecological and morphological variations of O. rufipogon were mostly included in the range of those in the northern and western regions. But, we discovered a new habitat of O. rufipogon in Magway city located in the central dry region in Myanmar. The plants showed typical features of wild rice growing in shallow swamp, namely, short grass-type, compact panicle-type, and long awn there. In case of the O. officinalis, wild rice plants were found in various places, from sunny to shady, and from damp to swampy. Some habitats of O. officinalis were also disturbed by livestock such as water buffalo. We found that several O. officinalis habitats in swamps and rivers with brackish water in Taninthayi Division, which was in the southeastern region. This exploration suggests that O. officinalis in Myanmar adaptive to diverse environments.ミャンマーはイネの在来品種のみならず近縁野生種の遺伝的多様性中心地のひとつとして知られている. 我々は2004年にミャンマー北部および西部で野生イネの探索・収集を行った. 今回は, 野生イネの探索がほとんど行われていない北西部および南東部を中心に野生イネの調査・収集を生物研ジーンバンク事業として実施した. 今回の探索では, O. rufipogon を40点, O. officinalis を14点の合計54点を収集した. ミャンマー北西部および南東部で収集した O. rufipogon は, 多くの野生イネが水田脇の湿地や水路に自生しており, 人や家畜による撹乱を受けていた. 水深の深い湿地や湖に自生する野生イネは浮稲性を示したが, 比較的浅い湿地では浮稲性を示す野生イネはほとんど見られなかった. 野外での観察では, 今回収集した O. rufipogon は北部や西部で収集した O. rufipogon とほぼ同様の生態的, 形態的な変異を示した. ただし, 我々はミャンマーでも乾燥が厳しい中央地域に位置する Magway 市周辺で O. rufipogon の自生地を新たに発見した. この野生イネは浅い沼地に自生する典型的な野生イネと同様の形態を示し, 短稈, 非開帳性の穂で長芒を持っていた. O. officinalis は日陰から日向, 軽く湿った場所から沼地など多様な環境に自生しており, いくつかの集団が水牛などの家畜による強い撹乱を受けていることを観察した. 南東部の Taninthayi 管区に見られた集団は汽水地域の沼地や小川に自生していた. 本探索の結果はミャンマーの O. officinalis が多様な環境に適応していることを示している