@article{oai:niigata-u.repo.nii.ac.jp:00002753,
 author = {笹原, 英樹 and 重宗, 明子 and 後藤, 明俊 and 三浦, 清之 and 福山, 利範},
 issue = {1},
 journal = {育種学研究, 育種学研究},
 month = {Mar},
 note = {維管束の転流効率が優れると考えられる維管束比(一次枝梗あたりの穂首維管束数)の高い遺伝資源を日本在来水稲103品種から探索したところ,1.5以上の維管束比を示す6品種が見出された.供試品種を判別関数で分類した結果,この6品種のうち,2品種はインド型で,4品種は温帯日本型であった.これら維管束比1.5程度の温帯日本型品種の穂の維管束走向をインド型品種ハバタキ(維管束比=2)および温帯日本型品種ササニシキ(維管束比=1)と比較したところ,両者の中間的な特徴を有していた.インド型品種を日本型品種改良の育種素材とした場合,不稔などの生殖的隔離や脱粒性,玄米の粒形などの不良形質が問題となる.実際に,高維管束比の供与親としてインド型品種および上記の温帯日本型品種の一つを用いた2種類の雑種集団を比較したところ,日印交雑F_2集団では高維管束比の個体の出現率は高いが,稔実率が極めて劣るのに対して,温帯日本型同士のF_2集団では稔実率が良好であり,維管束比も1.5前後の高い個体が分離した.本研究において見出した高維管束比の温帯日本型品種は,維管束系の改良による温帯日本型品種の多収化を目指す上で有効な遺伝資源となると考えられる., In order to identify the genetic resources of rice varieties with higher translocation efficiency, the ratio of a number of large vascular bundles in the peduncle (Vb) to that of the primary rachis branch (Rb) (V/R ratio) was investigated in 103 varieties of Japanese native lowland rice. We found 6 high V/R ratio (≤1.5) varieties, which consisted of two indica varieties and four temperate (Tm)-japonica varieties. The course of the Vb in the rachis of the Tm-japonica varieties with a high V/R ratio was compared with those of an indica variety, Habataki (V/R ratio=2), and of a Tm-japonica variety, Sasanishiki (V/R ratio=1). Varieties with a V/R ratio of 1.5 showed characteristics between Habataki and Sasanishiki in the course of Vb. Because of reproductive barriers between indica and japonica, and undesirable traits of indica, for example, the shattering habit of spikelet and grain shapes, it is difficult to use indica varieties directly as materials for introducing a high V/R ratio. In fact, high V/R ratio plants were segregated in higher frequency in the F_2 population of indica/Tm-japonica than that of the Tm-japonica/high V/R ratio Tm-japonica, but their seed fertilities were quite low. On the other hand, the F_2 population of the Tm-japonica/high V/R ratio Tm-japonica segregated some plants with a V/R ratio higher than 1.5 and normal fertility. Therefore, the Tm-japonica varieties with high V/R ratios identified in this study may be useful materials for breeding varieties with high yielding ability by improving the vascular bundle system.},
 pages = {1--7},
 title = {日本在来水稲品種から見出された高維管束比品種の育種利用における有用性},
 volume = {11},
 year = {2009}
}