Development of Integrated Molecular-Ecology System Assisting Adaptive and Harmonic Improvement in Forage Crops for Pasture.

将生态功能与分子遗传信息相结合，开发低投入高可持续牧草生产系统综合评价体系。1995-1997年，本基金资助了三个研究项目：(1)多年生黑麦草耐冷性的分子遗传研究；(2)分子标记在牧草育种中的应用；(3)牧草物种适应策略的生理机制。结果表明：(1)多年生黑麦草品种间耐寒性的遗传差异与叶片脂肪酸化学成分有关。(2)对低温胁迫后表达的20个基因进行了克隆和测序，并通过基因组文库的同源性检验估计了这些基因的功能。(3)鉴定了同工酶位点和RAPD标记的有用多态性，建立了遗传信息与生态功能之间的联系。(4)同工酶和RAPD标记分析表明，日本生态型和品种的遗传多样性低于欧洲群体。(5)多年生黑麦草品种抗旱性差异评价表明，二倍体品种水分流失快，细胞抗旱性好于四倍体品种。(6)耐旱性与耐寒性之间存在正相关关系，表明二者的生理机制相似。(7)相对竞争能力与干旱和低温胁迫耐受性呈负相关，表明对物理胁迫的耐受性与对资源的生长响应之间存在权衡关系。这些发现有助于在牧草育种项目中建立综合的基因型评价体系，从而在日本建立低投入、高可持续的牧草生产体系。

Development of integrated evaluation system for low-input and high sustainable pasture production system through linking ecological functions to molecular genetic infornmation. The following three research projects were performed by the grant for the three years (1995-1997) : (1) Molecular genetic studies of cold tolerance in perennial ryegrass, (2) Application of molecular markers to herbage breeding programs and(3)Physiological mechanisms of adaptive strategy in pasture species. The following results were obtained :(1) Genetic difference in cold tolerance between cultivars of perennial ryegrass was examined in relation to chemical components of fatty acids in leaves. (2) Cloning and sequencing of the twenty genes express after cold stress were carried out and functions of these genes were estimated by homology test with genomic libraries. (3) Useful polymorphism of isozyme loci and RAPD markers were indentified to establish the link between genetic information and ecological functions. (4) Analysis of isozyme and RAPD markers showed that ecotypes and cultivars in Japan tended to have lower genetic diversity than Europe populations. (5) Evaluation of cultivarietal differences in water stress tolerance in perennial ryegrass showed that diploid cultivars had more rapid water loss and higher drought tolerance of cells than tetraploid cultivars. (6) There was a positive correlation between drought tolerance and cold tolerance, which suggest similar underlying physiological mechanism responsible for the two tolerances. (7) There was a negative correlation between relative competitive ability and stress tolerance to drought and low temperature, which suggest a trade-off between tolerance to physical stress and growth response to resources.These findings seem to contribute to develop integrated system for evaluation of genotypes in a herbage breeding project which establish low-input and high sustainable pasture production system in Japan.