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

点击翻译按钮获取中文摘要

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.