Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Comparative analysis of drought resistance genes in Arabidopsis and rice

Auteur : Trijatmiko, K.R.

Université de soutenance : Wageningen Universiteit

Grade : Doctor Thesis 2005

Sommaire partiel
Irrigation of rice fields has been a part of Asian culture for many thousands of years. This most productive rice growing system contributes 75% of the world rice production. The combination of human population growth and climate change, however, may soon impact the reliability of the globe’s fresh water resources. To meet the increasing demand of rice in the future, therefore, we can not continue to depend solely on irrigated area. We need to improve and exploit the yield potential of the rice crop in rainfed areas. The major environmental constraint for rice production in rainfed areas is water deficit, to which rice is more susceptible than other cereals. The gap in productivity between irrigated and non-irrigated areas is still huge. Much more effort should be made to narrow the gap through genetic improvement of rice for water-limited environments. Breeding for drought stress resistance is complex due to the large number of genes affecting the trait and the difficulties in evaluation or selection of drought resistant cultivars. However, it is expected that genetic improvement for drought resistance in rice is possible given the recent advances in plant genomics. This thesis reports the study on the genetic control of drought resistance, using genomics information and tools from the model plants Arabidopsis and rice. The genetic dissection of drought resistance in a rice population, using molecular markers, reveals that a large part of the genetic effect for grain yield under drought condition is determined by a chromosomal region close to the dwarfing gene responsible for the ‘Green Revolution’. The parameters associated with the effect on grain yield under stress in this region were percentage of seed-set, grain number per panicle and surprisingly leaf rolling. Comparison with other populations showed that leaf rolling has been mapped in the similar position using different rice genotypes. Leaf rolling is indirect indicator of drought avoidance or tolerance mechanisms.

Mots clés : ORYZA SATIVA / RICE / ARABIDOPSIS THALIANA / DROUGHT RESISTANCE / GENES / GENETIC ANALYSIS / GENE EXPRESSION / PLANT BREEDING METHODS

Version intégrale