[O44] Root Genetics and Breeding

[O44-06] Functional Significance of Roots for Adaptation and Productivity of Crop Plants Grown under Various Environmental Stresses

^○Akira Yamauchi¹, Mana Kano-Nakata², Shiro Mitsuya¹, Yoshiaki Inukai², Roel Rodriguez Suralta³, Jonathan Manito Niones³ (1.Graduate School of Bioagricultural Sciences, Nagoya University, Japan, 2.International Center for Research and Education in Agriculture, Nagoya University, Japan, 3.Philippine Rice Research Institute, Philippines)

Roots play significant functional roles in adaptation and productivity of crop plants especially when grown under various abiotic stresses. We have accumulated experimental evidences showing that a root system of an individual plant is an integration of component roots with dissimilar morphology, anatomy, physiological functions, and in developmental responses to various soil conditions. The ability of plant to change its morphology, as environmental conditions change is defined as phenotypic plasticity. A series of experiments are now in progress to determine the functional roles of root plasticity by using various accessions/populations. Root plasticity has been phenotyped by using a range of methods, including rootbox-pinboard method, slant tube method, line source sprinkler system, and under field conditions using both monolith and core sampling. These results have consistently showed that the root plasticity specifically in branching, deep rooting, the associated aerenchyma formation, and rooting angle which are exhibited in response to varied soil conditions, substantially contribute to the maintained/promoted growth and productivity through enhanced physiological functions. Genotyping is also in progress by using some of the population to locate genes responsible for the root plasticity traits. Further study is in progress to more precisely identify the quantitative trait loci responsible for the root plasticity and to examine the physiological function of such plasticity for plant adaptation and productivity.