title: Genetic improvement for root growth angle to enhance crop production.
abstract: The root system is an essential organ for taking up water and nutrients and anchoring shoots to the ground. On the other hand, the root system has rarely been regarded as breeding target, possibly because it is more laborious and time-consuming to evaluate roots (which require excavation) in a large number of plants than aboveground tissues. The root growth angle (RGA), which determines the direction of root elongation in the soil, affects the area in which roots capture water and nutrients. In this review, we describe the significance of RGA as a potential trait to improve crop production, and the physiological and molecular mechanisms that regulate RGA. We discuss the prospects for breeding to improve RGA based on current knowledge of quantitative trait loci for RGA in rice.
authors.affiliation: National Institute of Agrobiological Sciences (NIAS) , 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602 , Japan.
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Uga
authors.affiliation: National Institute of Agrobiological Sciences (NIAS) , 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602 , Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kitomi
authors.affiliation: National Institute of Agro-Environmental Sciences (NIAES) , Tsukuba, Ibaraki 305-8604 , Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Ishikawa
authors.affiliation: National Institute of Agrobiological Sciences (NIAS) , 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602 , Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yano
keywords: auxins; drought avoidance; grain yield; gravitropism; phytoremediation; quantitative trait locus; root system architecture