%0 Journal Article
%T Effect of nitrogen application on the expression of drought-induced root plasticity of upland NERICA rice
%A Akira Yamauchi
%A Daigo Makihara
%A Daniel Makori Menge
%A John Collins Onyango
%A Mana Kano-Nakata
%A Mayumi Kikuta
%A Shuichi Asanuma
%A Tran Thiem Thi
%A Yoshiaki Inukai
%J Plant Production Science
%D 2019
%R https://doi.org/10.1080/1343943X.2018.1561194
%X ABSTRACT This study evaluated the effect of three N fertilization levels 60 (low), 120 (medium), and 180 (high) kg N ha£¿1 and soil moisture content gradients created by a line-source sprinkler on the expression of plasticity in lateral root branching and dry matter production (DMP) of upland new rice for Africa (NERICA) 1 and 4. There were no significant differences in DMP between NERICA 1 and 4 under well-watered, mild drought, and severe drought conditions regardless of N level. In contrast, under moderate drought (12¨C21% v/v of soil moisture content [SMC] in 2011 and 16¨C24% v/v of SMC in 2012), NERICA 1 had significantly higher shoot dry weight, total root length (TRL), lateral root length, and branching index than NERICA 4 at medium and high N; however, there was no significant difference between the two NERICAs in DMP at low N. TRL of NERICA 1 was significantly higher under moderate drought than well-watered conditions, but only with medium and high N. Regardless of N level, moderate drought did not enhance NERICA 4¡¯s root system. Thus, NERICA 1¡¯s root system exhibited plastic development, promoting lateral root branching at medium and high N. These morphological changes were associated with the greater DMP in NERICA 1 than NERICA 4 under moderate drought, whereas the lack of such plasticity at low N meant genotypic differences in DMP were obscured. Our findings implied that N application can improve upland NERICA productivity under moderate drought conditions, but differences in variety and field conditions may influence efficacy
%U https://www.tandfonline.com/doi/full/10.1080/1343943X.2018.1561194