Enhancing crop yield response to elevated CO2 concentrations (E-[CO2]) is an important adaptation measure to climate change. A high-yielding indica rice cultivar "Takanari" has recently been identified as a potential candidate for high productivity in E-[CO2] resulting from its large sink and source capacities. To fully utilize these traits, nitrogen should play a major role, but it is unknown how N levels influence the yield response of Takanari to E-[CO2]. We therefore compared grain yield and quality of Takanari with those of Koshihikari, a standard japonica cultivar, in response to Free-Air CO2 enrichment (FACE, +200 mu mol mol(-1)) under three N levels (0, 8, and 12g m(-2)) over three seasons. The biomass of both cultivars increased under E-[CO2] at all N levels; however, the harvest index decreased under E-[CO2] in the N-limited treatment for Koshihikari but not for Takanari. The decreased harvest index of Koshihikari resulted from limited enhancement of spikelet number under N-limitation. In contrast, spikelet number increased in E-[CO2] in Takanari even without N application, resulting in significant yield enhancement, averaging 18% over 3 years, whereas Koshihikari exhibited virtually no increase in yield in E-[CO2] under the N-limited condition. Grain appearance quality of Koshihikari was severely reduced by E-[CO2], most notably in N-limited and hot conditions, by a substantial increase in chalky grain, but chalky grain % did not increase in E-[CO2] even without N fertilizer. These results indicated that Takanari could retain its high yield advantage over Koshihikari with limited increase in chalkiness even under limited N conditions and that it could be a useful genetic resource for improving N use efficiency under E-[CO2].
1.Natl Agr & Food Res Org, Tohoku Agr Res Ctr, Morioka, Iwate, Japan 2.Natl Agr & Food Res Org, Inst Agroenvironm Sci, Tsukuba, Ibaraki, Japan 3.Natl Agr & Food Res Org, Res Ctr Agr Informat Technol, Tsukuba, Ibaraki, Japan 4.Natl Agr & Food Res Org, Hokkaido Agr Res Ctr, Memuro, Hokkaido, Japan 5.Tayo Keiki Co Ltd, Toda, Saitama, Japan 6.Azusa Pacific Univ, Dept Biol & Chem, Azusa, CA USA 7.Natl Agr & Food Res Org, Kyushu Okinawa Agr Res Ctr, Chikugo, Japan 8.Chiba Univ, Fac Hort, Matsudo, Chiba, Japan
Recommended Citation:
Hasegawa, Toshihiro,Sakai, Hidemitsu,Tokida, Takeshi,et al. A High-Yielding Rice Cultivar "Takanari" Shows No N Constraints on CO2 Fertilization[J]. FRONTIERS IN PLANT SCIENCE,2019-01-01,10