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Growth dynamics and genotypic variation in tropical, field‐grown paddy rice (Oryza sativa L.) in response to increasing carbon dioxide and temperature
Author(s) -
MOYA TOLENTINO B.,
ZISKA LEWIS H.,
NAMUCO OFELIA S.,
OLSZYK DAVE.
Publication year - 1998
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.1998.00180.x
Subject(s) - cultivar , oryza sativa , agronomy , germination , carbon dioxide , biomass (ecology) , paddy field , yield (engineering) , horticulture , zoology , environmental science , biology , materials science , ecology , biochemistry , metallurgy , gene
While previous studies have examined the growth and yield response of rice to continued increases in CO 2 concentration and potential increases in air temperature, little work has focused on the long‐term response of tropical paddy rice (i.e. the bulk of world rice production) in situ , or genotypic differences among cultivars in response to increasing CO 2 and/or temperature. At the International Rice Research Institute, rice (cv IR72) was grown from germination until maturity for 4 field seasons, the 1994 and 1995 wet and the 1995 and 1996 dry seasons at three different CO 2 concentrations (ambient, ambient + 200 and ambient + 300 μL L –1 CO 2 ) and two air temperatures (ambient and ambient + 4 °C) using open‐top field chambers placed within a paddy site. Overall, enhanced levels of CO 2 alone resulted in significant increases in total biomass at maturity and increased seed yield with the relative degree of enhancement consistent over growing seasons across both temperatures. Enhanced levels of temperature alone resulted in decreases or no change in total biomass and decreased seed yield at maturity across both CO 2 levels. In general, simultaneous increases in air temperature as well as CO 2 concentration offset the stimulation of biomass and grain yield compared to the effect of CO 2 concentration alone. For either the 1995 wet and 1996 dry seasons, additional cultivars (N‐22, NPT1 and NPT2) were grown in conjunction with IR72 at the same CO 2 and temperature treatments. Among the cultivars tested, N‐22 showed the greatest relative response of both yield and biomass to increasing CO 2 , while NPT2 showed no response and IR72 was intermediate. For all cultivars, however, the combination of increasing CO 2 concentration and air temperature resulted in reduced grain yield and declining harvest index compared to increased CO 2 alone. Data from these experiments indicate that (a) rice growth and yield can respond positively under tropical paddy conditions to elevated CO 2 , but that simultaneous exposure to elevated temperature may negate the CO 2 response to grain yield; and, (b) sufficient intraspecific variation exists among cultivars for future selection of rice cultivars which may, potentially, convert greater amounts of CO 2 into harvestable yield.