Projected increases in atmospheric CO2 concentration ([CO2 ]) and temperature (Ta ) have the potential to alter in rice growth and yield. However, little is known about whether Ta warming with elevated [CO2 ] modify plant architecture. To better understand the vertical profiles of leaf area index (LAI) and the flag leaf morphology of rice grown under elevated Ta and [CO2 ], we conducted a temperature gradient field chamber (TGC) experiment at Gwangju, Korea. Rice (Oryza sativa L. cv. Dongjin1ho) was grown at two [CO2 ] [386 (ambient) vs 592 ppmV (elevated)] and three Ta regimes [26.8 (~approx ambient), 28.1 and 29.8~circC ] in six independent field TGCs. While elevated Ta did not alter total LAI, elevated [CO2 ] tended to reduce (c. 6.6%) the LAI. At a given canopy layer, the LAI was affected neither by elevated [CO2 ] nor by elevated Ta , allocating the largest LAI in the middle part of the canopy. However, the fraction of LAI distributed in a higher and in a lower layer was strongly affected by elevated Ta ; on average, the LAI distributed in the 75-90 cm (and 45-60 cm) layer of total LAI was 9.4% (and 35.0%), 18.8% (25.9%) and 18.6% (29.2%) in ambient Ta , 1.3~circC and 3.0~circC above ambient Ta , respectively. Most of the parameters related to flag leaf morphology was negated with elevated [CO2 ]; there were about 12%, 5%, 7.5%, 15% and 21% decreases in length (L), width (W), L:W ratio, area and mass of the flag leaf, respectively, at elevated [CO2 ]. However, the negative effect of elevated [CO2 ] was offset to some extent by Ta warming. All modifications observed were directly or indirectly associated with either stimulated leaf expansion or crop phenology under Ta warming with elevated [CO2 ]. We conclude that plant architecture and flag leaf morphology of rice can be modified both by Ta warming and elevated [CO2 ] via altering crop phenology and the extent of leaf expansion.

Climate warming has the potential to deteriorate grain yield and quality of rice (Oryza sativa L.), offsetting the stimulative effects of elevating CO2. To know how the change in sink-source balances by reducing sink-size (RSS) may affect grain yield and quality of rice grown under various climate change scenarios, we conducted a temperature gradient chamber experiment with/without CO2 fumigation systems which were established in paddy field. Rice crops (cv. Ilmybyeo) were exposed to either ambient (396ppmV) or elevated CO2 of 673ppmV in three levels of air temperature [(Ta), local ambient Ta (24.8℃), 1.3℃ and 2.4℃ above ambient Ta] over whole seasons. Thus, the experiment was a 2×3 factorial design with three replicate plots of each CO2×Ta combination. At flowering, for two hills from each combination treatment total thirty (10 per each top, middle and basal parts of panicle) spikelets per panicle were removed with order of panicle appearance by scissors. This corresponded to a 25% reduction of total sink-size per hill. In ambient Ta and CO2 , grain yield decreased with RSS by 23.4%, approximately mirroring the reduced sink-size. With rising Ta, however, the yield reduction by RSS was significantly mitigated (-5.6% in 1.3℃ above ambient Ta), and the yield rather increased with RSS by 9.3% in 2.4℃ above ambient Ta. This was due primarily to the increased single grain mass with RSS. A similar response fashion of grain mass and yield with RSS to Ta was found in elevated CO2, but not CO2×Ta interaction. For brown rice, the fraction of normal rice was linearly reduced with rising Ta, ranging from 78.5～79.2% in local ambient Ta to 48.2～55.5% in 2.4℃ above ambient Ta over CO2 treatments. However, this deteriorative effect of rising Ta was significantly alleviated with RSS; the fractions of normal rice were a 81.9～84.1%, 75.9～77.2% and 64.0～66.3% in local ambient Ta, 1.3℃ and 2.4℃ above ambient Ta, respectively. The alleviative effect of RSS on rice quality was due mainly to the reduced immature rice, and was more conspicuous as Ta rises. These results suggest that current rice cultivars in Korea, at least cultivars tested in this experiment, will likely to be prone to source-limitation in the future projected warming with elevating CO2, and thereby will be needed a cultivar having either a greater source ability or a less sink size compared with current cultivars, in order to ensure a rice quality in the future warming conditions.

To know how interacting climate drivers may affect rice quality, we investigated physio-chemical properties of brown and milled rice. Rice crops (Oryza sativa L., cv. Ilmybyeo and Pyounganbyeo) were grown under either ambient [370ppmV (2008)/396ppmV (2009)] or elevated CO2 of 650ppmV (2008)/673ppmV (2009) in three levels of air temperature [(Ta), local ambient Ta [25.9℃ (2008)/24.8℃ (2009)], 1.3℃ and 2.4℃ above ambient Ta] over whole seasons, using six temperature gradient chambers established in paddy fields. Over 2 years, thus the experiments were a 2×3 factorial design with three replicate plots of each CO2×Ta combination. The fractions of normal brown rice were reduced with elevating CO2 by 8% (Ilmybyeo)～14% (Pyounganbyeo), and with rising Ta by 16% (+1.3 ℃)～27% (+2.4℃) in Ilmybyeo and by 27% (+1.3℃)～42% (+2.4℃) in Pyounganbyeo (p=0.015, 0.000, 0.059, 0.000 and 0.017 for CO2, Ta, CO2×Ta, cultivar and Ta×cultivar, respectively). With respect to immature rice, elevating CO2 increased milky-white rice, white-based rice and white-belly rice across cultivars. Warming also significantly increased all immature rice across cultivars, though no CO2×Ta interaction was observed. Over 2 years, the deteriorative effect of warming on brown rice quality was significantly greater in Pyounganbyeo than in Ilmybyeo. Across cultivars, protein contents of milled rice were decreased (c. 5～9%) with elevating CO2 but increased (c. 5%) with warming, though no CO2×Ta interaction was found (p=0.119). Elevating CO2 significantly increased whiteness of milled rice over cultivars but not amylose contents and gloss value of cooked rice, while warming had a strong affect these properties all related rice quality. Overall, our results suggest that warming and elevating CO2, in each alone or in combination, may have the potential to deteriorate physio-chemical properties of rice related to quality.

A new early maturing satsuma mandarin (Citrus unshiu Marc.) ‘'Haryejosaeng’' was developed as a nucellar seedling selection of ‘'Tachima Wase’' (C. unshiu Marc.) that was crossed with C. natsudaidai Hayata at the National Institute of Subtropical Agriculture in Jeju island in 1992. The ‘'Jegam ga No. 2’', a first selection from the seedlings fruited in 2001 was finally named “"Haryejosaeng”" through field evaluation trials at three locations in Jeju island from 2003 to 2004. ‘'Haryejosaeng’' produces seedless fruit maturing in early November, and has higher soluble solids and lower acidity than ‘'Miyagawa Wase’', the leading early-maturing satsuma mandarin cultivar in Jeju island. Fruit weight is moderate at about 80～90 g and its shape is compressed-oblate globose with a light orange color. The rind thickness of about 2 mm provides easy peeling. The flesh shows light orange colored and contains 10 to 11 Brix and 1 to 1.1% acidity when mature. Tree shows vigorous growth and spreading thornless twigs. Alternate bearing is similar to ‘iyagawa Wase’ ‘aryejosaeng’is susceptible to citrus scab disease and melanose, but resistant to citrus canker.

The objective of this study was to determine how elevated CO2 and temperature affected early growth and competition between direct seeded rice (Oryza sativa) and a common paddy weed (Echinochloa glabrascens). By using temperature gradient chambers. Rice and E. glabrescens were grown for 5 weeks at ratios of 1:0. 3:1 and 0:1 at three temperatures (16.4℃, 19.8℃, and 22.2℃) and either in ambient (361ppm) or elevated (566ppm) CO2. For both species. elevated CO2 had no effect on mainstem leaf number while air temperature had a slight positive effect which was greater in E. glabrescens than rice. With elevated CO2 rice leaf area index and plant height increased alightly in all species combinations but no increases were observed for E. Glabuescens. For rice in all combinations. elevated CO2 tended to increase the rot and total biomass much more than any other growth parameters: the increases in root and total biomass resulting from elevated CO2 ranged from 16% to 40%. depending on air temperature. At the lowest temperature, the decrease in rice biomass in combination with E. glabrescens was significantly greater at elevated CO2 (18%) than ambient CO2 (3%). At the highest temperature, however, the decrease in rice biomass at elevated CO2 (22%) was less than that at ambient CO2 (36%). The competitive ability of rice as measured by the decrease in biomass when grown in combination with E. glabrescens depended strongly on root growth and/or allocation. These results suggest that at higher temperatures elevated CO2 could enhance the competitive ability of direct seeded rice during early growth. However, at lower temperatures. the competitive ability of E. glabrescens seems to be greater.