Gas exchange characteristics of a leading cultivar of Korean strawberry (Fragaria × ananassa, 'Sulhyang')

- Gas exchange characteristics of a leading Korean strawberry are explained.
- Light saturation of photosynthesis (Pn) occurs at 1750-1900 μmol m−2 s−1 PPFD.
- The optimum temperature of Pn is 27-29 °C, depending on the growth period.
- CO2 saturation of Pn does not occur below 1400 μmol mol−1.
- Higher than usual light and CO2 conditions are preferred for practical cultivation.

The recently bred Korean strawberry (Fragaria × ananassa) cultivar 'Sulhyang' accounts for more than 83% of the strawberry cultivation area in Korea. Although strawberry growth properties vary among cultivars, knowledge related to those of 'Sulhyang' remains insufficient. We examined gas exchange characteristics in leaves of this cultivar in autumn and winter to obtain basic data related to this cultivar. The light saturation point of the net photosynthetic rate (Pn) at 25 °C leaf temperature and 400 μmol mol−1 CO2 was about 1750-2000 μmol m−2 s−1 PPFD. The optimum leaf temperature of Pn was about 29 °C, but values did not differ greatly between 19 °C and 31 °C, at 1200 μmol m−2 s−1 PPFD and 400 μmol mol−1 CO2. These results indicate that a high light condition is the most important factor affecting the strawberry cultivation in plastic houses and that temperature is the second most important. Results show that Pn did not saturate at 1400 μmol mol−1 CO2 under 1200 μmol m−2 s−1 PPFD and 25 °C leaf temperature, with its enrichment effect as high as 60-80% (Pn at 1400 vs. 400 μmol mol−1 CO2). The Pn and dark respiration rate (Rd) among the first to fifth leaves from the top expanded leaf showed no great difference. However, Pn was generally higher in autumn plants at initial flowering than in winter plants at vigorous fruit setting. These findings constitute important fundamental information to support the technological development of strawberry cultivation, especially of 'Sulhyang'.