Effects of rest period length and forcing temperature on yield, quality and vase life of cv. Mercedes roses

摘要

Young rose plants cv. Mercedes were grown either year-round or by interrupting the growing period in winter with a rest period of 2 or 6 weeks at 2degreesC. In fast start of forcing the temperature was immediately raised to 20degreesC for 2 weeks, whereas in slow start of forcing the temperature was kept at 8degreesC during the first week, at 13degreesC during the second and thereafter at 20degreesC. The growing temperature was 17degreesC and the photosynthetic photon flux (PPF) was either 100 or 65 mumol m(-2) s(- 1) 20 h day(-1). The lower PPF was tested only in fast forcing. Production with a rest period did not reduce the yield compared with year-round production. An interaction between rest period length and forcing rate on yield and quality was observed. Fast forcing at 100 mumol m(-2) s(-1) PPF resulted in a higher yield than did slow forcing at 100 mumol m(-2) s(-1) and fast forcing at 65 mumol m(-2) s(-1) PPF after a 6-week rest period. Plants with 2 weeks' rest, however, gave a higher yield with slow than with fast forcing at both PPF. Irradiance of 65 mumol m(-2) s(-1) PPF combined with a 6-week rest and slow forcing impaired flower quality. Vase life, when expressed as mean values, did not differ between treatments, but the proportion of cut flowers with a short vase life was higher after 6 than after 2 weeks' storage.