Geographic variation of flowering response to daylength in Perilla frutescens var. frutescens in East Asia.

摘要

Seventeen accessions of P. frutescens var. frutescens and one accession of the weedy type P. frutescens var. crispa, collected from China, Korea and Japan, were cultivated under three photoperiods, i.e. short (10 h light + 14 h darkness), natural (approximately 14 h light + 10 h darkness) and long (16 h light + 8 h darkness). The majority of the accessions showed accelerated and delayed flowering under short and natural photoperiods, respectively. The early-maturing accessions, i.e. KOR1, KOR6, JA1and JA8, showed earlier flowering than the intermediate and the late-maturing types, although they had not flowered even up to 170 days after sowing under long photoperiods. Under short and natural photoperiods, the late-maturing types, i.e. CH1, CH2, CH5, CH7, CH8, KOR11 and KOR40, showed extremely late flowering. Under similar photoperiods, the early-maturing accessions had the shortest plants, while the late-maturing accessions had the tallest. Most of the intermediate accessions, i.e. KOR 3, KOR7,JA2, JA3, JA4 and JA5, showed intermediate plant height. The number of internodes significantly decreased under short photoperiod, but increased under long photoperiods. The early-maturing accessions had the longest inflorescence and the highest number of florets under natural photoperiods, except KOR 6. All late-maturing accessions, except CH2 and CH7, showed longer inflorescence, but reduced number of florets, under short photoperiod compared with natural photoperiod. Days to flowering (DTF) was positively correlated with plant height and internode number under short and natural photoperiodic conditions. DTF was negatively correlated with inflorescence length and floret number under natural photoperiod, but was positively correlated under short photoperiods.