This study was conducted to analyse the quantitative growth and to clarify the effects of photoperiod on leaf production and quality in perilla using two cultivars, `Suweon 10´ which is early maturing, tall and low productivity, and `Gyeongsan´ which is late maturing, short and high leaf productivity.
1) Until 112 days after sowing, both cultivars showed the similar growth curves in the increase of dry weight of each organ such as leaf, stem and root, and their total dry weight and leaf area. But the higher dry weight of each organ and their total dry weight, and higher leaf area were observed in `Gyeongsan´ than those of ´Suweon 10´ as the crops grew.
2) Specific growth rate of whole plant weight, stem weight, leaf weight, root weight, and leaf area in both cultivars became maximum at 15∼28 days after sowing. Minimum specific growth rates of `Suweon 10´ was appeared twice at 57∼70 days and 99∼112 days after sowing, but once in `Gyeongsan´ at 71∼84 days after sowing.
3) Unit leaf area rate(ULAR) in both cultivars reached the maximum at 1∼14 days and 99∼112 days after sowing, and unit leaf weight rate(ULWR) reached the maximum at 15∼28 days and 99∼112 days after sowing. ULAR and ULWR of Suweon 10 revealed minimum values twice during the first to the second maximum periods, but those of `Gyeongsan´ revealed once during the same period.
4) Specific leaf area(SLA), leaf weight ratio(LWR), leaf area ratio(LAR) and surplus weight (SW) exhibited similar tendencies in both cultivars, but during 99∼112 days after sowing, surplus weight increased markedly in `Gyeongsan´ as compared with that of `Suweon 10´.
5) $oth cultivars flowered at about 50 days after sowing under 10.0∼13.0 hrs of day length condition. But under 14.0 hrs of day length, `Suweon 10´ flowered at 64 days after sowing (Oct. 29) and `Gyeongsan´ at 83 days after sowing(Nov. 17).
6) Both cultivars could not develop visible flower bud when night break contiuned for 30 minutes (24 : 00∼00 : 30) or for 60 minutes(24 : 00∼01 : 00). Leaf productivity became high under 60 minutes of night break treatment in `Suweon 10´, but no significant increase was observed in `Gyeongsan´ with two night break treatments.
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