Experiments were carried out to investigate some characters of introduced garlic cultivars and the effects of pretreatment of seed bulb with low temperature and night interruption in protected culture. It was also purposed to obtain useful data for selecting cultivars fit for such a cultivation methods.
1. Under field condition, the bolting date of ´Shanghai´, ´Shenyang´ and ´Jeju´, a southern ecotype, were May 12 and the bolting ratio was 100% as the northern ecotype, ´Euisung´ were June 8 and 30%, respectively. Ratios of neck diameter to bulb diameter were 0.2 in all four cultivars. Among them, ´Shenyang´ showed the heaviest bulb weight, 56.0g, and the length of flower stalk, from terminal leaf to bulblet, was relatively short, 2.0㎝, and also the entire plant was comparatively vigorous.
2. In protected cultivation during the winter season, the three southern ecotype cultivars began to sprout after about one week from planting regardless of low temperature treatment period. The sprouting duration were 19∼22 days in ´Shanghai´ , 17∼27 days in ´Jeju´ and 9∼12 days, the shortest in ´Shenyang´ , respectively. But the northern ecotype, ´Euisung´ showed generally much delayed sprouting, and the longer pretreatment of low temperature promoted the sprout as well as shortened the sprouting duration.
3. Light interruption and low temperature treatment showed no effects on root weight of three southern ecotype cultivars, but the bulb weight, bulb diameter and the number of cloves were increased as the duration of low temperature pretreatment prolonged, and increased by night interruption as compared with natural day length. Ratio of neck diameter to bulb diameter decreased gradually, especially by night interruption and exhibited good bulb-formation. These three southern ecotype cultivars revealed early and high percentage of bolting and early maturation as the pretreatment duration of low temperature was extended and by night interruption as compared with natural day length.
4. The root weight of the northern ecotype, ´Euisung´ increased as the duration of low temperature pretreatment was extended and was also recognized the increase of bulb weight, bulb diameter, number of cloves, and the decrease of the ratio of neck diameter to bulb diameter when low temperature and night interruption were treated as in southern ecotype ones. But ´Euisung´ showed vigorous growth by extended low temperature treatment and night interruption as compared with natural day length, and this cultivar did not show bolting.
5. In all the southern and nothern ecotype cultivars, 60 days of low temperature pretreatment and 60 miuntes of night interruption were most effective on marked increase of bulb weight and on decrease of ratio of neck diameter to bulb diameter and showed the best bulb-formation.
6. The mean weight of bulb of three southern ecotype cultivars in protected cultivation during winter was 47.5∼58.7% of those of field cultivations, and that of ´Euisung´, a northern ecotype, was 16.8%. The differences among ecotypes and cultivars were significant, and ´Shenyang´ showed the heaviest bulb weight, 56.0g and 26.6g in field and protected cultivation, respectively.
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