• Korean Journal of Environment and Ecology
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• v.36 no.2
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• pp.139-149
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• 2022

This study aimed to prepare basic data for protecting the habitat of Fairy Pitta Pitta nympha and coping with climate change by detecting songs with bio-acoustic recording technology and identifying phenological characteristics in protected areas in Korea. The study sites were 36 protected areas nationwide. Data were collected between January and December 2019, and the analysis period was from May 1 to August 31, 2019. The main results are described as follows. Firstly, songs were detected in 22 out of 36 study sites. Frequency analysis results of songs show that high frequency was observed in southern inland, including Jeju island, and the area with the highest latitude was Seoraksan National Park. Secondly, the first song was observed in Hallyeohaesang National Park Geumsan on May 14, 2019, and the last song was observed in Ungok wetland in Gochang on August 6, 2019. Thirdly, circadian rhythm analysis results of songs show that the frequency rapidly increased at five o'clock in the morning, peaked at six o'clock, and then decreased afterward. Fourthly, seasonal cycle analysis results of songs show that they were observed from May 14, 2019 to August 6, and the day with the highest accumulated frequency of songs was June 3, 2019 (Julian date: 154). The average temperature of the day the songs were detected was 17.4℃, the average precipitation was 0.02mm, and the average humidity was 82.6%. Fifthly, a correlation analysis result between Fairy Pitta's songs and meteorological factors shows that temperature indicated a negative correlation with Fairy Pitta's songs (p<0.001), but precipitation (p=0.053) and humidity (p=0.077) did not indicate a statistical significance (df=471). This study is significant in that it confirmed the distribution of Fairy Pitta's songs using bio-acoustic recording technology in protected areas nationwide and identified their ecological characteristics by precisely analyzing the relationship between the song period and meteorological factors.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.123-133
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• 1992

This study was conducted to clarify progressed changes of plant types and the effects of the physiological and ecological components on improving ideotype of winter wheat. 12 wheat varieties were planted at the experimental farm of Wheat and Barley Research Institute in Suwon in 1990. As results of intensive wheat breeding for early maturity since 1959, heading, flowering and maturing dates have been shortened by 17, 15 and 14 dagys, respectively. The shortened days from sowing to heading and from heading to flowering contributed to the early maturity to improved. Physiological factors associated with heading time of wheat could be reprsented by growth habit, photoperiod responses, earliness in narrow sense and winter hardiness. For improving an early maturity of winter wheat, it would desired to maintain some degree of winter habit(III-IV), and recombination of more insensitivity to short day length and more shortened earliness in narrow sense than that of Saemil and Chugoku 81, and higher degree of winter hardiness. For improving the early maturity the more effective way must be of shortened days from sowing to heading, and days from flowering to maturity than days from heading to flowering. Ideotype of wheat will be desired to recombine two semi-dwarf genes with erect plant type being about 70-80cm, less stem elongation by late spring, long spike and many grains per spikelet. Average spike weight ratio was about 45-49% in high-yielding varieties, stem fresh weight was lighter, but spike fresh weight was heavier in new one while leaf fresh weight was similar to each other during the maturing periods. Average spike dry weight ratio was higher about 40～48%, and stem and leaf blade dry weights were lower in the newly bred varieties. Stem dry weight was heavier than spike or leaf dry weight in the old varieties of Yungkwang, Jangwang and Jinkwang. Leaf area index for the varieties showed normal distribution curve as the maximum point in booting stage. The maximum point of this curve come in early maturing wheat, and late in old one. The maximum points of LAI were 6.4～6.8 in the high-yielding varieties. Totals of LAI in each period investigated of old one were higher than those of newly bred being 24.6～28.8. Chlorophyll content of the high-yielding varieties of Chokwang, Geurumil and Saemil as higher than that of the old varieties Jangkwang, Jinkwang, Wonkwang and Sinkwang from regrowing period to April 21. after then slightly and even after heading. Net assimilation rate (NAR) was higher in high-yielding varieties with good plant type, and lower in old ones. Grain yield of the newly released varieties increased rapidly but slowly in the old ones. Change in water content of grain at the growing stage in newly bred was lower than that of the old bred. Diminishing rate of water content of grain in establishment per day was 1.2% average that of the old varieties including Yungkwang was 1.5%, and those of the newly bred including Chokwang were 0.9～1.1%. Chokwang, Naemil, and Saemil were the highest-yielding varieties of the Korean cultivars. Yields were increased by spikes per m$^2$, grain weight for the varieties bred in Suwon, and by spikes per m$^2$ for the varieties bred in Milyang.