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Onions are a major vegetables in Korea. Short-day onions are grown in more than 95% in southern area of South Korea, and long-day onions are grown above 600-m altitude in the highlands. Onion cultivation in the highland areas has become difficult for farmers to obtain high income but stable production because of higher cost of seed and the intensive labor involved in production. Consequently, onion set culture by inexpensive onion seeds compared with expensive F1 seed has an advantage due to the higher proportion of marketable size bulbs. This study was conducted to find out the suitable sowing time and tray size for onion set culture in the highlands—the earlier the sowing time, the higher the number of onions set. The most appropriate sowing date and 1.6–3.5 g of onion set size was early to middle May, also with the highest distribution percentage. The highest set number (780.8 set/m2) of suitable onion set size (1.6–3.5 g) were harvested from the 288 trays, followed by 770 set from the bed (9 g/m2 of seed sowed), and (7/m2 of seed sowed) in the 406 tray.
There are 25 species of aster in Korea. There is a controversy about the taxonomical classification of Aster. The genus Aster was classified into four genera, Aster, Gymnaster, Kalimeris, and Heteropappus, by morphological characters. In order to clarify the phylogenetic position of aster, the nucleotide sequence of the nuclear ribosomal DNA internal transcribed spacer (ITS) region was compared among 11 taxa in Korean native aster. The size of ITS1 and ITS2 ranged from 283 to 286 bp and from 251 to 257 bp, respectively. The size of 5.8S region was 164 bp in 11 taxa. The total length of ITS1, 5.8S and ITS2, A. tripolium was shown to be the shortest length, 701 bp; and A. scaber was shown to be the longest length, 706 bp. The G+C content of ITS1 ranged from 47.9% to 51.2% and ITS2 ranged from 52.2% to 55.1%. The range of each taxon was narrow. The total length of the character matrix was 708 characters. Among them, total indel showed 9; in the ITS1 region indel showed 6 it was 67%; and in the ITS2 region, indel showed 3. Most of the indels showed deletion or insertion of only one base pair, but in A. spathulifolius deleted two base pairs and in A. tripolium deleted five base pairs. But in A. yomena, A. hayatae, A. koraiensis, and A. hispidus, the indel was not detected. Phylogenetic trees did not even make a difference inter-genus, but A. yomena and A. koraiensis called genus Kalimeris and genus Gymnaster, respectively; these constituted a clade. A. hispidus called genus Heteropappus was placed as a sister group to the clade of A. ageratoides and A. glehni.