A strain of Amphidinium species was established from samples collected from the intertidal zone of a sandy beach of Jeju Island, Korea. Its cells were 13.0-15.0 μm in length and 10.0-13.0 μm in width. Its cell shape was round or oval and dorsoventrally flat. A pyrenoid was located in the center of the cell and a nucleus was posteriorly located. Its epicone was small and left-deflecting. Its cingulum had V-shape on the ventral side, forming a ventral ridge and extending to the sulcus. Polygonal amphiesmal vesicles and ring-shaped body scales not described previous were observed on the surface of the cell. Its morphological features were consistent with those of previously described Amphidinium fijiense. Phylogeny based on ITS region and LSU rDNA sequences revealed that this Amphidinium isolate was clearly clustered with other A. fijiense strains, but separated from other Amphidinium species. These results indicate that this Amphidinium isolate is A. fijiense. This study reports its presence for the first time in the intertidal zone of a sandy beach of Jeju Island, Korea.

A study describing unrecorded and taxonomically undescribed indigenous species is in progress since 2006. Samples were collected from many sites in coastal waters and offshore of Korea as well as from Jeju Island. Since 2008, we have found ten unrecorded species of four genera belonging to family Dinophysaceae, Gonyaulacaceae, Gymnodiniaceae, and Heterocapsaceae. The species are as follows, Dinophysis elongata (2016 winter), D. nasuta (2016 winter), Gonyaulax alaskensis (2016 winter), G. diegensis (2017), G. monospina (2008), Amphidinium flagellans (2017), Heterocapsa circularisquama (2017), H. horiguchii (2017), H. lanceolata (2017), and H. pygmaea (2017) (note; The numbers in the parenthesis refer to the year in which the species was reported as unrecorded indigenous species by National Institute of Biological Resources, NIBR hereafter). Among them, seven species were described as newly recorded species in Korean waters, and three have been re-described in this study.

A research probing for the unrecorded and taxonomically undescribed indigenous species has been initiated since 2006. Samples were collected from an intertidal zone along the coasts of Korea as well as around the Jeju Island. We have found five unrecorded species of four genera belonging to the order Dinophysiales, Gymnodiniales, Peridiniales, and Prorocentrales. The species are as follows, Sinophysis canaliculata (2017) Bispinodinium angelaceum (2015), Cabra armorica (2016), Prorocentrum bimaculatum (2017), and P. tsawwassenense (2017) (note; The numbers in parenthesis refer to the year in which the species was reported as unrecorded indigenous species by National Institute of Biological Resources, NIBR hereafter).

Rice production is largely affected by various environmental conditions such as cold, heat and flooding. Here, to identify cold tolerant QTLs at seedling stage in rice, we generated RIL population derived from a cross between Hanareum 2 and Unkwang which are a highly cold sensitive and cold tolerant, respectively. We observed cold phenotype of this population in the growth chamber conditions and natural field conditions. For observation of cold tolerant phenotype of RIL population in the growth chamber, we treated cold stress (5~13℃) for 14 days and recovery for 4 days. When we examined the phenotype of RIL in the field conditions, temperature range in the field conditions was about 6 to 25℃ in 2015~2016. We named QTLs as Seedling Cold Tolerant (SCT) in growth chamber and Cold induced Yellowing Tolerant (CYT) in the field, respectively. Three QTLs for SCT and 5 QTLs for CYT were detected on chromosome 1, 6, 7, 8, 10, 11 and 12. Among these QTLs, qSCT12 on chromosome 12 showed 26.3 LOD score with 25.5% of phenotypic variation. When qSCT11.1 and qSCT12 were combined, cold tolerant was most strongest in our experimental conditions. qCYT10 on chromosome 10 was identified in field experiment on both 2015 and 2016. These results may provide useful information for a marker-assisted breeding program to improve cold tolerance in rice.

Direct seeding of sorghum (Sorghum bicolor L. Moench) has a problem of low yield including poor establishment. This poor establishment results from poor quality seed, poor seedbed preparation, seedling pests, poor sowing technique and high soil temperature. This study sought to establish the age at which sorghum seedlings can be transplanted with minimal effects on grain yield. Transplants were raised in 128 nursery tray pot. Five seedling ages were established by transplanting at 10 (T10), 15 (T15), 20 (T20), 25 (T25) and 30 (T30) days after planting (DAP). The treatment combinations were arranged in a randomized complete block design and replicated three times with an individual plot size of 6 x 5 m 2 . Each plot had five ridges with a planting space of 0.60 x 0.20 m 2 at one plants per stand. Results showed that seedling age on transplanting significantly affected growths and yields to sorghum after transplanting. Plant heights and diameters of transplants at T15 were longer than the other transplants. Conclusively, The advantages of this practice were better control of crop density and greater yields; either to fill gaps after emerging and thinning of crops or to compensate for a growth period that was too short for a complete crop cycle.

본 연구는 건강 기능성 농산물로 각광을 받고 있으면서 수요와 재배면적이 점차 확대되고 있는 기장의 생산량 증대와 자급률 향상을 위한 체계적인 재배기술을 확립하기 위한 기초자료를 얻고자 재식밀도와 PE 멀칭에 따른 생육 및 수량에 미치는 영향을 알아보았다. 1. PE 멀칭에 따른 간장은 1년차 PE 멀칭구에서 138 cm로 17 cm 길게 나타났으며, 간경은 8.33 mm로 2년차 PE 멀칭구에서 굵게 나타났고 지상부생체중은 무멀칭구보다 PE 멀칭구에서 연차간 모두 37.7%, 9.0% 많이 나타났다. 2. 연차간 재식밀도에 따른 생육특성에서 간장은 1, 2년차 모두 재식밀도가 높은 10 cm처리구에서 130, 142 cm로 가장 길게 나타났으며 재식밀도별 뚜렷한 차이를 보였다. 간경은 2년차에서는 간장과 반대로 재식밀도가 가장 낮은 20 cm처리구에서 가장 굵은 8.43 mm로 나타났다. 3. 이삭장은 PE 멀칭구에서 34.1, 40.7 cm로 무멀칭구 대비 20.1, 13.7% 더 긴 것으로 나타났다. 종실중 2년차에서는 PE 멀칭구에서 무멀칭구 대비 8.6% 더 무겁게 나타났으며, 천립중에선 무멀칭구에서 5.3% 더 무겁게 나타났다. 종실수량은 1·2년차 모두 뚜렷한 차이를 보였으며 1년차에서는 PE 멀칭구에서 305 kg·10a-1, 2년차에서는 242 kg·10a-1으로 나타났다. 4. 재식밀도에 따른 이삭장과 이삭당 종실중은 1·2년차 모두 재식밀도 낮을수록 길거나 무겁게 나타났으며 종실수량은 연차간 모두 15 cm처리구에서 265 kg·10a-1, 253 kg·10a-1으로 수량구성요소에서 높은 값을 보인 20㎝처리구 보다 10.0, 15.5% 높은 것으로 나타났다.