Seed dormancy is an important adaptive mechanism to protect seeds under the unfavorable environments. Unlike to wild type species, the seed dormancy trait of cultivated crops has been weakened by breeding programs during the domestication period. Weak seed dormancy often causes preharvest sprouting (PHS) problem in many cereal crops that result in significant economic loss. The seed dormancy is a quantitative trait loci (QTL) controlled by multiple genetic and environmental factors. So far, many QTLs for seed dormancy have been identified from rice and wheat as well as in the model plant Arabidopsis. Unveiling of QTL genes and complex mechanisms underlying seed dormancy is accelerated by the rapid progress of crop genomics. In the present study, we reviewed current status of research progress on the seed dormancy QTLs and correlated genes in Arabidopsis and cereal crops.

Lespedeza species are mainly used for wildlife food and cover and for erosion control. The germination of these species can be enhanced after a fire occurrence in forest, which is known as fire-activated seeds to germinate. While the heat treatment could break seed dormancy of Lespedeza, its germination rate was quite low. We investigated that chemical scarification could promote germination of L. tomentosa. Seeds were soaked in 100% sulfuric acid (H2SO4) for 0, 1, 3, 6, 12, 24, 48, 96, 192, and 384 min, and then washed in distilled water for 24 h. Very few seeds were germinated in control (H2SO4 for 0 min). More than 90% of seeds were germinated in H2SO4 for 24, 48, and 92 min. However, some damage was observed in roots and cotyledons of seedling dipped in H2SO4 for a long time. To search the optimal soaking time in H2SO4 without defects, seeds scarified in H2SO4 for 30, 60, 90, 120, 150, 180, and 300 min were sown the commercial soil medium. Seeds treated with H2SO4 for 90 min and 150 min emerged by about 92% and 84%, respectively. Therefore, H2SO4 treatment could break the seed dormancy of Lespedeza species, and especially in case of L. tomentosa the optimal treatment time in sulfuric acid was one to two hours. Germination of L. tomentosa began promptly following the scarification and was completed within about one month, indicating that seeds has no physiological dormancy, just has physical dormancy.

Background : Considerable time and effort is required to develop new Panax ginseng varieties. Ginseng breeders have been developing techniques to shorten the breeding cycle to resolve this problem. In this study, we investigated the effects of adding GA3 and alternating temperature (AT, 2℃→ −2℃ → 2℃) on breaking bud dormancy in the varieties (Chungsun and Sunun) of ginseng root. Methods and Results : The GA3 soaking treatment and AT were applied to one year old roots, which greatly accelerated the emergence of new buds. In one year old roots, new buds emerged from the 4th day post transplanting and after breaking dormancy with GA3 and AT treatments. The emergence of new buds was completed within two weeks. The rate of bud emergence for Chungsun was 60% - 98% over 15 - 60 days after the AT and GA3 treatments. The emergence rate of Sunun was 46% - 92%. Normal growth of the ginseng seedling was observed in spite of the early breaking of bud dormancy by combined GA3 and AT treatments. Conclusions : GA3 and AT treatments shortened the dormancy period and facilitated the stable emergence of ginseng seedlings. However, some plants suffered deformities and early sprouting owing to the combined GA3 and AT treatments. Early sprouting was free from dormancy after leaf fall from the of aerial part of the plant.

‘고운’은 농촌진흥청 국립식량과학원 고령지농업연구센터에서 가을재배용 칩가공용 품종을 육성하고자 1998년 건물함량이 높은 가공용품종 ‘Lemhi russet’와 수량성이 높은 단휴면 2기작 식용품종인 ‘추백’을 인공교배하여 육성하였다. 그후 봄재배와 가을재배를 통하여 실생세대와 생산력검정예비시험, 생산력검정본시험을 거치면서 H98005-4를 선발하였으며, 2005년과 2006년에 걸쳐 제주, 남해, 강릉 등 3지역에서봄, 가을재배를 통해 지역적응시험을 실시한 결과 그 우수성이 인정되어 2006년 농작물 직무육성 신품종 선정위원회에서국가목록 등재품종으로 선정되었다. ‘고운’은 남부 해안 2기작감자 재배지역에 적응하는 칩가공용 감자품종으로 숙기는중간정도이다. 반직립형으로 생장하며, 꽃색이 흰색이고, 자연조건하에서 열매는 거의 달리지 않는다. 괴경모양이 짧은 계란형으로 육색이 흰색이며, 내외부 생리장해 발생이 적다. 괴경의 건물함량이 높고 환원당 함량이 낮아 칩가공성이 우수하다. 괴경의 휴면기간은 수확후 60～70일 정도이다. 더뎅이병과 역병에 대하여 중도저항성이지만 감자바이러스Y에는 약하기 때문에 씨감자 채종재배시 진딧물 방제를 철저히 하여야한다. 풋마름병에 대해서는 저항성이 없으므로 풋마름병 발생지역에서는 재배하지 말아야 한다. ‘고운’의 수량성은 2005년부터 2006년까지 2년간 실시한 지역적응시험 결과 봄재배시33.2 ton/ha, 가을재배시 26.2 ton/ha로 나타나 ‘Dejima’에 비하여 각각 87%, 86%의 수량성을 보였다. ‘고운’의 적응지역은 전라북도 해안지역과 전라남도와 경상남도의 2기작감자 재배지역이다.

Experiments were conducted to investigated the change of primary dormancy and viability of Chinese milk vetch(CMV) seed buried in soil both as seed and pod with seeds under CMV-rice cropping system during the period of 2007～2009. The freshly harvested CMV seed alone and pods with seeds were buried in rice field at 0, 5 and 10cm depths and determined change of seed dormancy and viability at one to three month intervals for 10 months. The CMV seed had high dormancy of 95%, showing only 4～5% germination at the beginning in June but the seed dormancy was gradually broken at rice harvest time in autumn, showing 25 to 35% for seed and 55 to 61% for pod with seeds. The viability loss was faster in the seed than in the pod with seeds regardless of depths of placement in the soil base on decayed seeds. Also the seed placed on the soil surface lost viability faster than the 5～10 burial depths. However, appreciable number of CMV seeds still remained at even 4 months after burial in soil. These results indicate that seed dormancy was enable CMV plant to regenerate naturally from the remained soil seed bank at rice harvest time in autumn.

자운영 지속재배시 토양에 매몰된 종자의 휴면 및 발아특성을 조사하여 토양속 종자 동태를 구명하기 위해 자운영종자와 꼬투리의 토양매몰 깊이 및 기간별 휴면성과 종자활력 변화를 조사하고 또한 자운영 지속재배 포장에서 낙수후 자운영 종자의 토양속 분포 개수, 발아율 및 종자활력기간을 조사한 결과는 다음과 같다. 1. 자운영 종자 회수율은 종자 매몰 한달후부터 활력이 잃기 시작하여 낙수전 9월까지 52~65%, 낙수후 10월에는 급격히 떨어져 종자와 꼬투리 모두 30% 이하를 나타내었고, 꼬투리 매몰의 경우는 낙수전 9월까지 활력소실이 되지 않고 100%를 보였다. 2. 자운영 종자의 휴면은 수확당시는 95%로 높았으나 시간이 경과함에 따라 점차 파괴되어 9월에는 휴면율(경실율)이 종자는 12~22%, 꼬투리는 31~33%로 급격히 낮아졌고, 낙수후 10월에는 경실율이 종자는 2~8%, 꼬투리는 5~12%로 보다 더 낮아졌다. 3. 발아율은 토양 매몰전 종자는 4%로 낮았으나 토양에 120일간 매몰후 종자 및 꼬투리속 종자 발아율은 휴면이 타파되어 각각 21%~31%, 49~51%로 증가하였다. 4. 자운영 지속포장에서 9월 낙수후 토양속 잔존 자운영 종자는 로터리 부분경운이앙은 경운이앙보다 2.3~2.6배가 많았고, 자운영 종자분포 깊이는 로터리 경운은 0~15 cm 깊이에 고르게 분포되었으나 부분경운 이앙은 대부분의 종자가 5cm 이하 깊이에 분포하고 있었다. 5. 자운영 종자의 출아기간을 기준으로 한 토양 속에서 활력유지기간은 매몰 후 2년정도 인 것으로 조사되었다.

Freshly harvested seed of Chinese milk vetch (Astragalus sinicus L.; CMV) was strongly dormant because of hardseedness. Seeds of freshly harvested germinated only 8% while clipping the seed coat completely overcome the innate dormancy, which indicates inhibition of germination of the seed is mainly due to seed coat (87%). The dormant (intact) hard seeds did not imbibe water whereas the non-dormant (clipped) seeds took up rapidly. In natural environment condition, the hard seed coat dormancy was broken only after 5 months after seed harvest. To break such a strong seed coat dormancy, the chemical and heat treatments were effective. Concentrated sulfuric acid was more effective than dry heat and hot water treatments. Hot water treatment improved germination but the germination percentage was less than 41%. Treatments increased germination due to its effect on the seed coat integrity. A scanning electron microscope reveled that disruption of seed coat layers and subsequent development of numerous crack in the hilum region of the seed and on the seed coat surface of concentrated sulfuric acid treatment and formation of cracks in the dry heat treatments, respectively, were observed in the seed coat surface, which served as water entry points.

This study was carried out for the improvement of germination rate by breaking seed dormancy in barley, In spring and fall planting, Post-harvest treatment of seeds such as air-dried (24 hours) or soaked in the 100 ppm gibberellin for 10 to 30 minutes imp

Chinese milk vetch (AstragaIus sinicus L.) is a biennial leguminous plant. Although this species is becoming a commongreen manure croP, Chinese milk vetch seed has a low germination rate due to low water permeability of the seed coat which islimiting fact

This study was conducted to investigate the crossability, seed dormancy and overwintering ability of rice plant in GM (glufosinate ammonium-resistant lines. Iksan 483 and Milyang 204) and non-GM (their parents) or red rice (Andongaengmi). Seed-setting rate was not significantly different between GM and non-GM rice varieties. Iksan 483 and Milyang 204 showed the similar level of seed germination rate from 30 to 50 days after heading as compared to non-GM rice varieties. After overwintering in paddy field, seed germination rate of GM and non-GM rice varieties ranged from 14.3 % to 57.6 % in dry soil condition, but there was no germination in wet-soil except red rice. The result in wet-soil condition may help to set up a strategy for reducing the risk of gene flow of transgene via dispersal of seeds of GM plants. The crossability, seed dormancy and seed overwintering of Iksan 483 and Milyang 204, herbicide resistant GM rice varieties, were not significantly different compared to non-GM rice varieties. The results might be helpful to reduce the risk of transgene dispersal from GM crop via seeds and pollens.

앵초, 설앵초와 애기나리를 인위적으로 저온 처리하여 조기에 휴면 타파시켜 동계 생산에 필요한 저온요구시간을 구명하고자 저온시간을 각각 300, 500, 700, 900시간으로 처리하여 수행한 결과 앵초는 700시간이상, 설앵초와 애기나리는 모두 500시간 이상 저온(5℃)을 받으면 화경장이 신장되고 개화율도 높아지는 것으로 보아 휴면이 완전히 타파된 것으로 판단되었다. 따라서 앵초, 설앵초와 애기나리의 동계생산을 위해서는 5℃의 저온에 500~700시간 이상을 두었다가 온실로 옮겨 재배하면 2월 상순에 분화상품 생산이 가능할 것으로 생각된다.

Endogenous ABA and batatasins were first quantified in the stored tubers and bulbils of the Chinese yam, Dioscorea opposita Thunb. cv. 'Tsukune' by GC-MS with comparison of internal standard, and sugar content was also analyzed by HPLC with comparison of external standard. Endogenous ABA content in stored tubers and bulbils was rapidly decreased as storage period prolonged. ABA content of the bulbils was always higher than that of tuber during storage periods. All batatasins of stored tubers and bulbils at 30 days after storage decreased steadily compared to 120 days after storage. On the contrary, batatasin-Ⅲ of the stored tuber and bulbils was only decreased at 60 days after storage. In Dioscorea opposita Thunb. cv. 'Tsukune' like D. japonica, D. alata, and D. bulbifera, may be controlled by endogenous batatasins and ABA, In these compounds, batatasins rather than ABA might be closely related to dormancy-inducing compound during dormancy of the Chinese yam, Dioscorea opposita Thunb. cv. Tsukune.