Amur silver grass, Miscanthus sacchariflorus is one of the promising biofuel crops. A damage of noctuid pest, Leucapamea askoldis was firstly observed from Amur silver grass in Hwasun silver grass plantation during the survey of insect pests of Amur silver grass in Iksan, Hwasun, and Sancheong plantation areas in Korea. The host of L. askoldis was not known yet in Korea. Thus, M. sacchariflorus was the first known host in Korea. The L. askoldis damage was observed as larval feeding on newly grown shoots of M. sacchariflorus close to soil surface from early April to early May in 2013. Investigated larval density was 1.6 ± 1.1 per m2 on April 4 and damage rate of shoots was 0.8% ± 0.4 per hundred plants on May 4, 2013. The larvae bore into shoots of M. sacchariflorus and then feed inside of plant. The damaged shoots are easily pulled out and distinguished by the boring hole on the shoots.

본 연구는 반추동물의 조사료 자원으로서 거대억새를 개발하기 위한 목적으로 수행되었다. 우리나라에서 새롭게 개발된 품종인 거대억새 1호를 완숙기 이후에 채취하여 in vitro 반추위 발효를 이용해반추위내 pH, 암모니아태 질소, 가스발생량, 휘발성 지방산 생성량 및 건물소화율을 조사하였으며,볏짚과 비교하여 평가하였다. 거대억새는 볏짚에 비하여 유의적으로 높은 반추위내 pH를 나타내었다(p<0.01). 암모니아태 질소의 경우 배양 12시간 이후에는 두 처리구간의 유의적인 차이를 나타내지 않았다 (p>0.05). 배양 6시간 이후 부터는 거대억새의 가스발생량이 볏짚에 비하여 유의적으로 낮게 나타났다 (p<0.05). 휘발성 지방산 생성량에 있어 acetate, propionate, butyrate, valerate 및 총생상량에서 볏짚이 거대억새보다 높게 나타났다. 그러나 iso-butyrate와 iso-valerate에서는 두 조사료원별 차이는 발견되지 않았다. 건물소화율에 있어 배양 12~24시간 사이의 거대억새 소화율이 볏짚에 비하여 유의적으로 나타났다. 결론적으로 거대억새의 이용성은 볏짚의 약 80% 수준인 것으로 나타났다.

본 연구는 바이오에너지용 이질 3배체 억새(Miscanthus x giganteus) 품종육성 위한 교배재료인 물억새(M. sacchariflorus) 와 참억새(M. sinensis) 출수기 단축과 단교배 조건을 구명하기 위해 수행하였다. 물억새와 참억새를 12시간 일장, 자연일장 조건에서 재배하여 출수기 단축에 미치는 단일효과를 조사하였다. 출수기에 일중 화분 발아시간, 절단한 화분친 이삭 활력 유지 및 격리방법 등 단교배 조건을 구명하여 이를 활용한 억새의 자가수정 여부를 조사하고 시험교배를 실시하였다. 참억새와 물억새 모두 12시간 일장의 단일조건에서 재배한 것이 자연일장에 재배한 것에 비해 출수 소요일수가 단축되었다. 화분 발아 시간은 물억새는 오전 6시에 왕성하였으나 시간이 경과할수록 발아율이 낮아져 오전 8시에는 10% 이하만 발아하였다. 참억새 화분은 오전 7시에 50% 이상이 발아하였고 그 이후로 낮아졌다. 화분친인 참억새 이삭을 절단하여, 절화 보존액에 꽂아 백색 부직포로 격리하였을 때 절화 보존액량이 많을수록 활력 유지 일수가 증가하여 150 mL에서 물억새, 참억새 모두 7일간 개화 및 화분 비산을 지속하였다. 이 때 화분 발아율은 참억새와 물억새 모두 4일까지 40%를 유지하였다. 참억새와 물억새는 자가수정율이 2.5% 이하로 낮고, 자연교잡 임실율은 출수기가 빠른 유전 자원에서 54.4%까지 높았다. 억새 종간교배 방법 효과 확인을 위해 물억새 4배체와 참억새 2배체 간 14조합 시험교배 결과 총 437립의 교배종자를 얻었다. 본 연구로 도출된 억새 종간 단교배 방법은 우수한 종자친과 화분친으로 교배종자를 얻을 수 있어 향후 바이오매스 수량이 많으면서, 종자가 맺히지 않은 이질 3배체 품종육성에 활용할 수 있을 것으로 판단된다.

More than 300 Miscanthus accessions as a potential bioenergy crop were collected in Korea and their morphological traits were investigated at various growth stages. Among morphological traits, stem growth habit, the presence of awn in spikelet, and autumn new shoot are the most important key traits enabling to cluster Miscanthus accessions into M. sinensis and M. sacchariflorus groups. Miscanthus sinensis has bunch stem growth habit and awn in spikelet, and produces autumn new shoot, while M. sacchariflorus has scattering stem growth habit with no awn in spikelet and does not produce autumn new shoot. Interestingly, we found several Miscanthus accessions showing intermediate morphological traits. 7 M. sinensis accessions showed morphological traits similar to M. sacchariflorus and 17 M. sacchariflorus accessions showed morphological traits similar to M. sinensis. Flow cytometry and chromosome counting finally revealed 5 Miscanthus hybrids, suggesting that they are resulted from natural hybridization between M. sinensis and M. sacchariflorus. Therefore, these Miscanthus hybrids can be used to understand genetic recombination between these two Miscanthus species and our understanding may support future efforts for breeding new Miscanthus variety with high biomass productivity and environmental adaptability.

The rice stem borer (Chilo suppressalis Walker) was one of the most destructive pest of rice for the 1960s and 1970s in Korea. Recently, it is newly recognized as a potential risk factor to the biomass yield of bioenergy crops. The current research was firstly conducted to investigate overwintering larvae population density and pattern of rice stem borer attacking Miscanthus sacchariflorus cv. Geodae 1 which is referred to as an ideal lignocellulosic bioenergy crop in Korea. Population density of larvae per 1 m2 in stems and rhizomes at the Miscanthus experimental plots and rates of damage (wormhole, abscission) of M. sacchariflorus cv. Goedae 1 were investigated from October 2012 to March 2013. The population of larvae per 1 m2 in stems of Miscanthus were 23, 4, 1, and 1 in October, November, December 2012, and January 2013, respectively. Over the same period, the population of larvae in basal stem rots and rhizomes were increased, whereas decreased in stems. Interestingly, the positions of larvae for overwintering in Miscanthus were confirmed to 5~10 cm below the soil surface such as basal stem rot and rhizome, whereas the most common overwintering position known in rice is a part of stem on the ground such as rice straw and rice stubble. It would suggest that the larvae gradually moved to bottom of stems and rhizomes in soil in line with decline in temperature. Moreover, the damage rates of stems per 1 m2 were up to more than 50% in some places. In conclusion, this might be the first report that rice stem borer could affect the productivity of biomass of Miscanthus in case of mass cultivation. Moreover, it should be necessary to make a decision in insect control management for this bioenergy feedstock and other related crops.

Over the past few decades Miscanthus has been studied as a potential bioenergy crop in Europe but not much been studied in Korea although Korea has many native Miscanthus species and genetic resources. Because of their features, such as low demands of fertilizers and other agrochemicals, high water use efficiency and high productivity, Miscanthus can be cultivated in marginal lands. However, it is not known how Miscanthus can survive in saline soil and what extent Miscanthus can tolerate salt stress, one of main abiotic stresses in reclaimed lands or dry climates. Therefore, this study was conducted to investigate physiological response of Miscanthus species to salt stress and thus to establish a salt stress threshold. Miscanthus sinensis and M. sacchariflorus showed similar responses to salt stress. Chlorophyll contents, photosynthesis and plant growth were all significantly affected by salt stress. Both species were completely killed at > 100 mM NaCl. The GR50 values estimated by non-linear regression analysis with the logistic model were 116.2 mM and 63.1 mM for M. sinensis and M. sacchariflorus, respectively. These GR50 values can be used as their thresholds of salt stress. Further studies will be conducted to screen salt-tolerant Miscanthus genotypes.