Haploids are plants with a gametophytic number of chromosomes in their sporophytes. Androgenesis occurs from asymmetric division of pollen grains into generative cells and vegetative cells, followed by re-entry of the vegetative cell during S-phase, which causes microspores progress into G2/M transition in culture. One of the most interesting features of haploids is the possibility to produce doubled haploid (DH) individuals. Doubled haploidy is extremely useful to plant breeders because it enables shortened breeding periods and efficiency in selection of useful recessive agronomic traits. Doubled-haploid technology is not only applicable to breeding, but also to transformation programs of desired genes. In addition to practical breeding programs, DH lines provide useful materials of fundamental genetics including exploitation of QTLs and genes conferred with various agronomic traits by establishing DH populations. This paper provides historical overviews on androgenesis and describes several mechanisms associated with pollen embryogenesis, including mode of actions in pollen embryogenesis, mechanisms of chromosome doubling and factors affecting androgenesis. We also discuss recent progress in application of haploids to breeding, genes associated with in vitro response and drawbacks to anther culture for application of doubled haploids in crop breeding.

아밀로스 함량차이에 따른 배유전분의 이화학적 특성을 파악하기 위해 아밀로스 함량의 차이를 보이는 찰벼, 저 아밀로스, 중간 아밀로스, 고 아밀로스 품종의 외관특성, 화학특성, 호화특성 및 기계적 식미치를 조사하였으며, 그 결과를 요약하면 다음과 같다.1. 시료들의 아밀로스 함량은 6.3%∼30.9% 범위로 아밀로스 함량차이에 따라 4개 그룹 찰벼(A), 저 아밀로스(B), 중간 아밀로스(C), 고 아밀로스(D) 품종군으로 나눌 수 있었으며 각 그룹에 속한 품종들의 단백질함량은 5.8 ~ 7.5%로 품종간 차이가 있었으나 아밀로스 함량에 따라 분류된 그룹간 차이는 없었다.2. 시험재료의 외형적 특성을 보면, 백도는 찰벼 품종군이 가장 높고 저아밀 중간아밀로스 품종군이 가장 낮았다. 현미경도는 고 아밀로스 품종 및 찰벼 품종이 메벼품종과 저 아밀로스 품종보다 대체적으로 낮았다.알카리 붕괴도는 5.2∼6.9의 분포를 보였으며 아밀로스 함량이 증가할수록 붕괴도가 커졌으며, 아밀로스 함량과 알카리 붕괴도 간 매우 높은 양의 상관(r=0.884**)을 보였다.3. 아밀로그램 특성을 살펴보면 저 아밀로스 품종군은 호화개시온도가 중간 아밀로스 품종과 비슷한 반면 최고점도와 강화점도는 높고 최종점도와 치반점도는 낮았다. 고 아밀로스 품종군은 호화개시온도가 다른 품종군에 비해 높고, 최고점도와 최저점도가 매우 낮았으며 최종점도가 상대적으로 높아서 강하점도는 낮고 치반점도는 높은 특성을 보였다.4. 식미관련 이화학적 특성들 간 상관을 살펴보면 아밀로스함량은 알카리 붕괴도와 상당히 높은 양의 상관(r=0.88**)을 Toyo-윤기치와는 높은 음의 상관(r=-0.89**) 나타냈고, 아밀로그램 특성 중에서는 호화개시온도, 치반점도와 유의한 양의 상관을 보이며, 강하점도와는 음의 상관을 나타냈다.

국내 대학과 국립식량과학원 간의 협력 연구를 통해 확보된 32개 벼 형질전환 계통들 중 작물학적 성능이 유망한 11개 계통들에 대해 작물학적 특성과 미질 특성이 평가되었다. 주요 결과는 아래와 같다.1. 이들 계통들은 수량성, 환경스트레스저항성, 내병성에관여하는 7종의 유전자가 니폰바레, 낙동벼, 동진벼등에 형질전환 되어 육성된 계통들이다.2. 미질 특성과 관련된 11개 조사형질을 이용한 다변량분석결과, 형질전환에 이용된 모품종과 도입유전자들에 대한 각 형질전환 계통군들의 뚜렷한 집구현상은관찰되지 않았다.3. 실용적 측면에서는 작물학적 특성이 모품종과 유사하면서 미질 특성이 양호한 계통이 다수 확인되었다.4. 그러나 모품종의 유용한 작물학적 특성, 즉 ‘상품성’을온전히 견지하고 있다고 판단되는 계통은 선정하기 어려웠다.5. 도입할 유전자의 선정과 유전적으로 고정된 형질전환계통을 확보하는데 소요되는 경비와 시간을 고려할때, 향후 우량 벼 형질전환 계통의 육성효율을 제고하기 위해서는 기존에 비해 보다 구체적이며 차별화 된육종전략의 개발이 필요하다고 판단되었다.

국내 대학과 국립식량과학원 간의 협력 연구를 통해 확보된 32개 벼 형질전환 계통들에 대하여 주요 작물학적 특성및 수량성을 평가하였다. 이들 계통들은 수량성, 내병성, 스트레스저항성, 미질변이 등에 관여하는 17종의 유전자가 니폰바레, 낙동벼, 동진벼 등에 형질전환 되어 육성된 계통들이다. 주요 결과는 아래와 같다.1. 형질전환 계통들은 출수기, 간장, 수장, 수수 등의 주요작물학적 특성뿐만 아니라 수량성에서도 모품종과 상당한 차이를 보였다.2. 조사된 벼 형질 전환계통들에서 조사된 농업형질에 대한다변량분석 결과, 모품종에 비해 각 형질전환 계통군 내에서 관찰된 작물학적 상이성은 일정한 방향성이 없는무작위적이었으며, 그 변화폭도 3개의 모품종들의 작물학적 차이보다 훨씬 크게 관찰되었다.3. 따라서 우량 벼 형질전환 계통 육성의 효율성을 제고하기 위해서는 모품종에 형질전환 되어 발현될 유전자의우수성뿐만 아니라, 계통육성과정에서 다양한 유전학적요인에 의해 야기되는 ‘표현형 왜곡현상’을 적절히 제어할 수 있는 육종전략도 함께 고려되어야 할 것으로 사료되었다.

The green rice leafhopper (GRH), Nephotettix cincticeps Uhler, is one of the most serious insect pests affecting cultivated rice (Oryza sativa L.) in temperate regions of East Asia. To understand the genetic basis of the GRH resistance, a F2 population derived from across between a highly resistant variety,Cheongnam and a susceptible variety, Junambyeo was analyzed by genetic analysis and association mapping. GRH resistance was evaluated using the F2 populations. The results showed that a single dominant gene in Cheongnam. DNA from 22 F2 individuals being either resistant or susceptible were pooled to produce bulk resistant and bulk susceptible DNA samples. Parents and bulks were screened with 192 SSR markers and twolinked SSRmarker, RM6082 and RM20145 were identified.Subsequent mapping in the original mapping population showed that thelocusis flanked by the SSR markers, RM20130 and RM20152 on chromosome 6. To physically map this locus, the-linked markers were landed on the artificial chromosome clones of the reference cv., Nipponbare, released by the International Rice Genome Sequencing Project. The DNA markers found to be closely linked to Grh3 would be useful for marker-assisted selection for the improvement of resistance to GRH in rice.

The significance of genetic stability and bio-safety environment has been recently recognized by many GM plants. This study was to evaluate the GM stability of transgenic rice and to identify the environment variance. The GM rice of vitamin A　-enriched rice and four check cultivars were analyzed the data on agronomic characters and principal component for 2009-2011 in large-GM crop field. Cultivation environment was conducted in the large-GM field and greenhouse to determine grain characters. In this experiment, there was no significant difference in agronomic characters between GM rice of vitamin A-enriched rice and a donor plant, Nagdong. Related to grain characters, grain appearance and physicochemical characteristics were similar to GM rice of vitamin A-enriched rice and a donor plant, Nagdong. However, grain appearance in GM rice of vitamin A-enriched rice showed to white core and white belly when GM rice of vitamin A-enriched rice was planted in greenhouse. The type and distribution of dominant weed species also were not different from GM rice of vitamin A-enriched rice and a donor plant, Nagdong. Additionally that of gene flow was not detected in dominant weed species by PCR analysis.

This study was carried out to determine the contents of antioxidant activity of colored rice lines which derived from a mutant of MGI079 induced by MGI079 tissue culture in rice (Oryza sativa L.). The antioxidant activities were evaluated by assaying polyphenol, flavonoid, DPPH free radical and color values of colored rice lines, respectively. Among 8 lines including Heugnam of colored rice, the 70% ethanol extracts decreased in the order of MGI079-2-1>MGI079-2-6>MGI079-2-R,Heugnam>MGI079-1-R>MGI079-2-1>MGI079, MGI079-1-1, MGI079-1-6. The rice lines of highest polyphenolic compound was MGI079-2-6 and the next were Heugnam, MGI079-2-R, MGI079-2-1, MGI079-1-R, MGI079-1-6, MGI079-1-1, MGI079, MGI079-OP-R with the order of higher content. The flavonoid was higher in order of MGI079-2-1, MGI079-2-6, Heugnam, MGI079-2-R, MGI079-1-R, MGI079-1-6, MGI079-OP-R, MGI079, MGI079-1-1. The DPPH free radical was higher in order of MGI079-2-1, MGI079-2-6, Heugnam, MGI079-1-6, MGI079-1-1, MGI079-2-R, MGI079-1-R, MGI079-OP-R, MGI079. For chromaticity, a negative correlation was exhibited between the color value and the 70% ethanol extracts, polyphenolic compound, flavonoid, DPPH free radical. The grain characters in brown rice of a mutant of MGI079 showed similar to that of a donor plant, MGI079. Whereas, chemical characteristics of brown rice in two colored rice lines(MGI079-2-1, MGI079-2-6) were lower in amylose and lipid contents and were higher four times in zinc that of a donor plant, MGI079. Two colored rice lines(MGI079-2-1, MGI079-2-6) showed relatively high antioxidative activity in every results of antioxidant activity tests.

This study was carried out to develop expressed sequence tag-Simple sequence repeat (EST-SSR) markers of brown plant hopper resistance gene originated from a rice cultivar ‘Cheongcheong’ and sensitive rice cultivar ‘Nakdong’. Total RNA extracted from the leaves of ‘Cheongcheong’ and ‘Nakdong’ were used to synthesize a cDNA library. As a result of analyzing the cDNA library, EST-SSR sites were found and the EST-SSR primer sets were developed. This study enables to provide effective marker assisted selection (MAS) methods on the selection of white-backed planthopper resistance gene originated from a rice cultivar more simply, quickly and precisely. Furthermore, using this marker’s advantage of deriving from cDNA, it is possible to identity the white-backed planthopper resistance gene.

Somaclones regenerated from seed-derived callus culture of a rice cultivar, 'Ilpum', were evaluated for the agronomic and morphological characteristics. A total of 424 plants regenerated and the seeds collected from 297 lines were used for further analysis on morphological and agronomic traits. The results indicated that 21.5% (64 lines) of progenies showed significant differences from the donor cultivar 'Ilpum'. Somaclonal variations were induced leaf character, plant height, grain characters, heading date, and sterility. Among the variants, 8% (24 lines) of sterility, 1.4% (4 lines) of dwarf/semi dwarf, 1.7% (5 lines) of opaque, and 1.3% (4 lines) of leaf-rolling phenotypes were observed. The highest frequency of somaclonal variation was observed on heading date which occupied 9.1% (27 lines) of the entire lines included 6.4% (19 lines) of early heading and 2.7% (8 lines) of late heading. These results suggest that the somaclonal variation will be one of the promising genetic resources due to its wide variation and comparatively high frequency of mutation.

The whitebacked planthopper (WBPH) is one of the most serious insect pests of rice. The nymphs and adults suck the phloem sap which causes reduced plant vigor, stunting, yellowing of leaves. We employed a mapping population composed of 113 doubled haploid lines (DHLs), derived from a cross between resistant cultivar ‘Cheongcheong’ and susceptible cultivar ‘Nagdong’, to identify the quantitative trait loci (QTL) associated with WBPH resistance. The DH population was evaluated for resistance to WBPH using seed box screening test. The WBPH resistance of each lines or plants was estimated when susceptible check ‘Nagdong’ was killed using 1-9 scale according to Standard Evaluation System for Rice (IRRI, 1988). A linkage map was constructed with 119 polymorphic microsatellite markers using the Joinmap 4 software program to adjust for segregation distortion. Transgressive segregation was observed on WBPH resistance. Two significant QTLs conferring resistance to WBPH, qwbph6.1 and qwbph6.2, were detected in the regions of RM588-RM276 and RM527-RM528 on chromosome 6 with LOD scores of 3.7 and 2.4, respectively. They collectively explained 55% of phenotypic variation. These two QTLs have large effects on WBPH resistance and may be useful for establishment of marker assisted selection (MAS) in the rice breeding programs.

The objective of this study was to characterize the main-effect QTLs, epistatic QTLs and QTL-by-environment interactions (QE), which are involved in the control of protein content. A population of 120 doubled haploid (DH) lines derived from a cross between 'Samgang' and 'Nagdong', was planted and determined for protein content over three years. Based on the population and a genetic linkage map of 172 markers, QTL analysis was conducted by WinQTLcart 2.5 and QTLMAPPER. Three main-effect QTLs affecting protein content of brown rice were detected from 2004 to 2006 on chromosomes 1 and 11. The qPC11.2 was repeatedly detected across two years. Seven pairs of epistatic loci were identified on eight chromosomes for protein content and collectively explained 39.15% of phenotype variation. These results suggest that epistatic effects might be an even more important component of the genetic basis for protein content and that the segregation of the DH lines for protein content could be largely explained by a few main-effect QTLs and many epistatic loci.

A population of 120 double-haploid lines derived from Samgang/Nagdong was used for analyzing the developmental behaviors of plant height and tiller number by conditional mapping via composite interval approaches at five growth stages of rice. The traits were normally distributed with transgressive segregations in both directions. A total of 4 QTLs associated with plant height were identified in 40th/initial, 50th/40th and 60th/50th periods, respectively. The qph7.1 was observed in 50th/40th and 60th/50th periods, with increasing effects from Samgang and Nagdong alleles, respectively. This indicated that an individual gene or genes at the same genomic region might have opposite genetic effects at various growth stages. Five QTLs associated with tiller number were identified in four stages except 60th/50th stage. Four of five increasing effects of QTLs were from Nagdong alleles. Six of nine QTLs for two traits were detected before 60 days. It was evident that the expression of QTLs for plant height and tiller number was more active at early stages than at maturity stage. Furthermore, QTLs identified at early stages showed opposite additive effects on plant height and tiller number. These results provided a possible genetic explanation for the negative correlation between two traits.

With the development of diverse agricultures worldwide, biofortified rice noted for its preferable marketability and palatability plays an important role in the world's agricultural economics and rice breeding programs. In this report, several M5 of T-DNA inserted lines derived from the donor cultivars, 'Hwayong' and 'Dongjin', were selected for high or low protein, high lipid and low amylose content, respectively. The coefficients and ranges of variation for the chemical constituents between M4 and M5 T-DNA inserted lines were evaluated in comparison with those of the donor varieties. Results indicated that T-DNA insertion might be an effective way to generate useful variations for chemical composition of rice grains which could be used for the development of biofortified rice cultivars.

본 연구에서는 벼멸구 저항성 개통 육성과정 중에 수행한 PS와 MAS system간의 선발 효율을 정확성, 소요시간, 소요비용 등의 요인으로 비교･분석함으로써 MAS system의 선발 효율을 제시하고, 이를 이용하여 효과적인 MAS system을 구축하고 실용화하기 위한 방안을 제시하였다. DNA marker를 이용하여 벼멸구 저항성 개체를 선발하고 MAS 체제를 확립하기 위하여 ‘삼강/낙동’ 조합의 F2집단, RIL(F6), DH집단, 여교잡집단(BC6F5)을 대상으로 PS와 marker 검정을 병행하여 두 검정 방법 간에 각 잡종집단 및 세대별 저항성과 감수성 계통(개체)의 비율을 비교한 바 95%이상 일치하였다. MAS 체제와 PS간의 선발효율을 비교한 바 MAS는 PS에 비해 약 32%의 비용이 절감되었고, 검정에 소요되는 기간도 기존의 PS에서는 30일인데 비해 MAS에서는 7일로 크게 단축되었다. 이 결과를 바탕으로 MAS에 의한 벼멸구 저항성 계통 선발 체계를 확립 할 수 있었다.

Demand for high quality rice has always been a major factor in the international rice marketing. In the present study, doubled haploid (DH) population derived from anther culture of a Tongil/japonica hybrid was used for genetic analysis of rice grain quality. The average values of DH lines for grain weight, grain length and the ratio of grain length to width were near the mid-parent value. More than 40% DH lines showed transgressive segregation for grain weight, length, amylose and lipid content, but less than 10% DH lines observed on ratio of length to width and grain thickness were transgressive segregation. Correlation analysis between appearance qualities and physicochemical characters indicated that grain width and grain thickness both significantly and negatively correlated to protein and lipid content. A highly significant negative correlation between protein content and amylose content was observed.

Lodging is classified as root lodging caused by the loss of supporting force in the root, bending caused by the deformation of the stem and breaking where the stem breaks down as loads exceeding critical elasticity were applied. This research excluded breaking which is not in a state of equilibrium and tried to partition the level of lodging using an algebraic model in root lodging and stem lodging, or bending. When a vertical load was applied, the deformation of the stem of rice plant showed the form of a quadratic equation. The trace of the panicle neck in the process of lodging was an ellipse-shape. When loading was pure root lodging, the trace of the panicle neck became a circle of which culm length is the radius. When it was a pure stem lodging, the trace of the panicle neck is an ellipse of which major axis is culm length and minor axis is 0.64* culm length. When both stem lodging and root lodging occurred in a natural setting, the partitioning of lodging can be calculated by a formula using eccentricity of an ellipse, S=e*100/0.768(S is the ratio of stem lodging in the whole lodging, e is eccentricity of the ellipse). This method is expected to be useful in simple lodging partitioning. We could also calculate the partitioning of stem lodging and root lodging as units of angles as an accuracy method, by using a straight line calculated by differentiating a quadratic equation of stem deformation at the origin of the coordinates. These two methods for dividing root and stem lodging showed different values. However, each of them showed almost same values with different lodging degree in one plant.

Low temperature is one of the most severe abiotic stress factors limiting growth, productivity and distribution of winter cereals. Reliable field screening method, which can detect small differences in winter survival, is important for the effective selection and development of plants to identity superior cold tolerant winter cereal genotypes. This study was undertaken to provide improved screening method of winter hardiness in the field by increasing the accuracy in evaluating winter hardiness of barley (Hordeum vulgare L.). We introduced furrow in field screening of winter survival. By sowing the plants at the ridge and base, we could minimize the effect of topographic variation in a field by giving higher and lower level of stress at the same time. This method could be used by breeders to conduct accurate evaluation of winter hardiness by selecting the better treatment, which shows close to normal distribution, among the winter survival rate from the ridge, base and mean survival rate of the two in a screening field.

This study was carried out to select randomly amplified polymorphic DNA (RAPD) markers associated with grain weight of a large-grain mutant, Hyacp 39-26-1, derived from anther culture of a rice cultivar, 'Hwayeongbyeo'. The segregation mode for grain weight in an F2 population from a cross, 'Hwayeongbyeo/Hyacp 39-26-1', showed a nearly normal distribution. One hundred and ninety-one F2 plants ranged from 21.8 g to 34.7 g in 1,000-grain weight with a mean of 26.8 g. Five hundred and twenty primers were used to detect the RAPD markers associated with the grain weight of the large-grain mutant. Of these primers, 54 primers showed polymorphism between 'Hwayeongbyeo' and 'Hyacp 39-26-1'. Four RAPD markers (OPB18, OPH07, OPT20, and OPX20) were significantly related to the grain weight of twenty one F3 lines derived from the cross, 'Hwayeongbyeo/Hyacp 39-26-1'. This RAPD marker could facilitate the early and efficient selection of high-yield lines through improvement of grain weight in rice.