식물 육종은 변이를 확대하는 단계와 육종가가 원하는 유전자조합을 가진 계통을 선발하는 단계로 크게 나눌 수 있는데, 활용 가능한 유전자원 내에 육종가가 원하는 변이가 존재하는지의 여부가 육종의 성패를 좌우한다. 변이 집단을 만들기 위해 인공교배, 돌연변이 유기, 염색체 배가 등의 방법이 이용되어 왔다. 조직배양 기술이 확립되면서 체세포변이, 세포융합, 종속간교잡, 화분배양을 이용한 반수체육종 등의 방법도 품종육성 및 변이를 만드는 수단으로 이용되고 있다. 종간교잡은 Oryza, Brassica 속에서 널리 이용되었으며, IRRI에서 grassy stunt virus 병 저항성유전자를 Oryza nivara에서 도입하여 IR30 등 저항성품종을 육서한 것이 좋은 예다. 특히, 동형접합체 생산에 소요되는 기간을 단축시켜 내혼계의 육성에 소요되는 기간을 단축하는 반수체육종법이 큰 관심을 받고 있는데 옥수수 종자회사들이 최근 이 방법을 육종에 이용하고 있다. 가장 획기적인 방법은 교배가 불가능한 생물로부터 유용유전자를 분리해 교배과정을 거치지 않고 유용유전자를 도입하는 형질전환이다. 유전변이의 실체를 이해하기 위해서는 해결해야 할 과제가 많다. 중요한 것은 선발에 의해 육성된 고세대 계통들은 자연 상태의 유전자 pool보다 유전적 다양성이 결여되어 있다는 점이다. 작물 야생종이 보유하고 있는 유용한 유전자들이 순화와 육종가에 의한 선발 과정 동안에 도태되었으며 이러한 유전자들이 육종 연구에서 많이 이용되지 않은 유전자원에 내재되어 있다 (Tanksley and McCouch 1997). 콩도 순화 과정에서 약 81%의 희귀 유전자가 도태되었다 (Hyten et al. 2006). 그러므로 재래종과 야생근연종을 육종에서 적극적으로 활용하는 것이 매우 중요하다. 식물 육종에 이용 가능한 신기술이 개발되고 있다. 유전자 표적 기술로 게놈 내에서 특정유전자를 제거 혹은 대체하는 기술인 Zinc finger nuclease, TILLING (Targeting Induced Local Lesions in Genomes), RNAi 등의 활용 가능성이 검토되고 있다. 차세대 염기서열분석을 이용한 resequencing은 대상 식물의 표준 게놈과 실험 계통의 염기서열을 비교하여 염기서열변이와 표현형 변이 간의 연관성을 찾아내는 방법으로서 주로 염기서열 분석이 완료된 작물을 대상으로 시도되고 있다. 벼 기능유전체협의회는 20개 벼 품종의 염기서열을 분석한 결과 12개 염색체에 골고루 분포하는 250,000개의 SNP를 탐지하였다 (McNally et al. 2006). 유전체학은 육종가에게 새로운 도구를 제공하고 있는데 MAS가 대표적이다. MAS는 QTL의 탐지, 형질전환유전자의 이전, 야생종 유전자의 재배종으로 이입, 여러 유전자의 집적 그리고 연관지연의 감소 등 여러 분야에서 이용되고 있다. 새로운 육종기술은 경비가 적게 드는 방법을 요구하는데 대표적인 것이 Genome-wide selection이다 (Heffner et al. 2009). 기존의 분자표지를 이용한 육종은 DNA 표지와 목표 형질과의 연관 관계를 통계적 방법인 QTL 분석을 통해 밝히는 단계에서 시작한다. QTL 분석 결과 탐지된 유전자를 이입하고자 할 때 목표형질과 연관된 소수의 분자표지만을 이용하게 되는데 이는 식물 개량의 틀에서 볼　때 바람직하지 못한 면이 있다. 다수의 유전자가 관여하고 유전자간 상호작용이 있는 양적형질 특히 수량성을 목표로 할 경우가 대표적이다. Genome-wide selection은 목표형질과 연관을 보이는 몇몇 분자표지만을 이용하지 않고 육종 단계에 있는 모든 재료들의 유전자형을 검정하고 이들 중 일부 계통이 다음 단계로 넘어가 표현형 검정과 QTL 분석이 수행된다. 주동 및 미동 QTL을 고려하여 계산된 육종값에 근거하여 어느 계통을 다음 단계로 진전시킬 것인지를 결정한다. 표현형검정에 비해 유전자형 검정에 소요되는 비용이 저렴해지면 Genome-wide selection 기법은 보다 널리 이용될 것으로 전망된다. 전통적인 육종방법과 생명공학을 이용한 좋은 예가 내침수성 벼를 개발한 것이다. 아시아에서 침수는 연간 10억$의 경제적 손실을 가져오는데, 인디카벼에서 유래한 Sub 1A 유전자는 수량성에 영향이 없으면서 벼의 침수저항성을 증가시킨다. 국제벼연구소는 Sub 1A 유전자를 라오스, 방글라데시. 인디아 그리고 인도네시아 품종에 도입하여 침수저항성 벼를 개발 중에 있다. 육종은 어느 때보다 작물의 생산성 증가에 큰 역할을 할 것으로 기대된다. 기후 변화에 따라 육종의 목표도 다변화될 것이다. 유전체연구를 통해 얻어진 식물의 전염기서열 해독, 유전자발현, 유전자의 기능, 최종적으로 생합성경로에 관여하는 유전자들의 네트웤 등의 정보는 육종에 새로운 paradigm을 제공하여 준다. 이 모든 정보는 농업생산성의 근간이 되는 양적형질의 분석에 유용하게 이용될 것이다. 중요한 점은 이같은 대규모 유전자형 검정은 표현형이 정확하지 않을 경우 큰 의미가 없다 (Montes et al. 2007). 특히, 수량성 등 양적형질의 경우 정확한 표현형검정을 위해 적절한 실험설계, 충분히 큰 집단, 다년간 및 여러 장소에서의 반복 실험이 필요하다. 교배와 선발 등의 전통적인 기술, 분자표지와 염기서열 분석 등 신기술의 결합은 작물의 양적형질 변이에 대한 우리의 이해를 크게 증진시킬 것으로 기대한다. 이러한 연구는 육종가, 분자유전학자 등 여러 분야 전문가들의 공동연구가 절실히 요구되는 분야이며 각 전문분야의 강점을 최대한 살리는 방향으로 추진되어야 될 것이다.

Plant breeding is a multidisciplinary science of changing the genetic makeup of plants in order to generate desired traits or characteristics, and thus it can be accomplished through many different techniques ranging from simply selecting plants with desirable traits for propagation to more complex molecular techniques. Both conventional and genetically modified (GM) plant breeding alter or modify the genes of a plant so that a better variety is developed. Breeding using GM tools is achieved for the same reasons as conventional breeding. One prominent distinction is that instead of randomly mixing genes in conventional breeding, which occurs as a result of a sexual cross, a specific gene is directly transferred or selectively inactivated in the new plant variety through GM plant breeding. Site-specific mutagenesis and selection of gene knockout mutants are readily carried out in model plant species, such as Arabidopsis. However, targeted mutation of a specific gene is technically impractical, if not impossible, in most cases. As an alternative approach, RNA interference (RNAi), which is mediated by small interfering RNA (siRNA) and microRNA (miRNA), is routinely employed for targeted silencing of genes in academic and biotechnological studies. Recently, engineered nuclease-based genome editing tools, such as zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs), have been developed to induce site-specific genome modifications in both animals and plants. ZFNs are chimeric DNA restriction enzymes that consist of the nuclease domain of the Fok1 restriction enzyme, which triggers double strand breaks in genomic DNAs, and a custom-designed ZF DNA-binding domain, which guides the ZFNs to specific sequences within genomic DNAs. The double-strand breaks are rejoined by cellular DNA repair machinery, resulting in targeted mutagenesis or targeted gene replacement. In this work, we employed the ZFN tool to specifically inactivate two flowering genes, such as FCA and GI that also mediate high temperature responses and clock output signaling, respectively, in a bioenergy grass crop, Brachypodium distachyon. We designed extensive sets of ZF recognition sequences that recognize target sequences within the FCA and GI genes. The potential ZFN cassettes were transformed into Brachypodium ecotype Bd21-3. The transformants will be screened to identify those carrying targeted gene mutations. We will also discuss the extension of the ZFN tool to other plant species, including crops.

Plant breeding has at this moment two gene pools available: 1. plant breeders’ gene pool consisting of all crossable germplasm. All the genes from this source are available in classical plant breeding. Functional genes isolated from this natural source are called “cisgenes”; 2. a new gene pool consists of transgenes, which are chimeric and mostly partly or totally consisting of genes from non-crossable species, including bacteria, viruses, etc. When GM breeding started in the eighties of last century’ only transgenes belonging to the new gene pool were available. The complicated biosafety regulations, needed for this new gene pool, have been based on these so called transgenic traits but because of the transformation process accidentally they are also including cisgenes. In this way cisgenesis belongs to the expensive class of GM breeding which is only practiced by multinationals in the so called large crops such as maize, soybean and cotton. Reconstructed logic delivers several arguments against the classification of cisgenesis into the GMO class: 1. Cisgenes are already existing in nature and belong to the breeders gene pool, 2. It does not fit the definition of a GMO, 3. It is in practice classical breeding replacing existing introgression and translocation breeding with the advantage of absence of linkage drag, 4. The EFSA recently showed that cisgenesis is as safe as classical plant breeding, 5. Another EU committee on new techniques concluded in majority that a sequence of at least 20 bp is needed to come to a new combination which has to be classified as GMO. So, cisgenic plants, mostly without insertion of borders, are not considered to be a GMO. A simple rule should be developed, including criterions, for defining true cisgenic plants. In this presentation, the creation of cisgenic, more durable, resistance of potato against potato late blight will be discussed. This is based on working simultaneously on the genetics of both potato and Phytophthora infestance and on stacking of broad spectrum R-genes. Isolation and use of over 20 R-genes and more than seven Avr-genes will be described and the use of them to come to functional stacking of at least three R-genes. Another important issue is, because of absence of cisgenic selection markers, the setup of a marker free transformation system. Cisgenesis is the most effective way to improve in one step worldwide frequently used free potato varieties, which are highly susceptible to late blight. If needed additional broad spectrum R-genes can be added later by re-transformation.

Reverse breeding is a new plant breeding strategy based on crossover suppression during meiosis. This brings forth unprecedented possibilities like the almost instantaneous generation of homozygous parents for a chosen heterozygote. As a proof of concept, an Arabidopsis (Columbia-Landsberg) heterozygote was created that carried a RNAi:DMC1 construct stopping crossover formation. Gametes of this heterozygote were grown directly into doubled haploid offspring. These offspring show different combinations of (non-recombinant) Columbia and Landsberg chromosomes. Among these doubled haploids we retrieved the original Columbia parent and a complete set of chromosome substitution lines. From among these we could easily select two so called “complementing DHs” from which the Col-Ler hybrid could be re-created. Essentially, breeders can now bring single choice uncharacterized heterozygotes into a hybrid breeding program by creating parental lines for them. Reverse breeding superficially resembles apomixis (clonal reproduction through seeds) since both allow the preservation of heterozygous genotypes. Reverse breeding, however, has very different uses because it generates homozygous breeding lines. It thus allows for the improvement of the starting heterozygote because new traits can be introgressed into its newly produced parental lines. Reverse breeding is thought to be suitable for crops with smaller chromosome numbers (x ≤ 12). It will be discussed how reverse breeding could be developed for such crops, and it will be shown how reverse breeding presents very interesting new possibilities studying epistasis and heterosis through chromosome substitution lines. Further experiments with reverse breeding lines allow testing of a variety of intriguing breeding questions like to what extent a (heterozygous) genome actually determines a plants phenotype.

In a model plant species Arabidopsis, one of key determinants for flowering time is a MADS-box floral repressor, FLOWERING LOCUS C (FLC). FLC is silenced after a sufficient period of winter cold has been perceived (known as vernalization response). The lack of FLC expression allows plants to achieve the competence to flower in spring through the activation of floral integrator genes. Previous studies revealed that repression of FLC by vernalization is achieved in part by an evolutionarily conserved chromatin modifying complex, Polycomb repressive complex 2 (PRC2). In Arabidopsis, PRC2 (which contains CLF, an E(z) homolog, a H3K27 methyltransferase) is recruited to FLC chromatin upon vernalizing cold and mediates methylations at Histone H3 Lys 27 (H3K27me3), a repressive histone modification mark. Recent reports identified a plethora of long and/or short noncoding RNAs (ncRNAs), which contribute to the recruitment of PRC2 to its target chromatins. In vernlaization, a long noncoding RNAs (lncRNA), named as COLDAIR, was shown to mediate FLC silencing by vernalization. COLDAIR lncRNA binds directly to CLF, a PRC2 component, and is necessary for increased enrichment of PRC2 at FLC chromatin by vernalization. In addition, we have identified additional noncoding RNAs that are involved in various developmental processes in plants. Using the FLC regulation as a model, I will discuss our current understandings on epigenetic FLC silencing by protein and noncoding RNA components. As an alternative model system, we also have studied maize endosperm development to dissect epigenetic mechanism governing its developmental processes. I will briefly discuss our progress on the understanding of maize endosperm development as well.

As genotyping is becoming more of a commodity, the bottleneck in functional marker development is more and more shifted towards phenotyping. For this reason we invested in building a Crop Phenome Center at the KeyGene Wageningen facility at which we investigated various approaches for phenotype quality improvements. The KeyGene Crop Phenome Center focuses on a robust phenotyping platform in a greenhouse setup (PhenoFab) that allows for digital phenotyping as an approach to acquire more precise phenotypic data. The phenotyping is based on imaging technology and uses the potential of a track that moves all plants fully automated through the greenhouse compartment and scanning areas. The plants grow in individual containers and are photographed at pre-set points in time and from different angles. This approach was validated in various projects with diverse sets of crop plants and on both plant and root development. Data and conclusions of these experiments will be presented.

The world is facing a serious food and energy crisis. Plant mutation breeding has played an important role in overcoming this crisis and maintaining world stability. New techniques are required to achieve faster and more effective breeding. At RIKEN, we have developed a unique technology for mutation induction by using heavy-ion beams from particle accelerators at the RI Beam Factory. This development was achieved through an efficient synergistic link between agricultural science and accelerator physics. The use of ion beams for mutagenesis has a number of advantages: the approach has low exposure levels and high survival rates with high mutation rates, and it creates a wide variety of different mutations. Because heavy-ion beams provide a very high amount of energy, even a single ion is enough to significantly damage a gene – in fact, the beams have enough energy to break the double strand of the DNA. The technique is also very useful in producing mutants that lack just a single gene; multiple propagation technology can be used to convert these mutants into new cultivars. Examples of such breeds include ‘Safinia Rose’ (petunia), ‘Temari Bright Pink’ (vervena) and ‘Olivia Pure White’ (dianthus). The development period for producing new varieties is only 2 years. Over last decade, molecular biology has made great advancements through technological innovation. We use high-throughput DNA sequencing techniques such as next-generation sequence instruments and microarray technologies for analysis of gene mutations. Mutants have become more and more useful and important in modern genetic studies, enabling the discovery of genes that control important traits, and revealing the functions and mechanisms underlying their operations. The discovery of genes using mutants may lead to the emergence of a new field in biology, ‘Mutagenomics’.

The plant cell wall is an extracellular matrix, which can be viewed as a multifunctional subcellular compartment involving many fields of research: growth and development, plant-pathogen interactions, stress, cell-to-cell signaling, metabolic processes, biomaterials and biofuels, and many others. Given its importance, much of the research effort has been directed toward investigating the plant cell walls containing plant cell wall proteins, which are essential constituents of plant cell walls and play essential roles in many biological processes, and yet there is still not a distinct repertoire of the plant cell wall proteins. Several functional screen procedures including a yeast secretion trap, an Agrobacterium-mediated transient expression assay and a subcellular localization study, have been recently optimised to confirm secretion and localization of an ever-growing list of plant cell wall proteins. These functional screen approaches collectively provide a powerful suite of means to identify and characterize a dynamic and complex plant cell wall proteome. Thus, the potential outcomes of plant cell wall functional genomics will enable plant breeding programs to develop new strategies for improvement of crop quality.

The advances in marker technologies over the last two decades and particularly in the past few years have been astounding. These advances have meant that the accuracy and speed of obtaining results has been increasing while costs have been decreasing. Among the marker types, Single Nucleotide Polymorphisms (SNPs) have not only been proven to be the most reliable and cost-effective markers available, they are also the most abundant in plants, which is why they are the most widely used for genotyping. SNPs have been used as tools for a large number of plant breeding applications including: marker assisted selection, marker assisted backcrossing, genome wide association, fingerprinting, quality control and protection of intellectual property. In cases in which little sequence data are available for a species of interest, transcriptome or genome sequencing have also proven valuable for the discovery of SNPs. In this presentation a number of practical examples will help to elucidate several of the high throughput genotyping tools available for the plant breeding community in order to make agronomically better crops for the future.

Global warming and climate changing nowadays are known as one of the most harmful factors concerning the yield of worldwide crop plants. To adapt with new challenges, a well-known strategy of plants is water-balance control. Aquaporins are a gene family of integral membrane proteins which play a central role in water transport regulation. By searching diverse databases, we expanded the number of rice aquaporin family from 33 to 37 genes. After that, the phylogenomic data integrating anatomical expression patterns consisting of 1150 affymetrix arrays and 209 Agilent 44K arrays, and stress responsible expression patterns were constructed and analyzed. The systemic overview of gene expression for rice aquaporin family is used to evaluate functional redundancy within this family and identify suitable target genes in response to water stress. Functional gene network mediated by water stress relating aquaporin genes also suggested a useful platform for further researches.

Peppers (Capsicum spp.) with pungent (chili, hot pepper) and non-pungent (sweet pepper, bell pepper, paprika, capsicum) fruits are important spice and vegetable crops worldwide, especially in many developing countries of Asia and Africa. Among the five cultivated species of the genus Capsicum, C. annuum L. var. annuum is the most widely cultivated; over the past 25 years, AVRDC – The World Vegetable Center has focused on improving this commonly grown species. Other domesticated species also have been used as resistance sources against biotic stresses in breeding programs to improve C. annuum (for example, C. chinense and C. baccatum resistant to anthracnose). The major focus of the Center’s pepper breeding activities has been to identify and use host plant resistance to many biotic stresses, including viral (Cucumber mosaic virus, Chili veinal mottle virus, Potato virus Y, Tomato mosaic virus, geminiviruses), fungal (Phytophthora wilt, anthracnose, mildews) and bacterial (bacterial wilt, bacterial spot) diseases. The Center disseminates seeds of improved lines to cooperators in developing countries (usually public and private sector breeders), who make use of the germplasm in various ways: (i) direct release of supplied breeding lines as varieties through national varietal release procedures, (ii) reselection among the supplied populations according to local trait preferences and subsequent release as new varieties, (iii) use of supplied materials (possibly after further selection) as parental lines in hybrid breeding, and (iv) use in crosses in breeding programs. Examples from these categories will be presented.

Is backcrossing a good strategy for improving elite lines for quantitative traits in general? Results reported here demonstrate the effectiveness of a backcrossing program for improving quantitatively inherited disease resistance traits, which are strongly influenced by the environment. Through backcross breeding, we were able to improve an important commercial inbred line, FR1064, for ear rot and fumonisin contamination resistance without significantly lowering its yield potential, even with the use of a donor line with poor agronomic potential. Following one generation of selection on advanced backcross-derived lines, gains were observed for the primary trait of interest in advanced inbred generations. Following two generations of selection, we improved potential performance for ear rot resistance and reduced fumonisin accumulation in the 19 selected lines without significantly affecting important agronomic characteristics such as plant height, ear height, or flowering time compared to the recurrent parent, FR1064. The 19 selected lines were also significantly more resistant to ear rot under inoculated conditions than the FR1064 topcross without exhibiting significant reductions in topcross grain yield or other agronomic traits. Several individual lines were identified that were not statistically different from GE440 for ear rot or fumonisin content as inbreds or from the GE440 topcross for ear rot. These lines exhibited topcross yields comparable to the FR1064 topcross, although they were not competitive with commercial check yields. Thus, from a practical standpoint, the backcrossing method was effective at improving quantitative disease resistance in an elite commercial line using an unadapted donor parent. We also genotyped selected lines at DNA markers linked to ear rot and fumonisin resistance quantitative trait loci (QTL) identified in the BC1 generation of this cross to determine which QTL demonstrated allele frequency shifts due to selection.

Tsw, a single dominant resistant gene against Tomato spotted wilt virus (TSWV), has been mapped on chromosome 10 in Capsicum. Previously found molecular markers linked to the Tsw gene are not transferable for all pepper breeding materials. To develop segregating populations for the Tsw, commercial F1 cultivar C. annuum ‘Telmo’ was self-pollinated. An F2 population was obtained from the self-pollination of F1 plants deriving from a cross between C. annuum ‘Special’ and C. chinense ‘PI152225’. Twelve additional molecular markers linked to the Tsw gene were developed using tomato and pepper genome sequence database. A tomato scaffold sequence of 7841 kb in size covering the corresponding region of the Tsw locus was identified based on the sequence of Tsw-linked marker. Analyzing the tomato scaffold sequence, two sequences of pepper scaffold and contig at down and up site of the Tsw locus, respectively, were located. Three SNP markers linked to the Tsw locus (HRM1, HRM2, and HRM3) were developed using the pepper scaffold sequence of 419 kb in size. All three markers showed 2 recombinants (1.0 cM) out of 198 individuals of F2 ‘Telmo’ population. When analyzing these SNP markers in an F2 population deriving from C. annuum ‘Special’ and C. chinense ‘PI152225’, we detected 5 recombinants (0.76 cM) out of 659 individuals. HRM4, a SNP marker linked to the Tsw gene, was developed with a 99 kb pepper contig sequence. It showed 7 recombinants (3.5 cM) out of 198 individuals of F2 ‘Telmo’ population. We found 5 recombinants (0.76 cM) out of 659 individuals when HRM4 was analyzed in F2 population derived from C. annuum ‘Special’ and C. chinense ‘PI152225’. To narrow down the molecular markers linked to the Tsw locus, four SNP markers, HRM5, HRM6, HRM7, and HRM8, were developed with the pepper scaffold sequence. All of them showed 5 recombinants (0.76 cM) out of 659 individuals of F2 ‘SP’ population. Four other SNP markers, HRM9, HRM10, HRM11, and HRM12, were developed using the pepper contig sequence. HRM9 showed 5 recombinants (0.76 cM), HRM10 showed 4 recombinants (0.61 cM), and HRM11 and HRM12 showed 3 recombinants (0.46 cM) out of 659 individuals of F2 ‘SP’ population. The SNP markers developed in this study will be useful for fine mapping of the Tsw gene and for developing cultivars which carry TSWV-resistance gene.

Soybean is desirable as a forage crop because of it has high protein and oil concentration. Wild soybean, a progenitor of cultivated soybean, has a softer stem and higher protein content in seed than cultivated soybean. There is little information on yield and forage quality for wild soybean and its derivatives. The objective of this study was to determine the forage yield and quality of wild soybeans and selected soybeans derived from a cross G. max ×G. soja. Forage yield and quality were assessed for three grain soybean cultivars, three wild soybeans and three selected lines from G. max×G. soja. Forage quality attributes such as crude protein (CP), crude fat (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), digestible dry matter (DDM), dry matter intake (DMI) and relative feed value (RFV) were determined at the R2, R4 and R6 developmental stages. Forage yield and CF were highest at stage R6 in G. max, G. soja and selected G. max×G. soja lines. CP content was similar between R2 and R4 but increased sharply after R4 and peaked at R6 in G. max and selected lines from G. soja×G. max. On the other hand, CP content was similar between R4 and R6 stage in wild soybeans. Generally, NDF and ADF were highest at stage R4 but decreased at stage R6. DDM, DMI, and RFV increased between R4 and R6. These results suggest that R6 was the optimal harvest stage to provide forage of highest quality and yield. A study was conducted in 2011 to evaluate forage yield and quality at stage R6 in 25 lines from PI483463 (G. soja)×Hutcheson (G. max) and four cultivated grain soybeans. Hutcheson had the highest forage yield with 24.7t/ha infresh weight (FW) among grain soybeans. Line W11 had the highest forage yield(25.7t/ha,FW) among G. soja×G. max selections and four other lines had similar forage yield compared to Hutcheson. Generally the 25 lines from this G. max×G. soja cross had thinner main stems and branches than cultivated soybeans. When the 25 lines were evaluated for their feed quality as per forage grade by AFGC, nine lines rated prime grade and all 25 lines were classified as forage Grade 1. Results of this study indicate crosses between wild and cultivated soybean show promise for improving soybean as a forage crop.

The early senescence mutant was isolated from the japonica rice Koshihikari through Ethyl-methane-sulfonate(EMS) mutagenesis. The early senescence phenotype was controlled by a single recessive nuclear gene, tentatively symbolized as es-k. Using phenotypic and molecular markers, we mapped the es-k locus to the long arm of chromosome 7 between STS markers 147-1 and 150-1, a physical region of 370-kb. The symptom of early senescence appeared even before heading, while appeared after heading in those of the wild-type rice during senescence. Early stage physiological characteristics of the es-k mutant was similar to that of the wild-type. However, after heading, es-k mutants started to exhibit a significant decrease in chlorophyll content, soluble protein content 10 days earlier compared to normal type. To characterize the interaction with the environment factors, experiments were carried out under controlled temperature and light conditions, respectively. The wild-type leaf color appeared normal irrespective of temperature treatment, while the leaf of es-k mutant appeared pale-green at the low temperature and dark-green at the high temperature. During dark-induced senescence, mutant did not show significant differences compared to normal type. The results show that es-k is sensitive to temperature but not to light.

Amylose content of rice endosperm is one of the determinants of rice eating quality. This study was conducted to elucidate the mode of inheritance of dull gene in Milyang262, tentatively designated as du7(t), and to identify the molecular marker for du7(t) to be employed in marker-assisted breeding and gene pyramiding. Genetic analysis was carried out on F2 population derived from a cross between Junam and Milyang262. The low amylose content of Milyang262 was indicated to be under single recessive control. Allelism tests were as well conducted by crossing Milyang262 with Baegjinju and Baegokchal, which harbor du1 and wx gene, respectively. du7(t) was demonstrated to be inherited independently to du1 and wx. F2 population of Baegokchal/Milyang262 was used for molecular mapping. Linkage analysis was conducted on a population consisted of 120 individuals by several SSR markers. Initial mapping indicated that du7(t) is located on the end of long arm of chromosome 6 between SSR marker RM20590 and RM3509. To fine map the gene, a bigger population and several additional markers were employed. du7(t) was further mapped to a 1.74 Mb region between two SSR markers (RM6926 and RM412). Furthermore, we indentified three SSR markers that co-segregated with du(t) i.e. RM6811, RM3765, and RM176.

Rice is the most important crop as the staple food and two priorities in rice production are high yield and good quality in Korea. Far more improvements in grain quality, especially eating quality are required to meet the demand of consumers in rice producing areas. In the study presented here, a recombinant inbred lines (RILs) population derived from a cross between a temperate japonica and a tropical japonica and its genetic linkage map were employed to locate the QTL locus underlying six parameters of RVA profiles. Out of six RVA profile parameters, two characteristics, breakdown viscosity (BDV) and setback viscosity (SBV) are more correlated to eating quality of cooled rice. A total of four QTLs for two RVA profile parameters were identified. Two QTLs, qBDV-6 and qBDV-9 for BDV were detected on chromosomes 6 and 9. These QTLs increased the BDV by 26.2 and 16.4 from Ilpumbyeo allele, respectively. A QTL, qBDV-6 in the interval RM540-RM587 of the wx gene on chromosome 6 was reacted as a major QTL which could explain 26.2% of the total phenotypic variation. A QTL, qBDV-9 in the interval RM5688-RM444 explained 7% of the total variation as a minor QTL. Two QTLs, qSBV-6 and qSBV-9 for SBV also identified at the same region with QTLs of BDV on chromosomes 6 and 9. A QTL, qSBV-6 in the interval of the wx gene on chromosome 6 could explain 24.4% of the total phenotypic variation. A QTL, qSBV-9 in the interval RM5688-RM444 explained 8.2% of the total variation. These QTL region on chromosomes 6 and 9 would be use as useful marker to select elite lines of good eating quality in early generations in japonica rice breeding.

Scientific studies have shown that essential fatty acidintake can have a dramatic impact on human health. Soybean [Glycine max(L.) Merr.] oil from current commercial cultivars typically containsaround 8%linolenic acid (18:3) known as omega-3 fatty acid. Omega-3 fatty acid plays an important role to prevent cardiovascular disease and cancer. Relatively high 18:3 content in seed oil is a trait of the wild soybean (Glycine soja Sieb. and Zucc.) ancestor of modern soybean cultivars. Wild soybean is native to Korean peninsula and recently thousands of wild soybeans collected by soybean researchers in Korea. The objective of this study were to determine the linolenic acid content for wild soybean collection and to determine the stability of linolenic acid content derived from wild soybean over environments. Fatty acid profile for 1,806 wild soybean accessions collected from South Korea was determined by GC. The range of linolenic acid was 7.3 to 23.7% with an average 15.6%. We developed a recombinant inbred population from a cross PI483463 (wild soybean with 15% 18:3) and Hutcheson (cultivar with 8% 18:3). Three RILs, RIL156, RIL159 and RIL166, with high linolenic acid content (over 14%), parents and Williams 82 as checks were grown in nine environments over 2008-2011. Results showed that the content of linolenic acid for the PI483463, Hutcheson, and Williams 82 ranged from 14.8 to 17.1, 8.5 to 9.7, and 6.9 to 8.4 % and averaged 15.4, 9.2 and 8.0%, respectively. However selected RILs 156, 159, and 166 ranged from 10.7 to 15.7, 14 to 15.8, and 14.8 to 15.8, and averaged 13.9, 14.9, and 15.2, respectively. Among the tested accessions, RIL166 was the most stable with the lowest range and CV, and had a relatively lower stability coefficient value than other genotypes. Genes related to high linolenic acid from wild soybean may be useful in developing higher linolenic acid soybean genotypes and would broaden the use of soybean in food applications to improve human nutrition and health.

A cDNA clone encoding CBL-interacting protein kinase 1 (CIPK1) was isolated from Chinese cabbage seedlings. The gene, BrCIPK1 consisted of 1,982 bp long with 216 bp of the 5’-untranslated region (UTR), 1,509 bp of the coding region and 257 bp of the 3’-UTR. It is highly conserved CBL-interacting module with absolutely conserved domain among the 15 amino acid NAF domain of the 15 related genes. Southern blot analysis showed a single copy number. BrCIPK1 gene was localized in the cytoplasm and peripheral region in the plant cell which is highly expressed in seedling of rice and in the shoot and pistil of Arabidopsis. Analyses of gene expression on Ubi-1::BrCIPK1 rice lines was differentially accumulated by cold, salinity and drought, indicating its biological roles in the multiple stress response pathways in plants. Further, the expression of BrCIPK1 is hijacked by rice calcineurin-B-like protein (OsCBL5). Moreover, mRNA expression of P5CS1, a gene responsible for proline biosynthesis is regulated by the BrCIPK1 during abiotic stresses resulting to improved accumulation of proline. The interaction of BrCIPK1 with OsCBL5 along with the regulation of P5CS1 explained the enhanced tolerance of transgenic rice. This gene could be used in the development of rice varieties with enhanced tolerance to abiotic stresses.

Spikelets per panicle is one of the most important trait associated with rice yield component. In this study, IL28, near isogenic line (NIL) developed by introgressing chromosomal segments from Moroberekan into Ilpumbyeo, showed significantly higher number of spikelets per panicle than the recurrent parent Ilpumbyeo. Quantitative trait locus (QTL) analysis in 243 F2 plants derived from a cross between IL28 and Ilpumbyeo, indicated that a QTL for spikelets per panicle, qspp6, located in the interval RM3430 – RM20580. The fact that QTLs for panicle length and secondary branch number were mapped in the same interval as that for qspp6 indicated that this locus was associated with panicle structure. To map the QTL more precisely, substitution mapping of qspp6 using F4 lines was conducted. As a result, substitution mapping with ten F4 lines further narrowed the interval containing qspp6 to about 429kb between marker RM20521 and RM20562 based on the japonica genome sequence. The locus, qspp6 is of particular interest because of its independence from undesirable height and flowering time. SSR markers tightly linked to the qspp6 will facilitate cloning of the gene underlying this QTL as well as marker assisted selection for variation in SPP in an applied breeding program.