배추 순계통들에 대한 원원종 증식과 순도검정 = Foundation Seed Increase and Purity Check for Different Inbred Lines of Chinese Cabbage (Brassica rapa L.)

다국어 초록 (Multilingual Abstract)

This study was conducted to evaluate the role of foundation seeds and the process of increase in the number of foundation seeds, to set a systematic and reasonable standard for the management of the seeds. Six different inbred Chinese cabbage lines were developed using hybridization and pedigree breeding by the breeding team. The lines were adapted into different market segments, such as the spring, summer, and winter markets, and were developed as inbred lines with necessary characteristics for cultivation. By combining ability test scores, the breeder selected elite combinations and submitted the seeds of the parental inbred lines to the foundation seed team, to increase the number of foundation seeds.
SPF 2128 is the female line and SPM 2130 is the male line of the variety for the spring market. SUF 2126 is the female line and SUM 2132 is the male line of the variety for the summer market. WIF 1130 is the female line and WIM 1133 is the male line of the variety for the winter market. Bolting is an important trait for seed production. WIF 1130 and WIM 1133 were investigated as early bolting lines in the 6 inbred lines. Moreover, SRK class I and SRK class II markers were used to check for self-incompatibility in the 6 inbred lines. SPM 2130 and SUM 2132 showed positive results for SRK class I; thus, they were identified to have strong self-incompatibility. In addition, the seed set ratio, obtained by comparing bud pollination to open flower pollination, was the same for SPM 2130 and SUM 2132.
The results of the self–incompatibility tests can be used as important information on the lines for F1 seed production. After seed harvest, the foundation seeds were naturally dried and their moisture contents were measured to differentiate those that can be kept in storage. After the seeds were stored, they were tested for first germination and final germination, to certify that the foundation seeds were at the right level of germination. Another test was conducted to determine if the Chinese cabbages were infected with certain seed-borne diseases, such as black rot caused by Xanthomonas campestris pv. campestris and Xanthomonas leaf spot caused by Xanthomonas campestris pv. armoraciae. After confirming whether the seeds were infected or not, they were sanitized using hot water zinc and re-tested. After the seeds were confirmed to be free from diseases, the seed lots were stocked in the seed room. Through seed cleaning, malformed and viviparous seeds were eliminated, and thousand seed weight was measured to standardize the exact amount of foundation seeds needed to produce the required number of F1 seeds. The yield per plant was calculated for the 6 different inbred lines, to determine the number of transplanted plants when producing F1 hybrids.
The foundation seeds of the 6 inbred lines were vacuum-sealed to avoid contact with air and moisture and kept in isothermal–isohumidity controlled storage (13℃ and 30%, respectively) to slow down seed aging, for longer preservation. The ability of the stored seeds to germinate was tested every 3 years, and if the germination rate was less than 80%, then the number of foundation seeds was increased again to renew the seed lot. To confirm that there was no out-crossing with other inbred lines or mechanical seed-mixing during the processes, a PGO (purity grow-out) trial was conducted. On August 16, 2011, 150 seeds were sown into a plug tray and on September 7, 100 seedlings were transplanted into the field for the PGO trial. In the PGO trial, the plants were differentiated on the basis of the following categories: objectionable, highly objectionable, atypical, and degenerated; however, no objectionable or highly objectionable plants were found. All the tests were completed, and then the foundation seeds were collected. In addition, the foundation seeds were used to produce advanced breeder experimental seeds, stock seeds, and pre-commercial trial seeds for the development of new commercial varieties.
A few rules were established by the developers of the foundation seed team. First, foundation seeds will not act as cleansing agents for non-homogeneous lines. An atmosphere of open and easy communication will help the team to generate complete information on parent line characteristics, including seed producibility. Next, the foundation seed team needs to regularly assess the seeds.
Second, the foundation seeds should maintain all active germplasm sources, as well as non-active inbred lines, and this is ensured through regular updates on seed health, disease resistance claims, purity, germination, and vigor of the parent lines. Maintaining the genetic integrity of the parents throughout the life time of their progeny and updates on seed health specifications are also mandatory.
Third, all members must undergo yearly training on the procedures and systems of the company and learn to follow the standard packing and labeling that is discussed every 4 months for the packing procedures and quality requirements of the products. The foundation seed team also cooperates with the National Plant Quarantine Service and approves the commercialization of new hybrid varieties under certain conditions.
The ultimate goal is to produce high-quality foundation seeds. To make this a reality, crop specialists frequently visit and communicate with parent-line breeders. On the basis of the feedback from the breeders, team members must have a 3-year inventory for the annual species of established parent lines and a 6-year inventory for biennial species. All information collected by the company is trustworthy, and it used in developing foundation seeds for the establishment of parental lines. Standardized labeling and identification of all foundation seed inventory and utilization of all technological resources are needed to prevent the requirement for corrective action and to support the quality of each foundation seed lot.

목차 (Table of Contents)

• Ⅰ. 서 언 1
• Ⅱ. 연 구 사 5
• 1. 배추의 유래 및 재배특성 5
• 2. 육성된 배추 순계통(Inbred lines)의 특성 8
• 3. DNA 마커를 이용한 순도검정 및 SI 인자분석 8
• 4. 원원종 종자(Foundation seed) 증식 및 관리 10
• Ⅲ. 재료 및 방법 16
• 1. 배추 순계통 특성조사 16
• 2. DNA 마커를 이용한 배추 순계통의 순도검정 및 SI 인자분석 26
• 2.1. 배추 순계통의 게놈 DNA 추출 26
• 2.2. 중합효소반응 및 전기영동 27
• 2.3. SSR 마커 스크리닝 및 순도검정 27
• 2.4. PCR을 이용한 SI 인자분석 및 결실률 조사 38
• 3. 배추 순계통의 원원종 종자 증식 및 관리 39
• 3.1. 육묘 및 정식 39
• 3.2. 교배, 추대고 조사 및 화지정리 43
• 3.3. 수확, 종자수분함량 및 발아율 조사 44
• 3.4. 통계처리 46
• 3.5. 종자전염병 검정 및 종자관리 46
• Ⅳ. 결과 및 고찰 50
• 1. 배추 순계통 특성조사 50
• 2. DNA 마커를 이용한 배추 순계통의 순도검정 및 SI 인자분석 57
• 2.1. 배추 순계통의 게놈 DNA 추출 57
• 2.2. SSR 마커 스크리닝 및 순도검정 60
• 2.3. SRK 유전자를 이용한 SI 인자분석 및 결실률 조사 63
• 3. 배추 순계통의 원원종 종자 증식 및 관리 66
• 3.1. 육묘 및 정식 66
• 3.2. 교배, 추대고 조사 및 화지정리 67
• 3.3. 수확, 종자수분함량 및 발아율 조사 71
• 3.4. 종자전염병 검정 및 종자관리 75
• Ⅴ. 적 요 84
• Ⅵ. 인용문헌 87