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  • Author or Editor: Ki Taek Kim x
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To find fertile garlic clones to be used in the cross breeding program, 213 accessions were subjected to cytological study at meiosis I. Most accessions (185 clones) showed abnormal chromosome configurations of ring of four, six or eight, which are ascribed to single or multiple translocations. Two clones showed asynaptic behavior forming 16 univalents from zygotene to metaphase I, and 26 clones revealed regular chromosome paring of 8 bivalents.

Only six of 26 clones showing normal meiosis produced viable pollen grains, while the rest were male sterile. From the segregation of crosses between male sterile and fertile clones, the male sterility is presumed to be governed by single recessive gene.

Hybrid plants between the fertile clones appeared, in general, intermediate of the parents in field performance.

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This study was conducted to overcome the problems occurring in soil cultured Sandersonia, such as secondary tuber formation, tuber russeting, browning and surface cracking. For the tuber production, soilless culture medium compositions (peatmoss, perlite, cocopeat) and harvesting times [4, 6, 8, 10, and 12 weeks after flowering time (WAF)] were compared. The mother tubers were planted and grown in a plastic box (40 × 60 × 23 cm) under a PE film house with shading in summer season. The tuber number and weight were higher in peatmoss-based media of peatmoss, 1 peatmoss: 1 perlite, and 2 peatmoss: 1 perlite (by volume) than in the other media. Particularly, the plant height and the numbers of leaf and flower were also higher. The contents of total nitrogen and phosphorus in leaves were lower when the tubers were grown in perlite. Leaf area index per plant reached the maximum at 8 WAF and decreased thereafter. The optimal harvesting time for tuber production was 8-10 WAF.

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Self-incompatibility (SI) in Brassicaceae vegetables prevents self-pollination by recognizing self-pollens and rejecting them at the stigmatic surfaces. The S-haplotypes of 47 hybrid radish cultivars that are commercially available in Korea were classified and identified using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Twelve kinds of S-haplotypes were identified from the cultivars: S 1 , S 8 , S 11 , S 17 , S 18 , S 30, and S 31 haplotypes in class-I S-haplotype and S 4 , S 5 , S 13 , S 21, and S 26 haplotypes in class-II S-haplotypes. Even though the class-II S-haplotypes are supposed to exhibit weak and/or leaky SI activity, the class-II S-haplotypes showed the same allele frequency of class-I S-haplotypes in 38 fully classified commercial cultivars. The SI activity was examined using the pollen tube germination test, flower pollination test, and the seed set ratio analysis. The pollen tube test showed low correlation (R 2 = 0.13) with the flower pollination test, a conventional method. The results of seed set ratio analysis varied from 0% to 159%, and thus could distinguish the weak and strong SI activity clearly and showed high correlation with the flower pollination test (R 2 = 0.69). The seed set ratios of the cultivars possessing the class-I/class-I, class-I/class-II, and class-II/class-II genotypes were 0.6%, 17.4%, and 38.1%, respectively. Among the eight class-II/class-II cultivars, three cultivars showed strong SI activity. The SI activity of the S 4 S 17 , S 5 S 8, and S 4 S 26 genotypes varied among cultivars, but the S 1 S 17 , S 5 S 17, and S 8 S 26 genotypes showed constant strong, intermediate, and strong activity, respectively, among the cultivars. Results indicate that the SI activity of Brassicaceae vegetables depends not only on the S-haplotypes, but also on the genetic background of cultivars.

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Pear scab caused by Venturianashicolais one of the most important diseases of oriental pear. Breeding a variety resistant to scab can be improved through marker-assisted selection (MAS). Bulked segregant analysis (BSA) and amplified fragment length polymorphic (AFLP) analysis were performed to identify DNA markers linked to the scab-resistant gene (Vn) using a population from a cross between PS2-93-3-98 (resistant parent) and Yali (susceptible parent). A total of 480 EcoR I/MseI primer combinations were used to identify markers specific to PS2-93-3-98 and resistant pool. Three AFLP markers linked to Vn, E-AGT/M-CCA245, E-ATT/M-CCG300, and E-GGT/M-TCT225, were selected. Linkage analysis between the selected markers and Vn locus was conducted with 51 individual plants. The selected markers, E-AGT/M-CCA245, E-ATT/M-CCG300, and E-GGT/M-TCT225, were located at 3.9, 3.8, and 1.2 cm away from Vn, respectively. For practical application, we are currently converting selected markers to simple PCR-based markers. The markers could be used to increase selection efficiency in pear-breeding programs for scab resistance.

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