Seedlessness is the most important characteristic of citrus and one of its breeding purposes. Triploids are the most reliable way to secure seedlessness and can be developed through crosses between tetraploids and diploids or between diploids and diploids. We evaluated the characteristics of seed formation and recovery frequency of triploids in interploid crosses in this study. Normal seed formation was the highest (85.0%) in crosses of 2x×2x, followed by crosses 4x×2x and 2x×4x. Partially developed seeds were obtained at the highest rate (35.3%) from crosses of 4x×2x with 0.7 seeds per fruit, followed by 2x×2x and 2x×4x with 0.2 and 0.1 seeds per fruit, respectively. The number of undeveloped seeds per fruit was 1.1, 1.0, and 0.3 from the 4x×2x, 2x×4x, and 2x×2x crosses, respectively, and the lowest frequency was recorded in the 2x×2x cross. Diploid plants were mostly obtained in the 2x×2x cross (98.8%), while 73.0% triploids and 27.0% tetraploids were obtained with 4x×2x, and 14.3% diploids, 57.1% triploids, and 28.6% tetraploids were achieved with the 2x×4x cross. Diploid plants were mostly obtained from normal seeds, while ad triploid and tetraploid plants were mostly obtained from partially developed and undeveloped seeds. The results indicated that crosses of 4x×2x were the most efficient and that in vitro culture should be applied to rescue plants from partially developed and undeveloped seeds in triploid breeding programs.

Amphidiploid Brassica juncea (AABB, 2n=36) contains the synthesized genome of the diploid ancestors of Brassica rapa (AA, 2n=20) and Brassica nigra (BB, 2n=16), proven the ‘triangle of U’ model. Varieties of the B. juncea include vegetables, oilseed crops, and medicinal plants in South Asia, China, and other regions. ‘Dolsangat’, one of the cultivars of B. juncea is widely used as the main ingredient for ‘KatKimchi’, a kind of Korean traditional food Kimchi. To develop an efficient polyploidization protocol of B. juncea, we used twenty accessions. Among them, we could induce the amphidiploid plants with 0.23% in natural. A successful of polyploidization, it is essential of chromosome doubling regent treatment of B. juncea. At first, we tried to colchicine treatment in the embryo stage and it was very harmful to the embryo and could get few plants. The second, we made the regeneration plants from embryo to rooting phase and shocked them in 0.34% colchicine contained distilled water. We could induce amphidiploid plants with a success rate of 63.4%. Also, we surveyed glucosinolate content and JB1, Alsami, and JD6 showed high total contents. These plants will use for genetic materials for breeding, genetic and molecular studies.