배수성이 다른 만다린의 교잡에서 종자 형성과 3배체 후대 생성의 반응

Response of Mandarins to Seed Formation and Triploid Progeny Production in Interploid Crosses

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.