The so-called chromosome doubling method uses a colchicine solution to stop the chromosomes in embryonic cells from splitting after duplication, so that the diploid chromosome complement (with 19 pairs and 38 individual chromosomes) can become a tetraploid chromosome complement (with 76 individual chromosomes). In this way, wild species once again can be crossbred with fertile cultivars.
而所謂的染色體倍加技術，是利用秋水仙素等藥劑，在胚胎細胞染色體複製後阻擋其分裂，於是原本的 2 倍體（19 對、38 條染色體）就能倍增為 4 倍體（76 條染色體），讓原生種能再一次和栽培種進行雜交。