Induction and Characterization of Tetraploid Watermelon

摘要

Diploid watermelon lines weie treated with colchicine to develop tetraploid seed parents Seedlings of ten diploid lines were raised and injected twice with colchicine (02, 0.4, and 0.6%) for 3 consecutive days at emergence of true leaves Watermelon lines responded differently for colchicine concentrations but showed maximum mortality at 0 6% colchicine. The treated seedlings were evaluated on the basis of chloroplast count, DNA content and morphology. The chloroplast counts in each side of guard cells ranged 5-7 and 10-12 in diploids and tetraploids, respectively. Several plants characterized as tettaploids on the basis of chloroplast count did not prove theit tetraploidy on flow cytometric test. The efficacy of treatments indicated that 0.2% colchicine produced more polyploids However, the recovery of solid tetraploids varied 3 3 to 5 5% in different lines. Tetraploid plants yielded higher leaf area and male flower size than diploids Pollen morphology showed 3 and 4 colpi in diploids and tetraploids, respectively.