Induction of female 2n gametes and creation of tetraploids through sexual hybridization in cassava (Manihot esculenta)

In order to exploit the induced female 2n gametes for cassava (Manihot esculenta) breeding, a detailed histological observation of female gametogenesis was conducted to correlate with the morphological characteristics of inflorescences and female flower buds. The SC5 gynoecia at the stage of prophase I were selected for unreduced megaspores induction with 0.3 % colchicine and 1 % dimethyl sulfoxide-soaked cotton plugs for 2 days. The resulted female cyathia were artificially pollinated with ploidy-level mixed pollens of SC10. Out of 250 hybrid progenies, two plants which exhibited morphological variations were confirmed as sexual tetraploids by flow cytometry and chromosome counting. Our results demonstrated that induction of 2n gametes combined with hybridization can be an effective approach for sexual tetraploid production for cassava.