Fruit, seed and embryo development of different cassava (Manihot esculenta Crantz) genotypes and embryo rescue

Fruit, seed and embryo developments of different cassava (Manihot esculenta Crantz) genotypes, as well as embryo rescue, were investigated. The fruits of three genotypes after uncontrolled open pollination presented the same progressive development with similar sizes at different stages. There are large differences in the fruit set as well as the embryo development between different genotypes. Days after pollination (DAP) was found not to be an adequate predictor of embryo size as their size ranged from almost invisible to 8.7 mm in length at 32 DAP even within the different locules of the same fruit. The ideal stage for embryo rescue in cassava was from 32 to 36 DAP, because at that stage most embryos are visible (> 0.7 mm); and their excision without injury is feasible. Also, in vitro germination of the cotyledonary embryos at that stage had a high success rate. A half Murashige and Skoog (MS) medium supplemented with 1.0 mg/l GA3, 2% sucrose and 0.2% gel rite proved to be adequate for embryo rescue.Keywords: Manihot esculenta Crantz, day after pollination (DAP), fruit set, seed size, embryo size, embryo rescueAfrican Journal of Biotechnology, Vol 13(14), 1524-152