Abstract
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. Key words: Manihot esculenta Crantz, day after pollination (DAP), fruit set, seed size, embryo size, embryo rescue.
Highlights
Cassava (Manihot esculenta Crantz), a member of the Euphorbiaceae family, is a perennial vegetative propagated shrub widely planted in tropical and subtropical regions of the world
Embryo rescue demonstrates potential roles in cassava breeding: (1) rescue plantlets from the younger fruits when confronted with adverse climate (Uma et al, 2011); (2) rescue in vitro plantlets following interspecific hybridization (Clarke et al, 2011; Cisneros et al, 2013); (3) shorten the breeding cycle by recovering the plantlets from younger seeds, replace germinating the seeds harvested after breaking the dormancy (Kagithoju et al, 2013; Gbadamosi, 2013)
Parental genetic, phenological and physiological differences can contribute to variations in the in vitro responses of rescued embryos (Clarke et al, 2006). This is an important contribution to our understanding of cassava fruit, seed and embryo development of different genotypes and an improvement on previous protocols for embryo rescue in cassava (Fregene et al, 1999)
Summary
Cassava (Manihot esculenta Crantz), a member of the Euphorbiaceae family, is a perennial vegetative propagated shrub widely planted in tropical and subtropical regions of the world. Along with maize, sugarcane and rice, constitutes the most important sources of energy in the diet of most tropical countries of the world (Ceballos et al, 2004). It has played an important role in food security as a famine reserve crop historically, and become potentially highly resilient to future climate changes (Jarvis et al, 2012). This research was conducted to explore fruit, seed and embryo development of different cassava genotypes, and recover the plantlets from younger seeds This information is crucial for ongoing research to obtain doubled haploids through wide crosses with
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
