Those seeds that did not reach or pass this stage were assessed as failures (coded as 0). We tested whether medium, light condition, pretreatment duration and the interaction between these three factors, influenced the probability of success of reaching or passing the protocorm formation stage by using generalized linear models (Sileshi, 2012) with a binomial distribution function in R project epicalc package (version 3.1.1 R Development Core Team, 2011).