GENETIC ASPECTS OF FINAL EMERGENCE AND RATE OF EMERGENCE

Germination is considered to be an escape of the embryo from restraints often involving maternal or part-maternal tissues. Previous conclusions indicating genetic control of variation in the efficiency of these processes is considered with further observations indicating the occurrence of genetic variation in species with slow or more rapidly germinating seeds. Variance in germination is seen as arising from the presence and variable efficiency of the restraints and embryos. It is proposed, as evidence has already shown, that selection could modify performance but there may be correlated responses which are harmful. The characters of seeds which cause variation are also those which are related to their protection both before and after release from their parent and also their sustenance before photosynthesis begins.