Calibration of EMS treatment. Aliquots of 100 seeds were treated with 0, 1, 1.5, 2 and 2.5% EMS and sown in germination trays. Percent germination was recorded after 9 and 16 days, and seedlings exhibiting somatic mutations in the cotyledons, first and second true leaf were counted and expressed as percent of the fully germinated seedlings. Mutations included smaller or distorted cotyledons or leaves, as well as dark–light leaf patterns. Standard errors of the percentage of the final germination or mutated seedlings rates was computed as 100× [b × (1-b)/n]0.5, where b is the proportion of a given class, and n – the total number of plants .