A Study of Progenies of a Colchicine Treated F1 Hybrid of Zea mays L

Field studies of 140 F2 lines derived from colchicine treated plants of the maize single cross SD5 x SD7 were made to establish the possibility of duplicating the production of true-breeding homozygous variants as reported for sorghum. These 140 lines were compared with 60 nontreated F2 lines out of the same cross. The results obtained did not indicate differences between the treated and untreated material, either as entire classes or as individual lines, for these six phenotypic measurements: plant height, ear height, stalk diameter, ear length, ear diameter, and ear weight. Nor were differences in variability within individual treated progenies, or treated progenies as a class, established in comparison to the controls. No clear-cut evidence for the recovery of homozygous variants or inbred lines in one generation as a result of colchicine treatment of the single cross could be demonstrated. Some reasons for the differential performance of this single cross as compared to the sorghum variety Experimental 3 are given, and some suggestions are made with regard to the direction of further work