EVALUATION OF GENETIC VARIABILITY FOR HEADING DATE AND HEIGHT IN TRITICALE OBTAINED BY INDUCED MUTATIONS AND ARTIFICIAL CROSSES

Abstract

The adjustment of adaptative characters such as heading date and height, allows one to arrange successive culturcs and to apply efficient agronomic techniques, resulting in productivity increase. Methods that increase genetic variability have great significance in plant breeding, once they amplify the opportunities for selecting superior genotypes. The aim of this study was to evaluate the effect of induced mutations and reciprocai crosses in families segregating for heading date and height and to analyze the correlation between these characters. The populations were obtained from reciproca] crosses and induced mutation with gamma radiation. In the latter, radiation dosages of 0, 5, 10, 20, 40 kR were obtained from exposition to Cobalt - 60. Changes in the mean and variance in two triticale genotypes Triticale BR4 e EMBRAPAI8, were analyzed. The results obtained indicated families with wide scgregation patterns for heading date and height and also suggested the possibility to identify families with distinct values compared to the control population for both characters and both genotypes. There was a tendency to reductions in height and increases in heading date for the families evaluated. However, there was not an expressive correlation between heading date and height for the majority of the treatments, therefore allowing the breeder to select plant types adapted to the enviroment of cultivation.