Mutation breeding for earliness in IAC-8 soybean cultivar

Abstract

Mutation breeding through ethyl methanesulphonate seed treatment (0.05 M) was conducted in order to obtain earliness in the soybean Glycine max cultivar IAC-8 in a way that the other plant characteristics remain unchanged. At the M2 generation, ten plants with less number of days to flowering than IAC-8, were selected. By further selections and advancing the generations, five mutant lines were selected and tested in four yield trials carried out in 85/86 (Piracicaba), 86/87 (Piracicaba, Sertãozinho and Assis) in São Paulo, Brazil. In these trials, the following data were noted: number of days to flowering and maturity, yield, total plant height and length to the first pod insertion, colour of flower, pod pubescence and seeds and type of plant growth. The results indicated that among the mutants, two of them (mutants numbers 2 and 9) were of interest because on the average of the four trials, showed earliness of seven to ten days in maturity in comparison with the original cultivar. With the exception of plant height, which was shorter than the control, these mutants maintained unchanged the other characteristics of the original cultivar IAC-8.