Induction of mutations for earliness in the soybean cultivar Paraná

Abstract

Mutation induction breeding through gamma ray seed treatment (22 krad) was used to obtain earliness in the soybean cultivar Paraná. Plants flowering earlier than Paraná were selected at the M3 generation. Eight mutant lines were isolated by further selections through several generations and tested in four yield trials carried out in 85/86 (Piracicaba) and 86/87 (Piracicaba, Sertãozinho and Assis) in São Paulo State. The following data were taken in these trials: number of days to flowering, yield, total plant height and height to pod insertion, flower color, pod pubescence and seed and plant growth type. Two of the mutants are of agronomic interest because they were, on average, seven to 10 days earlier in maturity than the control in all trials. Except for shorter plant height, the other agronomic characteristics remained unaltered.<br>Através da indução de mutações pelo tratamento de sementes com 22 krad de raios gama, objetivou-se a obtenção de mutantes precoces no cultivar de soja Paraná, que mantivessem inalteradas as outras características agronômicas. Foram selecionadas na geração M3 plantas com menor número de dias de florescimento que Paraná controle. Através de seleções posteriores e avanço de gerações, foram selecionados oito mutantes mais precoces que foram ensaiados no campo em quatro experimentos em 85/86 (Piracicaba) e 86/87 (Piracicaba, Sertãozinho e Assis). Nestes ensaios, foram anotados o número de dias para florescimento e maturação, produção, altura de plantas e inserção de vagem e observadas a cor da flor, vagem e pubescência e sementes e hábito de crescimento. Os resultados indicaram que, dentre os mutantes, dois deles apresentaram interesse por serem em média sete e 10 dias mais precoces na maturação do que o original em todos os experimentos, mantendo inalteradas, com exceção da altura de plantas que foi menor, as demais características agronômicas originais

Radiation as a tool to remove selective marker genes from transgenic soybean plants

“…This technique has been used to induce mutations and improve several seed propagated crops, including soybean (Maluszynski et al 1991, Tulmann-Neto and Alves 1997, Ahloowalia and Maluszynski 2001. The objective of the present study was to evaluate the effectiveness of γ-radiation to physically eliminate marker genes introduced into the soybean genome.…”

“…Results support the hypothesis that γ-radiation can be utilized to physically remove a specific gene (gus) from a transgenic soybean line, that contains other genomically integrated transgene. Reports have demonstrated that soybean seeds have been mutagenized with either ethyl methanesulphonate (EMS), γ-radiation or sodium azide (NaN 3 ) (Carroll et al 1986, Tulmann-Neto andAlves 1997). EMS is notably recognized as the most utilized and efficient agent in generating soybean non-sense mutant plants.…”