RAPD analysis of herbicide-resistant Brasilian rice lines produced via mutagenesis

Over the last two decades, mutational techniques have become one of the most important tools available to progressive rice- breeding programs. In a mutation-breeding program initiated in 1999 at the Instituto Agronômico of Campinas, SP, Brazil, a rice line, IAC103, was selected for mutational studies with gamma radiation and ethyl methyl sulfonate mutagenesis, with the aim of developing a herbicide-resistant crop. After mutagenesis, surviving plants were exposed to glufosinate to check for herbicide resistance, which was examined up to the second generation. A detailed RAPD analysis was made of the resistant plants. Eighty Operon technology primers were tested and 10 were selected for a detailed study of RAPD markers that could tag herbicide resistance genes. Resistant and susceptible lines produced variation in the RAPD patterns and certain bands were found only in certain lines. These results suggest genetic ligation that will be confirmed through a genetic segregation study

Induçäo e uso de mutante de hábito determinado e precoce em feijoeiro (Phaseolus vulgaris L.) / Induction and use of early and determinate growth habit mutant in common bean (Phaseolus vulgaris L.)

Na geraçao M2 proveniente do tratamento de sementes do cultivar de feijao (Phaseolus vulgaris L.) Carioca (hábito de crescimento indeterminado) com 32 krad de raios gama, foram selecionados dois mutantes de hábito de crescimento determinado e que apresentavam precocidade ao redor de nove dias na maturaçao em relaçao ao cultivar original. A análise genética efetuada com o mutante mais promissor (CAP-1070) revelou que a mutaçao para hábito determinado, foi de origem monogênica recessiva, observando-se que estava associada a precocidade. Após ensaio de produçao, o melhor mutante (CAP- 1070) foi multiplicado para plantio no Paraná. Tal mutante foi incluido em programa de cruzamento de "FT Pesquisa e Sementes", originando o cultivar FT-Paulistinha, recomendado para cultivo no Paraná a partir de 88/89. As características de CAP- 1070 e de FT-Paulistinha e aspectos de induçao de mutaçao no melhoramento do feijoeiro sao apresentadas e discutidas neste trabalho.