Inheritance was studied in natural variants of the soybean cultivar Paraná, developed under photoperiodic conditions ranging from 13 h 31 min day light, at sowing, to 14 h 23 min, 59 days afterwards. Results indicated that early flowering and maturity are controlled by a single dominant gene. Natural mutations that originated cultivars Paranagoiana and SS-1 occurred at the same locus of cultivar Paraná. It was not possible to determine if the recessive alleles of these mutant cultivars are different. The designation E 6 was proposed for the alleles determining earliness in cultivar Paraná, and e 6 for the gene determining late flowering and maturity in cultivars Paranagoiana and SS-1, until the individuality of the alleles of Paranagoiana and SS-1 is confirmed.

RESUMO -O objetivo deste trabalho foi verificar se as cultivares de soja lançadas após 1990 para o Estado do Rio Grande do Sul continham, nos grãos, teores de proteína e de óleo diferentes dos contidos nos grãos das cultivares em uso anteriormente a esse ano. Na safra de 1996/97, foi realizado um estudo envolvendo genótipos produzidos em três locais do Rio Grande do Sul. O teor de óleo foi determinado pelo método de Soxlet, e o de proteína, pelo método de Kjeldahl. A maior parte das cultivares lançadas entre 1991 e 1996 apresentou menor teor de proteína e maior teor de óleo do que as mais antigas. A utilização das cultivares União e Industrial como genitores deve ter contribuído para o menor teor de proteína apresentado pelas cultivares. As linhagens experimentais apresentaram teor de proteína tão elevado quanto o das cultivares em cultivo desde antes de 1990, o que pode ter sido causado pela mudança de genitores. As correlações fenotípicas indicaram que existe uma associação negativa significativa somente entre os teores de óleo e de proteína.Termos para indexação: Glycine max, correlação genética, composição química. OIL AND PROTEIN CONTENT IN SOYBEAN GENOTYPES DEVELOPED AFTER 1990ABSTRACT -The objective of this work was to investigate whether oil and protein contents of soybean cultivars released after 1990 for the State of Rio Grande do Sul, Brazil, differ from the contents found in cultivars in use before that year. A study was carried out in 1996/97 involving cultivars recommended at different periods, produced at three sites of that state. Oil content was determined by the Soxlet method, and protein content was determined by the Kjeldahl method. It was found that most cultivars released between 1991 and 1996 showed lower protein content and higher oil content than older cultivars. The use of the União and Industrial cultivars as parents should be one of the main reasons to the lower protein content in these cultivars. The change of parents provided a recuperation in the protein content of new lines up to the level found in the cultivars released before 1990. Phenotypical correlations indicated that there is a significant negative association between oil and protein contents only.

Termos para indexação: Glycine max, análise dialélica, componentes genéticos. GENETIC ASPECTS OF THE TIME TO FLOWERING IN NATURAL VARIANTS OF SOYBEANABSTRACT -The parents and F 2 generations of a diallel cross with soybean (Glycine max (L.) Merrill) cultivar Paraná and its natural variants Paranagoiana, SS-1, and Pirapó 78 were studied with the objective of expanding the available knowledge on the genetic mechanisms of the time to flowering in soybean. Data were obtained under field conditions with photoperiod varying from 13 hours and 31 minutes, at planting date, to a maximum of 14 hours and 23 minutes, 59 days afterwards. No presence of epistasis was found in trait determination. The main component of genetic variation was additive. The results showed that the delay in initial flowering was determined by recessive alleles. The alleles conditioning earliness were partially dominant. Broad and narrow sense heritabilities were 99.68% and 89.96%, respectively.The genetic information presented on the time to flowering, if evaluated jointly with the results obtained by other investigators, indicated that the type of inheritance is more dependent on the genotypes considered than on a specific photoperiodic band.

RESUMO Com o objetivo de avaliar o comportamento de cultivares de soja de diferentes ciclos, em semeaduras realizadas entre os dias 10 e 30 de dezembro, na região do Planalto Médio do Rio Grande do Sul, foram conduzidos em Cruz Alta, nos anos agrícolas de 1994/95 a 1997/98, e em Passo Fundo, nos anos de 1994/95 e 1997 /95 up to 1997/98, and Passo Fundo, in 1994/95 and 1997

BRS 66, oriunda do cruzamento BR 83-147 x FT-Abyara, é indicada para cultivo no Rio Grande do Sul. Na média de 21 ambientes no RS, no período de 1993/94 a 1995/96, essa cultivar apresentou rendimento médio de grãos de 2.883 kg/ha. Apresenta resistência ao cancro-da-haste, à podridão-parda-da-haste, à mancha-olho-de-rã, à raça 1 de Phytophthora sojae, à pústula-bacteriana e ao oídio. Tem flor branca, pubescência marrom, tegumento da semente amarelo-fosco, hilo marrom e tipo de crescimento determinado. É de ciclo médio e apresenta estatura da planta de média a alta, com boa resistência ao acamamento.