ABSTRACT. The type of stem growth in soybean is a distinguishing feature of cultivars. The genes Dt1 and Dt2 affect the termination of the stem, and the types of growth are classified as determinate, semideterminate and indeterminate. Phenotypic characterization of the type of growth is complex and is occasionally erroneously described. The objective of this study was to map and validate molecular markers to classify the type of soybean growth to facilitate the description of cultivars and genotypic selection. Two populations were used for mapping and validation of molecular markers F 2:3 : T 117 (semi-determinate growth type) x Igra RA 518 RR (indeterminate growth type) and CD 235RR (determinate growth type) x Igra RA 518 RR. The study demonstrates that the association of the molecular marker with the gene GmTFL1b was efficient in the classification of soybean growth types. The marker sat_064 is connected to the Dt2 gene, which is located in the Liaison Group G of the consensus map of soybeans with a recombination frequency of 19.4%. Molecular markers for Dt1 and Dt2 genes efficiently described the genotypes of soybean stem growth and selection.

The use of effective methodologies for the identification of more stable lines with wide adaptation is an indispensable tool in genetic improvement. Diverse methods of estimation are presently available, each one with specific features. This study evaluated the adaptability and stability of 21 soybean lines/cultivars grown in 78 environments in the southern and central regions of Brazil, between 2001 and2003, using four methodologies. In the stability analyses, the four methods led to the same results. In the analyses of adaptability, the methods Eberhart and Russel (1966) and of Cruz et al. (1989) presented basically the same results, though the latter presented additional information regarding the adaptability of lines to favorable and unfavorable environments. The analysis by the AMMI method led to the establishment of the models AMMI3 (Central Region) and AMMI4 (southern region), making the analysis of adaptability by biplots very complex. Six stable lines were identified in the central region and two in the South.

RESUMO O milho (Zea mays L.) é um dos cereais mais utilizados e relevantes, devido às suas propriedades nutricionais, composição química e diversidade de utilização, tanto na alimentação humana quanto animal. Com as constantes inovações no setor agropecuário, buscando-se uma melhor produção e redução de custos, surge um crescente interesse por prover alternativas que maximizem os resultados produtivos do setor. Nesse contexto, o objetivo deste experimento foi analisar os resultados e variações da cultura do milho, em relação ao seu desenvolvimento e produtividade, obtida em diferentes profundidades de plantio. O experimento foi implantado em condições de campo, utilizando o delineamento em blocos casualizados, constituídos de 4 tratamentos e 4 repetições, em 4 linhas, espaçadas a 0,55 metros entre linhas e 16 metros de comprimento, totalizando 35,2m² por parcela. Foram empregados quatro tratamentos: 1, 2, 3 e 4, definidos a 1 cm, 3 cm, 5 cm e 7 cm respectivamente. Foram avaliados os seguintes parâmetros: índice de velocidade de emergência, diâmetro de colmo, altura da planta e produtividade. Com este estudo, observouse que o índice de velocidade de emergência sofre influência da profundidade de semeadura, quanto menor, mais rápido a planta emerge. Em relação à produtividade, o resultado foi inverso ao IVE, ou seja, quanto maior a profundidade, melhor o índice produtivo da cultura analisada, ratificado pelo melhor índice de diâmetro do colmo, altura e produção. Palavras-chave: Cultura do milho; influência; profundidade; produção.

RESUMO. Foram analisados os efeitos da interação entre genótipos e ambientes (GxE) sobre a adaptabilidade e a estabilidade do rendimento de 9 linhagens elite de soja (Glycine max (L.) Merrill) e uma testemunha (IAS 5) ABSTRACT. Analysis of adaptability and stability in soybean elite lines. The effects of genotype x environment interaction (GxE) on the stability and adaptability of 9 soybean (Glycine max (L.) Merrill) elite lines and one control (IAS 5) were studied in 11 locations in the States of Paraná, Rio Grande do Sul, São Paulo and Mato Grosso do Sul, during the 2000/01 and 2001/02 crop seasons. A complete randomized block design, with three replications, was used in all environments. Significant differences for the effect of genotypes, environments and interaction GxE were observed for grain yield. Statistical models followed the standard method, ecovalence, Eberhart and Russel, Cruz, Torres and Vencovsky and AMMI methodologies. Genotypes CD 97-922 and CD 98-3118 were responsive under unfavorable environments. Lines CD 97-1243, OC 95-3006, OC 95(10)-3441 and IAS 5 showed a large adaptability and desirable stability, while OC 95-2806, CD 96-437, CD 97-945 and OC 95-3152 showed good adaptability but not high stability. In spite of the similarities detected among results obtained from different methodologies, every one gave its contribution to a better understanding of the observed GxE relationships.