Éder Matsuo

Análise da repetibilidade em alguns descritores morfológicos para soja

Studies involving additional descriptors has been important for soybean genetic improvement, so this study aimed to estimate the repeatability the length coefficient of hypocotyl, epicotyl, the internode between the unifoliated leaf nodes and the first trifoliate leaf, from the petiole and from the rachis of the first trifoliate leaf stage and determine the minimum number of evaluations needed to predict the real value of the genotypes. The study was conducted at the Universidade Federal de Vicosa, analyzing 85 soybean genotypes in four experiments in a completely randomized design. The numbers of necessary evaluations were calculated from the estimates of repeatability and coefficient of determination obtained by the methods of analysis of variance of the principal component and by the structural analysis. It was concluded that the lengths of the hypocotyl, epicotyl and the internode required fewer measurements compared with the length of the petiole and rachis to the same level of reliability, and with 15 measurements 85% of reliability was obtained for hypocotyl length by ANOVA and AE(correl) methods and 90% by CP(correl) and CP(cov) methods; 90% reliability was obtained for epicotyl and internode length by ANOVA, CP(correl), CP(cov) and AE(correl) method; 80% reliability was obtained for rachis length by ANOVA, CP(correl), CP(cov) and AE(correl) methods; and for petiole length, 21 measurements were needed for reliability by ANOVA and AE(correl) methods and 85% for CP(correl) and CP(cov) methods.

Genetic diversity in soybean genotypes with resistance to Heterodera glycines.

The purpose of this study was to analyze the genetic diversity among soybean genotypes inoculated with Heterodera glycines race 3. The experiments were conducted in a greenhouse. In two performance tests of morphological characteristics and resistance to the pathogen, 27 soybean genotypes were assessed. The coefficient of genotypic determination was estimated by the method of analysis of variance and the genetic diversity analyzed based on dendrograms and optimization method. The estimated coefficients of determination indicated a predominantly genetic origin of the genotypic differences in the traits. The genetic variability was maintained in the superior genotypes, which can be used in breeding programs for resistance to soybean cyst nematode.

Resistência de genótipos de soja ao herbicida glyphosate

Resistance of ten soybean genotypes (Glycine max) to the herbicide glyphosate was evaluated. The randomized block experimental design was used under factorial scheme 10 x 4 and four replicates. Factor A was composed of 10 soybean genotypes and factor B of four glyphosate doses. The herbicide was applied when the second trifoliate leaf of the soybean plants was completely developed. The following characters were evaluated: plant intoxication, number of nodes at the main stem, plant height and dry mass. When evaluating plant intoxication either at four days after application (DAA) of the herbicide and at 28 DAA, the conventional genotypes showed statistically higher averages, compared to the glyphosate-resistant genotypes (RR). In evaluations accomplished at 0 DAA or at 28 DAA under 0.0 g e.a. ha-1, the genotype responses were different for all characters under evaluation, except for the number of nodes at 28 DAA. These differences were attributed to the physiological and environmental effects or to the characteristics of the material itself. At other doses, the behavior of the RR genotypes was superior to that of the conventional ones. Taking into account all characters under evaluation, it can be stated that Valiosa RR, BCR945G110, BCR945G114, BCR892G132, BCR892G140, BCR1067G210, BCR1070G244 and M-SOY 8008RR behaved similarly for glyphosate resistance when subjected to doses up to 2.160 g e.a. ha-1 .

Resistance to Diseases

The soybean crop is the target of many diseases, caused by fungus, bacteria, virus, and nematodes. Those diseases can cause severe loses, depending on several factors such as biotype of the pathogen, variety, environmental conditions, and the interaction of those factors. In this chapter the many diseases occurring in soybean and the strategies and methods to develop resistant cultivars are discussed. Genetic resistance has been a relevant goal in many breeding programs around the world due to the benefits in the reduction agrochemical use and costs.

Breeding for Nematode Resistance

Nematode control is complex; therefore, the prevention of an initial phytonematode infestation in pathogen-free areas is of fundamental importance. However, after the entry of the nematode into an area, it is virtually impossible to eradicate because it is a soil-dwelling organism. In this respect, the genetic resistance of plants to nematodes is considered one of the most efficient and economically feasible methods to prevent production losses. Thus, breeding for nematode resistance is essential in crop management to obtain a high yield and stable production. This chapter contains discussions related to phytopathology, genetics, and breeding that are of great importance for the development of nematode-resistant cultivars.

Vegetative and Reproductive Morphology

Knowledge of the vegetative and reproductive morphology of soybean is important for cultivar development. The breeder should be able to distinguish each trait and understand the variation in the soybean germplasm before pursuing the goals in cultivar development. To efficiently select lines in a breeding program requires familiarity with the traits and the range of available variation. In this chapter the root system, stem, leaves, flower, fruit, and seeds of the soybean plant with breeding purpose in mind are addressed.

Glyphosate Formulations on Nutritional Condition and Productivity of Roundup Ready Soybean

ABSTRACT We evaluate the effect of different commercial formulations of glyphosate on the nutritional status of Roundup Ready soybeans (TMG 125). The experiment was conducted under field conditions for two agricultural years. The experimental design used was randomized blocks with four repetitions. The treatments were the implementation of Roundup Original, Trop, Roundup Ultra, Roundup WG, Roundup Transorb R and Zapp QI formulations, all at a dose of 720 g e.a. ha−1 of glyphosate and two controls (weeding and no weeding). There was no difference in the accumulation of macronutrients. In the second year of evaluation (2011/2012), manganese (Mn) accumulation was affected by the Trop formulations, Roundup Transorb, Zapp QI, Roundup Ultra, Roundup WG. To the accumulation of zinc (Zn), there was a reduction in the application of Trop formulations and Zapp QI. However, this reduction observed did not influence the response of plants in relation to the productive yield.

Avaliação de genótipos de soja em relação ao nematoide de cisto

Heterodera glycines is a phytonematode of economic importance in the soybean crop. Therefore, the objective was to compare methodologies for evaluation of soybean genotypes in relation to H. glycines. Two experiments were conducted (trials A and B) under greenhouse condition in a completely randomized design with six replications. In the trial A, ceramic pots of 0.8 dm3 and standard methodologies of inoculation and assessment were used. In the trial B, polyethylene pots filled with 0.5 dm3 infested soil and visual analysis were used. Promising genotypes obtained by different soybean genetic breeding programs were evaluated. Seventy four percent of the studied genotypes presented similar numbers of females in both trials. The correlation coefficient between the number of female in trial A and the number of female in trial B was 0.85 (p<0.01) and between the number of female in trial A and the visual rating of the number of females in trial B was 0.90 (p<0.01). The standard methodologies of inoculation and evaluation using infested soil and visual analysis were, in general, mutually consistent. Genotypes identified as resistant (UFVS 2010 and BCR1070G229) and moderately resistant (BCR132390, BCR945G114 and BCR1057G163) to the cyst nematode race 3 were found by the two methods of assessment.