Douglas André Mallmann Schmidt

Comparações entre medidas de dissimilaridade e estatísticas multivariadas como critérios no direcionamento de hibridações em aveia

Genetic dissimilarity measures are commonly used by plant breeders to identify different genotypes to get desired segregant populations. This study was proposed to establish the relationship between different multivariate techniques to estimate divergence. The experiment was performed during the growing season of 2001, where twelve oat cultivars were tested for seven agronomic traits, using the random blocks experimental design with four replications. Euclidian and Mahalanobis distances showed low correlation (0.529) and when used to build dendrograms did not show similar clustering. The graphic techniques analysis through principal components and canonical variables also showed distinct spreading patterns. However, in spite of the observed discrepancies among the methodology analyzed, it was possible to recognize dissimilar genotypes with high average that can be used with large success probability in selected artificial hybridizations in oats.

Dissimilaridade genética entre genótipos de aveia

Dezoito genotipos de aveia foram testados quanto a dissimilaridade genetica, com e sem o controle de molestias da parte aerea. As variaveis avaliadas foram rendimento de graos desaristados, peso de mil graos, peso do hectolitro, estatura de planta e dias da emergencia a floracao. Foram empregados analises por variaveis canonicas e tecnicas de agrupamento por meio dos metodos de otimizacao de Tocher e o metodo hierarquico do vizinho mais proximo, tendo como medida de dissimilaridade a distância generalizada de Mahalanobis. Pelos resultados, constatou-se significativa dissimilaridade genetica entre os genotipos, indicando a existencia de variabilidade para os caracteres avaliados. O metodo de Tocher e o metodo do vizinho mais proximo permitiram a separacao dos genotipos em grupos distintos, possibilitando a identificacao de futuros genitores que possam ser utilizados em cruzamentos artificiais que produzam progenies com maior heterose. Os caracteres que mais contribuiram para a dissimilaridade genetica foram o peso do hectolitro e a estatura de planta.

Aplicability of phenotypic and canonic correlations and path coefficients in the selection of oat genotypes

Indirect selection through traits of higher heritability and of case measurements can result in larger genetic progress compared to using direct selection. This work was performed with the following objectives: (1) to estimative the phenotypic correlations between individual plant grain yield and agronomic traits of importance in the selection of white oat (Avena sativa L.) genotypes; (2) to identify traits that have the higher direct and indirect effects on grain yield; (3) to determine the intensity of association between primary and secondary components of grain yield; and, (4) to evaluate the consistency of these estimates using five oat genotypes crossed in a diallel format. The number of panicles per plant (NPP) showed to be the trait highest correlated with individual plant grain yield (GY) both through single correlations and through direct effects on grain yields. For weight of a thousand grains (WTG) ´ GY, in most crosses there was no detected association, leading to possible troubles for breeders, since larger grains were not associated to higher yield, except for the crosses UPF16 ´ UFRGS17 and UFRGS17 ´ URPel95/015. The trait number of grains per plant (NGP) was directly correlated with GY in all crosses, although the direct effects estimates on GY were negative for the crosses UPF16 ´ UPF18, UPF16 ´ URPel95/015, UPF18 ´ UFRGS17 and UFRGS7 ´ URPel95/015, indicating that correlations are not the main causes altering GY, which could be explained, in the present work, by indirect effects via NPP and mainly via panicle weight (PW).

Variabilidade genética em trigos brasileiros a partir de caracteres componentes da qualidade industrial e produção de grãos

The breeding for wheat bread making quality represents a great opportunity to incorporate commercial value to agricultural products. Wheat has one of the best relationship between end product quality and farmer earnings. Genetic variability among 22 different genotypes based on bread making quality traits and grain yield and the degree of their association was assessed. This research was performed at Centro Agropecuario da Palma experimental field of Universidade Federal de Pelotas, Capao do Leao (RS), Brazil. The results indicated that it is likely the existence of genetic variability for the assessed traits. BRS 208, Rubi and Safira were the best genotypes for breeding programs aiming at high grain yield and bread making quality. Grain yield showed negative correlation with flour protein content. Thus, grain yield improvement can negatively affect protein content. However, the total protein content did not show a significant correlation with gluten strength, suggesting that the protein in the flour is not efficient for predicting bread making quality. Therefore, selection for grain yield can be performed without affecting bread making quality.

Caráter stay-green e produtividade de grãos em trigo

ABSTRACTSTAY-GREEN TRAIT AND WHEAT GRAIN YIELD The stay-green trait is one of the factors that can aid the breeder in obtaining higher yieldingplants due to a delay in leaf senescence, favouring grain filling. The objective of this study was to evaluatethe performance of different wheat lines with and without the stay-green trait and investigate if longergreen period; foster an increment of grain yield. The field experiment was conducted in randomizedcomplete block design with three replications in two crop years. Genetically superior lines facilitate thebenefits of the stay-green trait for grain yield. The stay-green trait promotes yield stability under differentenvironments.Key words: Triticum aestivum L., green permanence, plant breeding.( 1 ) Recebido para publicacao em 5 de dezembro de 2006 e aceito em 5 de julho de 2007.( 2 ) Departamento de Estudos Agrarios - Agronomia/Universidade Regional do Noroeste do Estado do Rio Grande do Sul (Unijui),98700-000 Ijui (RS). E-mail: jose.gonzales@unijui.edu.br(

Early generation selection strategy for yield and yield components in white oat

Several studies have searched for higher efficiency on plant selection in generations bearing high frequency of heterozygotes. This work aims to compare the response of direct selection for grain yield, indirect selection through average grain weight and combined selection for higher yield potential and average grain weight of oat plants (Avena sativa L.), using the honeycomb breeding method. These strategies were applied in the growing seasons of 2001 and 2002 in F3 and F4 populations, respectively, in the crosses UPF 18 CTC 5, OR 2 ´ UPF 7 and OR 2 ´ UPF 18. The ten best genetic combinations obtained for each cross and selection strategy were evaluated in greenhouse yield trials. Selection of plants with higher yield and average grain weight might be performed on early generations with high levels of heterozygosis. The direct selection for grain yield and indirect selection for average grain weight enabled to increase the average of characters under selection. However, genotypes obtained through direct selection presented lower average grain weight and those obtained through the indirect selection presented lower yield potential. Selection strategies must be run simultaneously to combine in only one genotype high yield potential and large grain weight, enabling maximum genetic gain for both characters.

FAEM Chiarasul: new white oat cultivar with high yield and grain-processing quality

The white oat cultivar FAEM Chiarasul was developed from a cross between UFRGS 17 and UFGS 10/ Coronado2/Cortez3/Pendek/ME 1563. It is characterized by reduced plant height, and high yield, grain quality and grain-processing quality.