Resumo: A seleção e utilização de genótipos de soja com sementes de alta qualidade fisiológica é importante para possibilitar maior probabilidade de estabelecimento e sucesso da cultura em campo, e, consequentemente, alcançar altas produtividades. Objetivou-se neste trabalho avaliar o controle genético da qualidade fisiológica de sementes de soja a partir de um dialelo parcial. Seis cultivares de soja, previamente selecionadas, grupo 1 (CD 201, CA 115, MS 8400) e grupo 2 (CD 202, Syn 1263, Syn 1279), foram intercruzadas utilizando-se um esquema de dialelo parcial, gerando 24 tratamentos. Sementes dessas cultivares e destes cruzamentos foram avaliadas quanto à qualidade fisiológica das sementes a partir de testes de germinação, primeira contagem de germinação, envelhecimento acelerado, emergência e índice de velocidade de emergência de plântulas. Foram avaliados os teores de lignina nos tegumentos das sementes de soja. Foram analisados os efeitos da capacidade geral (CGC) e específica de combinação (CEC) e os efeitos recíprocos. Há efeito significativo dos genes aditivos e não aditivos para os caracteres de qualidade de sementes, e efeito pronunciado de recíprocos, o que sugere a presença do efeito materno. Não há correlação entre o teor de lignina e testes fisiológicos para os genótipos estudados.

Abstract: The selection of soybean genotypes with seeds of high physiological quality is key to increasing the likelihood of establishment and success in the field and thus reaping higher yields. The aim of this study was to evaluate the genetic control of the physiological quality of soybean seeds from a partial diallel cross. Six previously selected soybean cultivars, group 1 (CD 201, CA 115, MS 8400) and group 2 (CD 202, Syn 1263, Syn 1279), were intercrossed by a partial diallel cross, totalizing 24 treatments. Seeds from these cultivars and crosses were evaluated for seed physiological quality based on germination tests, first germination count, accelerated aging, seedlings emergence, and emergence speed index. The lignin content in the soybean seed coat was evaluated. The effects on general and specific combining ability and reciprocal effects were analyzed. There were significant additive and non-additive effects of the genes on the seed quality traits and pronounced effects on the reciprocal traits, which suggest the presence of a maternal effect. Lignin content was not correlated with the physiological test results in the studied genotypes.

Resumo O objetivo deste trabalho foi avaliar a reação de linhagens de feijoeiro (Phaseolus vulgaris) ao fungo Sclerotinia sclerotiorum, a agressividade dos isolados, e a herança de resistência ao mofo-branco, em duas condições ambientais. Os experimentos foram realizados em condições de campo e casa de vegetação. Em cada um deles, quatro isolados foram inoculados em 14 linhagens de feijoeiro-comum pelo método de inoculação “straw test” e a severidade nas plantas foi avaliada. Não se identificaram linhagens de feijão-comum com alto nível de resistência ao mofo-branco, e a maioria delas mostrou-se moderadamente resistente ao patógeno. Em geral, as cultivares BRS Campeiro, BRS Radiante, BRSMG Talismã e Ouro Negro destacam-se quanto à resistência. Na condição de campo, o isolado UFLA 3 discrimina bem as linhagens, enquanto, na casa de vegetação, UFLA 26 e UFLA 92 são os isolados mais agressivos. Além disso, de acordo com o estudo genético, a maior parte da variação encontrada pode ser atribuída à resistência horizontal, embora uma pequena parte esteja associada à resistência vertical.

Abstract The objective of this work was to evaluate the reaction of common bean (Phaseolus vulgaris) lines to Sclerotinia sclerotiorum, the aggressiveness of the isolates, and the inheritance of resistance to white mold, under two environmental conditions. The experiments were carried out under field and greenhouse conditions. In each one, four isolates were inoculated in 14 common bean lines using the straw-test inoculation method and severity on plants. No common bean line with a high level of resistance to white mold was identified, and most of the lines were moderately resistant to the pathogen. In general, the BRS Campeiro, BRS Radiante, BRSMG Talismã, and Ouro Negro cultivars stand out for resistance. Under field conditions, the UFLA 3 isolate discriminates well the lines, while, under greenhouse conditions, UFLA 26 and UFLA 92 are the most aggressive isolates. Furthermore, according to the genetic study, most of the observed variation can be attributed to horizontal resistance, although a small part is associated with vertical resistance.

Abstract The objectives of this study were to estimate the genetic progress of mass selection for white mold resistance in common bean, evaluated in a greenhouse in cycle XII of recurrent selection (900 S0 plants), and compare it with field selection in previous cycles. In addition, progress was compared with microsatellite marker-assisted selection (MAS) among S0:1 progenies. The 79 most resistant S0:1 were evaluated under field conditions using a 9×9 simple lattice design; the 21 best S0:2 and those selected from cycles IX, X, and XI were evaluated in a 6×6 triple lattice. Genetic progress was 4.25% per cycle, and 12.17% between cycles XI and XII, showing higher selection efficiency in the greenhouse. The phenotypic gain and gain from assisted selection among the S0:1 progenies were 5.08 and 1.57%, respectively, and the low value of MAS was due to only two markers (BM189 and BMD20) explaining the resistance.

ABSTRACT White mold, caused by Sclerotinea sclerotiorum (Lib.) de Bary is one of the most important diseases of the common bean (Phaseolus vulgaris L.) worldwide. Physiological resistance and traits related to disease avoidance such as architecture contribute to field resistance. The aim of this study was to verify the efficiency of recurrent selection in physiological resistance to white mold, “Carioca” grain type and upright habit in common bean. Thirteen common bean lines with partial resistance to white mold were intercrossed by means of a circulant diallel table, and seven recurrent selection cycles were obtained. Of these cycles, progenies of the S0:1, S0:2 and S0:3 generations of cycles III, IV, V and VI were evaluated. The best (8 to 10) progenies of the seven cycles were also evaluated, in two experiments, one in the greenhouse and one in the field. Lattice and/or randomized block experimental designs were used. The traits evaluated were: resistance to white mold by the straw test method, growth habit and grain type. The most resistant progenies were selected based on the average score of resistance to white mold. Subsequently, they were evaluated with regard to grain type and growth habit. Recurrent selection allowed for genetic progress of about 11 % per year for white mold resistance and about 15 % per year for the plant architecture. There was no gain among cycles for grain type. Progeny selection and recurrent selection were efficient for obtaining progenies with a high level of resistance to white mold with “Carioca” grain type and upright habit.

Este estudo foi realizado com o objetivo de verificar a resistência ao mofo branco de progênies de feijão, provenientes de seleção recorrente para resistência à mancha angular. O material vegetal utilizado foi obtido de um programa de seleção recorrente, iniciado com o intercruzamento entre sete linhagens com grãos tipo carioca e dez fontes de resistência à mancha angular no esquema dialelo parcial. Para avaliação da resistência ao mofo branco, foi verificada a reação desses 17 genitores mais as 35 progênies obtidas, ao ácido oxálico. Foi observada uma ampla variabilidade nos genitores, indicando que alguns possuem alelos de resistência ao mofo branco e, assim, há possibilidade de associação desses alelos no programa de seleção recorrente e obtenção de progênies com níveis superiores de resistência. As progênies que se apresentaram como mais resistentes foram MAV-1.7, MAV-3.36, MAVI-21 e MAVI-60. Mesmo em ciclos iniciais, algumas progênies apresentaram nota média de reação ao mofo branco semelhante à da cultivar 'G-122', que apresenta bom nível de resistência a essa doença. Isso leva a inferir que a população original utilizada já possuía algum nível de resistência fisiológica para a reação à absorção ao ácido oxálico e também para a resistência à mancha angular. Assim, entre as progênies selecionadas para a resistência à mancha angular, tipo de grão e produtividade, pelo menos quatro apresentam nível de resistência ao mofo branco semelhante à fonte de resistência 'G-122'.

This study was realized with the objective of verifying the resistance to white mold of common bean progenies derived from recurrent selection for resistance to angular leaf spot. The plant material used was obtained from a program of recurrent selection, which was started by crossing seven lines with carioca grain type with ten sources of resistance to angular leaf spot according to the partial diallel scheme. To evaluate the resistance to white mold, it was verified the reaction of 17 parents plus 35 selected progenies, to oxalic acid. Huge heterogeneity among the parents was observed, showing that some of them have resistance alleles to white mold, and thus, there is a possibility of recombine these alleles through the recurrent selection and obtaining progenies with high levels of resistance. Even in initial cycles, some progenies exhibited resistance to white mold similar to the one of cultivar 'G-122', which presents good level of resistance to this disease. This leads to infer that the original population already had some level of physiological resistance for the reaction to absorption of oxalic acid, and also for resistance to angular leaf spot. Thus, among the selected progenies for resistance to angular leaf spot, grain type and high yield, at least four progenies have resistance to white mold similar to the source of resistance 'G-122'.

This study was carried out in order to verify whether natural selection acts on segregating common bean populations grown in the presence and absence of N, and to verify that natural selection affects the frequency of microsatellite alleles specifically, and in order to identify those that can assist in selection. Four populations from the crosses Ouro Negro x CI-107 and VC-5 x IAPAR-81 were carried forward in bulk to F8 at both levels of N. Ouro Negro and VC-5 are considered stress tolerant to nitrogen and IAPAR-81 and CI-107 responsive. One hundred progenies were obtained from each cross and grown in the presence and absence of N. DNA was extracted from 400 progenies, of which 194 were evaluated in the rainy season and 79 in the winter crop for grain yield. These progenies were evaluated in two separate experiments with and without N, in a 14 x 14 lattice design during rainy season and 9 x 9 in the winter season. We selected 35 pairs of polymorphic primers from the parents, with 20 being common from the two crosses. Using DNA of the 400 progenies, it was found that natural selection acted in 33 loci, in at least one environment and cross, and that alleles of the four parents were favoured by natural selection. QTLs were identified for the response rate of N and for grain yield and the linked markers are potential for assisted selection, especially the two most stable; BMD-20, in response to the use of N and PVBR-93 for grain yield.

Natural selection acts to select better adapted individuals or alleles in segregating population and help plant breeding. The objective of this work was to verify the effect of natural selection on microsatellite alleles as indicators of better adaptation and identification of quantitative trait loci (QTLs) for grain yield. This study evaluated 107 progenies from the F8 and 107 from the F24 generation derived from crossing Carioca MG and ESAL 686 lines, carried out by the bulk method, and evaluated in three different seasons: winter 2001; rainy 2001 and dry 2002. It was utilized 22 polymorphic markers and the natural selection acted in all of them. The frequency of the alleles of the parent Carioca MG, the most adapted, was increased in all of the 22 loci in F8 and 19 loci in F24. Selection affected each locus with different intensities in different generations. All of the selected alleles can be important for breeding program. QTLs were identified in generation F8 and F24 at varied magnitudes. The best marker PVttc002 explained 11.76% of variation in grain yield. However, an elevated interaction between QTLs and the environments was observed, showing the great difficulty in assisted selection.

Molecular markers may accelerate selection through the identification of plants with higher proportion of recurrent parent genome, as well as identifying those plants bearing target alleles like quantitative traits loci (QTLs) for white mold resistance. The objectives of this work were: 1) to employ microsatellite markers (SSR) in order to accelerate the recovery of recurrent parent genome 2) to validate sequence characterized amplified region (SCAR) Phs associated with a QTL that confers resistance to white mold, as previously identified in bean populations. Lines G122 and M20 were crossed, which generated 267 F1 plants from backcross (BC) BC1 and 113 plants from backcross BC2.SSR polymorphic markers were adopted. The relationship between BC plants and the recurrent parent was estimated based on the recurrent genome proportion (PR) in each BC plant, and the Sorensen-Dice genetic similarity (sg ir). To determine how much the phenotypic variation is explained by SCAR Phs, 56 F1:2BC1 progenies were evaluated on the field following a random block design with two replications through the straw test method. SSR markers are efficient in identifying individuals with a greater proportion of the recurrent genome. SCAR Phs was not efficient for the indirect selection of common beans for white mold resistance.

Objetivou-se neste trabalho, selecionar famílias de feijoeiro promissoras para a produtividade de grãos com tipo de grãos ideal utilizando informações fenotípicas e de marcadores moleculares ligados a QTLs. Foram utilizadas 100 famílias F3:7, avaliadas em três safras, com dois experimentos/safra, totalizando seis experimentos. A primeira safra foi a da seca/2007, na qual conduziu-se um experimento em Lavras-MG e o outro em Ijaci-MG. Nas safras de inverno/2007 e águas 2007/2008, foram conduzidos, em cada uma, um experimento em Lavras-MG e outro em Lambari-MG. Em todos eles foi utilizado o delineamento látice triplo 10x10, com parcelas de duas linhas de dois metros. As famílias foram avaliadas pela sua produtividade de grãos. Em apenas um dos experimentos de cada safra foi avaliado o tipo de grão. Os dados foram submetidos à análise de variância individual e conjunta, por local e por safra. 480 marcadores microssatélites foram testados para identificar polimorfismo entre os genitores. Os oito marcadores polimórficos identificados foram utilizados para a genotipagem das famílias. Entre esses, cinco explicaram parte da variação da produtividade de grãos. Os marcadores explicaram pequena porcentagem da variação fenotípica e apresentaram alta interação QTLs x ambientes. O ganho com a seleção fenotípica para produtividade de grãos foi de 7,4%, e de 9,6% para tipo de grãos, adotando a intensidade de seleção de 5%. A seleção assistida por marcadores foi equivalente à fenotípica para produtividade de grãos, porque apenas um marcador mais estável contribuiu para a seleção com base na média dos ambientes.

The objectives of this research were to select com mon bean families with high grain yield and ideal grain type using phenotypical information and molecular markers linked to the QTLs. One hundred F3:7 families were evaluated in three seasons, in two field experiments per season. Two experiments were set up in the counties of Lavras and Ijaci in the dry season/2007, other four experiments were set up in Lavras and Lambari, two in the winter season/2007 and two in the 2007/2008 rainy season. A 10x10 lattice design was used in all experiments, using 2m-long plots and rows 50cm apart. The families were evaluated based on grain yield in all experiments, and based on grain type in one experiment per season. Moreover, 480 microsatellite markers were tested in the parents. Eight markers were polymorphic and used for genotyping the families. Among them five explained part of the grain yield variability and presented high interaction by environments. Selecting 5% of the families the genetic gain was of 7,4% for grain yield and 9,6% for grain type. The marker-assisted selection gave a similar result to the phenotypic selection because only one more stable marker of the along with average grain yield was used in the selection.

A seleção precoce de clones que possuam níveis elevados de matéria seca e baixos teores de açúcares redutores é uma necessidade nos programas de melhoramento para a qualidade de processamento da batata (Solanum tuberosum L.) na forma de palitos fritos ou chips. A seleção precoce tornou-se possível com a utilização de marcadores genéticos, visto que permitem a identificação precisa de indivíduos superiores. Assim, procura-se cada vez mais encontrar marcadores capazes de caracterizar tais indivíduos e utilizá-los via seleção assistida. O objetivo deste trabalho foi avaliar a eficiência da seleção assistida, utilizando os marcadores identificados por ANDREU (2004) que estariam associados ao teor de matéria seca e açúcares redutores em tubérculos de batata. Clones provenientes de 20 famílias foram avaliados nas gerações de plântula (P), primeira geração clonal (C1) e segunda geração clonal (C2). As estimativas das correlações simples para os caracteres entre gerações foram significativas, porém, baixas, confirmando a inviabilidade de se efetuar a seleção precoce nas primeiras gerações com base apenas em informações fenotípicas. Os marcadores utilizados forneceram um total de 16 marcas. Pela regressão múltipla stepwise, apenas sete dessas marcas tiveram associação com os caracteres estudados. Além disso, nenhuma marca associada ao teor de matéria seca de tubérculos na geração C1 teve associação significativa na geração C2. Isso também foi observado com o teor de açúcares redutores, o que é um indicativo da interação QTLs x ambientes. A seleção assistida não se mostrou eficiente em relação à fenotípica em nenhum dos casos avaliados, portanto, não sendo útil em uma possível seleção precoce. Esses resultados indicam que tais marcadores não estão próximos aos genes controladores dos caracteres desejados, sendo necessária a identificação de novos marcadores mais associados que possibilitem maior eficiência da seleção assistida.

Early generation selection for clones with high content of tuber dry matter and low levels of reducing sugars is required for potato (Solanum tuberosum L.) processing. Selection of superior clones at early generations became possible with the deployment of genetic markers, and can precisely identify the superior individuals. Therefore, it is necessary to identify genetic markers closely linked to genes of interest to do assisted selection. The aim of this research was to evaluate the efficiency of marker assisted selection with genetic markers previously identified by ANDREU (2004), which are assumed to be associated with dry matter and reducing sugars content in potato tubers. Clones from 20 families were evaluated during the seedling generation (S), first clonal generation (C1) and second clonal generation (C2). The estimated coefficients of correlation for all traits among generations were significant, even though of low magnitude, confirming that selection at early generation based only on phenotypic traits is inviable. A total of sixteen bands were amplified using these markers. However, by multiple stepwise regression, only seven of these bands showed association with the evaluated traits. Moreover, no markers associated with dry matter and reducing sugars content in the C1 were significantly associated with these traits in the C2, suggesting the existence of QTLs x environment interactions. The marker assisted selection resulted less efficient than the phenotypic selection in all cases studied, and thus is not recommended for early generation selection of clones for the processing industry. These results suggest that the markers used are not closely linked to the genes controlling the traits most important for processing. Therefore, it is important to identify new markers closely linked with such traits of interest that could improve the efficiency of marker assisted selection.