The common bean (Phaseolus vulgaris L.) is the world’s most important legume for human consumption. Anthracnose (ANT; Colletotrichum lindemuthianum) and angular leaf spot (ALS; Pseudocercospora griseola) are complex diseases that cause major yield losses in common bean. Depending on the cultivar and environmental conditions, anthracnose and angular leaf spot infections can reduce crop yield drastically. This study aimed to estimate linkage disequilibrium levels and identify quantitative resistance loci (QRL) controlling resistance to both ANT and ALS diseases of 180 accessions of common bean using genome-wide association analysis. A randomized complete block design with four replicates was performed for the ANT and ALS experiments, with four plants per genotype in each replicate. Association mapping analyses were performed for ANT and ALS using a mixed linear model approach implemented in TASSEL. A total of 17 and 11 significant statistically associations involving SSRs were detected for ANT and ALS resistance loci, respectively. Using SNPs, 21 and 17 significant statistically associations were obtained for ANT and angular ALS, respectively, providing more associations with this marker. The SSR-IAC167 and PvM95 markers, both located on chromosome Pv03, and the SNP scaffold00021_89379, were associated with both diseases. The other markers were distributed across the entire common bean genome, with chromosomes Pv03 and Pv08 showing the greatest number of loci associated with ANT resistance. The chromosome Pv04 was the most saturated one, with six markers associated with ALS resistance. The telomeric region of this chromosome showed four markers located between approximately 2.5 Mb and 4.4 Mb. Our results demonstrate the great potential of genome-wide association studies to identify QRLs related to ANT and ALS in common bean. The results indicate a quantitative and complex inheritance pattern for both diseases in common bean. Our findings will contribute to more effective screening of elite germplasm to find resistance alleles for marker-assisted selection in breeding programs.

BackgroundCommon bean (Phaseolus vulgaris L.) is the most important grain legume for human diet worldwide and the angular leaf spot (ALS) is one of the most devastating diseases of this crop, leading to yield losses as high as 80%. In an attempt to breed resistant cultivars, it is important to first understand the inheritance mode of resistance and to develop tools that could be used in assisted breeding. Therefore, the aim of this study was to identify quantitative trait loci (QTL) controlling resistance to ALS under natural infection conditions in the field and under inoculated conditions in the greenhouse.ResultsQTL analyses were made using phenotypic data from 346 recombinant inbreed lines from the IAC-UNA x CAL 143 cross, gathered in three experiments, two of which were conducted in the field in different seasons and one in the greenhouse. Joint composite interval mapping analysis of QTL x environment interaction was performed. In all, seven QTLs were mapped on five linkage groups. Most of them, with the exception of two, were significant in all experiments. Among these, ALS10.1DG,UC presented major effects (R2 between 16% - 22%). This QTL was found linked to the GATS11b marker of linkage group B10, which was consistently amplified across a set of common bean lines and was associated with the resistance. Four new QTLs were identified. Between them the ALS5.2 showed an important effect (9.4%) under inoculated conditions in the greenhouse. ALS4.2 was another major QTL, under natural infection in the field, explaining 10.8% of the variability for resistance reaction. The other QTLs showed minor effects on resistance.ConclusionsThe results indicated a quantitative inheritance pattern of ALS resistance in the common bean line CAL 143. QTL x environment interactions were observed. Moreover, the major QTL identified on linkage group B10 could be important for bean breeding, as it was stable in all the environments. Thereby, the GATS11b marker is a potential tool for marker assisted selection for ALS resistance.

Os objetivos do trabalho foram avaliar e indicar parâmetros de seleção para classificação de grãos de feijão que atendam as exigências do mercado consumidor. Foram instalados experimentos contendo 19 genótipos de feijoeiro em nove ambientes, no Estado de São Paulo. A produção de grãos foi estratificada em peneiras de classificação 10 (10/64" pol.) a 15 (15/64" pol.) e avaliada a produção relativa de grãos em peneiras 13 e 14, rendimento de peneira, massa de 1.000 grãos, tamanho de grãos e para os índices J=perfil e H=forma do grão. A produção relativa de grãos, rendimento de peneira, forma e perfil foram as características que apresentaram diferenças estatísticas significativas, indicando presença de variabilidade genética. Por meio da comparação dos resultados com testemunhas de feijoeiro já recomendadas para o setor produtivo, conclui-se que uma cultivar de feijoeiro deve apresentar alta massa de 1.000 grãos (251 a 300g), produção relativa de grãos em peneiras 13 e 14 com valores acima de sete, rendimento de peneira acima de 70,0% e também sementes elípticas e perfil semiachatado.

The performance of bean lines brought forth in breeding programs or of cultivars in use can be affected by environmental variability. The adaptability and stability of grain yield of 18 common bean cultivars and lines in 23 environments (combinations of seasons, years and locations) were evaluated in the State of São Paulo, Brazil. 'IAC-Carioca' and 'IAC-Carioca Eté' were used as standard cultivars for the carioca grain type, while 'FT-Nobre' and 'IAC-Una' represented the standard for black grains. The experiment was set up in a randomized complete block design with four replications and plots consisting of two, two central five meters rows flanked by border rows. Stability parameters were estimated by the methods Maximum Yield Deviations (MYD) and by the Additive Main Effects and Multiplicative Interaction Analysis (AMMI). For the identification of the most stable cultivars, the two methods led to consistent results, although by MYD the highest stability was always associated to the highest yield. 'MAC-733327' and 'LP 9637' were the most suitable cultivars and lines for the joint seasons, while 'LP 9637' and 'FT-Nobre' were the most suitable for the dry season. The MYD method combined a simple procedure, easiness of result interpretation, uniqueness of parameters, and association between stability and yield. On the other hand, the AMMI method simplified the identification of stable cultivars by visual inspection, also providing information on the environments. However, the complex nature which combines uni-and multivariate techniques hampers its widespread use in breeding programs.

ESTABILIDADE DE CULTIVARES E LINHAGENS DE FEIJOEIRO EM DIFERENTES AMBIENTES NO ESTADO DE SÃO PAULO ( 1 )SÉRGIO ABSTRACT STABILITY OF COMMON BEAN CULTIVARS AND LINES IN DIFFERENT ENVIRONMENTS IN THE STATE OF SÃO PAULOThe present study had the objective of a genotypic evaluation of common bean lines in the state of São Paulo. Genotypic values of the lines for each location and for the environment mean of all locations were predicted as well. Studies on the adaptability and stability of the predicted genotypic values were realized by the BLUP procedure. The cultivar Graúna and line GEN 96A31 presented an average superiority of 10% over the general mean of the 15 environments. These values were computed including the penalization of the lines for the instability across locations and simultaneously crediting the response capacity (adaptability) to improved environments, using intrinsic properties of the MHPRVG method (Harmonic mean of the relative performance of the genetic values). The methods MHPRVG, Lin & Binns and Annicchiarico selected the same lines. Moreover, the results provided by the method MHPRVG were in the same measurement scale of the evaluated trait and were directly interpreted as genetic values simultaneously, for yield, stability and adaptability.

RESUMONo procedimento de registro e muitas vezes de proteção de novo cultivar de feijão, certas exigên-cias de mercado têm de ser atendidas e, entre elas, tão importantes quanto à produtividade e à resistência a doenças, está a qualidade tecnológica do produto (grão) comercializado, que vai chegar ao consumidor final. Desse modo, em um programa de melhoramento, visando ao processo de aceitação do novo cultivar no comércio, deve-se observar a importância da seleção de genótipos que apresentem tanto o tempo de cocção reduzido, com tegumentos que não se partam durante o cozimento, como também a alta expansão volumétrica após o cozimento. O objetivo deste trabalho foi avaliar a qualidade tecnológica de dezenove genótipos de feijoeiro que compuseram os experimentos regionais (7 locais; 12 experimentos) para determinar o Valor de Cultivo e Uso (VCU), nas épocas da seca, de inverno e das águas em 2000, no Estado de São Paulo, bem como as diferenças entre os genótipos e as correlações existentes nos caracteres avaliados. As avaliações revelaram que as condições locais de obtenção dos grãos para análi-se de qualidade tecnológica influenciam nos resultados e na diferenciação entre os genótipos, indicando alta interação Genótipo x Ambiente. Também reportaram que os genótipos FT-Porto Real, IAPAR-80, PF902998, FT901909 e o GenC97-10 foram superiores aos padrões correspondentes quanto ao tempo de cocção. O uso de seleção precoce com base em correlações fenotípicas existentes entre os caracteres não é expressiva devido a sua baixa/média magnitude.Palavras-chave: feijão, tempo de cocção, variabilidade, expansão volumétrica, embebição em água. ABSTRACT COOKING QUALITY PARAMETERS OF COMMON BEAN GENOTYPES, SOWN IN DIFFERENT SEASONS AND LOCATIONSDuring the process of cultivar releasing and registration, several marketing requeriments, as important as yelding potential and disease resistance , should be taken into account in a bean breading program. These are related to the grain cooking quality and can determine the level of acceptance by the final consumer: a) reduced cooking time; b) stability of grain tegument during cooking; c) high volume expansion after cooking, and so on. The main aims of this research work has been to evaluate cooking quality of nineteen common bean genotypes, sown in seven experimental sites and three different growing seasons (summer, winter and dry periods) in the State of São Paulo, Brazil, as well as the possible correlation with agronomic characters. High and significant genotype x environment interactions have been detected as to cooking quality characters but correlation with agronomic characters ware of low values. Genotypes FT-Porto Real, IAPAR-80, PF 902998, FT 901909 and Gen C 97-10 have revealed statistically shorter cooking times as compared to control checks.

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