Resumo:O objetivo deste trabalho foi avaliar a resistência de genótipos de feijoeiro aos principais patógenos da cultura, bem como a adaptabilidade e a estabilidade de produção de grãos desses genótipos. Avaliaram-se 26 genótipos de feijoeiro quanto à resistência a Colletotrichum lindemuthianum, Fusarium oxysporum f. sp. phaseolie Xanthomonas axonopodis pv. phaseoli, por meio de inoculação, em laboratório, e em 19 ensaios de valor de cultivo e uso (VCU), em diferentes locais do Estado de São Paulo, nas safras das "águas", "seca" e "inverno", durante os anos agrícolas 2011, 2012 e 2013. Dezoito genótipos foram considerados resistentes: sete deles a C. lindemuthianum, sete a F. oxysporumf. sp. phaseolie quatro a X. axonopodispv. phaseoli. A reação de resistência aos patógenos está associada à estabilidade dos genótipos. Por meio das análises GGE biplot, foi possível identificar genótipos com adaptabilidade e estabilidade superiores às das testemunhas, nos dois grupos de tegumento avaliados, em todas as épocas de semeadura.

No abstract

Common bean (Phaseolus vulgaris L.) is frequently grown in weathered soils with low phosphorus (P) availability, and this is one of the main limitations on its production. This study aimed to assess 20 common bean genotypes in a hydroponic system to select the best P concentration for inducing nutritional deficiency and to classify the genotypes in terms of nutrient utilization efficiency. The concentrations of P applied were 8.00, 4.00, 2.00 and 0.05 mg L -1. At 21 days, in the plot subjected to an application of the most severe stress, the 0.05 mg L -1 dose of P, had smaller plant size and early leaf abscission was observed. The 4.00 mg L -1 dose of P was the most efficient in inducing stress for discrimination of cultivars in terms of efficiency of use of P. The following genotypes: IAPAR 81, Carioca Comum, IAC Carioca Tybatã, IAC Imperador and G 2333 stood out as being efficient and responsive to P, while the two cultivars DOR 364 and Jalo Precoce were the most inefficient and unresponsive.

This paper aimed at selecting parents to compose a common bean breeding program for drought tolerance. General and specific combining abilities were evaluated under controlled conditions, using drought tolerant parents (BAT 477 and SEA 5), elite cultivars developed at IAC (IAC Alvorada and IAC Carioca Tybatã) and their progenies obtained from a complete diallel, including the reciprocals. Sowing was done in soil following a randomized block design with three replications for both experiments, the control with irrigation and the drought stress experiment imposed from pre-flowering stage. Plants remained under drought stress for 30 days. Physiological and morphological traits as well as yield components and grain yield were evaluated, detecting additive and non-additive effects controlling these traits. The parents used in this study had contributed in different proportions in the crosses they participated in. Regarding the drought stress condition in the pre-flowering stage, the parents SEA 5 and IAC Alvorada presented greater positive effects for the general combining ability for the yield and weight of one thousand seeds, whereas the parent SEA 5 also showed a positive effect for the number of seeds per pod, suggesting the increase of these traits in the crosses they participated in. The hybrid combinations SEA 5 × IAC Alvorada showed a positive result for grain yield, related to the higher positive effect for specific combining ability and because they have as parents the cultivars which confer the best positive values for general combining ability.

Given the impact of climate issues and their direct influence on agricultural production, the aim of this study was to identify superior genotypes of dry edible common bean under water deficit. Thus, 30 common bean genotypes were evaluated under controlled greenhouse conditions in a randomized block experimental design with split plots and four replications; the plots consisted of the water treatments (irrigated and water deficit) and the split plots consisted of the genotypes. The results showed genetic variability among the accessions evaluated, and in spite of significant reduction in grain yield and stomatal conductance under water deficit, these two traits showed significant, positive correlation and are able to be applied in early selection of genotypes under this stress condition. Another important response was in relation to the genotypes SER-16, SEN 92, FT Paulistinha, Carioca Precoce, IAC Imperador, and SXB 410, which showed the best yield performances in the two water treatments applied. They can be widely used in breeding programs for development of new cultivars, especially aiming at drought tolerance.

The aim of this study was to evaluate twelve genotypes of common bean for intermittent drought stress and for root growth angle. The water deficit experiments were conducted in 2015 and 2016 in a randomized block experimental design with split plots and three replications. Two treatments were applied: an irrigated treatment and a water deficit treatment, in which irrigation was suspended in pre-flowering and remained suspended up to the time at which the matrix potential of the soil was measured to be near-199 kPa. At the maximum point of water deficit, physiological and morphological traits were evaluated, and at physiological maturity, the yield compounds and grain yield. To evaluate root growth angle in 2016, a growth pouch system was used in a randomized block design, with five replications.

Common bean is a highly important food in tropical regions, where most production occurs on small farms with limited use of technology and, consequently, greater vulnerability to abiotic stresses such as nutritional stress. Usually phosphorus (P) is the most limiting nutrient for crop growth in these regions. The aim of this study was to characterize the gene expression profiles of the genotypes of common bean IAC Imperador (P-responsive) and DOR 364 (P-unresponsive) under different P concentrations using RNA-seq transcriptome sequencing technology. Plants were grown hydroponically, with application of two P concentrations (4.00 mg L-1 restrictive level and 8.00 mg L-1 control level). Differential expression analyses, annotation, and functional classification were performed comparing genotypes within each P rate administered and comparing each genotype response to the different P levels. Considering differential expression analyses within genotypes, IAC Imperador exhibited 1538 up-regulated genes under P restriction and 1679 up-regulated genes in the control, while DOR 364 exhibited 13 up-regulated genes in the control and only 2 up-regulated genes under P restriction, strongly corroborating P-unresponsiveness of this genotype. Genes related to phosphorus restriction were identified among the differentially expressed genes, including transcription factors such as WRKY, ERF, and MYB families, phosphatase related genes such as pyrophosphatase, acid phosphatase, and purple acid phosphatase, and phosphate transporters. The enrichment test for the P restriction treatment showed 123 enriched gene ontologies (GO) for IAC Imperador, while DOR 364 enriched only 24. Also, the enriched GO correlated with P metabolism, compound metabolic processes containing phosphate, nucleoside phosphate binding, phosphorylation, and also response to stresses. Thus, this study proved to be informative to phosphorus limitation in common bean showing global changes at transcript level.

RESUMO.Com o advento da agricultura moderna, as sementes crioulas foram, em geral, substituídas por cultivares híbridos, com elevado potencial produtivo, porém mais dependentes de insumos e tecnologias intensivas. O objetivo deste trabalho foi avaliar variedades de milho crioulo, de forma a identificar materiais mais produtivos e que propiciem o processo sustentável no qual os próprios grãos possam ser utilizados como semente. Foram avaliadas 15 variedades de milho crioulo, tendo como testemunhas as cultivares comerciais BR 106 e IPR 114. Os experimentos foram conduzidos em Arapongas e Imbaú, Estado do Paraná, durante o ano agrícola de 2004/2005, sem a utilização de insumos externos. O delineamento utilizado foi o de blocos casualizados com quatro repetições. As parcelas foram constituídas por duas linhas de 4 m, espaçadas 90 cm entre linhas e com 20 plantas/linha. As variedades crioulas P-13, P-15 e P-05 demonstraram potencial produtivo elevado em sistemas de baixo nível tecnológico, dentro de cada local, assim como na média dos locais. As variedades P-19 e P-10 têm sua recomendação restrita à localidade de Imbaú, enquanto que P-16 e P-17 serão direcionadas para a localidade de Arapongas.Palavras-chave: Zea mays L., variedades locais, melhoramento. ABSTRACT. Evaluation of maize landrace cultivars under a low-tech system.With the advent of modern agriculture, landrace seeds were replaced by hybrid cultivars, which feature high grain yield potential -though more dependent on intensive technologies. The objective of this work was to evaluate maize landraces, in order to identify more productive materials that can lead a sustainable process in which the grains themselves in which can be used as seed. Fifteen maize varieties were evaluated, with commercial cultivars BR 106 and IPR 114 as controls. The experiments were carried out in Arapongas and Imbaú (Paraná State), during the 2004/2005 agricultural year, without external input. The design used was randomized blocks with four replications. The plots were two 4-m rows, spaced 90 cm apart, with 20 plants/row. The landrace varieties P-13, P-15 and P-05 showed high productive potential in low technological level systems, at each location, as well as in the average of both locales. The varieties P-19 and P-10 have their recommendation restricted to Imbaú, while P-16 and P-17 will be indicated for Arapongas.Key words: Zea mays L., landraces, breeding. IntroduçãoA agricultura familiar constituída por pequenos e médios agricultores representa a maioria dos produtores rurais no Brasil, sendo estes os maiores responsáveis pela produção de grande parte dos alimentos que abastecem a mesa dos brasileiros, como o feijão, arroz, milho, hortaliças, mandioca e pequenos animais.No entanto, a maior parte dos agricultores familiares brasileiros está localizada em regiões onde é empregado um baixo nível tecnológico e áreas de plantio com problemas que dificultam adequado manejo fitotécnico das culturas trabalhadas. Leite et al. (2004) citam que, dos solos em assentamentos rurais, some...