Selecting tropical wheat genotypes through combining ability analysis.

The selection of parents to originate promising base populations, as well as the knowledge of the gene effects controlling agronomic traits by means of diallel, are useful to drive genetic gains in Brazilian tropical wheat breeding programs. The goals of this study were to select tropical wheat parents with a high frequency of favorable alleles and segregating populations with high potential to originate superior progenies through partial diallel analysis. Thus, 14 parents were divided in two groups and crossed in a 7 × 7 partial diallel scheme to originate 49 F1 combinations. After obtaining F2 generation, the populations and the parents were evaluated in the field in the summer of 2021. Days for heading, plant height, rust and yellow spot resistance, and grain yield were evaluated. The data were subjected to partial diallel analysis. There were significant effects of general combining ability for all traits. The specific combining ability effect was significant for days for heading and plant height. The additive gene effects were predominant over the non-additive ones. The parents with the highest frequency of favorable alleles for the traits evaluated were selected in each group. Four populations with high genetic potential to originate superior progenies were selected.

Physiological responses of beet and cabbage plants exposed to copper and their potential insertion in human food chain.

Copper (Cu) can be toxic to vegetables when it is absorbed and accumulated at large concentrations, a fact that increases the risk of excessive addition of this metal to the human food chain. The aims of the current study are (1) to determine the Cu concentrations that have critical toxic effects on beet and cabbage plants, and the potential of these plants to enter the human food chain, as well as (2) to assess the physiological and biochemical responses of representatives of these vegetables grown in nutrient solution presenting increasing Cu concentrations. Beet and cabbage plants were grown for 75 days in pots filled with sand added with nutrient solution presenting six Cu concentrations: 0.00, 0.52, 1.02, 1.52, 2.02 and 2.52 mg Cu L-1. Dry matter yield and Cu accumulation in different plant organs were evaluated. Photosynthetic pigment contents, lipid peroxidation levels (TBARs), superoxide dismutase (SOD) and peroxidase (POD) activity and hydrogen peroxide (H2O2) concentrations in leaves were evaluated. Critical Cu concentrations that led to toxicity in plant organs such as beetroot and cabbage head, which are often found in human diets, corresponded to 1.43 mg Cu L-1 and 1.59 mg Cu L-1, respectively. High Cu concentrations in the nutrient solution have increased Cu concentrations and accumulation in plant tissues. This outcome justified the increased POD and SOD enzyme activity in the leaves of beet and cabbage plants, respectively, and was the cause of reduced plant growth in both crops. Cabbage plants presented higher tolerance to increased Cu levels in the growing environment than beet plants. However, it is necessary being careful at the time to consume both vegetables, when they are grown in Cu-enriched environments.

Combined selection in beans for cycle, plant architecture and grain yield / Seleção combinada em feijão para ciclo, arquitetura de planta e produtividade de grãos

The selection of common bean cultivars for high agronomic performance can be difficulty by genotype x environment interaction. The objectives of this work were to evaluate if common bean cultivars differ for cycle, plant architecture and grain yield in different growing seasons, and to select early, upright and highly grain yield common bean cultivars, by the use of selection index. For this, five experiments were conducted in the randomized blocks design, with three replicates. A total of 26 common bean cultivars were evaluated and the multiplicative index was used to select superior cultivars. A significant cultivar x season interaction for flowering, cycle, insertion of the first pod, insertion of the last pod, number of pods per plant and grain yield was observed. The common bean cultivars have early or semiearly cycle in rainy season and upright plant architecture. The cultivars Macanudo, BRS Campeiro, IAPAR 81, and IPR Juriti presented high grain yield in most growing seasons. The four superior common bean cultivars selected by the multiplicative index were BRS Campeiro, Macanudo, IPR Juriti, and Guapo Brilhante. The cultivars BRS Campeiro, Macanudo, and IPR Juriti presents earliness, upright plant architecture, and high grain yield and will be selected for the breeding program.

A seleção de cultivares de feijão com alto desempenho agronômico pode ser dificultada pela ocorrência de interação genótipo x ambiente. Os objetivos desse trabalho foram avaliar se cultivares de feijão diferem para ciclo, arquitetura de planta e produtividade de grãos em diferentes épocas de cultivo e selecionar cultivares de feijão precoces, eretas e altamente produtivas pelo uso de índice de seleção. Para tanto, cinco experimentos foram conduzidos em delineamento de blocos ao acaso, com três repetições. Um total de 26 cultivares de feijão foram avaliadas e o índice multiplicativo foi usado para selecionar cultivares superiores. Interação cultivar x época de cultivo significativa foi constatada para a floração, ciclo, inserção da primeira vagem, inserção da última vagem, número de vagens por planta e produtividade de grãos. As cultivares de feijão avaliadas possuem ciclo precoce ou semiprecoce no cultivo de safra e arquitetura de planta ereta. As cultivares Macanudo, BRS Campeiro, IAPAR 81 e IPR Juriti apresentaram alta produtividade de grãos na maioria das épocas avaliadas. As quatro melhores cultivares de feijão selecionadas pelo índice multiplicativo foram BRS Campeiro, Macanudo, IPR Juriti e Guapo Brilhante. As cultivares BRS Campeiro, Macanudo e IPR Juriti apresentam precocidade, arquitetura de planta ereta e alta produtividade de grãos, portanto serão selecionadas pelo programa de melhoramento.