Abstract This study aimed to investigate the presence of maternal effect on the inheritance of flax seed coat color. Direct and reciprocal crosses were performed between four yellow flax seed lines and two brown flax seed cultivars. F1 and F2 populations of direct and reciprocal crosses were evaluated for coat color. Four F2 populations were selected for analysis of coat color in the F3 generation. The phenotypic segregation pattern was assessed by the chi-square test. The nuclear genotype of the female parent influenced all F1, F2, and F3 populations. F1 and F2 seeds were always equal to the phenotype of the female parent. F3 populations had a 3:1 ratio of plants producing yellow and brown seeds. The maternal effect resulted from the transfer of gene products from maternal cytoplasm to offspring, with evidence of the effect of a single gene with a dominant allele for the yellow phenotype.

Abstract The objective of this work was to evaluate the performance and yield stability of yellow flax genotypes, as well as to identify the best ones for breeding. Nineteen lines and a local variety were cultivated in the 2018, 2019, and 2020 crop seasons in two environments (municipalities) in the state of Santa Catarina, Brazil. Number of capsules per plant, plant yield, grain yield, and final stand were determined. Data were analyzed across genotypes within each environment and across environments within genotypes. Genotype × environment interactions were evaluated by a joint analysis, in which stability and adaptability parameters were estimated. Correlations between final plant stand and yield components were also estimated. There is a high variability in the productive performance among genotypes. The genotype × environment interactions influenced plant traits. The effect of factors related to soil, climate, and population density on number of capsules and grain weight must be considered. The flax genotypes present high grain yield means in all environments. The analysis of stability and adaptability reveals that genotypes LINPG87 and LINPG88 stand out in productive performance and stability.

Resumo O objetivo deste trabalho foi avaliar o desempenho e a estabilidade produtiva de genótipos de linhaça amarela, bem como identificar os melhores para seleção. Dezenove linhagens e uma variedade local foram cultivadas nas safras de 2018, 2019 e 2020, em dois ambientes (munícipios) no estado de Santa Catarina, Brasil. Foram determinados número de cápsulas por planta, rendimento de plantas, rendimento de grãos e estande final. Os dados foram analisados entre genótipos dentro de cada ambiente e entre ambientes dentro dos genótipos. As interações genótipo × ambiente foram avaliadas por análise conjunta, em que foram estimados os parâmetros de estabilidade e adaptabilidade. Também foram estimadas as correlações entre o estande final de plantas e os componentes da produção. Há alta variabilidade no desempenho produtivo entre os genótipos. As interações genótipo × ambiente influenciaram as características das plantas. Deve-se considerar o efeito de fatores relacionados ao solo, ao clima e à densidade populacional sobre o número de cápsulas e o peso de grãos. Os genótipos de linho apresentam elevados rendimentos médios de grãos em todos os ambientes. A análise de estabilidade e adaptabilidade revela que os genótipos LINPG87 e LINPG88 se destacam em desempenho e estabilidade de produção.

ABSTRACT The photosynthetic metabolism is a key point to improve soybean yield. In this work, we demonstrated that radiation use by soybean plants can be improved, aiming to improve the grain yield in the lower canopy. The objective of this study was to observe whether the increase in solar radiation input in the canopy of soybean plants improves their yield performance. Three experiments were carried out during the 2017/2018 season. For each experiment, treatments consisted in the opening of one or two side rows of cultivation at the R2 and R5 stage of soybean plants (NA5909RR) until maturity, plus a control. Increase on solar radiation provided by the oppening of rows enhanced the yield potential in the nodes of the lower canopy, mainly when two rows were opened. The main benefits of increasing the radiation available throughout the canopy of soybean plants are observed in the number of pods and thousand-grain weight, demonstrating the importance of increasing the availability of assimilates in lower leaves. Interestingly, the benefits of the increase in solar interceptation were observed regardless of the yield potential of the area, which varied between 4.9 and 6.7 ton ha-1.

ABSTRACT. Heterosis has been one of the most studied phenomena since genetic studies were conceived. Knowledge of this phenomenon for the root distribution trait in beans (Phaseolus vulgaris L.) can favour the development of genotypes that are more tolerant to abiotic stresses. This study aimed to verify the occurrence of heterosis for the root distribution trait in hybrid F1 populations of common bean derived from crosses within and between gene groups. Thirty-six populations (six parents and 30 hybrids) were evaluated under field conditions in the agricultural years 2016/17 and 2017/18. The root distribution was assessed with the adapted Bohm method. The genotypes responded similarly to environmental changes (absence of an interaction). However, the root distribution differed significantly between the agricultural years. Comparisons between the mean of hybrids from crosses within each gene pool and the mean of parents did not reveal heterosis. The comparisons between gene groups showed significant differences only between BRS Embaixador x IPR Uirapuru, CBS 14 x IPR Uirapuru, and BAF 53 x IPR Uirapuru and the mean of parents. The absence of heterosis in the root trait can be explained by the degree of kinship between the gene groups, as well as some epistatic interactions.

ABSTRACT Genetic variability is essential for gains in breeding programs. The cyclic process of progeny recombination is a strategy to raise the chances of selecting better genotype combinations. The objective of this study was to identify superior progenies between common bean genes groups in first recurrent selection cycle for root system traits. Parents of the Andean and Middle American gene groups were hybridized in a complete diallel scheme. Thereafter, the parents and F1 and F2 populations were planted in the field. To establish the base population of recurrent selection (C0), seven segregating populations (F2) with superior performance for root system were selected and intercrossed, resulting in recombinant progenies (C1). To estimate the selection gain, the parents and C0 and C1 genotypes were compared with regard to the following variables: total root length (TRL, cm), projected root area (PRA, cm2), root volume (VOL, cm3) and number of root tips (RT). The difference between genotype combinations indicates the presence of genetic variability and effectiveness of recurrent selection. The mean genetic progress for root system-related traits was 12.9% (TRL), 12.6% (PRA), 12% (VOL) and 11.5% (RT) in the first recombination cycle. The mean phenotypic performance of seven of the C1 progenies exceeded that of their parents for all root system traits. These progenies are promising as base populations of the next selection cycle.

ABSTRACT This study was carried on evaluating effects of inoculation with Bacillus species and generations of genetically improved seeds on Pinus taeda growth in nursery conditions. Two experiments, based on distinct inoculation methods (sowing and post-emergence) were performed under a 3 x 2 factorial, completely randomized block design (3 levels of inoculation and 2 levels of genetic improvement of Pinus taeda). Plant height and diameter were measured at different stages along seedling development. At harvest, root volume, root fresh and dry mass, shoot fresh and dry mass and quality index were also estimated. Data were submitted to a two-way analysis of variance (p<0.05) and Tukey´s test was used to separate means (p<0.05). Data from experiment with inoculation at sowing showed that Bacillus amyloliquefaciens improved plant height (20%) and shoot dry mass (28%) of 2.0 generation seedlings compared to control plants. Regarding post-emergence inoculation, plants from 1.5 generation presented more pronounced effects of Bacillus amyloliquefaciens. Overall, inoculated seedlings were 9.8% taller and produced 60% more root dry mass than non-inoculated plants. Regardless of seedling generation, B. amyloliquefaciens increased Dickson Quality Index by 30%. These results suggest that each generation of genetically improved P. taeda has different growth responses to B. amyloliquefaciens. Methods of inoculation, combined with level of genetic improvement, must also be considered to obtain the best benefit to seedling development when using this rhizobacterium. Based on the current findings, inoculation with B. amyloliquefaciens should be incorporated as a silvicultural practice to improve growth of P. taeda under nursery conditions.

RESUMO Quando combinados distintos grupos gênicos por meio de hibridações, é necessário o conhecimento do tipo de ação gênica preponderante na expressão de um caráter. O entendimento dessa informação ampara melhoristas para a tomada de decisões nas etapas de condução e seleção de populações segregantes no decorrer do programa de melhoramento genético. Assim, o objetivo do trabalho foi determinar os efeitos da capacidade de combinação e ação gênica para a característica distribuição radicular dos grupos de feijão Andino e Mesoamericano. Seis genitores de feijão dos grupos andino e mesoamericano foram hibridados em esquema de dialelo completo, resultando em 30 híbridos F1. Os genitores e híbridos foram conduzidos a campo em delineamento látice simples. A característica alvo foi a distribuição das raízes, calculada como a quantidade relativa de raízes no solo superior. O efeito da capacidade geral de combinação foi significativamente maior em relação aos efeitos de capacidade específica de combinação (58%) e efeito recíproco (41%). As estimativas de combinações foram modificadas em função da ordem dos grupos gênicos utilizados. As combinações IPR Uirapuru x BAF53 (mesoamericano x andino), BAF53 x CBS14 (andino x andino) e CBS14 x IPR Uirapuru (andino x mesoamericano) foram as principais responsáveis por incrementar a média da característica distribuição radicular. No entanto, mesmo que realizando combinações entre grupos gênicos, a maior fração da variância genética foi relacionada a componentes aditivos (60%). Consequentemente, a ação gênica aditiva foi predominante na expressão do caráter distribuição radicular em feijão independente do grupo gênico utilizado.

ABSTRACT When different gene groups are combined by hybridization, the expression of predominant genes for a trait must be known. This understanding is fundamental to the decisions made by breeders in the stages of cultivation and selection of segregating populations during the breeding program. Thus, the objective of this study was to determine the effects of combining ability and gene action for the root distribution traits of the Andean and Mesoamerican common bean gene groups. Six common bean parents from the Andean and Mesoamerican groups were hybridized in a complete diallel mating scheme, resulting in 30 F1 hybrids. The parents and hybrids were planted in the field in a simple lattice design. The target trait was root distribution, calculated as the relative number of roots in the topsoil. The effect of the general combining ability was significantly higher than that of the specific combining ability (58%) and the reciprocal effect (41%). Particularly, the combination estimates were modified according to the order of the gene groups used. The combinations IPR Uirapuru x BAF53 (Mesoamerican x Andean), BAF53 x CBS14 (Andean x Andean), and CBS14 x IPR Uirapuru (Andean x Mesoamerican) mainly exhibited an increase in the mean root distribution. However, the highest fraction of genetic variance correlated with additive components (60%), even in crosses involving different gene groups. Consequently, the additive gene action was predominant in the expression of root distribution trait in common bean, irrespective of the gene group used.

RESUMO Dentre as doenças que afetam as lavouras de feijão está a antracnose, causada pelo fungo Colletotrichum lindemuthianum (Sacc. & Magnus), com ocorrência em todo o Brasil, acarretando perdas de até 100 % na produção de grãos. Cerca de 20 genes que conferem resistência a raças específicas do patógeno já foram descritos na literatura. Objetivou-se avaliar as variedades de feijoeiro dos estados de Santa Catarina e Paraná, no que diz respeito à resistência a antracnose, em duas safras. Além disso, duas cultivares comerciais foram utilizadas como controles: IPR Tangará, como suscetível; e BRS Campeiro, como moderadamente resistente. A maioria das variedades locais foi considerada resistente ou moderadamente resistente, sendo mais pronunciada a cultivar Amendoim, com grãos grandes e tegumento vermelho, evidenciando resistência em ambas as avaliações. A este respeito, a possibilidade de utilizá-las como fontes de resistência à antracnose pode ser considerada, pois, também, demonstram adaptabilidade às condições ambientais.

ABSTRACT Anthracnose is an important disease caused by the Colletotrichum lindemuthianum (Sacc. & Magnus) fungus in bean crops. It occurs throughout Brazil and may cause losses of up to 100 % in grain production. About 20 genes that confer resistance to specific races of the pathogen have already been described in the literature. This study aimed to evaluate bean varieties from the Brazilian states of Santa Catarina and Paraná, regarding the resistance to anthracnose, in two cropping seasons. In addition, two commercial cultivars were used as controls: IPR Tangará, as susceptible; and BRS Campeiro, as moderately resistant. The majority of the local varieties was considered resistant or moderately resistant, being more pronounced the Amendoim cultivar, with large grains and red tegument, evincing resistance in both evaluations. Regarding this, the possibility of using them as resistance sources to anthracnose may be considered, since they also show adaptability to the environmental conditions.