ABSTRACT. The objective of this study was to develop segregating wheat populations for resistance to gibberella through the introgression of synthetic wheat genes in traditional cultivars and to present the results using the backcross method. In addition, to evaluate these populations in F1RC2, agronomic aspects and type II and III resistance to Fusarium head blight (FHB). The cultivars BRS Guamirim and BRS 179 were used as male parents and three synthetic wheat cultivars (CIGM90.909, CIGM92.1666, and CIGM93.298) as female parents, both previously characterized for the reaction to FHB. Crossing and backcrossing methodological procedures were performed to provide adequate controlled conditions. The F1 (winter 2016), RC1 (summer 2016/2017), and RC2 (winter 2017) populations were developed through emasculation and pollination procedures. In the winter of 2018, segregating populations were evaluated in the field using a randomized block design. In the three generations developed in a greenhouse, it was observed that the best crossbreeding combinations, verified by the number of grains, were obtained with the male parent BRS 179. Under field conditions, all segregating populations were considered moderately susceptible and susceptible to type II resistance. In type III resistance, all segregating populations, except for CIGM90.909/BRS 179 and BRS 179, showed values above 50%. Thus, it was evident that the crossings performed with the male parent BRS 179 generated better resistance to the disease.

Resumo: O objetivo deste trabalho foi avaliar a resposta androgênica, via cultura de micrósporos, de genótipos de trigo com diferentes graus de resistência à Gibberella zeae. Contou-se o número de embriões androgenéticos por espiga, e de plantas verdes e albinas para os genótipos BRS 179 (moderadamente resistente), Frontana e Sumai 3 (resistentes), e BRS 194, Embrapa 27 e Fielder (suscetíveis). A interferência dos genótipos doadores de ovários Fielder, Pavon 76 e Sumai 3, utilizados para cocultivo das células de micrósporos, também foi avaliada na resposta androgênica. A eficiência de indução variou de 0,33 embrião por espiga para Embrapa 27 a 109,8 embriões para Frontana. Sumai 3 apresentou a segunda melhor resposta, e Embrapa 27 se comportou como altamente recalcitrante. O cocultivo de ovários do genótipo Fielder se destaca dos demais e interfere positivamente na indução dos embriões. Não foram observadas diferenças significativas para a regeneração de plantas verdes; no entanto, para plantas albinas, BRS 194 produziu as taxas mais altas. Frontana e Sumai 3 apresentam as mais elevadas taxas de resposta androgênica e podem ser explorados em programas de melhoramento para o rápido desenvolvimento de cultivares resistentes à Gibberella zeae.

Abstract: The objective of this work was to assess the androgenic response, via microspore culture, of wheat genotypes with different levels of resistance to Gibberella zeae. The number of androgenic embryos per spike, and of green and albino plants was counted for the BRS 179 (moderately resistant), Frontana and Sumai 3 (resistant), and BRS 194, Embrapa 27, and Fielder (susceptible) genotypes. The degree of interference by the Fielder, Pavon 76, and Sumai 3 ovary-donor genotypes, used for co-culture with the microspore cells, was also assessed regarding androgenic response. Induction efficiency ranged from 0.33 embryo per spike for Embrapa 27 to 109.8 embryos for Frontana. Sumai 3 presented the second best response, and Embrapa 27 behaved as highly recalcitrant. The co-culture of ovaries from the Fielder genotype stands out from the others and positively interferes in the embryo induction rate. No significant differences were observed for the regeneration frequency of green plants; however, for albino plants, BRS 194 produced the highest rate. Frontana and Sumai 3 present the highest androgenic response rates and can be used in breeding programs for the rapid development of cultivars resistant to Gibberella zeae.

Abstract The wheat cultivar ‘BRS 331’ was developed by Embrapa. It results from an interspecific cross between wheat and maize by double-hapolid method. ‘BRS 331’ shows solid stem in the base of the plant, short leaves and super-early cycle to maturity. It is classified as bread wheat in all of the regions that is recommended in the States of Rio Grande do Sul, Paraná and Santa Catarina, Brazil.

RESUMO: Trigos sintéticos são resultados do cruzamento entre uma espécie tetraploide ( Triticum turgidum, AABB) e uma espécie diploide ( Aegilops tauschii , DD) originando um híbrido estéril, seguido por duplicação cromossômica, por meio de colchicina, para restabelecer um trigo hexaploide fértil. A principal importância do uso de trigos sintéticos no melhoramento é que possibilitam aumentar a variabilidade genética, bem como introgredir genes de resistência a estresses bióticos e abióticos. O presente estudo teve como objetivo avaliar a presença de micronúcleos (MCN) e índice meiótico (IM) na fase de tétrades, em acessos de trigos sintéticos e cultivares testemunhas ( T. aestivum ), armazenadas no Banco de Germoplasma da Embrapa Trigo, a fim de selecionar os acessos estáveis geneticamente e disponibilizar ao melhoramento. Cinco plantas por genótipos, na fase anterior à antese, foram coletadas e fixadas em solução Carnoy. As lâminas citológicas foram preparadas pelo método de maceração e a coloração das células com carmim acético 1%. As observações foram em microscópio óptico. Observou-se a presença de micronúcleos em todos os genótipos analisados e foi encontrado variabilidade quanto à estabilidade genética nos dois anos de análises. Em 2014, o percentual máximo de IM dos acessos de trigos sintéticos foi de 96,86% e o mínimo de 46,32%. Em 2015, o percentual de IM máximo foi de 96,60% e o mínimo de 47,96%. Com base nos resultados, alguns genótipos foram considerados meioticamente estáveis e, poderão ser utilizados em programas de melhoramento genético de trigo.

ABSTRACT: Synthetic wheat is developed by crossing tetraploid species ( Triticum turgidum , AABB) with a diploid species ( Aegilops tauschii , DD), followed by chromosome duplication through the use of colchicine to restore the resultant sterile hybrid to a fertile hexaploid plant. The main importance of producing synthetically improved wheat is to increase their genetic variability and to incorporate genes that code for resistance to biotic and abiotic stressors. This study aimed to evaluate the presence of micronuclei (MN) and the meiotic index (MI) in the tetrad phase in synthetic wheat accessions and cultivars ( Triticum aestivum ) stored at the Germplasm Bank of Embrapa Trigo (Brazil), in order to identify and select genetically stable accessions for plant improvement. Five plants were collected by genotype, prior to anthesis, and the tissues were fixed in Carnoy solution. Cytological slides were prepared by the smash method, and the cells were dyed with 1% acetocarmine and observed under an optical microscope. Presence of MN was observed in all genotypes analyzed, and variability of genetic stability was reported in the two years of analysis. In 2014, the highest MI of synthetic wheat accessions was 96.86% and the lowest was 46.32%. In 2015, the highest MI was 96.60% and the lowest was 47.96%. Based on the results, some genotypes were considered meiotically stable and suitable for use in wheat breeding programs.

A cultivar de trigo 'BRS Marcante' foi desenvolvida pela Embrapa, envolvendo um híbrido F1 do cruzamento entre as linhagens PF 980533 e PF 970227 com a cultivar 'BRS Guamirim', realizado em telado, na Embrapa Trigo, no inverno de 2003. As gerações segregantes foram conduzidas pelo método genealógico e a linhagem resultante, nomeada de PF 080310. A cultivar caracteriza-se pela sua ampla capacidade de adaptação às condições de cultivo do sul do Brasil, pelo bom potencial de rendimento de grãos e qualidade industrial da classe Pão

The wheat cultivar 'BRS Marcante' was developed by Embrapa, as a result a cross between F1 hybrid between lines PF 980533 and PF 970227 with 'BRS Guamirim' and carried out in a green-house of Embrapa Wheat, on 2003 winter season. The segregate generations were conducted by genealogic method and the genotype resulted was named PF 080310. It has wide adaptation ability to south Brazilian conditions, high grain yield potential and belongs to Bread Class