Maize responsiveness to Azospirillum brasilense: insights into genetic control and genomic prediction

• Ano de defesa: 2019
• Autor(a) principal: Vidotti, Miriam Suzane
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Zea mays; Análise dialélica; Association mapping; Bactérias promotoras de crescimento de plantas; Diallel analysis; Estresse de nitrogênio; Genomic prediction; Mapeamento associativo; Nitrogen stress; Plant Growth-Promoting Bacteria (PGPB); Predição genômica
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/11/11137/tde-01042019-124901/

The inoculation with Azospirillum brasilense is one of the main strategies to supplement the inorganic inputs of nitrogen (N) and to increase the root development in maize. However, the beneficial inoculation effects are not always reached, which, in part, is due to genotypic variation in the plant host, resulting in different degrees of outcome. In this context, we aimed to study the genetic control and genomic prediction of maize traits related to the responsiveness to A. brasilense inoculation. For this, 118 maize hybrids were conducted under N stress and N stress plus A. brasilense treatments in controlled conditions over 2016 and 2017 seasons. We evaluated root and shoot traits and performed diallel analyses, association mapping, and genomic prediction methods considering 59,215 Single-Nucleotide Polymorphism (SNP) markers. Our results revealed a quantitative inheritance of the partnership-related maize traits, with both additive and non-additive genetic effects involved in the genetic control. Furthermore, several candidate genes were identified for the maize-A. brasilense association, especially with heterozygous (dis)advantage effects. In general, the prediction accuracies were higher mostly for the inoculated treatment compared to the non-inoculated. Finally, our findings enable a deeper understanding towards the genetic basis of the maize responsiveness to A. brasilense and may support plant breeders to establish selection strategies aiming the development of superior genotypes for this association.