Brazilian seedless (Annona squamosa L.): conservação da mutação do gene INO, padrão de herança e validação de marcadores moleculares

Abstract

The development of seedless cultivars represents a major advance in agriculture, benefiting producers, consumers and the food processing industry. In the Annonaceae breeding program at Unimontes, a mutant accession without seeds of pinecone (Annona squamosa L.), called Brazilian seedless (Bs), was introduced and used to study the transfer of apyrenic character through intraspecific and interspecific crosses for the hybrid of atemoya ‘Gefner'. In the present work, the Bs parent and the hybrid progenies obtained were used to obtain segregating ‘populations in order to verify the molecular mechanism and the inheritance of the seed absence character, generating data to assist in the selection assisted by molecular markers (MAS) of new ‘genotypes’ carrying the trait of interest. This thesis was divided into two articles. In the first one, sequencing and molecular studies of Bs were performed to confirm the conservation of the INNER NO OUTER (INO) gene deletion; the study of the inheritance of the presence/absence of seeds in A. squamosa from segregating generations; and validation of INO gene specific ‘markers’. As a result, confirmation of the conservation of the deletion in Bs was obtained; that the apyrenic character is monogenic and recessive; and that the markers can be used for use in the SAM of genotypes carrying the absence of seeds. In the second article, the MAS strategy associated with the INO locus was used for the early selection of individuals for the absence of seeds in the segregating progeny (F2) of atemoya tree ‘Gefher' x Bs. The results showed that the primers remained discriminative in the hybrid parents, corresponding perfectly to the phenotypic expectations for the presence of seeds and in the F2 generation, MAS allowed to designate candidate genotypes for the absence of seeds, for continuity in the genetic improvement program.