Creation of new model system for genetics in Capsicum sp

• Autor(a) principal: Naves, Emmanuel Rezende
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: https://locus.ufv.br//handle/123456789/28273
• topic: Pimenta; Hibridação; Heterose; Produtividade; Plantas - Crescimento; Fisiologia de Plantas Cultivadas

Capsicum is a genus appreciated for its pungency, which favored the interaction with man and thus domestication. However, through crosses, pungency was removed in modern cultivars and fruit size and productivity were increased, the result of which is what we know as bell peppers. In Capsicum there are gaps in knowledge about phenomena related to hybridization such as heterosis, used to obtain highly productive varieties. This motivated us to perform intra and interspecific crosses with commercial cultivars of C. annuum and C. chinense to determine the extent of the phenomenon of heterosis. Intraspecific hybridization proved to be efficient in maintaining and even improving productive characteristics, while interspecific hybridization promoted extreme vegetative development to the detriment of the reproductive one. In addition, it was observed that reciprocity, compatibility and germination were dependent on the direction in which the crosses were made and the genotypes involved, as well as the influence of the pollen source on the fruit set, size and biometry of fruits. Capsicum fruits are not climacteric, which positions the genus favourably to create a new model system for genetics and physiology. The search for a productive cultivar, with small size and easy cultural management that can be tailored to laboratory work would represent a valuable first step. With this aim in mind, we scanned a germplasm bank for cultivars, mainly of C. annuum, with small size, fast cycle, prolificity and productivity with the task of representing in a reliable way, but in miniature, the productive and genetic potential of Capsicum found in commercial cultivars. After an initial screening of 14 Capsicum cultivars as candidates for the model plant, we found two cultivars of C. annuum here named 75 and CVO. These two cultivars were precocious in the cycle until anthesis and until the first ripe fruit, with compact size and more than adequate prolificacy. In addition, growth and reproduction were not compromised when grown under conditions of high density and root volume limitation, showing that they are able to grow in small spaces and containers, tofacilitate large-scale phenotyping and thus genetic studies. Thus, we found two cultivars suitable to represent in miniature the genetic potential of C. annuum, to allow and facilitate the advancement of genetic studies, and in addition with characteristics inherent and exclusive to the genus Capsicum such as pungency. This new model could represent a valuable contribution to the genetics of non-climacteric fruit ripening and fruit metabolism. Keywords: Plant model. Chili pepper. Hybridization. Heterosis. Yield. Plant growth.