Capacidade combinatória e seleção de pessegueiro para baixa necessidade de frio hibernal

• Autor(a) principal: Silva, José Osmar da Costa e
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4498
• topic: Prunus persica; Adaptação; Brotação; Prunus persica; Adaptation; Vegetative budbreak; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL

The peach (Prunus persica) specie is a temperate fruit plant. It can be also grown in mild winter areas through use of genotypes developed for mild winter climate. This specie show dormancy in buds and seeds. The chilling is the principal form for breaking the buds and seed dormancy. Generally plants with low chilling requirement to break dormancy of buds produced seeds with similar tendency in relation to chilling requirement to germinate. The dormancy from these two organs appeared have interrelation, although this relation is not totally well understood. Based on the probable link existed between them, the selection with base on the chilling requirement of seeds to get plants with similar chilling requirement, experiment were studied. Therefore, it is necessary to understand the control processes of seed dormancy for that it will be possible. This work constitute three studies: i) the response of twenty two families of peach tree in F2 generation in the mild winter region were observed. The families were obtained from the combination of nineteen genotypes (varieties and selections) showed low and medium chilling requirement. The characteristics evaluated were vegetative budbreak percentage, tree height and main stem diameter; ii) the general combining ability (GCA) and specific combining ability (SCA) between two groups of progenitors was evaluated from the progenies at F2 generation using partial diallel analysis. In this analysis two varieties (Premier and Rubro-sol) were used as male parents and five varieties (Biuti, Cristal, Doçura, Real and Relíquia) were used as female parents. The vegetative budbreak percentage, plant height and main stem diameter were evaluated. iii) to evaluate the influence of the genotype of the embryo in the seeds dormancy of peach tree, the experiment was realized with seeds obtained from open pollinated peach plant Campinas 1 (low chilling requirement) and crossed with Miraflores (high chilling requirement). The seeds were stratified and the stratification time for germination was compared between the seeds. Eight of twenty two families studied in relation of the adaptation for subtropical condition showed superiority in relation of vegetative budbreak, indicated high adaptability for the area of production. The two variables that it indicate vigor (diameter and tree height) did not showed significant correlation with budbreak percentage, but there was significant correlation (0.8231**) when compared it. The diallel analysis showed significant for the variance of general combining ability and specific combining ability for all the variables studied, indicating the involvement of additive and non-additive genetic effect in the control of these characteristics. In the female parent, the Rubro-Sol variety presented high GCA for budbreak percentage, while Premier variety presented high GCA for tree height and stem diameter. Within the female parents the Biuti variety showed high GCA for all the characteristics evaluated. The best specific combination was Rubro-sol x Biuti crossing which showed high genetic gain for all of the characteristics evaluated. The peach seed tree showed dormancy due to the effect of the genotype of the embryo.