Seleção de híbridos de uva sem semente para múltiplas características agronômicas, resistência ao cancro bacteriano e ao míldio

Abstract

The genetic breeding of grapevines seeks to develop cultivars adapted to the environmental conditions of specific regions, which have high yield, resistance to diseases and quality adequate to market requirements. The objectives of the present study were to select superior seedless table grape hybrids for multiple agronomic traits, resistance to bacterial canker (Xanthomonas campestris pv. viticola) and downy mildew (Plasmopara viticola). The thesis structure is divided into four papers. In the first paper, two hundred hybrids of table grapes were evaluated during six harvests for twelve quantitative morphoagronomic traits. The mixed model methodology (REML/BLUP) was used to estimate variance components and predict breeding values. Individual genotypic selection allows high genetic gains for bunch and berry traits and satisfactory gains for quality traits. In addition, three superior genotypes ('BRS Tainá', CPATSA 05.168 and CPATSA 79.100) were simultaneously identified for eight traits, one of them ('BRS Tainá') classified as seedless. In the second paper, one hundred and ten seedless grape genotypes were evaluated in relation to multiple traits of agronomic interest. The mixed models methodology was used to predict the breeding values and the FAI-BLUP index for the selection of superior genotypes. The FAI-BLUP index allowed the selection of ten superior seedless table grape hybrids and can be used in grapevine genetic breeding. In the third paper, two experiments were carried out, one under field conditions, where 569 hybrids were evaluated for symptoms of bacterial canker and selected using mixed model methodology (REML/BLUP); and another, conducted in a greenhouse, where ten seedless grape hybrids were evaluated in relation to resistance to bacterial canker of the vine, using epidemiological parameters. Forty grape hybrids with lower breeding values were selected for resistance to bacterial canker. The hybrids CPATSA 49.25 and CPATSA 49.86 showed greater resistance to bacterial canker in all epidemiological parameters evaluated, under greenhouse conditions. In the fourth paper, 15 seedless grape hybrids and the cultivar 'Thompson Seedless' (susceptibility pattern) were evaluated in relation to resistance to downy mildew, under greenhouse conditions, through natural infection and artificial infection. The hybrid CAPTSA 28.14 showed greater resistance to downy mildew on grapevine, both under natural and artificial infection.