Peaches tree genetic divergence for brown rot reaction

Abstract

It was evaluated the genetic divergence in peach genotypes for brown rot reaction. It was evaluated 26 and 29 peach genotypes in the 2009/2010 and 2010/2011 production cycle, respectively. The experiment was carried out at the Laboratório de Fitossanidade, da UTFPR - Campus Dois Vizinhos. The experimental design was entirely randomized, considering each peach genotype a treatment, and it was use three replication of nine fruits. The treatment control use three replication of three peach. The fruit epidermis were inoculated individually with 0.15 mL of M. fructicola conidial suspension (1.0 x 10(5) spores mL-1). In the control treatment was sprayed with 0.15 mL of distilled water. The fruits were examined 72 and 120 hours after inoculation, and the incidence and severity disease were evaluated. These results allowed realized study for genetic divergence, used as dissimilarity measure the Generalized Mahalanobis distance. Cluster analysis using Tocher´s optimization method and distances in the plan were applied. There was smallest genetic divergence among peach trees evaluated for brown rot, what can difficult to obtain resistance in the genotypes.

QTL mapping for brown rot (Monilinia fructigena) resistance in an intraspecific peach (Prunus persica L. Batsch) F1 progeny

“…An example is the high BR resistance in the clingstone cultivar "Bolinha," associated with a more compact arrangement of epidermal and subepidermal cells, thicker cuticle, fewer trichomes, and higher phenolic content at full ripening (Feliciano et al 1987;Adaskaveg et al 1991). Despite poor fruit quality (high susceptibility to enzymatic browning, reduced fruit size, and high rate of pre-harvest fruit drop), Bolinha has been used as donor of BR resistance in conventional breeding for canning and low-chill peach (Gradziel et al 2003;Topp et al 2008;Wagner Júnior et al 2008;Wagner Junior et al 2011). The F1 population from "Contender"×"Elegant Lady" (C×EL) melting flesh peach cross provides an attractive system for the genetic dissection of the trait in cultivars for the fresh market (Bassi et al 1998;Bassi and Rizzo 2003).…”

Brown Rot Strikes Prunus Fruit: An Ancient Fight Almost Always Lost

“…Activity showed a pattern similar to PR-10, that is, no significant change in PR-5 transcript levels after infection in resistant cultivars (‘Violetta’ and ‘Stanley’) and a rapid increase in susceptible genotypes (‘Veeblue’ and ‘Victory’). Furthermore, the ectopic overexpression of this protein in Arabidopsis thaliana transformants increased resistance to Alternaria brassicicola, as well as a higher induction of camalexin biosynthesis, and transcript abundance of genes coding to phenylalanine ammonia-lyase (PAL; a central point in phenylpropanoid and phytoalexin biosynthesis) and to three cytochrome P450s involved in the biosynthesis of some antifungal phenolics . Finally, the same authors, described a very similar expression pattern after M.…”

“…Furthermore, the ectopic overexpression of this protein in Arabidopsis thaliana transformants increased resistance to Alternaria brassicicola, as well as a higher induction of camalexin biosynthesis, and transcript abundance of genes coding to phenylalanine ammonia-lyase (PAL; a central point in phenylpropanoid and phytoalexin biosynthesis) and to three cytochrome P450s involved in the biosynthesis of some antifungal phenolics. 155 Finally, the same authors, 156 described a very similar expression pattern after M. fructicola infection in the gene coding to MYB3 transcription factor of European plums, suggesting an intermediary role of this transcription factor in the hormone-mediated defense responses that result in the induction of PR proteins. The study of the variability of these genes, which have effects in defense pathways, in Prunus germplasm collections has a crucial importance in the generation of knowledge for the development of more resistant varieties of fruit species.…”

“…The peach cultivar known to have one of the highest levels of resistance is the Brazilian cultivar ‘Bolinha’. , Feliciano et al investigated resistance in peach cultivars and found that ‘Bolinha’ had fruit with particularly small size and a thick cuticle with high phenolic content. This cultivar has been used as a donor of BR resistance in conventional breeding for canning and low-chill peaches despite its poor fruit quality, high susceptibility to enzymatic browning, reduced fruit size, and high rate of preharvest fruit drop. ,,, The case of ‘Bolinha’ demonstrates the challenge of breeding for BR, as characteristics associated with fruit resistance may conflict with commercial requirements. As mentioned before, Bostock et al suggested that cuticular characteristics may be involved in BR resistance.…”

Phenotypic divergence of Plinia spp. genotypes based on plant growth behavior

“…The genetic divergence analysis among genotypes of jabuticaba population is a useful data to characterize the available genetic resources (DANNER, 2009), as well as to increase the efficiency of breeding programs (RODRIGUES et al, 2010;WAGNER JÚNIOR et al, 2011a;WAGNER JÚNIOR et al, 2011b).…”