Influences of Propagation Method, Rootstock, Number of Axes, and Cultivation Site on ‘Fuji’ Scions Grown as Single or Multi-Leader Trees in the Nursery

The adoption of high-density plantings (HDP) in apple orchards started with the introduction of dwarfing rootstocks from East Malling’s (UK) breeding program. A range of spindle-derived training systems have been developed to improve light interception/distribution with a variation in leader numbers. Many of these training systems cannot guarantee early, consistent, and uniform illumination of the entire canopy. For this reason, planar 2-D canopies have been developed with varying numbers of primary axes with numerous second-order shoots. In this trial, carried out at the nursery level, three sites were selected: one in New Zealand (Hawke’s Bay Research Centre) and two in Italy (Bologna and Trento). Trees were produced with a single-, bi-, and tri-axis system utilizing three rootstocks (‘M27’, ‘M9’, ‘MM106’), characterized by an increasing level of vigor. The cultivation site played an important role in modulating early tree performance. Multi-leader trees reduced average shoot length in the Italian sites in the first year after grafting. The number of shoots and total growth developed on multi-leader trees was higher than single-axis trees. This may benefit growers that seek to use canopy architecture manipulation to fill space and control vigor when establishing HDP orchards

The Hungarian pear germplasm as source of genetic variability for breeding programmes

TheHungarian pear collection (Pyrus communis L.) consists of 423 genotypes distributed over seven genebanks inHungary. This is oneof themost extensive collections of native and cultivated pears found in Eastern Europe and includes a wide range of genotypes with small size fruit(referred to as “Miniature pears”). Based on the in situ and ex situ measures taken by governmental and other institutions for fruit tree conservationin Hungary, an overview is given on some activities regarding areas of Pyrus collection and genebanks where pears are collected and grown.Descriptions of traits of miniature pears found in Hungarian genebanks for the interest of genetic characterization and breeding are presented

QTL dynamics for fruit firmness and softening around an ethylene-dependent polygalacturonase gene in apple (Malus×domestica Borkh.)

Apple fruit are well known for their storage life, although a wide range of flesh softening occurs among cultivars. Loss of firmness is genetically coordinated by the action of several cell wall enzymes, including polygalacturonase (PG) which depolymerizes cell wall pectin. By the analysis of ‘Fuji’ (Fj) and ‘Mondial Gala’ (MG), two apple cultivars characterized by a distinctive ripening behaviour, the involvement of Md-PG1 in the fruit softening process was confirmed to be ethylene dependent by its transcript being down-regulated by 1-methylcyclopropene treatment in MG and in the low ethylene-producing cultivar Fj. Comparing the PG sequence of MG and Fj, a single nucleotide polymorphism (SNP) was discovered. Segregation of the Md-PG1SNP marker within a full-sib population, obtained by crossing Fj and MG, positioned Md-PG1 in the linkage group 10 of MG, co-located with a quantitative trait locus (QTL) identified for fruit firmness in post-harvest ripening. Fruit firmness and softening analysed in different stages, from harvest to post-storage, determined a shift of the QTL from the top of this linkage group to the bottom, where Md-ACO1, a gene involved in ethylene biosynthesis in apple, is mapped. This PG–ethylene-related gene has beeen positioned in the apple genome on chromosome 10, which contains several QTLs controlling fruit firmness and softening, and the interplay among the allelotypes of the linked loci should be considered in the design of a marker-assisted selection breeding scheme for apple texture

Training systems and soil management for Southern European pear orchards

The main trend in European pear orchard design is to increase planting density. High density plantings (HDP) in pear are expanding due to the widespread use of quince rootstocks to reduce tree size and induce early bearing. However, since HDP entails high investments, the break-even point occurs 5 to 8 years after planting. Planting density in many districts is increasing to achieve high yields, i.e. over 40-50 t/ha. Nevertheless, planting density still ranges from less than 1,000 to 13,000 trees/ha. Increasing pear yields beyond a certain limit can reduce fruit quality if orchard efficiency is not maintained. Research must advance to upgrade tree efficiency via the use of dwarfing or semi-dwarfing quince or pear clonal rootstocks. At the moment the most suitable rootstock for HDP is quince C. The planting density with quince C can range from 4,000 to 13,000 trees/ha but the level of management practices and inputs must be high to avoid a loss of tree efficiency. For densities ranging from 2,000 and 3,000 trees/ha, the main quince stocks are BA29, which is declining in popularity, and the new Sydo which is gaining in popularity. New quince stocks with vigour similar to quince C are the East Mailing selection QR193-16, marketed as MH, and Adams. The most important stocks for LDPs are seedlings. The clonal seedlings from the OH 7F series include some especially interesting genotypes like OH 7F40 (Farold\uae 40). Many training systems are suitable to increase planting density, especially the V and vertical axis systems. New ideas regarding tree shape include plants with 2 or 4 axes so as to divide the vigour over more branches. Nurseries can provide pre-formed trees with two axes (Bibaum\uae) ready to be planted or, alternatively, knip the trees for spindle. In pear a very intensive pruning can enhance fruit set of such cultivars as 'Abb\ue9 F\ue9tel', 'Doyenn\ue9 du Cornice' and 'Passe Crassane'

Training systems and soil management for Southern European pear orchards.

Si tratta di una relazione ad invito sulla gestione degli impianti di pero in Europ

I regolatori di crescita aiutano ad avere astoni di forma ideale.

Analisi dell'utilizzo dei fitoregolatori in vivai