Malus domestica

Taxonomy:Eukaryota; Viridiplantae; Streptophyta; Streptophytina; Embryophyta; Tracheophyta; Euphyllophyta; Spermatophyta; Magnoliophyta; eudicotyledons; core eudicotyledons; rosids; eurosids I; Rosales; Rosaceae; Maloideae; Malus

Introduction

The apple is the pomaceous fruit of the apple tree, Malus domestica in the rose family. It is one of the most widely cultivated tree fruits. Apple trees grow best in temperate countries with a cool climate and plenty of rain during the winter. The tree requires a winter period, in which it is dormant, in order to fruit in the spring, but must be protected from frost while the flowers and fruit are young. The tree is small and deciduous, reaching 3 to 12 m tall, with a broad, twiggy crown. Blossoms are produced in spring simultaneously with the budding of the leaves. The flowers are white with a pink tinge that gradually fades. The fruit matures in autumn, and is typically 5 to 9 cm in diameter. The tree originated from Central Asia, where its wild ancestor is still found today. There are more than 7,500 known cultivars of apples resulting in range of desired characteristics. Cultivars vary in their yield and the ultimate size of the tree, even when grown on the same rootstock. Different cultivars are available for temperate and subtropical climates. Commercially popular apple cultivars are soft but crisp. Other desired qualities in modern commercial apple breeding are a colourful skin, ease of shipping, lengthy storage ability, high yields, disease resistance, ...

Like most perennial fruits, apples ordinarily propagate asexually by grafting. Seedling apples are an example of "extreme heterozygotes", in that rather than inheriting DNA from their parents to create a new apple with those characteristics, they are instead different from their parents, sometimes radically. Most new apple cultivars originate as seedlings, which either arise by chance or are bred by deliberately crossing cultivars with promising characteristics. Apple trees are susceptible to a number of fungal and bacterial diseases and insect pests, the reason why many commercial orchards pursue an aggressive program of chemical sprays to maintain high fruit quality, tree health, and high yields. A wide range of pests and diseases can affect the plant; three of the more common diseases/pests are mildew, aphids and apple scab. Among the most serious disease problems are fireblight, a bacterial disease; and Gymnosporangium rust, and black spot, two fungal diseases. Young apple trees are also prone to mammal pests like mice and deer, which feed on the soft bark of the trees, especially in winter.

At least 55 million tonnes of apples are yearly grown worldwide, with a value of about 6 billion euro.

Our involvement

While for many organisms we are involved in the gene annotation of the genome, here we are partner to elucidate the evolutionary history of the species. The achieve this we're applying sophisticated software (i-ADHoRe) to detect duplicated segments. Also making Ks-age distributions is a part of our analysis. Being the first rosaceae species to have its genome sequences were are interested to see whether the hexaploidy event at the origin of the angiosperms can be confirmed with results obtained from the evolutionary analysis of this genome sequence.

In collaboration with:

• Istituto Agrario S. Michele all'Adige (IASMA), Italy