A brief history of apricot breeding

The primary gene centre of apricot is situated in the territory of China, from where it reached a number of places around the world with human help. These places include temperate zone and subtropical areas where environmental conditions allow apricot production (Figure 5.1.). The ancient Silk Road had an important role in its spreading as well. Apricot has arrived from its Chinese homeland to the territory of Europe about 2000 years ago. First it was propagated from seed in all areas, therefore genotypes adapted to the specific environmental conditions of the place could be selected.

Figure 5.1. Origin and spread of apricot Source: Lichou and Audubert (1989)

The activity, during which trees with the best fruit quality were further propagated, firstly from seed then vegetatively, can be considered the first step of breeding. This is often referred to as ―folk selection‖. The next step is regional selection, which is a conscious collection, evaluation of genotypes developed in the production areas as well as a selection of varieties suitable for commercial production.

In Hungary, this work started in the beginning of the 20th century, with most important results reached by Ferenc Nyújtó, Gyula Korponai, Sándor Brózik and their teammates. There are today many cultivars in production selected by regional selection (‗Ceglédi bíborkajszi‘, ‗Gönci magyar kajszi‘). The next step of breeding is the conscious cross-breeding. Concurrently with regional selection, the creation of new cultivars has begun in Hungary as well, firstly by crossing regional varieties, then by involving other genotypes from different areas. During the 20th century, three breeding teams have developed in Hungary. Apricot breeding is carried out at the Fruit Research Institute of Cegléd, at the Fruit Research Institute in Érd and at the Corvinus University of Budapest, Department of Genetics and Breeding. Their current commercial cultivars: ‗Ceglédi arany‘, ‗Ceglédi kedves‘, and ‗Ceglédi Piroska‘ from Cegléd,

‗Pannónia‘ from Érd as well as ‗Budapest‘, ‗Harmat‘ and ‗Korai zamatos‘ from the Budapest breeding programme.

There is an intensive breeding work in all important apricot producing countries, and new cultivars continuously come to production. At present there is about 1800 registered apricot cultivars around the world, about 600 of them is younger than 40 years. However, most of the yield is produced by only 30-40 cultivars in plantations. Apricot breeding is influenced in principle by the limited ecological adaptation ability which is characteristic of the species. As a result of this limited adaptation ability, cultivar use is different in Mediterranean and in continental areas.

Summary of breeding methods:

 Folk selection - since apricot was domesticated in China, in the territory of Hungary since about 2000 years

 Regional selection - in Hungary since the beginning of the 20th century

 Cross-breeding

o In Hungary: Magyar Gyula (1884-1945), first Hungarian breeding programme. Main aims: frost resistance, fruit quality, Monilia resistance

o Breeding of new commercial cultivars since 1952, Pál Maliga, Ferenc Nyujtó, István Tamási, Mária Magdolna Kerek, Andrzej Pedryc

o The most important apricot producing countries: the USA, Canada, Italy, Spain, France, New-Zealand

 Clone selection (in Hungary since 1960, Nyujtó, Korponay, Brózik)

 Biotechnological methods

 Naturalization (introduction from foreign countries) 5.2 Current international cultivar use, major aims of breeding

Because of the limited ecological adaptation ability of apricot cultivars, variety use of the Mediterranean-subtropical and temperate zone areas has become totally different. The spread of cultivars is influenced by their frost hardiness and chilling requirement. In temperate zone areas, mainly in the northern border of possible apricot production, Mediterranean cultivars cannot be produced, because their overwintering organs are regularly damaged by frost. On the other hand, temperate zone cultivars with high chilling requirement are not suitable for the Mediterranean, because they do not get the chilling quantity required for breaking dormancy. In the past few decades breeders are involved in creating cultivars with higher adaptation ability, which can be produced in milder and colder climatic conditions as well. Today, as a result of this work, there are some overlaps in the variety use of different areas. Examples are cultivars ‗Goldrich‘ and ‗Hargrand‘, which can be found in southern and northern production areas as well, however, most popular cultivars in all areas are those, which had been developed on site and had been accommodated to the specific conditions (Table 5.1).

Table 5.1.

Cultivar use of the most important apricot producing countries

COUNTRY MAIN CULTIVARS IN PRODUCTION

SPAIN Bulida, Canino, Moniqui, Velaquez Fino, Gitano, Mauricio, Valenciano, Currot, Palau, Ginesta, Tadeo, Pepito del Rubio

FRANCE Bergeron, Orangé de Provance (Polonais), Orange Red, Goldrich, Hargrand

Rouge de Roussillon Bergarouge, Malice, Fantasme, Sortilege, Helena du Roussillon, Tardif de Tain

ITALY San Castrese, Monaco Bello, Portici, Palummella, Fracasso, Boccuccia, Pellecchiella, Ninfa, Aurora, Perla, Pinkcot, Spring Blush, Tardif de Tain GREECE Bebecou, Tirynthos, Boccuccia, Baracca

TURKEY Hacihaliloglu, Turfanda, Cologlu, seedlings

ROMANIA Traian, Neptun, Saturn, Venus, Mamaia, Callatis, Litoral, Sulmona, Comandor, Sirena, Olimp, Augustina

UKRAINE Krasnoschokij, Ananas, Krimskij amur

ARMENIA Salah (Jerevani), Sateni, Nushi, Ordubadi, Anban, seedlings

IRAN Shastomi, Malayer, Ghorban, Felfely

CHINA White Silver, Red Rainbow, Ji Pu, Ying Ji Sha, Li Guang, Hong Yu Li Ke

CALIFORNIA Blenheim (Royal), Tilton, Castelbrite, Modesto, Patterson, Westley NEW-JERSEY NJA series, Orange Red (Bhart)

CANADA Hargrand, Harogem, Harcot, Harglow, Harlayne,Veecot, Velvaglo, Viceroy, Vivagold, Tilton, Goldrich, Perfection

AUSTRALIA Moorpark, Trevatt, Story, Watkins, Pannach, Hunter

NEW-ZEALAND Moorpark, Sundrop, Clutha-sorozat, Gabriel, Dunstan, Benmore, Vulcan, Alex

REPUBLIC OF

SOUTH-AFRICA Bulida, Royal (Blenheim), Peeka, Supergold, Palsteyn (Imperial)

The most important goal of former breeding programs was the improvement of fruit quality.

Resistance of cultivars was not properly considered. Therefore a lot of cultivars got into production which were susceptible to diseases and frost. Nowadays the first goal of breeding is the improvement of resistance in all breeding programmes. Naturally, outstanding fruit quality and reliable productivity are both still very important. Because of the bad ecological adaptation ability of apricot cultivars, plantations consist mostly of local varieties in all production areas. These cultivars ripen nearly at the same period, causing a hardly manageable work peak in the plantation and a dumping in the market with low prices.

Therefore it is everywhere a goal while widening the cultivar assortment, that the harvest period should be extended. Beside cultivars ripening in the high season, more and more early and late harvest varieties are intended to be involved in production. In areas near the Equator the aim is to enter the market as early as possible, while as we approach the poles, the later harvesting period has to be regarded. The goal of modern, intensive plantations is to form small trees which set first fruit early. Less vigorous trees with small canopy but with high yield are the most suitable for this purpose. In the apricot as a species, all versions occur from self-sterile to perfectly self-fertile cultivars. Therefore understanding the fertility patterns of new cultivars is very important. Suitable pollinators have to be planted with self-sterile cultivars, otherwise we cannot expect any yield. Beside open field fertility examinations, the understanding of S-genotype helps as well to choose pollinators for self-sterile cultivars. Unfortunately, we do not know the S-genotype of all self-sterile cultivars in production yet.

Table 5.2 gives a summary of the known S-genotypes. Apricot cultivars which can be recommended as pollinators for self-sterile varieties are indicated in cultivar descriptions.

Table 5.2. S-genotype of self-sterile apricot cultivars based on literature data

Cultivar S-genotype Reference

 Abiotic stress resistance (frost and winter hardiness, late flowering)

 Biotic stress resistance (resistance against illnesses caused by viruses, bacteria and fungi)

 Safe and systematic yield

 Lengthening of the ripening period

 Fruit quality

 Reduction of tree size

 Self fertility

5.3 Genetic sources of breeding

5.3.1 Frost tolerance and winter hardiness

There are frost tolerant varieties among produced cultivars of the species Prunus Armeniaca, but this feature is usually combined with poor fruit quality. Hungarian examples of this are members of the so called rosy apricot variety group, such as ‗Borsi-féle kései rózsa‘ or ‗Rózsakajszi C.1406‘. Among cultivars of Central and Eastern Asia, there are varieties of outstanding frost tolerance. An example is

‗Zard‘, which is widely used as a genetic source of breeding. István Tamássy and Bogdán Pejovics made crosses in 1957, and they used Asian gene sources as well beside Hungarian cultivars. The result of this work was the good frost and winter tolerant cultivar ‘Budapest‘, which was certified by the state in 1973. In Canada, one of the main goals of apricot breeding was to improve frost tolerance, and this work resulted in a series of cultivars (‗Harlayne‘, ‗Hargrand‘, ‗Harglow‘, ‗Harcot‘). Among cultivars produced in France, variety ‘Bergeron‘ has an outstanding frost tolerance, this cultivar is widely produced in Hungary as well. Regarding related species, Prunus sibirica and Prunus mandsurica contains excellent frost and winter tolerant genotypes, which can also be well used as genetic sources of frost tolerance. The main problem is, that their fruit quality does not satisfy the up-to-date market requirements.

5.3.2 Late flowering

A possible way of avoiding spring frost damages is to breed late flowering cultivars. In this aspect a good genetic resource is the Central Asian ‗Zard‘. In Romania, a late flowering cultivar series was created using ‗De Silistra‘ and ‗Re Umberto‘ varieties, the most valuable members of this are

‗Comandor‘ and ‗Sirena‘. In Hungary the latest flowering cultivars are the rosy type varieties, such as

‗Borsi-féle kései rózsa‘. Blooming time is highly influenced by environmental factors, primarily temperature, therefore there are higher differences in the blooming time between years than between cultivars at a production site.

5.3.3 Fruit quality

External appearance, physical parameters and inner values of fruits basically determine the market value of cultivars. The market‘s need is increasing for large, coloured, hard-fleshed varieties for fresh consumption. Cultivars with fruits larger than 50 mm in diameter can be considered as large. Such cultivars are ‗Ceglédi óriás‘ and ‗Ligeti óriás‘ (Hungarian cultivars), ‗Goldrich‘ (American cultivar), and

‗Mari de Canad‘ and ‗Selena‘ (Romanian cultivars). There are a lot of genotypes with large fruit in China and Armenia, which can be used as gene sources in breeding. The following Armenian cultivars can be mentioned in this respect: ‗Ararat‘, ‗Arzami‘ and ‗Salah‘. Hungarian breeders have created ‗Ceglédi arany‘ by crossing ‗Ceglédi óriás‘ and ‗Rózsabarack C.1668‘. In America, the main genetic source of large fruit is the cultivar ‗Goldrich‘. In New-Zealand, genetic sources of large-fruited „Clutha‖ series were cultivars ‗Moorpark‘ and ‗Sundrop‘. Apricots are highly diverse regarding flesh and skin colour. In different parts of the world cultivars of different skin colours are spread, which is related to their ecological needs as well. Cultivars of the Mediterranean and subtropical areas are usually lighter in colour than varieties of the temperate zone. The fresh consumption market is increasingly determined by new American cultivars, the fruits of which are dark orange, with vivid and nice red covering colour.

Such cultivars are for example ‗Pinkcot‘, ‗Big Red‘ and ‗Kioto‘. Additionally, regional varieties with the

traditional colours remain present in regional markets. A typical example of this in Hungary is ‗Gönci magyar kajszi‘. Transportability of fruits are determined basically by flesh hardness. Cultivars with soft flesh can only be left for regional markets, where fruits get to consumers in a short time after harvest. In global market, hard flesh is a requirement. American breeders use the cultivar ‘Goldrich‘ as genetic source of hard flesh mainly. Unfortunately, good taste is recently neglected as a requirement, but in the long term, buyers can only be kept by selling them tasty fruits. In this respect, traditional Hungarian cultivars (‗Gönci magyar kajszi‘, ‗Ceglédi óriás‘, ‗Mandulakajszi‘) have outstanding values.