APPLE BREEDING FOR QUALITY, DISEASE RESISTANCE AND GROWTH HABIT

R. Eyssen
General information

Apple breeding has become very popular last decades both in Western and Eastern Europe. This coincided with the introduction and worldwide spread of some good new varieties like ‘Jonagold’ and ‘Elstar’. It resulted in an almost complete new assortment for the consumers and a prosperous time for apple growers. Since growers and nurseries have been looking for mutants and new cultivars intensively, giving rise to some new apple breeding programs like in Sint-Truiden/Heverlee and in Gembloux (both located in Belgium).

Apple breeding at the Fruitteeltcentrum K.U. Leuven.

Our breeding program at Heverlee/Sint-Truiden is set up by the Fruitteeltcentrum (Fruit Growing Center) of the University of Leuven and the nursery company Jo Nicolaï. The first crosses were performed in 1983, but started in 1990 at a larger scale with the financial support from the I.W.O.N.L. (Instituut tot aanmoediging van het Wetenschappelijk Onderzoek in Nijverheid en Landbouw; Belgian government) for the conventional breeding. In 1991 a research program on the possibilities of transformation and doubled haploids was started with the aid of the VLAB (Vlaams Aktieprogramma voor de Biotechnologie; Flemish government).

As most (conventional) breeders we're not keen on using sophisticated and expensive techniques for the screening of thousands of seedlings each year. This does not mean that we're not interested in DNA-analysis methods like DNA-fingerprinting methods, RFLP's and RAPD's (Nybom, 1993; King, 1993). But for the moment it's still too expensive for mass use and the number of traceable polygenetic regulated characteristics is very low. Unluckily those are often the ones that breeders are really interested in : fruit size and colour, growth habit,… (Brown, 1975).

Each year handcrosses are performed to make about 15000 to 20000 seeds. Those seedlings originating from crosses with scab resistant parents are artificially inoculated and all non-resistant genotypes are removed. All the rest, together with the ones crossed for other purposes, are planted in the field. At this stage some 10000 plants remain and are grown for two years in a nursery. The scab resistant types are not sprayed against scab, all the others receive a normal spraying scheme. During the second year in the nursery the scab resistant genotypes are minimally sprayed against mildew to track down the most susceptible ones. These are removed. The same happens with the genotypes that have a normal growth habit in the crosses that were performed for a columnar growth. In the winter following that second growing season from all remaining seedlings, some 5000 to

Eyssen, R. (1994). APPLE BREEDING FOR QUALITY, DISEASE RESISTANCE AND GROWTH HABIT. Acta Hortic. 355, 173-182
DOI: 10.17660/ActaHortic.1994.355.18
https://doi.org/10.17660/ActaHortic.1994.355.18

Acta Horticulturae