Obtained from plant material supplied between 1999 and 2003 by eight breeding centres (USA, Canada, France, UK, Czech Republic, Australia), the 22 cherry accessions including
SIR TOM , PENNY®, ZOE®, SUMMER SUN®, FERPACTCOV, FERIACOV, FEROBRICOV,
NY 270, Black Pearl TM, NY 2131, SPC 086, SPC 232, 11 W 2707,
SUMELE® SATINTM , SPC 108, 11 W 15-37, Vc 18/73, JACINTA®, HELGA®, TIM®,75, V 690630 and TEHRANIVEETM were tested in Belgian pedoclimatic conditions on Damil® rootstock in the CRA-W's experimental plots in Gembloux.
The observations highlight the different institutions’ common breeding aims, such as the colour (crimson black to black) and size of the fruit (10.1 grams on average for the new accessions, peaking at 11.7 g in the case of TIM®).
A good cherry should be crunchy in the mouth. The average firmness of the accession fruit reached an index of 17, which counts as very good, with PENNY® emerging as the firmest.
As cherries are the embodiment of freshness and have a limited shelf life, extending the harvesting period is another major concern for breeders. With these 22 varieties the harvest covers a period of 40 days, from mid-June (HELGA®) to early August (PENNY®) in our conditions.With these few late-ripening varieties the cherry harvest was further complicated by numerous wasp attacks on the fruit.
Research into variety self-fertility to enable single variety orchards to be planted is a more recent breeding criterion; only four of the 22 varieties concerned have this promising trait. The other 18 still need cross-fertilisation to be performed, but fortunately, the determination of compatibility alleles by molecular biology techniques now makes the choice of pollinating varieties easier and more reliable.
On the other hand, despite numerous attempts, spectacular results have not so far been achieved as regards improving the cherry rain cracking rate. More than 70% of these varieties still have a cracking rate of over 50%, which is unacceptable in our climate. In fact as soon as the 30% cracked cherries threshold is reached the costs of selective picking and subsequent sorting become prohibitive.
The data sheets for these 22 sweet cherry varieties have been produced and added to the 161 existing data sheets in ‘The Cherry in Intensive Orchards’.