The health of propagation materials starts with the breeders

05 Apr 2023
2262

Luigi Catalano - Agrimeca / Civi Italia (IT)
Cherry Times Scientific and Technical Committee

Some considerations on how to better qualify varietal innovation through breeding certification programs for a new sustainable and competitive cherry crop.

Always considered a minor species among stone fruits, cherry cultivation has been undergoing a major technical revolution in recent years involving canopy management and breeding systems with a wide range of new rootstocks and varieties proposed.

Higher planting densities, 2D hedge training systems, plant cover, weak rootstocks and a range of new varieties covering an 8-week harvest calendar characterize innovation in cherry cultivation.

The nursery industry has not been unprepared to meet this challenge. There are now specialized nurseries offering a wide range of rootstocks and holding propagation rights to the new varieties, all of which are protected by plant breeding rights.

Among the stone fruit species regulated by EU legislation on the multiplication, marketing and certification of nursery production, the cherry tree is the one that guarantees the absence of the greatest number of harmful organisms: 22 viruses, 2 phytoplasmas, 4 bacteria, 4 fungi, as well as nematodes and insects.

For nurseries that want to qualify their production more by joining the voluntary genetic-health certification scheme, the availability of starting propagation materials (Pre-basics) of new varieties, which meet the required phytosanitary requirements, is reduced.

Many nurseries, after purchasing the concession for a protected variety, initiate the procedures for its inclusion in the voluntary certification scheme.

Increasingly, the diagnostic techniques used to constitute the primary sources of new varieties to be enrolled in the certification scheme, whether woody indexing or more advanced and sensitive biomolecular techniques (PCR, RT-PCR, HTS - High-troughput sequencing, etc.), show the presence of viral entities - not only those provided for in the technical standards - already in the original materials received from the breeder or publisher in charge of managing the protected variety.

In some cases, harmful organisms-whose danger to the crop is yet to be ascertained and demonstrated-regulated organisms are also present, of which the nurseryman must guarantee the absence in the plants sold to fruit growers, assuming full responsibility.

It should be remembered that EU regulations also require breeders to produce new genotypes, which then become varieties, free of regulated pests. Therefore, greater consideration of phytosanitary aspects is needed right from the selection of parents for crosses and in the subsequent selection stages.

Before filling out the list of harmful organisms, it would be the case that these r

Cherry tree - harmful organisms recognized by voluntary certification scheme QVI - Quality Nursery Italy

Harmful organism/pathology
SigalCodice EPPO

VIRUS



American plum line pattern virusAPLPVAPLPV0
Peach mosaic virusPcMVPCMV00
Little cherry virus 1LChV1LCHV10
Little cherry virus 2LChV2LCHV20
Tomato ringspot virusToRSVTORSV0
Cherry rasp leaf virusCRLVCRLV00
Plum pox virusPPVPPV000
Prune dwarf virusPDVPDV000
Prunus necrotic ringspot virusPNRSVPNRSV0
Apple mosaic virusApMVAPMV00
Apple chlorotic leaf spot virusACLSVACLSV0
Cherry leaf roll virusCLRVCLRV00
Cherry necrotic rusty mottle virusCNRMVCRNRM0
Cherry mottle leaf virusCMLVCMLV00
Arabis mosaic virusArMVARMV00
Raspberry ringspot virusRpRSVRPRSV0
Strawberry latent ringspot virusSLRSVSLRSV0
Tomato black ring virusTBRVTBRV00
Cherry green ring mottle virusCGRMVCGRMV0
Cherry twisted leaf associated virusCTLaVCTLAV0
Plum bark necrosis stem pitting-associated virusPBNSPaVPBNSPaV

PHYTOPLASMA



‘Ca. Phytoplasma prunorum’
PHYPPR
‘Ca. Phytoplasma pruni’
PHYPPN

BACTERIA



Xanthomonas arboricola pv. pruni
XANTPR
Xylella fastidiosa
XYLEFA
Agrobacterium tumefaciens
AGRBTU
Pseudomonas syringae pv. morsprunorum
PSDMMP

NEMATODES



Pratylenchus vulnus
PRATVU
Pratylenchus penetrans
PRATPE
Meloidogyne javanica
MELGJA
Meloidogyne arenaria
MELGAR
Meloidogyne incognita
MELGIN
Xiphinema rivesi
XIPHRI
Meloidogyne hapla
MELGHA

FUNGI



Phytophthora cactorum
PHYTCC
Rosellinia necatrix
ROSLNE
Chondrostereum purpureum
STERPU
Armillariella mellea
ARMIME

INSECT & MITES


Quadraspidiotus perniciosus
QUADPE

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