METHODS AND RESULTS OF VIRUS SANITATION IN THE CZECH REPUBLIC Jiří Sedlák, František Paprštein, Jana Suchá Research and Breeding Institute of Pomology Holovousy Ltd.. 508 01 Hořice v Podkrkonoší, Česká republika, sedlak@vsuo.cz
CONTENT 1. Introduction viral diseases of cherry 2. Methods of testing 3. Methods of sanitation 4. Results of sanitation, recommendation of suitable methods
Introduction Sweet cherry (Prunus avium L.), member of the subgenus Cerasus, is a globally important vegetatively propagated fruit crop. Due to higher return, cherry is gaining popularity in commercial orchards in Central Europe including the Czech Republic. In 2012, there were 952 ha of commercial sweet cherry plantations in the Czech Republic (Buchtova, 2012). Sweet cherries are also regularly grown and very popular in home gardens.
Introduction viral diseases of cherry Unfortunately field grown trees and trees in nurseries are threatened by the viral diseases. Prune dwarf virus (PDV) PDV causes malformations, decrease in vigor and decrease in yield. PDV is widespread in its distribution in Europe. The natural infection rate of this virus on sweet cherry is higher than 30 %. Transfer: vegetative propagation, pollen, seeds. Symptoms: chlorotic rings, later necrotisation in sensitive varieties, dwarfing
PDV (Prune dwarf virus on Bing 595)
Introduction viral diseases of cherry PNRSV (Prunus necrotic ringspot virus) affects plum, cherry etc. Spreading: grafting, budding, plantation of infected trees, pollen from infected trees. Symptoms: light chlorotic rings on leaves, later necrosis and holes in leaves.
PNRSV (Prunus necrotic ringspot virus)
Introduction viral diseases of cherry PPV (Plum pox virus) detected by prof. Milan Navratil in cherries in the area of the Czech Republic, until now not commercially important in cherries.
Methods of testing Testing is carried out by RT-PCR (molecular method) and ELISA (imunoserological testing). Plants are further tested on herbaceous and woody indicators.
Methods of sanitation All methods of sanitation enables only sanitation of small area in the plant shoot tip (2-3 mm shoot tip meristem). All methods of sanitation are based on taking of this small part and its regeneration. Sanitation of the whole rooted plant is practically impossible! 1/ Thermotherapy = sanitation with high temperature 34 40 C, a) in vitro, b) ex vitro in containers. 2/ Chemotherapy in vitro = using antivirotics (ribavirin 10-50 mg/l) in culture media.
Cultivation box for sanitation
Ex vitro thermotherapy of sweet cherries in containers.
In vitro culture prepared for sanitation by chemotherapy
Results recommendation of suitable methods Number of počet surviving rostlin plants 60 50 40 30 20 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Number počet dní of days Idared Šampion Max Red Bartlett Lucasova Karešova Fig 1. Testing of temperature resistance of in vitro plants at 39 C.
Results recommendation of suitable methods Number of počet surviving rostlin plants 60 50 40 30 20 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 počet dní Number of days Idared Max Red Bartlett Lucasova Karešova Fig 1. Testing of temperature resistance of in vitro plants at 34 C.
Wilting shoot tips of ex vitro plants of sweet cherry Kordia in containers (7th day of thermotherapy at 34 C)
Results recommendation of suitable methods For in vitro thermotherapy at 39 C, it is needed to take the meristem between the 5th and 10th day of cultivation. It is possible to take the vital shoot tips after 10th day of cultivation using lower temperature 34 C. We recommend temperature 34 C for sanitation of sweet cherry by ex vitro thermotherapy in containers. Shoot tips should be taken between the 4th and 6th day. For in vitro chemotherapy we recommend the ribavirin concentration 20 mg/l. This concentration was not phytotoxic for sweet cherry.
Results In sweet cherry cultivars, the success of sanitation was at about 10 % in the case of PDV virus.
Acclimatization and transfer to ex vitro conditions
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