Genetic multiplex state study of some advanced potato clones conferring Potato virus Y NTN (PVYNTN ) extreme resistance

Potato virus Y is known as the most important potato-infecting agent in many parts of the world. In this study, the genetic structure of ۱۶ advanced potato clones that carry the alleles of Ry as an extreme resistance genewereinvestigated.  Additionally, multiplex (duplex, triplex or quadruplex) state of genetic of selected clones, where the alleles  originate from different species such as Solanum stoloniferum (۴X), S. tuberosum subsp. andigena (۴X), S. hougassi (۶X), were evaluated using artificial mechanical and graft inoculations under greenhouse conditions. ELISA was used to confirm experimental materials infection. Results showed that potato clones designated as ۹۶.۳۵۳, ۹۷.۵۵۷, ۹۷.۵۵۹, ۹۷.۵۶۰, ۹۸.۴۳۳, ۹۹.۳۷۳, ۹۹.۳۸۴, ۳۹۷۰۹۷-۲, ۳۹۷۰۸۲-۱۰, ۳۹۷۰۷۴-۹, ۳۹۷۰۸۱-۱ and ۳۹۶۱۳۶-۱ contain extreme resistance genes (ER) against PVYNTN.. These selected clones were crossed with a PVYNTN susceptible line, S۴۴۰. At least ۲۰۰ genotypes of each family were evaluated in three replications using mechanical infection with the PVYNTN. Chi square test was used to prove the fitness of observed segregation ratios in comparison to predicted ones. The results of X۲ test showed that ۹۹.۳۷۳, ۹۹.۳۸۴ and ۹۸.۴۳۳ clones follow the duplex manner while ۹۶.۳۵۳, ۹۷.۵۶۰ and ۹۷.۵۵۹ were carrying the resistance gene in a simplex state. For ۹۷.۵۵۷, ۳۹۷۰۹۷-۲, ۳۹۷۰۸۲-۱۰, ۳۹۷۰۷۴-۹, ۳۹۷۰۸۱-۱ and ۳۹۶۱۳۶-۱, there was a significant difference between the observed and expected ratios even for simplex, duplex or triplex stages. The identified duplex genotypes have the potential to provide a durable PVY genetic resistance and can decrease the virus titer in the harboring genotype.

Keywords:

hetero multiplex , Potato , resistance