ABSTRACT
Downy mildew (Plasmopara viticola) and anthracnose (Sphaceloma ampelinum) are two of the major diseases of most grapevine (Vitis vinifera L.) cultivars grown in Thailand. Therefore, breeding grapevines for improved downy mildew and anthracnose resistance is crucial. Factorial crosses were made between three downy mildew and/or anthracnose resistant lines ('NY88.0517.01', 'NY65.0550.04', and 'NY65.0551.05'; male parents) and two or three susceptible cultivars of V. vinifera ('Black Queen', 'Carolina Black Rose', and/or 'Italia'; female parents). F1 hybrid seedlings were evaluated for downy mildew and anthracnose resistance using a detached/excised leaf assay. For both diseases, the general combining ability (GCA) variance among male parents was significant, while the variance of GCA among females and the specific combining ability (SCA) variance were not significant, indicating the prevalence of additive over non-additive gene actions. The estimated narrow sense heritabilities of downy mildew and anthracnose resistance were 55.6 and 79.2%, respectively, suggesting that downy mildew/anthracnose resistance gene(s) were highly heritable. The 'Carolina Black Rose x NY65.0550.04' cross combination is recommended for future use.
Subject(s)
Disease Resistance/genetics , Peronospora/immunology , Plant Diseases/immunology , Saccharomycetales/immunology , Vitis/genetics , Breeding , Genes, Plant , Immunity, Innate , Infections/immunology , Mycoses/immunology , Vitis/immunologyABSTRACT
The coat protein gene and part of the 3' non-coding region of five strains of peanut stripe virus (PStV) from Thailand have been cloned and sequenced. Phylogenetic comparisons of these strains, known as T1, T3, T5, T6 and T7, and related sequences showed that these strains are indeed strains of PStV. Further, PStV strains appear to be related to each other according to their geographic origin. That is, the Thai strains are more closely related to each other than they are to strains from the USA or Indonesia, despite the variety of symptoms caused by these strains and the overlap of symptom types between the strains from different locations. Like other PStV strains, PStV-Thai can be considered strains of bean common mosaic virus (BCMV) but can be distinguished from bean-infecting strains of BCMV and blackeye cowpea mosaic virus (B1CMV) through sequence and host range. No evidence was found that PStV-Thai strains, unlike PStV-Ib, are recombinants of PStV and B1CMV, although the T3 strain may be a recombinant of different PStV sequences. Phylogenetic analyses of viruses of the BCMV group suggest that acquisition of the ability to infect peanut may have occurred only once.
