Studies on Inoculation Methods of Guava (Psidium guajava L.) Seedlings with Nalanthamala psidii (syn. Myxosporium psidii) and the Screening for Resistance
Date Issued
2012
Date
2012
Author(s)
Chen, Yun-Hao
Abstract
Myxosporium wilt, caused by the pathogen Nalanthamala psidii (Sawada et Kurosawa) Schroers & M. J. Wingf. (≡Myxosporium psidii Sawada et Kurosawa), belongs to one of systemical fungal diseases. This disease has been the most severe and destructive disease of guava (Psidium guajava) cultivation in Taiwan since the 1970s due to the development of pruning techniques for nonseasonal production. The pruning techniques result in numerous wounded sites and increase chances for the invasion of this pathogen. No chemical could prevent or cure this disease and no other solution is available except to burn and remove infected trees from the orchards immediately as the symptoms ocurred. Therefore, breeding for disease resistance is requied.
The objectives for the present studies were to: (1) study the effectiveness of inoculation methods for guava seedlings; (2) screening seedlings for N. psidii resistance; (3) evaluate the pathogenicity of N. psidii culture filtrate to seedlings. In the present study, pitiching and root trimming severely injured seedlings and caused a lot portion of seedlings died. Therefore, the effectiveness of the two inoculation methods could not be compared; and thus, the effects of wounding method, seedling stage and inoculum concentration on inoculation of N. psidii could not be determined. Among 2760 seedlings we screened after 3 inoculations within 2 years, 132 puataive resistant plants were obtained. Half of them were ‘Pei-pa’ open-pollinated (OP) progenies. After wounding branches of ‘Pei-pa’ hybrid and OP seedlings of other lines were inoculated with agar plugs of N. psidii Mp-02 isolate, wilting symptoms of most plants only occurred above the wounds. The observation period, 2 months, was not long enough to determine their resistance/susceptibility. However, pathogenicity of N. psidii culture filtrate to guava seedlings could not be confirmed.
Subjects
guava
Psidium guajava
Nalanthamala psidii
Myxosporium psidii
Myxosporium wilt
seedlings
inoculation
screening for resistance
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-101-R98628106-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):54260053b57f4f5108a7bc229aa724a7