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Powdery mildew (Sphaerotheca fuliginea) resistance in melon is selectable at the haploid level
M Kuzuya1, K Hosoya, K Yashiro
1Plant Biotechnology Institute, Ibaraki Agricultural Center, Iwama, Nishi-ibaraki 319-0292, Japan. mkuzuya@agri.pref.ibaraki.jp
Abstract:
The major cause of powdery mildew in melons (Cucumis melo L.) is the fungus Sphaerotheca fuliginea. There are several cultivar- and season-specific races of this fungus. In order to control powdery mildew, it is important to introduce resistance to fungal infection into new cultivars during melon breeding. Haploid breeding is a powerful tool for the production of pure lines. In this study, it was investigated whether powdery mildew resistance could be manifested at the haploid level from two disease-resistant melon lines, PMR 45 and WMR 29. the effects of various races of S. fuliginea on diploid and haploid plants of PMR 45 and WMR 29 and of a disease-susceptible line, Fuyu 3 were measured. The responses of haploid and diploid plants to powdery mildew were identical. In addition, haploids that were generated from hybrids between Fuyu 3 and disease-resistant lines were examined. Seven out of 13 haploids from a Fuyu 3xPMR 45 cross and 10 out of 12 haploids from a Fuyu 3xWMR 29 cross were classified as resistant plants because they showed the same responses as their disease-resistant diploid parents to the various fungal races. These results indicate that resistance in PMR 45 and WMR 29 is selectable at the haploid level. All of the plant responses were observed by microscopy. A possible mechanism for generating powdery mildew resistance in two different melon lines is discussed.
Insights
Powdery mildew resistance in melon lines PMR 45 and WMR 29 is selectable at the haploid level. Haploid and diploid plants showed identical responses to fungal infection, confirming resistance inheritance.
Area of Science:
- Plant pathology
- Plant breeding
- Genetics
Background:
- Powdery mildew, caused by Sphaerotheca fuliginea, is a major disease in melons (Cucumis melo L.).
- Developing disease-resistant cultivars is crucial for effective powdery mildew control in melon breeding programs.
- Haploid breeding offers a method for rapidly producing pure lines, potentially accelerating breeding efforts.
Purpose of the Study:
- To investigate if powdery mildew resistance can be identified at the haploid level in melon lines.
- To assess the expression of resistance in haploid plants derived from resistant and susceptible melon lines.
- To determine the inheritance pattern of powdery mildew resistance using haploid breeding techniques.
Main Methods:
- Evaluated the response of diploid and haploid plants from resistant (PMR 45, WMR 29) and susceptible (Fuyu 3) melon lines to various Sphaerotheca fuliginea races.
- Generated and analyzed haploid plants from crosses between susceptible (Fuyu 3) and resistant (PMR 45, WMR 29) melon lines.
- Observed and quantified plant responses to powdery mildew infection using microscopy.
Main Results:
- Haploid and diploid plants exhibited identical responses to powdery mildew, indicating resistance is expressed at the haploid level.
- A significant proportion of haploids derived from crosses with resistant lines (Fuyu 3xPMR 45 and Fuyu 3xWMR 29) displayed resistance.
- These resistant haploids showed similar disease responses to their resistant diploid parents.
Conclusions:
- Powdery mildew resistance in melon lines PMR 45 and WMR 29 is indeed selectable at the haploid level.
- Haploid breeding is a viable strategy for identifying and potentially accelerating the development of powdery mildew-resistant melon cultivars.
- The study provides evidence supporting a mechanism for generating powdery mildew resistance in different melon lines.