Powdery mildew (Sphaerotheca fuliginea) resistance in melon is selectable at the haploid level

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.