Watermelon Research
Resistance to Gummy Stem Blight in Watermelon
Gabriele Gusmini, Todd C. Wehner, and Gerald J. Holmes
Purpose
The purpose of this research project is:
- to develop methods for evaluation of watermelon for resistance to
gummy stem blight
- to use those methods to screen the watermelon germplasm collection
in comparison with commercial cultivars and resistant cucumbers
- to calculate inheritance for watermelon resistance to bummy stem
blight
- to characterize Molecular Markers to tag genes for resistance
- to breed resistant cultigens with commercial cultivars to make them
resistant to gummy stem blight
So far we have developed a reliable screening method and we are developing
a faster method based on inoculation of detached leaves only, we have
finished the screening of 1274 PI Accessions from USDA Germplasm Collection,
which involved multiple replications and years (from 1998 through 2001)
in field and greenhouse.
We have already done P, F1, F2, BC1, and BC2 generations for the inheritance
study and we are preparing the F3 generation for inheritance study and
Molecular Markers.
The inheritance study and Molecular Markers experiment will be finished
until Spring 2003 and resistant varieties might be released until 2005.
Personnel
- Gabriele Gusmini, MS Candidate
- Todd C. Wehner, Professor, Horticultural Science
- Gerald J. Holmes, Professor, Plant Pathology
Objectives
- Collect watermelon cultigens for use in screening
- Collect isolates of GSB for methods development
- Develop a method for screening the germplasm
- Screen the germplasm for resistance to GSB
- Determine inheritance in resistant x susceptible crosses
- Develop elite inbred lines with high resistance to GSB
Value
Research from this project will provide effective screening methods
for use by seed company personnel in testing their cultivars for resistance
to GSB. More important, resistant accessions identified could be used
in breeding programs to develop improved watermelon cultivars. Resistance
to GSB would provide growers with protection against loss by this disease,
which is difficult to control, and requires multiple applications of
fungicides during crop production.
