Cucurbit Genetics Cooperative Report 2:28 (article 17) 1979
B. B. Rhodes
Edisto Experiment Station, Blackville, SC 29817
Chambliss and Cuthbert (1) determined that resistance to Diabrotica in watermelon was controlled by a single recessive gene. No association between this gene and other genes has been reported. We are currently investigating the assortment of genes for Diabrotica resistance, dwarf habit, entire leaf, fruit shape, and seed size.
Lines inbred for four generations from crosses with ‘Sugar Loaf’, a Diabrotica resistant cultivar, were obtained from F. P. Cuthbert (U.S. Vegetable Lab, Charleston, SC). These were selfed and first evaluated for field resistance in 1977 (Table 1).
F1, F2, and backcross populations have been obtained among F5 Diabrotica lines and cultivars with contrasting morphological characters. Field resistance ratings and scoring of morphological characters will be made in the field in 1979.
Table 1. Striped cucumber beetle populations and damage ratings of watermelon lines and cultivars.
Genotype z |
No. beetles/plant y |
Damage index |
| E56 | 0.00 | 0.01 |
| E61 | 0.04 | 0.07 |
| E51 | 0.07 | 0.10 |
| E67 | 0.07 | 0.37 |
| E69 | 0.08 | 0.13 |
| E66 | 0.10 | 0.24 |
| E60 | 0.10 | 0.04 |
| E68 | 0.13 | 0.20 |
| Sunshade | 0.56 | 1.44 |
| Coconutmelon | 0.92 | 0.36 |
| Charleston Gray | 0.92 | 0.54 |
| Kengarden | 1.15 | 0.54 |
| Supersweet | 1.38 | 0.76 |
| Crimson Sweet | 1.60 | 0.72 |
| Chris Cross | 2.25 | 0.92 |
| Allsweet | 2.29 | 0.71 |
| Jubilee | 2.75 | 1.00 |
z Diabrotica resistant lines are designated E
y Mean beetle number per sampling date.
Literature Cited
- Chambliss, 0. L. and F. P. Cuthbert, 1969. Biennial Report of Veg. Breeding in the Southern U.S., Hawaii, and Puerto Rico. U. S. Vegetable Breeding Lab, Charleston, SC, p. 51.