This article appears in the June 2019 issue of Potato Grower.
With some help from our friends at the Potato Variety Management Institute, this month’s Smorgasbord takes a look at Defender, a long-season, high-yielding, lightly russeted variety notable for having foliar and tuber resistance to late blight infection. Defender is an excellent choice for organic production and is suitable for processing into french fries and other frozen potato products directly from the field or from short-term storage, and may also be used for fresh markets.
Check www.pvmi.org for a full list of seed growers.
History
- Parentage: Ranger Russet × KSA195-90
- Developed by the Tri-State Breeding & Research Program, released in 2004
- PVP applied for in 2004
Strengths
- Resistant to late blight, early blight, PVX and net necrosis
- Consistently produces greater total and U.S. No. 1 yields than Russet Burbank
- Consistently high specific gravity (comparable to Ranger Russet)
- High vitamin C levels (69 percent higher concentration than Russet Burbank)
- Moderately resistant to Verticillium wilt, pink rot, foliar early blight, corky ringspot and soft rot
- Moderately resistant to dry rot in storage
Weaknesses
- Susceptible to common and powder scab
- Susceptible to potato leafroll virus
- Moderately susceptible to dry rot and PVY
- Shorter dormancy: 95 days at 48 degrees; 125 days at 42 degrees
Management
- Resistant to Metribuzin
- About 190 to 210 lb. N/acre. One-third to one-half of the seasonal N requirement should be applied at or near planting with the remainder applied before Aug. 10.
- Soil moisture between 65 and 80 percent ASM throughout the growing
- Vines remain green and vigorous late in the season and use 10 to 20 percent more water than Russet Burbank.
