Results from Northern Colorado onion seed trials conducted at the Adams County Extension Office of Dr. Thaddeus Gourd, extension director and agent in agriculture, have been released, and several varieties show themselves well suited to conditions in the Centennial State.
The trials were undertaken at Sakata Farms fields in Northern Colorado, and Bob Sakata, founder of the operation and longtime onion industry member, commented on varieties he sees as the best.
“In our judgment it’s the Bejo Delgado,” Sakata said.
Several dozen varieties were tested, and Dr. Gourd said in his summation of the trials that the research is intended to provide onion producers with “information to make educated decisions when selecting onion varieties based on environmental and pest conditions” in the state.
Two avenues of research were taken on 30 varieties, one for percent of harvest yield and one for emergence, thrips and maturity.
The two Sakata Farms locations used are just northwest of Brighton, CO, (the Howard Farm) and north of Ft. Lupton (the Zaiss Farm).
“In general, weather conditions were cooler and wetter than normal in April and May which did have an impact on bulbs sizing up,” Dr. Gourd reported. “Onions were planted at the Howard Farm location on March 23 and at the Zaiss Farm on March 31. The Howard Farm used sprinkler center pivot irrigation, and the Zaiss Farm used flood irrigation.”
Research evaluations performed this year at both locations included emergence, thrips severity, maturity and yield. Onion emergence evaluations occurred on June 16 at the Howard Farm and June 18 at the Zaiss Farm. Good emergence was noted at both locations. Thrips populations were counted on June 26 at the Howard Farm and July 10 at the Zaiss Farm. The Howard Farm averaged only 6.2 thrips per onion plant, and the Zaiss location averaged 14.8 thrips per plant.”
Dr. Gourd said the low thrips pressure “could explain why very little Iris Yellow Spot Virus (IYSV) was observed at either location in 2015.”
Maturity data was taken on Aug. 18 and Sept. 10 at Howard Farm location and Aug. 31 and Sept. 14 at the Zaiss Farm location.
Harvest at the Howard Farm location occurred on Sept. 10, followed by processing on Sept. 11. Harvest at the Zaiss Farm location occurred on Sept. 14, processing on Sept. 15. Bulbs were checked for disease at time of harvest at both locations. Onion storage data will tentatively be collected on Jan. 7, 2016.
Working with Dr. Gourd were Eric Hammond, agent in horticulture, and Cassey Anderson, master gardener coordinator in horticulture.
Bob Sakata said Nunhems’ Joaquin is “always a good onion, able to overcome Fusarium, but it’s not a long keeper.”
He said in addition to the Delgado, Sakata Farms likes the Bejo Hamilton, “and for whites, we like the Cometa from Nunhems.”
However, he added, “I wish all the seed breeders would some something with the red. We still are with the Red Wing, but it’s gone downhill over the years. It’s just not getting size.”
He said that when the onions are taken out of storage in January for evaluation, “I could have an entirely different report for you.”