Variety Trials

ProTone Plant Growth Regulator Has Been Tested Successfully on Three Major Varieties

Valent BioSciences Corporation’s ProTone Plant Growth Regulator has been successfully used on all three popular red table grape varieties: Flame Seedless, Crimson Seedless, and Red Globe. Application timing and yield results do vary among the cultivars, however. Here are the highlights.

Flame Seedless

Flame Seedless trials conducted in Mecca, California, showed that one application of ProTone followed by ethephon contributed to an average harvest of 730 boxes per acre, with a gross income of $10,950. Pick dates were June 9 and June 18, and price per 19-pound box was at $16. Application rate was 150 grams active ingredient (a.i.) per acre.

Flame Seedless Field Results - Flame Seedless - Click to enlarge
  Click to enlarge chart

By contrast, an ethephon-only treatment yielded an average of 642 boxes per acre, with a gross income of $9,630 – 12% less than the ProTone + ethephon pick.

In Kingsburg, California, a late-season ProTone rescue treatment on September 1 increased boxes per acre by 627. That followed a standard combination application of ProTone plus ethephon done earlier.

In general, Valent BioSciences scientists have determined that growers should apply ProTone at veraison, when 50% of the harvestable fruit has softened, at a rate of 150 grams a.i./acre per application.

Crimson Seedless

Crimson Seedless trials done in Kingsburg, California, revealed that one application of ProTone contributed to an average harvest of 984 boxes per acre, with a gross income of $15,774. Pick dates were August 21, September 10, October 16, and November 3, and price per 19-pound box was $16. Application rate was 150 grams a.i./acre.

Crimson Seedless Field Results - Crimson Seedless - Click to enlarge
  Click to enlarge chart

 In fact, grower cooperators found that when ProTone was applied twice – at a rate of 75 grams a.i. each time – the harvest-per-acre average rose to 1,055 boxes with a gross income of $16,880.

An ethephon-only treatment yielded an average of 699 boxes per acre, with a gross income of $11,184.

In general, Valent BioSciences experts recommend ProTone be used one to three weeks after veraison, when 50% of the harvestable fruit has softened, at a rate of 150 grams a.i./acre per application.

Red Globe

Most recently, Valent BioSciences has established a use pattern for ProTone on Red Globe table grapes. This variety is the production leader in countries outside the U.S., such as Peru.

Red Globe

Application should be made one to two weeks after veraison, when 50% of the harvestable fruit has softened, at a rate of 150 grams a.i./acre per application.

Full Variety Trials Data