Early Autumn Cauliflower Variety Trial (1986)

Trials to evaluate the heat tolerance of cauliflower have been conducted at the North Willamette Station for several years. These trials were transplanted in late May for July harvest. The 1985 trial differed in that the varieties were transplanted in early July for late summer to early autumn harvest. As with the earlier trials, the major desired quality is the ability to withstand high temperatures without ricing or discoloration while producing a high density, moderately sized head.

Methods

Ten varieties or lines of cauliflower were seeded on May 31, 1985, in 2-inch pots of peat-vermiculite mix and placed in a glasshouse. Seedlings were transplanted to a Willamette silt loam, pH 5.9, on July 5. Land preparation included broadcast and incorporation of 500 pounds/acre of 14-14-14 fertilizer, 7.5 pounds B, 0.75 pounds trifluralin/acre, and 1.3 pounds chlorpyrifos/acre. Diazinon was applied as a drench at 1 pound/acre on July 26. An additional 300 pounds/acre of calcium nitrate was sidedressed on August 7 and again on August 21. Plant spacing was 3 feet between rows and 1.5 feet in the row. Varieties were replicated three times in randomized block design. Heads were harvested at 3- or 4-day intervals and were not tied to determine which cultivars were adequately self-blanching.

Results

Seed sources, yields, and harvest spans are presented in Table 1. Table 2 contains comments on curd quality. Weather from transplanting until the end of August was unusually warm and sunny. Plant growth was less than in most previous trials and some of the earlier varieties, particularly Andes, had reduced head weight. Weather during the harvest period of September 3 to October 7 was cooler than normal with higher than normal rainfall in early September. As a result some of the varieties, particularly Cervina, had greatly improved curd quality compared to previous trials.

Highest gross yields and head size were with Silverstar. The highest percentage of Grade No. 1 (white curd, no defects) was with Silverstar, Cervina, and Andes. The performance of Silverstar in this trial was similar to that previously obtained for July and August harvest. Cervina and Vernon also appear promising, with good curd color, density, and head weight. Andes had good curd quality, but head size was less than 1 pound, compared to 1.5 pounds or better in some years. Dok did not perform up to expectations.

These results are too preliminary to serve as a guide for planting. Several years of trials are necessary to insure that performance of a variety will be consistent.

 

Table 1. Source, yield, and grade of cauliflower varieties, 1985                                                      Mean     Yield ofY    Gross      %                       Harvest period     head      No. 1       yield    No. 1  Variety    SourceZ  First  Peak  Last  wt. (g)  heads (T/A)   (T/A)    heads  Andes          4     9/03  9/09  9/27    439        3.3         3.7      84  Cervina        4     9/16  9/27 10/01    701        5.9         6.2      90  Dok            1     9/16  9/20  9/27    578        2.9         4.8      58  Hormade        6     9/03  9/13  9/23    538        2.8         5.7      46  Matra          4     9/20 10/01 10/07    760        2.7         4.7      57  Silverstar     5     9/23  9/27 10/07    974        7.3         7.7      94  Snowball 42    3     9/16  9/20 10/04    581        2.0         5.1      40  Snowball 123   2     9/13  9/20 10/04    587        1.2         4.9      21  Suprimax       4     9/09  9/16  9/27    668        3.3         6.5      45  Vernon         4     9/20  9/23  9/27    737        3.4         4.9      73        LSD(0.05)                          141        1.5         1.6      19   Z1. Elsoms 2.Harris-Moran 3.Ferry Morse 4.Royal Sluis 5. Rijk Zwaan   6. A.R. Zwaan. Some varieties available from more than one source. Source  listed above provided the seedlot used in this trial.  YGrade No. 1: Curd white; free of defects such as riciness, fuzz; no leaves   or bracts in curd; dense and tight.      Table 2. Comments on cauliflower curd quality, 1985                                                  Andes: Small, fairly dense heads. Small plants had less cover than usual. A few (16%) yellow heads.  Cervina: Many ricey heads in July and August (previous trials) but only 10% ricey or discolored            heads in this trial. Appears to be well adapted to early autumn cropping.  Dok:   Major problem was bracts or leaves in curd. Hormade: Rather small heads, many discolored.  Matra: Good size but many heads with fuzzy curd.  Silverstar: Good size and color. Curd a little rougher than usual, but still graded No. 1.  Snowball 42: Ricey curd.  Snowball 123: Ricey and yellow curd, some pink curd.  Suprimax: Major defect was riciness; some yellowing and leaves in curd.  Vernon: Fairly good. size, some heads discolored but majority were snow white.                         

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