This report deals with the continuation of a series of tests of overwinter cauliflower (Brassica oleracea L. var. botrytis) production which began in 1977. Previous research established the feasibility of overwinter cauliflower production in the Willamette Valley and centered on cultivar and planting date trials, and the effect of spring-applied N on yields. The 1980-81 experiments reported here included a cultivar trial and a planting date trial. The 1981-82 experiments included cultivar testing, a planting date trial, and an evaluation of the effectiveness of metalaxyl fungicide in controlling mildew on cauliflower leaves and heads.
Methods
Plant spacing was 0.91 m x 0.45 m for all experiments except the mildew trial which was planted on 0.91 m x 0.61 m spacing. In each case, the plot areas received a broadcast, incorporated application of 900 kg/ha of 10-20-10, 2.2 kg B/ha, 55 kg/ha of Epsom salts, 11 kg/ha of Fritted trace elements, 0.8 kg/ha of trifluralin herbicide, and 1.1 kg/ha of fonofos insecticide. All trials were established with greenhouse-grown transplants.
In the 1980-81 trials, an additional 112 kg N/ha as ammonium nitrate was sidedressed on March 2, 1981. The three 1980-81 cultivar trials were seeded on August 5, 15, and 22, and transplanted on September 11, 17, and 30, respectively. The 1980-81 planting date trials with Armado April cultivar were seeded on July 25, August 2, and August 15, and transplanted on September 5, 11, and 17, respectively.
In the 1981-82 trials, an additional 56 kg N/ha as calcium nitrate was applied on January 25, 67 kg N/ha as ammonium nitrate on March 11, and 56 kg N/ha as ammonium nitrate on April 5, 1982. The single cultivar trial was seeded on July 30 and transplanted on September 2, 1981. In the planting date trial, Morse's March, Armado April, and Vision were seeded on July 15, July 30, and August 14, and transplanted on August 21, September 2, and September 21, 1981, respectively. The mildew trial with Armado April was seeded on August 14 and transplanted on September 21, 1981. Treatments included untreated check, one metalaxyl application at 1.1 kg/ha on September 22, 1981, and two applications of 1.1 kg/ha each on September 22, 1981, and January 20, 1982.
The material was banded on the soil surface in granular form with four replications of each treatment in completely randomized design. Mildew ratings were taken at the single harvest on April 22, 1982. All other trials were harvested twice weekly in both years.
Results and Discussion
1980-81
Armado April was the best of the early to mid-early cultivars in yield and quality (Table 1). Armado May and Maya were the superior mid-to-late lines. Because of the very mild winter, there was no winterkill and all cultivars made some growth throughout the winter. Early maturing varieties such as March and Superb Early White were exposed to night temperatures as low as -7°C (20°F) after curd formation had started. However, damage was slight. Cold weather in February and March retarded development of foliage; plant size was smaller than normal for all but the latest cultivars. Nearly all cultivars had a russeting of the leaves and curd, perhaps because of crane fly or Hylemya fugax larvae, mildew (Peronospora), or black rot (Xanthomonas). Quality was significantly reduced. This problem had not occurred in previous trials.
Within the 12-day range (Table 2) for transplanting Armado April, there was no effect on yield or harvest date. Past trials have indicated a greater effect of planting date on mean head size. However, this trial supports the previous conclusion that a range of cultivars is a more effective means of spreading the harvest period than is a succession of planting dates.
1981-82
Twenty cultivars, with more than a two-month spread in maturity, were included in the trial. The 1981-82 winter was cold; on several nights, temperatures in the low teens (0 F) were recorded. Plants had essentially no growth during the winter, and a cold, dry spring further retarded plant development. Peak harvests averaged two weeks later in 1982 than in 1981. The earliest cultivars such as Superb Early White, March Early, Morse's March, Armado Quick, and Preminda did not size sufficiently to produce acceptable yields (Table 4), although each produced some heads with adequate curd quality. The mid-early Armado April also had low yields, although curd quality was good. The best combination of yield and quality occurred with mid-maturity cultivars such as Maya, Arminda, and Inca. Inca was included in the trials for the first time and looked promising for a mid-early to middle maturity line. Late cultivars such as Midsummer, June, and Vision had excellent gross yields but poor curd quality. In general, the earliest varieties suffered the greatest degree of winterkill.
The effect of transplant date on yield and quality of three cultivars is seen in Table 5. For all three, mean head weight and gross yield declined with later transplant dates. Grade of Armado April also declined at the later dates. However, winterkill of the very early variety Morse's March was greater with the earlier plantings, confirming results obtained in 1979. Curds of Morse's March suffered freeze damage, particularly with the first planting. A one-month spread in seeding and transplant dates led to a 19-day spread in peak harvest for Morse's March, but had little or no influence on peak harvest of Armado April or Vision. However, planting date did affect first harvest of Armado April.
Table 6 presents a summary of relative maturity of all cultivars included in trials in the last four years. Averages are for two or more years except as noted. The span of peak harvests from the earliest (Morse's March) to the latest cultivar (Vision) is nearly 60 days. Armado April was used as a standard for comparison, with other cultivars given in terms of days earlier or later maturity than Armado April.
Metalaxyl treatments had no statistically significant effect on leaf mildew, curd mildew, or yield of Armado April cauliflower. Disease pressure was mild in 1982. No fly larvae were found in heads in 1982.
Table 1. Overwinter Cauliflower Variety Trial, 1980-81. Harvest Summary Mean head Harvest range Est. gross Cultivar Source wt.(g) First Peak Last yield (MT/ha) A. Early Planting (transplanted 9/11) April 3Z 380 4/01 4/13 4/21 9.0 Armado April 5 650 3/16 4/01 4/10 5.5 Armado May 2 863 4/01 4/16 5/01 20.7 Armado Quick 5 547 3/19 3/23 4/01 13.1 Armado Tardo 2 NMY 4/10 NM NM NM Arminda 5 NM 4/01 NM NM NM Heralda 2 473 3/16 4/01 4/01 11.3 March Early 3 445 3/09 3/16 3/27 10.8 Markanta 2 NM 4/10 NM NM NM Preminda 2 522 3/16 4/01 4/10 12.6 B. Mid-Planting (transplanted 9/17) Aprilex 2 732 4/06 4/21 5/01 17.6 Armado Clio 5 775 4/21 5/01 5/14 18.7 March 2 387 3/09 3/09 4/01 9.2 Marchpast 2 619 3/23 4/01 4/16 15.0 Maya 1 690 4/24 4/27 5/11 16.7 Maystar 2 704 4/10 4/27 5/11 16.9 Midsummer 2 834 4/27 5/14 5/18 20.0 Mirado 5 479 4/21 5/01 5/05 11.5 Superb Early White 2 336 3/09 3/16 3/23 8.1 Vision 2 655 5/01 5/14 5/22 15.8 C. Late Planting (transplanted 9/30) Barrier Reef 4 201 4/01 4/13 4/27 4.7 CB-1 4 212 3/09 3/19 4/13 5.2 CB-4 4 142 3/09 3/12 4/24 3.5 290 4 207 3/12 3/27 4/16 5.0 1291 4 154 3/12 3/16 4/01 3.7 Z1=Bejo Zaden, 2=Elsoms, 3=Ferry Morse, 4=Royal Sluis, 5=Rogers Bros. YNM: not measured. Table 2. Effect of Planting Date on Yield and Harvest Period of Armado April, 1980-81 Transplant Mean weight Harvest dates Est. gross yield date (g/head) First Peak Last (Mt/ha) 9/05/80 665 3/23 4/01 4/13 16.0 9/11 656 3/16 4/06 4/10 15.8 9/17 623 3/16 4/01 4/10 14.9 Table 3. Description of Cultivars April: Few leaves, poor cover. Small heads but better than average curd quality when protected. Usually no leaves or bracts in head. Aprilex: Fair to good cover. Good curd quality. Yield only fair for mid- maturing cultivar. Armado April: Good cover on larger plants. Excellent curd quality on well-sized plants. Fair yield. Best of early cultivars. Armado Clio: Fair to good cover. Good yields. Tends to have leaves in curd. Multiple stems. Armado May: Good cover. Fair to good yield. Tendency to leaves in head but good curd quality. Armado Quick: Poor cover, small size. Too early for cold winter/ spring. Heads small but curd quality usually better than average. Armado Tardo: Good cover, but yield and head size small for mid-maturing variety. Multiple stems. Arminda: Good cover, yield, head size. Very good curd quality. Barrier Reef (Rogers Bros.): Fair cover, small plants. Not true overwinter type. Heralda: Fair cover. Poor protection from wrapper leaves but older leaves form stovepipe. Poor yield, fair quality. Igloo (Keystone Seed Co.): Headed in December, frozen out in January. Not adapted for overwinter culture. Inca: Good cover, good plant size for early to mid-maturity range. Good yield, head size, quality. June: Good cover and plant size. Late maturing. Poor curd quality. "Fuzzy" curds, leaves and bracts in head. March Early: Too early to size sufficiently. Poor yield, curd quality. Thirty percent winterkill. Marchpast: Good cover, but small to medium size plants. Good head size for mid-early variety. Fifteen percent winterkill. Very good curd quality. Markanta: Good plant size but only fair cover. Low yield for mid-maturity variety. Very prone to green stems. Fifteen percent winterkill. Maya: Good cover,yield, head size. Good curd quality. Best of mid- maturing varieties. Maystar: Good cover and yield, but only fair curd quality. Low density heads. Midsummer:Good cover, large plants. Late maturing. Multiple stems. Large heads but very poor curd quality: "fuzzy", bracts in head. Mirado: Good cover, medium size plants. Fair yield. Conical, knobby curds. Morse's March: Poor cover, small plants. Too early to size sufficiently. Poor curd quality. Average of 35 percent winterkill. Preminda (Armado Primo): Poor cover and plant size. Too early to size sufficiently. Average curd quality. Strong Osena (Keystone Seed Co.): Headed in December, frozen out in January. Not adapted for overwinter culture. Superb Early White: Poor cover and plant size. Too early to size sufficiently. Poor curd quality. Thirty percent winterkill. Vision: Good cover, large plants. Late maturing. Excellent gross yields but curd quality poor. "Fuzzy" curds, bracts in head. Multiple stems. Superior to other late varieties. Table 4. Overwinter Cauliflower Variety Trial, 1981-82. Harvest Summary Est. Mean Gross Yield of Harvest range head yield #1 heads MeanY Cultivar Source First Peak Last wt.(g) (MT/ha) (MT/ha) grade April 3Z 4/23 4/30 5/07 555 11.7 7.9 1.4 Aprilex 2 4/30 5/03 5/17 565 13.7 8.6 1.4 Armado April 2,4 4/02 4/13 4/23 492 10.4 6.5 1.4 Armado Clio 2,4 5/03 5/14 5/17 666 19.1 9.9 1.6 Armado May 2,4 4/16 4/30 5/11 613 15.8 9.2 1.6 Armado Quick 2,4 3/16 4/13 4/26 329 7.0 4.1 1.5 Armado Tardo 2,4 4/26 5/07 5/14 486 13.9 8.1 1.5 Arminda 4 4/30 5/07 5/14 858 15.6 11.3 1.3 Inca 1 4/16 4/23 5/07 750 18.0 14.4 1.4 June 2 5/15 5/17 5/28 1011 23.0 1.8 1.9 March Early 3 3/29 3/29 4/13 144 2.0 0.5 1.8 Marchpast 2 4/13 4/23 4/26 712 11.7 10.4 1.2 Markanta 2,1 4/23 5/03 5/07 588 11.5 5.9 1.7 Maya 1,2 4/30 5/07 5/17 846 17.8 12.4 1.4 Maystar 2 4/26 5/07 5/14 699 18.9 9.9 1.6 Midsummer 2 5/11 5/21 5/28 923 16.7 0.0 2.0 Morse's March 2 3/16 3/16 4/02 236 3.6 1.0 1.8 Preminda 2,4 3/19 4/20 4/23 381 9.2 5.0 1.5 Superb Early White 2 3/16 3/29 4/23 207 3.2 0.8 1.8 Vision 2 5/25 5/25 5/28 897 25.0 5.9 1.8 Z1 = Bejo Zaden 2 = Elsoms Seeds Ltd. 3 = Ferry Morse 4 = Royal Sluis. When two sources are listed, the seed lot from the first source listed was used in the trial. YGrade 1.0 = all heads free of defects; tight, white curd. All heads given a score of either 1 or 2. Grade 2.0; all unacceptable. Table 5. Effect of Planting Date on Yield, Grade, and Winter Mortality of Three Winter Cauliflower Cultivars, 1981-82 Est. Trans- Mean gross Yield of Winter- plant Harvest head yield #1 heads kill Mean Cultivar date First Peak Last wt.(g) (MT/ha) (MT/ha) (%) grade Morse's March 8/21 3/10 3/10 3/29 554 3.4 0.0 50 2.0Z 9/12 3/16 3/16 4/02 236 3.6 1.0 31 1.8 9/21 3/19 3/29 3/29 158 2.3 0.5 13 1.9 Armado April 8/21 3/19 4/13 4/16 611 12.8 12.2 13 1.1 9/12 4/02 4/13 4/23 492 10.4 6.5 0 1.4 9/21 4/13 4/16 4/26 384 5.9 2.7 19 1.6 Vision 8/21 5/21 5/25 5/25 910 34.2 13.0 6 1.7 9/12 5/25 5/25 5/28 897 25.0 5.9 0 1.8 9/21 5/21 5/25 5/28 688 12.4 4.3 0 1.7 ZFreeze-damaged curds on early maturing heads. Table 6. Relative Maturity of Overwinter Cauliflower Cultivars Compared to Armado April DaysZ earlier or later than A. April Cultivars -20 to -11 Morse's March, March Early, Superb Early White -10 to -3 Armado Quick, Preminda -2 to +2 HeraldaY, Armado April +3 to +10 Marchpast, Barrier ReefY, IncaY +11 to +20 April, Armado May, Aprilex, Markanta +21 to +30 ArmindaY, Armado Tardo, Maystar, Maya, MiradoY, Armado Clio, PinnacleY Over +30 JuneY, Midsummer, Vision _____________________________________________________________________________________ ZWithin each category, varieties listed in order of maturity. YBased on one year of observations.