The purpose of these trials was to obtain and evaluate cultivars of cauliflower for summer harvest. The major desired quality is heat tolerance: the ability to withstand high temperatures without ricing and to maintain the high curd quality typical of autumn-harvested cauliflower. A second desired quality is long wrapper leaves for self-blanching. Tying leaves must be minimized.
Fully satisfactory cultivars have not been available to Oregon growers. It would be helpful for both fresh market and processors to have a high quality summer crop. The possibility exists for double cropping, particularly if combined with overwintered cauliflower. The research involved comparing common autumn-harvested types with named cultivars or lines from several seed companies which might be useful for a summer crop.
Methods
In 1981, 37 cultivars or lines of cauliflower were seeded in a glasshouse on April 10 and were transplanted to the field on May 15. In 1982, seeding date for the 24 cultivars was April 19 and transplant date was May 24. Land preparation in both years included broadcast and incorporation of 1,120 kg/ha of 10-20-10, 56 kg/ha Epsom salts, 2 kg/ha boron, 6 kg/ha of Fritted trace elements, 0.84 kg/ha trifluralin, and 2 kg/ha fonofos. Diazinon, as a 1 kg/ha drench, was applied in June when root maggot damage became apparent. In 1981, N was sidedressed as ammonium nitrate at 56 kg/ha on June 23. In 1982, an additional 45 kg N/ha was applied as calcium nitrate on June 15 and 45 kg N/ha as ammonium nitrate on June 29. Plant spacing was 0.91 m x 0.45 m. Each variety was replicated three times in randomized block design. Heads were harvested at three-day intervals from July 6 to July 30.
Results
1981
Weather during the 1981 harvest period was not very conducive to poor curd quality. High temperatures ranged from 94 to 98°F on July 3-5, immediately before first harvest on July 6. This may have lowered quality for early varieties such as Alert, King, and Snow Crown. Temperatures were then mild until July 15-17, when highs of 82 to 88 were reached. Temperatures then remained under 80° until the very end of the harvest period. For the entire harvest period, the high temperature averaged 72°,he low averaged 53°.
Highest yields were obtained with Snowcrown, Alert, King, and Dok Elgon, but of these only Dok Elgon had acceptable curd quality (Table 1). The other three cultivars were slightly overmature at first harvest. Best quality curds were found in Dominant, Maveron, Self-blanche, Silverstar, Dok Elgon, Delira, Snowball 16, and White Summer. Quality was based on white color, firmness, lack of leaves or bracts in the curd, and depth of curd.
1982
Weather conditions during harvest were moderately conducive to poor curd quality. From July 6 to July 30, the mean maximum temperature was 81°, exceeding 85°F seven times. The mean minimum temperature was 52°F. This may have contributed to the generally lower percentage of high quality heads harvested in 1982 as compared to 1981.
Highest gross yields were obtained with Snowball Y and two seed lots of Rijk Zwaan Type 165 (Table 2). Snowball Y failed to produce high quality heads, and its yield of Grade #1 heads was below average. Highest yields of Grade #l heads were from the two seedlots of Type 165, Silverstar, White Summer, and Dominant.
Of the 24 cultivars in the 1982 trial, 18 were also evaluated in 1981 and 5 were evaluated in 1978. Head weights were generally greater in 1982 than in 1981. Cultivars performing well in both 1981 and 1982 included Dominant, Silverstar, and White Summer. Those performing average or better in 1978 or 1981 but poorly in 1982 included Dok Elgon, Delira, Marva Record, Maveron, Self-blanche, Snowball Y, Snowball 16, Venus, and White Empress. Consistently average cultivars included Imperial 10-6, Type 338A, and King. Repeated trials will be necessary to evaluate the long-term potential of these cultivars. Descriptions of cultivars are found in Table 3.
Table 1. Yield and Grade of Summer Cauliflower, 1981 Harvest % #1Z Mean head Yield of #1 Gross yield Cultivar span heads wt.(g) heads (MT/ha) (MT/ha) Alert 7/6 (all)Y 0 882 0.0 21.4 Begum 7/6-7/14 31 506 3.2 12.2 Balanza 7/6-7/10 27 596 3.6 14.4 Climax 7/6-7/17 44 373 4.3 9.0 Dok Elgon 7/10-7/17 71 709 13.1 17.1 Delira 7/6-7/17 75 519 9.9 12.6 Dominant 7/10-7/20 77 640 11.0 15.5 Extra Early Snowball 7/6-7/10 44 542 5.6 13.1 Fortados 7/6-7/10 50 529 7.2 12.9 Hornstar 7/6-7/14 19 369 1.6 9.0 Hormade 7/6-7/17 50 463 7.4 11.3 Imperial 10-6 7/6-7/17 50 631 8.1 15.3 Idol Original 7/6-7/14 22 491 2.5 11.0 Kibo Giant 7/6-7/14 13 658 1.8 15.8 King 7/6 (all)Y 31 819 7.7 19.8 Lawyna 7/17-7/27 0 386 0.0 8.8 Le Cerf 7/10-7/17 13 257 1.4 6.3 Lero 7/17-7/20 0 216 0.0 5.2 Marva Record 7/6-7/10 53 623 8.8 15.1 Maveron 7/6-7/17 81 494 9.5 11.9 MSU 817 All riced before 7/6, no measurements made Nevada 7/6-7/17 50 341 4.3 8.3 Polar Ice 7/10-7/27 13 496 1.4 12.8 Self-blanche 7/6-7/20 80 517 10.1 12.4 Silverstar 7/10-7/20 81 537 10.6 13.0 Snowball Y 7/6-7/17 60 641 8.1 15.5 Snowball 16 7/6-7/20 69 484 8.8 11.7 Snowball 123 7/6-7/14 63 446 7.9 10.8 Snowcrown 7/6 (all)Y 13 1009 2.3 24.3 Snowmound 7/6-7/20 56 385 5.9 9.2 Torina 7/6-7/20 7 512 0.5 12.4 Venus 7/6-7/14 63 646 10.5 15.5 White Empress 7/6-7/10 50 514 7.5 14.9 White Summer 7/6-7/20 69 484 9.0 11.7 White Top 7/6-7/17 40 430 6.5 10.3 Type 338A 7/6-7/17 50 504 5.7 12.1 Type 404 Y 7/17-7/27 0 244 0.0 5.4 ZTo achieve grade #1, heads must weigh at least 400g, have white curds, and be free of defects such as leaves in head, loose or knobby curds. YSlightly overmature at first harvest. Table 2. Yield and Grade of Summer Cauliflower, 1982 Gross Yield of Harvest span Mean head yield #1 heads %, #1 Cultivar First Peak Last wt. (g) (MT/ha) (MT/ha) heads Alert 7/06 7/08 7/13 486 10.8 5.4 55 Dok Elgon 7/16 7/19 7/26 777 16.9 4.5 22 Delira 7/13 7/19 7/20 558 12.8 4.3 26 Dominant 7/15 7/19 7/21 793 18.0 8.8 40 Imperial10-6 7/13 7/19 7/21 797 18.4 4.7 32 King 7/13 7/13 7/15 959 18.7 6.8 38 Marva Record 7/13 7/15 7/15 850 18.9 1.1 6 Matra 7/15 7/19 7/23 698 16.9 1.6 8 Maveron 7/13 7/13 7/15 677 15.8 2.3 14 Self-blanche 7/13 7/19 7/21 706 15.1 1.4 7 Snowball Y 7/15 7/19 7/26 899 21.8 4.5 17 Snowball 16 7/13 7/19 7/21 836 18.4 0.0 0 Snowball 42 7/13 7/19 7/30 813 19.8 2.3 13 Snowball 76 7/13 7/19 7/30 856 19.8 2.3 9 Snowcrown 7/06 7/13 7/13 469 12.2 1.4 18 Silverstar 7/13 7/19 7/30 701 16.5 14.0 83 Suprimax 7/13 7/15 7/09 706 17.1 4.1 21 Venus 7/06 7/13 7/15 761 18.4 5.0 23 White Empress 7/08 7/13 7/19 572 14.0 1.6 13 White Summer 7/13 7/15 7/30 648 16.5 9.9 60 Type 165 Lot 2320 7/19 7/21 7/30 920 20.5 19.8 95 Type 165 Lot 9238 7/19 7/26 7/30 894 20.9 17.8 91 Type 338A 7/08 7/13 7/21 581 13.6 6.8 43 LSD (.05) 155 4.1 4.5 18 Table 3. Sources of Cauliflower Varieties and Comments, 1981 and 1982 Cultivar Source Comments Alert 8Z Plants medium size. Upright stovepipe but few wrapper leaves. Harvested overmature in 1981. Leaves in curd. Begum 1 Plants medium size, upright. Small bracts in heads. Some purple curds. Balanza 1 Plants large, spreading. Rices easily. Climax 1 Plants medium size, upright. Small heads, fair quality. Dok Elgon 3 Plants medium size, upright. Large head, tight curds, good quality. Some leaves in curd. Mid-maturity. Delira 3 Plants large; wrinkled, dark green leaves. Small to medium heads, good quality, but leaves in head. Mid-early. Dominant 3 Plants medium size, spreading. Medium to large heads with good cover. Good quality. Mid-maturity. Extra Early Snowball 8 Plants small, spreading. Medium heads, Fair quality. Rice easily. Fortados 7 Plants small, spreading. Early heads, good quality. Later heads yellow. Hornstar 1 Plants small, spreading. Small heads. Hormade 1 Plants medium size, spreading. Side shoots. Many heads with purple curd. Imperial 10-6 4 Plants large, spreading. Good quality but rices easily; large heads with some leaves in curd. Mid-early. Idol Original 8 Plants medium size, upright. Ricey, yellow and purple curds. Kibo Giant 3 Plants large, upright. Large heads, purple curds. King 3 Plants large, upright. Large heads. Rices easily, bracts in curd. Mid-early. Lawyna 3 Plants medium size, spreading. Small heads. Knobby, conical florets. Le Cerf 3 Plants medium size, spreading. Small heads, poor quality curds. Lero 1 Plants small, spreading. Small heads. Poor quality curds. Marva-Record 2 Plants medium size with good cover. Medium to large heads. Matra 7 Medium size, semi-spreading plant. Fair curd cover. Fair head size and yield but leaves, bracts in curd. Mid-maturity. Maveron 1 Plants medium size, spreading. Small to medium heads, good quality curd with leaves and bracts. Mid-early. MSU 817 12 Plants small, upright, but poor curd cover. Heads small, ricey. Nevada 3 Plants medium size, upright. Small heads, fair to good quality curd. Polar Ice 5 Plants medium size, upright. Small to medium heads, small bracts in curd. Self-blanche 4 Plants medium size, stovepipe, good cover but few wrapper leaves. Fair quality curds, sometimes fuzzy, yellow. Mid-maturity. Silverstar 10 Plants small, spreading. Medium heads. Very good curd quality. Mid-late. Snowball Y 4 Plants medium large, spreading. Medium to large head. Average curd quality. Mid-late maturity. Snowball 16 9 Plants medium large, upright. Head small to medium size. Snowball 42 13 Medium-large semi-upright plants with good cover. Good head size and yield but bracts, leaves in curd. Mid-late. Snowball 76 13 Medium-large spreading plants with fairly good curd cover. Good head size and yield but bracts, leaves in curd. Mid-late. Snowball 123 4 Plants medium large, upright. Heads small. Good curd quality. Snowcrown 6 Plants medium large, spreading. Heads large, overmature. Purple curds. Early. Snowmound 8 Plants medium size, spreading. Small heads. Good curd quality. Suprimax 7 Medium size semi-upright with fair cover. Riced easily. Mid-early. Torina 2 Plants medium size, upright, poor curd cover. Small to medium heads; conical, knobby curds. Venus 1 Plants medium size, upright. Large heads, good curd quality but bracts in curd. Early. White Empress 14 Plants medium size, spreading. Medium heads, some with bracts. Fuzzy, ricey. White Summer 8 Plants medium large, upright, dark green. Average size heads with good quality. Large spread in maturity. White Top 8 Plants medium size, upright. Many discolored curds. Type 165, 2320 and 9238 10 Medium large semi-upright with good cover. Excellent yield and curd quality. Late maturity. Type 338A 11 Plants medium size, upright. Medium heads. Fair curd quality. Type 404 Y 11 Plants medium large, spreading. Small heads. Very late. Leaves in head. Z1=A.R. Zwaan, 2=Bejo Zaden, 3=Elsoms Seeds Ltd., 4=Harris Seeds, 5=Hurst, Gunson, Cooper, Taber Ltd., 6=Burpee Seeds, 7=Royal Sluis, 8=Stokes, 9=Northrup King, 10=Rijk Zwaan, ll=Roger Bros., 12=Michigan State University, 13=Ferry Morse, 14=Moran