Overwintered Onion Variety Trial, 1977-1978

Methods

The trial was conducted on a Willamette silt loam, pH 5.8. Seed sources were Moran Seed Co. (Advance), Vilmorin (French lines), and Takii (all others). Plots were seeded on August 1, August 20, and September 20, 1977, with four replications of each variety at each planting date. Plots were a 10-foot section of a single row. Initial fertilizer application consisted of 1,700 pounds/acre of 10-20-10 incorporated into the seedbed along with 2 pounds/acre of diazinon. DCPA (Dacthal) at a rate of 9 pounds/acre was applied and irrigated in immediately after planting. An additional 300 pounds/acre of ammonium nitrate was applied on January 27 and again on March 8. All plots were harvested on June 30, 1978.

Results

Although there was considerable variability in rate and percent of emergence of the various lines, an acceptable initial stand was obtained in every case. However, the third planting was killed during the winter. Apparently the plants had not achieved sufficient size to overwinter successfully. Both the first and second plantings overwintered successfully but with considerable losses and damage from diseases and apparent fertilizer burn. Consequently, the yield data obtained did not include four replicates for each variety and were not subjected to statistical analysis. In contrast to a preliminary trial in 1976-1977, all varieties experienced a significant degree of seed-head formation in the spring. On April 21, Express Yellow, Kaizuka, Extra Early, and Advance had the highest percentage (over 30 percent) of bolters, while Mulhouse de Auxonne and Senshyu Yellow Globe had the smallest percentage (less than 10 percent).

Yield data for the best replicate for each variety in the first planting are shown in Table 1. Data for the second planting are in Table 2. The varieties Presto, Advance, and Senshyu Yellow Globe were the highest yielders at both planting dates. Yield was much smaller at the second planting date, except for the varieties Hatif de Paris and Keep Well. Largest bulb size was obtained with the varieties Senshyu Yellow Globe, Presto, Keep Well, and Express Yellow, but very acceptable size and quality were obtained with several other varieties. Bulb size was much smaller at the second planting, except for Hatif de Paris and Presto. All varieties had tops down at harvest except for those noted in Table 1 as having unusually large necks. Planting date did not greatly affect degree of bolting. The earlier planting data gave superior yields, at least for this season.

  Table 1. Yield per plot and mean bulb weight of overwintered onions, first           planting, August 1, 1977                                                    Variety                Yield       Rank    Mean bulb    Rank    Comments                       lb/20 feet            size, lb                                  Advance                50.6          2        0.55       6      Med. large,                                                                  yellow,globe  Dragon Eye             46.3          3(tie)   0.58       4(tie) Med. large,                                                                  yellow,squat  Express Yellow         23.2         10        0.58       4(tie) Med. large, yellow,                                                                  squat to globe  Hatif de Paris         22.8         11        0.34      11      Med., very                                                                   white, squat  Hatif de Vaugirard     30.3          9        0.47       7(tie) Med. large,                                                                  green-white, squat  Imai                   16.1         13        0.67       3      Large,yellow, squat  Kaizuku Extra Early    31.8          8        0.47       9      Med. large, yellow,                                                                  squat to globe  Keep Well              14.3         14        0.89       1      Very large,                                                                  yellow, globe  Mulhouse de Auxonne    39.6          5        0.27      14      Small bulb, large                                                                  neck, yellow globe  Mulhouse de Selestat   35.2          6        0.42      10      Small bulb, large                                                                   neck, yellow globe  Paille des Vertes      20.8         12        0.33      12      Small bulb, large                                                                  neck, yellow globe  Presto                 62.6          1        0.47       7(tie) Med. large, yellow                                                                  squat  Printanier Parisien    34.6          7        0.27      13      Small, white, squat  Senshyu Yellow Globe   46.3          3(tie)   0.68       2      Large,yellow,                                                                  squat to globe           Table 2. Yield per plot and mean bulb weight of overwintered onions,   second planting, August 20, 1977                                        Variety                     Yield       Rank      Mean bulb    Rank                            lb/20 feet              size, lb              Advance                     34.0          2         0.28       6 (tie)  Dragon Eye                  14.6          8         0.28       6 (tie)  Express Yellow              16.1          6         0.40       3  Hatif de Paris              21.6          4         0.32       5  Hatif de Vaugirard          15.6          7         0.20      11 (tie)  Imai                        10.0         10         0.28       6 (tie)  Kaizuku Extra Early          4.4         14         0.22      10  Keep Well                   19.4          5         0.37       4  Mulhouse de Auxonne          6.1         12         0.14      13  Mulhouse de Selestat         7.6         11         0.24       9  Paille des Vertes            5.5         13         0.12      14  Presto                      41.0          1         0.46       1  Printanier Parisien         12.1          9         0.20      11 (tie)  Senshyu Yellow Globe        26.4          3         0.41       2        

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