Erik Feibert, Clint Shock, and Monty Saunders
Malheur Experiment Station
Oregon State University
Ontario, Oregon, 1995
Soybean is a potentially valuable new crop for Oregon. Soybean could provide a high quality protein for animal nutrition and oil for human consumption, both of which are in short supply in the Pacific Northwest. In addition edible or vegetable soybean production could be exported to the Orient and provide a raw material for specialized food products. Soybean would also be a valuable rotation crop because of the soil improving qualities of its residues and N2-fixing capability.
Because of the high value irrigated crops in the Snake River valley, soybeans may be economically feasible only at high yields. Hoffman and Fitch in 1972 demonstrated that Evans soybeans adapted to Minnesota could yield 50 to 65 bushels/acre at Ontario. The most productive lines averaged 60-65 bushels/acre for several years. Furthermore, yields were increased by approximately 20 percent for certain cultivars by decreasing row widths to 22 inches. Yields could also be increased by increasing the seeding rate from 200,000 seeds/ac to 300,000 seeds/ac if semi-dwarf lines were found adapted to local conditions.
Soybean varieties developed for the midwestern and southern states are not necessarily well adapted to Oregon due to lower night temperatures, lower relative humidity and other climatic differences. Previous research at Ontario has shown that, compared to the commercial cultivars bred for the midwest, plants for Oregon need to have high tolerance to seed shatter and lodging, reduced plant height, increased seed set, and higher harvest index (ratio of seed to the whole plant). In addition there is a need to identify cultivars that will grow and yield well under high seeding rates and narrow row spacing.
In 1992, 241 single plants were selected from five F5 lines that were originally bred and selected for adaptation to eastern Oregon. Seed from these selections was planted and evaluated in 1993. A total of 18 selections were found promising and selected for further testing in larger plots in 1994 and 1995. This report summarizes work done in 1995 as part of the continuing breeding and selection program to adapt soybeans to Eastern Oregon.
The 1995 trials were conducted on a Greenleaf silt loam previously planted to sugar beets. Dual at 1 lb ai/ac was broadcast and incorporated with a bed harrow on May 9. Seed was planted on May 15 at 300,000 seeds/acre in rows 22 inches apart. Rhizobium japonicum soil implant inoculant was applied in the seed furrow at planting. The crop was furrow irrigated as necessary.
Thirteen of the single plant selections from 1992, 11 single plant selections made in 1993, and 8 older cultivars were planted in replicated plots four rows wide by 25 feet long in 1995. The experimental design was a complete randomized block with five replicates. Fifteen single plant selections made in 1994 were planted in single rows 25 feet long.
Plant height and reproductive stage were measured weekly for each cultivar. Prior to harvest the cultivars were evaluated for lodging and seed shatter. The middle two rows in each 4 row plot and single rows from the single plant selection plots, were harvested on October 13 using a Wintersteiger Nurserymaster small plot combine. The beans were cleaned, weighed and oven dried for moisture content determination. Dry bean yields were corrected to 13% moisture. Single plant selections were cut at ground level, threshed in the small plot combine and labeled individually.
Results and Discussion
Emergence started on May 22 and was poor due to inadequate soil moisture.
Yields ranged from 7 to 55 bu/ac (Table 1). Three
hail events on June 16, June 19, and July 29 decreased the performance
of all crops at the Malheur Experiment Station during the 1995 season.
The older cultivars, in general, lodged heavily and took too long to mature
or did not reach adequate harvest maturity for efficient combining. Seven
of the 1992 single plant selections reached physiological maturity in 115
days or less, had no lodging, and had seed sizes large enough for the manufacturing
of tofu (< 2,270 seeds/lb). Three of the 1994 selections matured in
115 days or less, had no lodging, and had seeds large enough for the manufacturing
of tofu (Table 2).
Table 1. Performance characteristics of soybean cultivars. Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1995.
|Cultivar||Days to maturity1||Days to harvest maturity2||Lodging||Shatter||Height||Yield||Seed count|
|days from emergence||0-103||%||cm||bu/ac||seeds/lb|
|1Pods yellowing, 50% of leaves yellow. 295% of pods brown, stems dry enough to be combined. 3 0= none, 10= 100 percent lodging. n= never reached harvest maturity.|
Table 2. Performance characteristics of single-plant soybean selections made in 1994. Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1995.
|Cultivar||Days to maturity1||Days to harvest maturity2||Lodging||Shatter||Height||Yield4||Seed count|
|days from emergence||0-103||%||cm||bu/ac||seeds/lb|
|1 Pods yellowing, 50% of leaves yellow. 2 95% of pods brown, stems dry enough to be combined. 30= none, 10= 100 percent lodging. 4Yields are not necessarily realistic due to lack of border, on single row plots. n= never reached harvest maturity.|