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 is valuable as a rotation crop because of the soil-improving qualities of its residues and its N2-fixing capability. Because of the high-value irrigated crops typically grown in the Snake River Valley, soybeans may be economically feasible only at high yields.
Soybean varieties developed for the midwestern and southern states are not necessarily well adapted to Oregon's 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 eastern 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). There is also a need to identify semi-dwarf cultivars that will grow and yield well under high seeding rates and narrow row spacing. Yields could also be increased by increasing the seeding rate from 200,000 seeds/acre to 300,000 seeds/acre if semi-dwarf lines adapted to local conditions could be identified.
M. Seddigh and G. Jolliff at Oregon State University, Corvallis, identified a soybean line that would fill pods when subjected to cool night temperatures. Those lines were crossed at Corvallis with productive lines to produce 'OR 6' and 'OR 8', among others. At this point, the development moved to Ontario, OR. The later two lines were crossed at our request for several years with early-maturing high-yielding semi-dwarf lines by R.L. Cooper (USDA, ARS, Wooster, OH) to produce semi-dwarf lines with potential adaptation to the Pacific Northwest. Selection criteria at the Malheur Experiment Station included high yield, zero lodging, zero shatter, low plant height, and maturity in the available growing season. 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. Eighteen selections were found promising and selected for further testing in larger plots in 1994 and 1995. Starting in 1995, all lines were planted at 300,000 seeds/acre. This report summarizes work done in 2000 as part of the continuing breeding and selection program to adapt soybeans to eastern Oregon.
The 2000 line evaluation trial was conducted on Owyhee silt loam previously planted to wheat. The herbicide Dual at one lb ai/acre was broadcast preplant and incorporated with a bed harrow on May 9. Seed was planted on May 12 at 200,000 seeds/acre in rows 22 inches apart. Rhizobium japonicum soil-implant inoculant was applied in the seed furrow at planting. Emergence began on May 19. The crop was furrow irrigated as necessary. Eight of the single plant selections from 1992, nine cultivars, and 'OR 6' and 'OR 8' were planted in replicated plots four rows wide by 25 ft long in 2000. The experimental design was a randomized complete block with four replicates. All plots were cut to 22 ft.
Plant height and reproductive stage were measured weekly for each cultivar. Stand counts were made in 3 ft of row in each plot in 1996, 1997, 1999, and 2000. Prior to harvest, each plot was evaluated for lodging and seed shatter. Lodging was rated as the degree to which the plants were leaning over (0 = vertical, 10 = prostrate). The middle two rows in each four-row plot were harvested on September 26 using a Wintersteiger Nurserymaster small plot combine. Beans were cleaned, weighed, and oven dried to determine moisture content. Dry bean yields were corrected to 13 percent moisture. Data were analyzed by analysis of variance. Means separation was determined by the protected least significant difference (LSD) test.
Results and Discussion
Yields ranged from 37 bu/acre for 'OR-8' to 60 bu/acre for 'Korada'(Table 1). Lodging ranged from zero to two for the 1992 single plant selections and from zero to seven for the other cultivars. Of the 1992 single plant selections, 'M92-085', 'M92-213', and 'M92-330' had seed counts sufficient for the manufacturing of tofu (< 2,270 seeds/lb) in 2000 (Table 2). The cultivars 'M92-330', 'OR-8', 'Evans', and 'Sibley' had seed counts of less than 2,270 seeds/lb every year that seed counts were made. The lines 'M92-085' and 'M92-213' combine early maturity, no shatter, no lodging, seed counts and hilum color adequate for tofu (Table 3). The lines 'M92-225' and 'M92-237' made reasonable tofu in food quality tests in 1999.
In 1995 the planting rate was increased from 200,000 to 300,000 seeds/acre (Table 4). In 1999 the seeding rate was reduced to 200,000 seeds/acre. However, plant populations in 1996 and 1997 were not different from 1999 (Table 5). Plant populations were below the target of 300,000 plants/acre in 1996 and 1997 and 200,000 plants/acre in 1999 and 2000.
Table 1. Performance of soybean cultivars, Malheur Experiment Station, Oregon State University, Ontario, OR, 2000.
|Cultivar||Days to maturity*||Days to harvest maturity†||Lodging||Shatter||Height||Yield||Seed count||Hilum color|
|days from emergence||0-10‡||percent||cm||bu/acre||seeds/lb|
|*Pods yellowing, 50 percent of leaves yellow.|
|†Stems dry enough to be combined, 95 percent of pods brown.|
|‡0 = none, 10 = 100 percent lodging.|
Table 2. Seed counts for soybean cultivars for 5 years, Malheur Experiment Station, Oregon State University, Ontario, OR, 2000.
|---------------------------- seeds/lb ---------------------------|
Table 3. Maturity (days from emergence), lodging (0-10), and height (cm) of soybean lines, 1994-2000, Malheur Experiment Station, Oregon State University, Ontario, OR, 2000.
Table 4. Yield of soybean cultivars in 7 years; Hail depressed yields in 1998. Malheur Experiment Station, Oregon State University, Ontario, OR, 2000.
|---------------------------------------- bu/acre -------------------------------------------|
Table 5. Plant population for soybean cultivars for 4 years, Malheur Experiment Station, Oregon State University, Ontario, OR, 1999.
|------------------------------ plants/acre -----------------------------|