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Soybean Variety Selection
Although many producers have made their soybean variety selections, below are a few considerations that need to be evaluated before choosing varieties.
Yield Potential. By far, the most important criteria in selecting varieties should be the potential yield of that variety. Since yield varies from year to year and location to location, it is suggested that multi-year and location yield data from replicated experiments be used in selecting varieties. There is a tendency for one to choose varieties based only on local data, but it has been shown that variety rankings change little between locations and multiple locations allows for a more confident selection. Table 1 lists the top yielding varieties in the 1996-98 Virginia Official Variety Tests. Varieties listed are restricted to those that have been tested a minimum of two years and 6 locations. Yields are listed as relative yield. Relative yield is calculated by dividing the yield of that variety by the average yield of all varieties within a maturity group at an individual site. A variety with a relative yield of 105 was 5% above the average of all varieties. Relative yield is not actual yield, but a value relative to all other yield values. The number in parenthesis ( ) is the total number of site/years per cropping system that the variety was tested. The more site/years, the more confident the data.
Maturity. While yield is important, selecting the proper maturity group that fits the growing region and individual operation is just as, if not more important. Maximum potential yields can be met if the soybean crop can produce a "leaf area index" (LAI) of approximately 4.0 square feet of leaves per square foot of land. But, early maturity groups cannot always produce this needed leaf area because of the shorter growing season. Therefore, later maturity groups generally out-yield earlier maturity groups, especially if planted double-crop following small grain harvest. Below are long term average yield of varieties grouped by maturity for five locations. In general, late maturity group 4 and maturity group 5 yields best in Virginia. However, under good growing conditions, maturity group 3 or early 4 varieties can yield as well or better than later maturing varieties. Maturity group 6 varieties should only be grown in areas in which an early autumn frost can be avoided. Although obtaining maximum soybean yields are important, harvest need to be accomplished in a timely manner or yield of the entire cropping system may suffer. While later maturity groups generally yield higher than early maturity groups, such varieties could delay small grain planting and lower the overall cropping system yield and profitability. There is approximately 10 days difference in maturity dates between maturity groups, therefore selecting high yielding varieties from multiple maturity groups is an excellent way to spread out the harvest. Remember that the relative yields shown in table 1 are based on a comparison with other varieties within that maturity group.
Full-Season Long Term Average Yields (1987-1998).
| Location | No. of Years | 3 | Early 4 | Late 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| Blackstone | 12 | --- | --- | --- | 42.2 | 39.3 |
| Orange | 11-12 | 41.5 | 39.2 | 40.7 | 39.4 | --- |
| Painter | 11-12 | --- | 42.2 | 45.8 | 43.5 | 43.1 |
| Suffolk | 10-12 | 52.3 | 54.7 | 55.7 | 50.0 | |
| Warsaw | 11-12 | 42.5 | 41.5 | 42.4 | 42.0 | --- |
Double-Crop Long Term Average Yields (1987-1998).
| Location | No. of Years | Early 4 | Late 4 | 5 |
|---|---|---|---|---|
| Painter | 10-11 | 32.6 | 33.3 | 35.7 |
| Suffolk | 9-11 | 38.3 | 38.2 | 42.1 |
| Warsaw | 9-10 | 34.7 | 39.3 | 37.7 |
Cropping System. Over half of the soybean grown in Virginia is planted double-crop following small grain harvest. Many of Virginia-grown varieties perform relatively better when grown in this system versus when grown full-season. There are also varieties that perform relatively better when grown in a full-season system. Therefore, the planting date should be a criteria involved in selecting varieties. Note in Table 1 that the best full-season varieties are not always the best double-crop varieties, and vice-versa.
Disease/Nematode Resistance. Soybean varieties contain resistance to various diseases that can rob the crop of yield. These include soybean mosaic virus, frogeye leafspot, phytophtora, stem canker, and nematodes. Probably the most significant is nematodes. There are several species present in Virginia. They include root-knot, lesion, stubby root, and soybean cyst nematode. Many soybean varieties with good yield potential carry resistance to soybean cyst nematode (Table 1), but few carry resistance to the other nematodes. Some varieties resist southern root knot (Meloidogyne incognita), but not northern root knot (Meloidogyne hapla). Therefore, do not assume that just because a soybean variety has cyst nematode resistance that is also has resistance to other nematodes.
Herbicide Resistance. Many soybean varieties carry resistance to Roundup and additional tolerance to sulfonylurea herbicides (STS varieties). These varieties have been extensively tested in the Virginia Soybean Variety Tests. Although a yield drag or lag was at first thought to be a problem, it is currently felt that many Roundup-Ready varieties are yielding as well as conventional varieties. STS varieties tend to be among the top yields. Below are graphs of two ways of comparing Roundup-Ready varieties with conventional varieties.
Relative yield of conventional & Roundup-Ready soybean varieties. Average of all varieties, 1997-98.
Relative yield of conventional & Roundup-Ready varieties. Average of top 5 varieties, 1997-98.
Other Value-Added Traits. Value-added traits are those traits contained in specific varieties that add value or increase the price of the crop. Currently, we have just one example of that. These are the small-seeded soybeans that are marketed directly to Japan for food consumption. Growers can currently contract with Montague Farms of Center Cross, VA to grow these varieties. Although a higher price per bushel is available, yield is not always as high as conventional varieties. Universities and seed companies are focusing on breeding in other value- added traits. These "specialty" soybeans should be available in the near future.
Table 1. Relative yield of soybean varieties grown in Virginia. Relative yield is calculated by dividing the yield of that variety by the average yield of all varieties at an individual site. Relative yield is not yield, but a value relative to all other yield values.
Relative performance of Maturity Group 3 Soybean Varieties, 1996-98.
| Brand | Variety | Nematode Resistance | Herbicide Resistance | Full-Season Relative Yield (# site/years) | Double-Crop Relative Yield (# site/years) |
|---|---|---|---|---|---|
| Terra | TS 415 | --- | --- | 109 (18) | 97 (5) |
| Terra | TS 387 | --- | --- | 109 (8) | 103 (5) |
| S. States | HT-381-STS | --- | STS | 108 (8) | 106 (5) |
| Asgrow | AG3701 | C3 | RR | 107 (8) | 109 (5) |
| Pioneer | 9395 | --- | --- | 105 (8) | --- |
| Asgrow | AG3601 | --- | RR | 102 (8) | 108 (5) |
| Public | Macon | --- | --- | 102 (11) | 98 (5) |
| Pioneer | 93B81 | --- | STS | 101 (8) | --- |
| S. States | RT-386 | --- | RR | 100 (8) | 109 (5) |
| Pioneer | 94B01 | C3,14 | RR | 99 (5) | 110 (8) |
Relative performance of early Maturity Group 4 Soybean Varieties, 1996-98.
| Brand | Variety | Nematode Resistance | Herbicide Resistance | Full-Season Relative Yield (# site/years) | Double-Crop Relative Yield (# site/years) |
|---|---|---|---|---|---|
| Asgrow | A4341 | --- | --- | 112 (12) | 91 (3) |
| Mycogen | 5430 | --- | --- | 110 (8) | 95 (8) |
| S. States | FFR-439 | --- | --- | 105 (13) | 102 (13) |
| Dynagro | DG 3444N | C3,14 | --- | 104 (9) | 99 (8) |
| Asgrow | AG4601 | C3,14 | RR | 104 (9) | 103 (8) |
| Public | Stressland | --- | --- | 103 (17) | 105 (13) |
| Public | Magellan | --- | --- | 103 (17) | 97 (3) |
| Pioneer | 9421 | --- | STS | 102 (9) | 104 (8) |
| NK | S42-60 | --- | --- | 100 (9) | 104 (2) |
| Pioneer | 94B41 | C3,14 | RR | 99 (9) | 99 (8) |
Relative performance of late Maturity Group 4 Soybean Varieties, 1996-98.
| Brand | Variety | Nematode Resistance | Herbicide Resistance | Full-Season Relative Yield (# site/years) | Double-Crop Relative Yield (# site/years) |
|---|---|---|---|---|---|
| Hoffman | 7484 | --- | --- | 111 (7) | 113 (5) |
| Mycogen | 470 | --- | --- | 109 (11) | 100 (12) |
| Pioneer | 9482 | --- | --- | 108 (16) | 105 (12) |
| AgriPro | AP4880 | --- | --- | 106 (9) | --- |
| Terra | TS 474 | --- | --- | 104 (12) | 108 (9) |
| Deltapine | DP 3478 | --- | --- | 104 (16) | 99 (12) |
| Pioneer | 9492 | C3,14 | RR | 100 (9) | 107 (7) |
| Public | Manokin | C3, Rai | --- | 100 (16) | 107 (12) |
| S. States | FFR-493 | --- | --- | 100 (16) | 100 (12) |
| S. States | FFR-478N | C3,14 | --- | 95 (8) | 93 (7) |
Relative performance of Maturity Group 5 Soybean Varieties, 1996-98.
| Brand | Variety | Nematode Resistance | Herbicide Resistance | Full-Season Relative Yield (# site/years) | Double-Crop Relative Yield (# site/years) |
|---|---|---|---|---|---|
| Pioneer | 9594 | --- | --- | 111 (15) | 95 (11) |
| S. States | FFR-553 | --- | --- | 107 (9) | 107 (3) |
| Pioneer | 9511 | --- | --- | 107 (9) | 110 (6) |
| AgriPro | AP 543RR | C3,14 | RR | 107 (8) | 107 (8) |
| Pioneer | 9552 | C3,14 | --- | 106 (9) | 104 (6) |
| Pioneer | 95B41 | C3, Ri | RR | 106 (5) | 105 (8) |
| Public | Delsoy 5500 | C3,14 | --- | 105 (17) | 103 (14) |
| Public | Clifford | --- | --- | 104 (18) | 107 (14) |
| Deltapine | DP 3519S | C3,9,14 | STS | 104 (14) | --- |
| Delta King | 5961RR | C3,14 | RR | 104 (9) | 104 (8) |
| S. States | RT-540N | C3,14 | RR | 104 (8) | 109 (8) |
| Deltapine | DP 5644RR | C3,14 | RR | 104 (8) | 109 (3) |
| Public | Hutcheson | --- | --- | 102 (23) | 103 (19) |
| S. States | FFR-563N | C3,14 | --- | 100(14) | 107 (11) |
| Pioneer | 95B71 | Ri | RR | 99 (9) | 108 (8) |
| Dynagro | DG 3530N | C3,14 | --- | 97 (5) | 108 (11) |
| Public | Wicomico | C3 | --- | 96 (17) | 105 (14) |
| Public | Accomac | C1,3,Ri | --- | 95 (17) | 98 (14) |
| AgriPro | AP 588RR | C3 | RR | 91 (3) | 110 (8) |
Relative performance of Maturity Group 6 Soybean Varieties, 1996-98.
| Brand | Variety | Nematode Resistance | Herbicide Resistance | Full-Season Relative Yield (# site/years) | Double-Crop Relative Yield (# site/years) |
|---|---|---|---|---|---|
| Public | Dillon | C3, Ri | --- | 105 (10) | --- |
| Hartz | H6686RR | C3,9, Ri | RR | 104 (7) | --- |
| Public | Brim | --- | --- | 104 (10) | --- |
| Hartz | H6255RR | --- | RR | 103 (7) | --- |
| Public | TN 6-90 | C3,14 | --- | 100 (7) | --- |
| Pioneer | 9631 | --- | --- | 98 (6) | --- |
| S. States | FFR-594 | --- | --- | 98 (10) | --- |
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