2005 Annual Report
Dickinson Research Extension Center
1089 State Avenue
Dickinson, ND 58601
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Evaluation of Alfalfa Varieties Solid Seeded into Cropland
Llewellyn L. Manske PhD
North Dakota State University
Dickinson Research Extension Center
An alfalfa variety trial that included both Medicago sativa and Medicago falcata was conducted to evaluate the performance of hay- and pasture-type alfalfas under the environmental conditions of western North Dakota. The performance of the alfalfa varieties was compared to the performance of Vernal, which was selected as the standard variety because of its long record of high production across the northern United States. The study was conducted at the Dickinson and the Hettinger Research Extension Centers from 1979 through 1985. Results from the study were presented in papers by Manske and Goetz (1984a and 1984b), Manske (1985), and Manske and Conlon (1986), which are summarized in this report.
Alfalfa variety plots of 10 X 25 feet were arranged in a randomized block design with four replications at Dickinson and three replications at Hettinger. Alfalfa was solid seeded into cropland that had been previously used for annual cereal production. The Dickinson site was seeded May 1979, and the Hettinger site was seeded May 1981. The alfalfa plots were managed with a simple one-cut system, and the alfalfa was swathed and baled for hay at the full flower stage, usually during late July or early August. Alfalfa variety herbage biomass production data were collected by the clipping method. Five quarter-meter frames per plot were clipped at the early flower stage, during late June or early July. The herbage samples were oven dried at 140°F. Alfalfa plant density was determined by a count of the number of individual plants rooted within each quarter-meter frame before the herbage biomass was clipped. Mean stem weight was determined from the weight of one hundred individual stems selected from the oven-dried herbage material.
Root rot damage was determined from three to six plants excavated from each plot during August of the seventh growing season. The crown and primary root were divided into two pieces by a cut on the center line. The outside diameter of the main root and the diameter of the infected and damaged portions were measured across the root at the base of the crown. The length of the damaged root tissue was determined in one-third-inch increments starting at the point where the root could be identified from the crown. An index scale rating relative severity of damage caused by alfalfa root rot was developed to assist with evaluation of the damage levels observed in alfalfa plants.
Twenty-four varieties of alfalfa were evaluated during this study. Fourteen varieties were developed by university or government plant breeders working at public research facilities, and ten varieties were developed by plant breeders in private industry (table 1). The alfalfa varieties were categorized into types based on the sources of the parent material (table 2). The four alfalfa types were northern pasture types, Ladak hay types, Vernal hay types, and a general group of Mid West hay types.
Precipitation during the study period occurred at the regional extremes from drought to wet conditions (table 3). The spring months, April through June, had rainfall that ranged from 2% to greater than 200% of the long-term mean monthly precipitation. The seeding year at the Dickinson site, 1979, had low rainfall during May. The following year was considered to have a drought growing season with water deficiencies in April and May, and the precipitation was less than half the normal level during April through June. The seeding at the Hettinger site was postponed in 1980 because of the low soil water that spring. Low rainfall occurred in April and May of 1981. High rainfall occurred in April and May of 1982, and greater-than-normal precipitation occurred in June. Very high rainfall occurred in August, September, and October of 1982. In 1983, low rainfall occurred during April and May, and greater-than-normal precipitation occurred in June. April and June of 1984 were wet months, and a water deficiency occurred in May. Low rainfall occurred during April and June of 1985, and May was a wet month.
The precipitation levels during April through June influenced the herbage production of the alfalfa varieties. Herbage production during the drought year of 1980 was very low, with most varieties producing between 200 and 400 pounds per acre. During 1981, a recovery year that had two spring months with low rainfall, alfalfa herbage production was about a third of the potential production. Herbage production was high during 1982, 1983, and 1984 as a result of favorable conditions, including high precipitation during at least one spring month or high rainfall during the fall of the previous year. In 1985, the herbage production was less than half the potential. Some of this reduction resulted from low rainfall during two spring months, and some of the reduction was caused by other factors.
The annual aboveground herbage biomass production for each variety (table 4) was very similar. No significant differences among the varieties were found at the Hettinger site (Manske and Goetz 1984a) or at the Dickinson site, except that one variety, Kane, had greater herbage biomass than the other varieties in 1982 (Manske and Goetz 1984b).
Most alfalfa varieties had mean herbage production greater than 4000 lbs/ac during the three years with favorable precipitation, 1982 to 1984 (table 4). Three varieties produced an average of less than two tons of herbage per acre, Agate, Polar II, and 532. The three-year mean herbage biomass produced by the pasture types, Ladak types, Mid West hay types, and Vernal types were 4569, 4484, 4214, and 4198 pounds per acre, respectively. Vernal produced an annual average of 4190 lbs/ac during 1982 to 1984. The varieties with three-year mean herbage production 105% or greater than that of Vernal (table 5) were Drylander (4800 lbs/ac), Spredor II (4792 lbs/ac), Ladak 65 (4659 lbs/ac), Kane (4634 lbs/ac), Ladak (4576 lbs/ac), Prowler (4545 lbs/ac), Nugget (4541 lbs/ac), Norseman (4488 lbs/ac), 520 (4468 lbs/ac), Rangelander (4466 lbs/ac), Polar I (4461 lbs/ac), and Travois (4440 lbs/ac) (table 4).
Vernal has performed well in western North Dakota. Most of the varieties in the trial performed as well as or better than Vernal (table 5). Only three varieties, Agate, Polar II, and 532, consistently performed more poorly than Vernal. The pasture-type alfalfas and the Ladak-type alfalfas generally performed at levels greater than Vernal under a one-cut system in western North Dakota. Both the pasture- and Ladak-type alfalfas have M. falcata as 45% to 100% of their parentage. Vernal has M. falcata as about 33% of its parentage.
The amount of herbage biomass produced per acre is determined by the height and weight of each stem and by the density of the alfalfa plants. The mean weight of individual stems did not differ among the alfalfa varieties: the stems of most varieties weighed between 0.25 and 0.50 ounces, with between 64 and 32 stems required to weigh one pound (table 6). The plant density per square foot did not differ among the alfalfa varieties. The density of most alfalfa varieties was between 3.0 and 4.0 plants per square foot (table 7).
The performance of alfalfa varieties can be influenced from attacks by pests. The major pests of alfalfa include fungi, bacteria, viruses, nematodes, and insects. These pests can cause plant diseases and tissue injury that can result in substantial reductions in herbage production and quality. The vulnerability of plants to attacks from pests varies greatly among the different alfalfa varieties, which range from susceptible (S) to resistant (R) to the attack of individual pest types.
Resistance to bacterial wilt was the first physiological trait alfalfa breeders tested and reported as showing variations in response to plant pests among alfalfa varieties. The resistance ratings for the alfalfa varieties in this trial are included in table 8. Most alfalfa varieties grown in the Northern Plains are resistant to bacterial wilt. This disease is generally not a problem for dryland alfalfas in North Dakota because the bacterium requires warm, moist conditions to develop serious infections.
Root rot, a disease caused by soil-borne fungi, is widespread across North America. The disease infects the woody centers of the roots and slowly progresses outward. The extent of root rot damage to the primary root ranged between 35% and 50% of the root diameter at the base of the crown for most alfalfa varieties in this trial (table 8). Travois had the lowest percent damage to the root, 26.8%. The length of the root rot damage ranged between 1.00 and 2.33 inches into the root from the base of the crown. This level of tissue damage from root rot was considered moderate. Every variety in the trial had some root rot damage; however, none of the varieties had severe damage. Moderate levels of root rot damage could cause reductions in herbage production, decreases in tolerance to cold and dry conditions, and diminished resistance to other diseases and pests.
The similarity in performance among the varieties in this trial resulted because of the similarities in the sources of parental germplasm. The alfalfa varieties that perform well in Canada and the northern United States have a high proportion of parental material originating from a few accessions, Grimm ( M. media ), Cossack ( M. media ), Don Siberian ( M. falcata ), Orenburg Siberian ( M. falcata creeper), Semipalatinsk Siberian ( M. falcata creeper), and Ladak ( M. falcata ).
Vernal was developed in Wisconsin from parental material selected from plants that had survived the environmental extremes of the Plains in old fields that had been planted with seed produced from the early accessions of plant material introduced from Siberia and southern Asia into North America during the first decades of the 1900's. Vernal has performed well under a wide range of environmental conditions of the United States and Canada and has become the standard variety to which alfalfa breeders and researchers compare all other varieties.
The improved performance level of the pasture- and Ladak-type alfalfa varieties appeared to be related to the amount of M. falcata in their parentage. The two major species of perennial alfalfa grown in North America are M. sativa, which has dark blue or purple flowers, and M. falcata, which has white or yellow flowers. The natural cross between them is M. media , which has variegated flowers. The M. sativa alfalfas have large rounded leaves and tend to have one main tap root growing from a narrow raised crown. The M. falcata alfalfas (Ladak types) have lanceolate leaves and have numerous branching roots growing from a moderately wide crown. The M. falcata alfalfas (pasture types) have smaller narrow lanceolate leaves and an extensive branching root system that grows from a wide crown located mostly below ground level. The pasture types are creeping alfalfas and can reproduce vegetatively from rhizomes, which are horizontal underground stems.
The varieties with high proportions of M. falcata perform well when managed with a one- or two-cut system because they recover relatively slowly after cutting and reduce aboveground production during late summer and early fall. The varieties with a high percentage of M. falcata parentage have very high tolerance to cold and dry conditions and persist through adverse conditions.
The varieties with high proportions of M. sativa tend to produce greater quantities of herbage than M. falcata varieties during growing seasons with favorable precipitation because M. sativa varieties recover rapidly after cutting and can be harvested several times per year. However, during dry growing seasons, herbage production of M. sativa varieties tends to be much lower than that of M. falcata varieties. The varieties with a high percentage of M. sativa parentage have lower cold tolerance and are susceptible to winterkill in the Northern Plains; these traits result in short stand longevity.
The alfalfa varieties included in this study had been previously tested at other locations in North America and had performed well. The objective of this trial was to determine if these varieties also performed well in western North Dakota. All of the varieties performed as well as or slightly better than Vernal. The parental origins of the varieties in this trial were similar, and the varieties that performed a little better had sources with a higher percentage of M. falcata . The traits that predispose plants to tolerance of adverse cold and dry conditions are derived from the M. falcata germplasm. The alfalfa varieties that can be successfully grown under the conditions of western North Dakota have high percentages of M. falcata in their parentage.
I am grateful to Sheri Schneider for assistance in production of this manuscript and for development of the tables and figures. I am grateful to Amy M. Kraus for assistance in preparation of this manuscript. I am grateful to Lisa J. Vance for digitizing the figures.
Manske, L.L., and H. Goetz. 1984a. Alfalfa variety trial, 1982-1984, at the Hettinger Experiment Station. Progress Report. North Dakota State University Agricultural Experiment Station. Fargo, ND. 7p.
Manske, L.L., and H. Goetz. 1984b. Alfalfa variety trial, 1980-1984, at the Dickinson Experiment Station. Progress Report. North Dakota State University Agricultural Experiment Station. Fargo, ND. 8p.
Manske, L.L. 1985. Alfalfa variety trial, 1980-1985. Range Research Annual Report. Dickinson Experiment Station. Dickinson, ND. p. 297-303.
Manske L.L., and T.J. Conlon. 1986. Alfalfa variety performance trial. Annual Report. Dickinson Experiment Station. Dickinson, ND. p. 36-39.
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