C4-Lancaster Farming, Saturday, February 9, 2002 A Summary Of Alfalfa Hybrid Performance In University Variety Trials Daniel W. Wicrsma Unixersity Of Wisconsin-Madison MADISON, Wis. While the potential of hybridizing al falfa has been demonstrated lor many years, producing large quantities ol seed has limited cummcicial development of hybrid allalfa. Seed production economics prompted the search tor less expensive ways to pro duce hybrid seed. In the spring of 2001, a new hybrid alfalfa variety (HybriForce-400) was released and sold on a commercial basis. II this and future alfalfa hy brids can contribute to forage yield like corn hybrids contrib uted to grain yields, then we have entered a new and exciting era. An examination ot the con cepts of breeding alfalfa hybrids and a look at current data on hybrid performance follows. Yield Trends Of Alfalfa And Corn Forage yield of alfalfa has in creased during the time period from 1919 to the present, based on USDA data. However, the in crease in yield has not been strictly linear. Yield trends remain flat until about 1955, and then increased steadily each year until the mid to late 1970’s after which yield gains stagnate. Early in the 20th century, yield gains of corn due to breed ing were minimal. Until the 19305, corn growers used prima rily open pollinated corn, and the average yield at that time was about 20 bu./ac. Following the development and adoption of corn hybrids, grain yields in creased steadily. Researchers report an average yield gain of 1-2 bu./ac. per year for corn (Hallaucr ct al., 1988). Today average corn yields in the US top 130 bu./ac., and modern hy brids regularly yield in the 200- 250 bu./ac. range. Several researchers have re ported on the contribution of breeding to alfalfa yield. These studies show that genetic yield gains of 0.15-0.3 percent per year have been obtained for al falfa since the late 1950 s (Hill et al., 1988; Holland and Bingham, 1994). A study by Loisellc (1992) indicates a one percent alfalfa yield gain per year for varieties release between 1997 and 1992. Analysis of alfalfa variety per formance studies at Universities in the Midwestern US indicate Richard Weiss Named COO Of National Grange WASHINGTON, D.C. The National Grange has named Richard Weiss as chief opera ting officer, a new position. As COO he will be responsible for the operational efficiencies and member services throughout the organization with emphasis on programs, membership develop ment and retention, financial controls, fund-raising systems, and operations. Weiss has worked with the National Grange as a communi cations consultant since 1999. Prior to that, he was senior vice president for public relations for the National Dairy Board and director of public relations for the National Paint and Coatings Are Hybrids The New Yield Force In Alfalfa? that there is no evidence to con clude that alfalfa yields have changed during the last two dec ades (Wicrsma et al., 1997). In fact this analysis indicates a slight decline in yield during this time period. Most recent ad vances in alfalfa varieties have been a result of breeding for pest resistance. When pest resistant varieties are grown in environments where pest development is fa vorable, there is a marked differ ence between resistant and susceptible varieties. However, in the absence of pest pressure, resistant varieties do not im prove yield over susceptible varieties. Overall, alfalfa genetic yield progress is very slow with accu mulated yield gains of about 10 percent to 15 percent during the last 50 years. Alfalfa Breeding Methods Like other species, the goal of breeding and selection of alfalfa for improved varieties involves a process of increasing the fre quency of desirable genes in the population of plants. In crosspollinated crops like corn and alfalfa, mass selection was the first type of genetic im provement undertaken. How ever, mass selection was not always effective in producing better varieties. Corn and alfalfa breeders began using other breeding methods for the devel opment of new varieties. With corn, the development ot vigorous inbred lines and the case of pollen control (i.e., detas seling) led to the development of hybrids. In contrast, breeding of alfalfa is predominantly accom plished through recurrent phe notypic selection methods because of economic limitations associated with hybridization in this crop. Recurrent selection is the identification of individual plants with superior perform ance for a given trait or group of traits. Once identified, the supe rior plants are intermated to produce a new population, called FI plants. The selection process then begins again on the improved population of plants. It usually takes two to five cycles of selec tion and reselection to exploit the genetic variability present in the population. Once a desirable population of plants is identified, plants are allowed to randomly intermate Association. His private sector experience includes marketing positions with The Keebler Company, Abbott Laboratories and the Alberto-Culver Company. He holds a master’s degree in busi ness administration from the Amos Tuck School of Business Administration at Dartmouth College and a bachelor of arts degree from Dartmouth College. “I am honored to be named COO of this fine organization. Under the ‘New Grange,’ Na tional’s mission is to help strengthen the Subordinate and State Granges. My goal is to put us in a position to fulfill that mission quickly and efficiently,” Weiss stated. and seed is collected from the group of plants and identified as a synthetic variety. This seed is then used in the production of additional seed. Unlike a corn hybrid, each in dividual seed in a bag of alfalfa carries a unique set of genes. The population of plants grown from these seeds is then charac terized for phenotypic traits such as disease resistance, flower color, or gladular hairs. Commercial Alfalfa 11} brid Development The primary allalfa breeding method is called recurrent phe notypic selection. This method involves choosing parents that are crossed to produce a syn thetic variety. It is not a method of hybridization and does not take full advantage of the het erosis effect that occurs when two inferior parents are crossed to produce superior progeny. Like most agronomic species, alfalfa plants produce self pollinated seed during normal flowering unless special steps are taken. Such steps often in volve some sort of “male sterili zation,” as in corn, for example, where the tassels are removed from the female parent plants to prevent self-fertilization. Since hybrids are the result of controlled pollinations, a system of making male plants nonfunc tional is needed to achieve de sired cross-pollination. Development of female plants (male sterile) that successfully cross with male plants results in a hybrid. The introduction of HybriForce-400 by Dairyland Seed Company utilizes a male sterility system of hybridization called MsSunstraTM. In effect, selected male sterile (female) al falfa plants are grown together with other male fertile plants and allovyed to cross. The result ing seed from these plants (FI) it predominantly hybrid, although some seed will still be self pollinated. Proper selection of alfalfa parents (male and female par ents) is the key to making a suc cessful hybrid variety. Because BUY, SELL, TRADE OR RENT THROUGH THE CLASSIFIED ADS IN Lancaster Farming PHONE 717-626-1164 OR 717-394-3047 commercial hybrid seed is F. seed, it is likely to be more vigor ous than a commercial synthetic variety that has been through multiple cycles of crossing to in crease seed quantity. Performance Of Hybrid Alfalfa In company advertising, Dairyland Seeds claims that HybriForce-400 has eight to 15 percent greater yield over the life of the stand than non-hybrid alfalfa varieties. If this is true, it means that the breeders have made a large jump in alfalfa’s yield potential. Beginning in 1997, HybriForce-400 has been tested as an experimental variety (DS -9705) in various University vari ety performance trials. The seed used for these studies was pro duced in a research setting and did not come from large seed lots. Data for this summary were reported in the Central Alfalfa Improvement Conference (CAIC) Variety Test report during 1998-2000. Trials with HybriForce-400 were conducted in, lowa, Michigan, Minnesota, Nebraska, Pennsylvania, and Wisconsin. In this summary, an environ ment is defined as the total yield from a single site in a single year. In 24 test environments, HybriForce-400 yielded the same as or beat the trial mean, averaging 0.65 ton DM/acre higher. The yield of HybriForce -400 was significantly (95 percent confidence level) higher than Vernal in 21 environments. In 21 of 25 environments, the yield of HybriForce-400 was not statistically different than the average of the three highest yielding commercial non-hybrid varieties in each study. In three test environments, HybriForce-400 was signifi cantly higher yielding than the best non-hybrid variety. In one environment, HybriForce-400 was significantly lower yielding than the best non-hybrid variety. Compared to other experi mental alfalfa varieties, HybriForce-400 was signifi cantly lower than the best exper- 8m What Lana M I It Using 2T January and Mmtmf you can submit I 2 Mailbox Markets each month! *Ads must be different each time . • ' x , v v. ✓ Kx,.,' CT/ Ov imental varieties in three environments, but not different than the best experimental vari eties in 22 environments. This preliminary evidence shows that HybriForce-400 is as high or higher yielding than cur rently available non-hybrid al falfa varieties. However, there are commercial and experimen tal varieties that are capable of producing yields comparable to HybriForce-400. Company representatives in dicate that field performance of the commercially produced seed has been visually better than the performance of alfalfa plots where research seed was used. They feel that this is attributed to better isolation and less outcrossing in a commercial seed field. One feature of this data set is that HybriForce-400 consist ently yields in the top 10 percent of each test environment. Forage crop researchers know that it is very difficult to find an alfalfa variety that will yield consist ently in the top 10 percent of a trial in 25 environments. In this summary we com pared HybriForce-400 to the av erage of the three top yielding varieties or experimental lines. Most of these varieties were dif ferent for each environment. The next most consistent variety had just four appearances in the top yield category. Selecting alfalfa varieties that consistently perform at a high yield level is a difficult task that requires many test environments to accomplish. Also, because varieties change frequently and yield differences are relatively small, there are often not enough test environments for an accurate evaluation of new vari eties. Consistent ranking in the top 10 percent of each test environ ment indicates that HybriForce -400 is very stable and may have improved yield potential com pared to other non-hybrid varie ties on the market. Future advances in alfalfa hybrids may offer greater yield potential for this crop.
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