In fact, those are at the very bottom of a list of steps for choosing alfalfa varieties compiled by Dan Putnam, Extension agronomist at the University of California, Davis.
Speaking at a recent alfalfa field day at the Kearney Research and Education Center, Parlier, Putnam stressed that yield potential of a variety is the most important economic factor in selection.
"In some cases, you almost might say seed companies ought to pay growers to grow cheaper varieties because of yield the grower can loose in buying the cheaper seed."
He said growers should visit as many trial plots as they can, perhaps even plant their own, and look for a group, ideally the top one-third, of high-yielding, certified varieties from relative trials over multiple years.
Growers can visit http://alfalfa.ucdavis.edu to find the current UC variety trial database to use as a gauge. "We put all our trial data on the Web site before it is published elsewhere."
The second step is determining your fall dormancy requirements and preferences, which include stand life and quality.
Fall dormancy-free varieties are typically grown in Wisconsin or Minnesota, but Putnam said some Central Valley growers are gravitating toward lower dormancy varieties because of the higher quality hay they produce.
Some of higher fall dormancy varieties that grow more actively during winter, he added, "often do go out a little bit quicker than the lower dormancy group. That is generally true, although not in every case."
General recommendations of fall dormancy ratings of 8 and 9 are generally recommended for the San Joaquin Valley and a 10 rating is recommended for the Imperial Valley.
As a guide in comparing fall dormancy with yields developed last year at Davis, Putnam said for every unit less in fall dormancy rating, going from a 9 to an 8, for example, the average yield drops about a half ton per acre per year.
He plans to monitor plots at KREC to see if the same is true there. "But I have no reason to believe we will see significantly different results. Of course, there are exceptions, and it is important to watch for them."
He said some growers using dormant varieties prefer to extend their cutting schedule. "That’s a reasonable proposition, although we don’t have much data on that and we are continuing the trial at Davis for a second year to look at that issue."
Putnam said fall dormancy and ADF, or the standard acid-detergent-fiber, measurement of forage quality and value in the California industry, must be in balance with yield.
"Going from 10 or 11 tons per acre down 7 tons per acre, due mostly to fall dormancy, goes from fair to supreme quality under the California marketing system, and that has to be balanced against the reduced yield."
He went on to say that, given the complex formula, growers cannot calculate yield and forage quality in isolation from the yield potential of the crop.
"A key issue for breeders is to have both high yielding and high quality varieties."
Pest resistance need
The next step in selection is determining the pest resistance needs for your area. "A lot of growers ignore this. Many varieties have excellent pest resistance packages.
"Remember that buying resistance is like buying an insurance policy. You might not see the particular pest but one out of eight or 10 seasons. We all buy insurance for our cars or pickups, even though we don’t have a claim every year."
Putnam recalled that growers around Davis have had problems with losses to stem nematode and resistant varieties are the only solution to the problem.
Another step in the process is to look for evidence of a variety’s persistence and forage quality. "Sometimes data is a little scarce on the forage quality side, and unfortunately some seed companies are better at putting out attractive brochures than they are at producing data on a variety’s quality."
Putnam said the current KREC variety trials are cut and irrigated on the same schedule to show only differences between varietals.
"We see pretty significant differences between some of the older, check varieties and some of the better varieties. Those differences amount to about two and one-half tons to the acre between the top and the bottom yielders."
On the issue of seed costs, Putnam said a higher price may well bring far greater returns given other inputs are equal.
In a comparison of the venerable CUF101, one of the cheapest seeds on the market, vs. an improved variety priced at $2 per pound more, up to $600 per acre more can be made with the improved variety during the three-year life of the stand.
"Sure, it’s painful to write a check for seed costing 50 or even 100 percent more than you usually pay," he added. "But the message here is look at the value of the improved variety seed, then look at its price.
Value more important
"Price is important, but value will become more important, especially as we move to varieties having special genetic packages such as Roundup Ready or other values."
Growers, he said, should remember to consider multi-year yield results in reaching their variety decisions. "We have seen varieties that started off slow and then did better the second and third season. We also saw some that did well the first year but then weakened over time."
The length of a grower’s rotation in alfalfa has a bearing. While a two-year program in alfalfa may be less critical, Putnam said most growers are interested in sustained yields during three to four years or more, where performance over time is more economically relevant.