Economic Returns Due to Alfalfa Cultivar Selection Over 30 Years of Testing in California Environments.

Although there are many influences on crop productivity, selection of alfalfa (Medicago sativa) cultivar sets the upper genetic potential for yield and other performance traits.  Variety testing programs, such a those at the University of California provide a scientific approach to selection by growers and seed companies, but variety selection is still determined to a great extent by growers who favor inexpensive seed.   Long-term potential economic returns due only to the selection of variety were determined for each multiple-year trail conducted in the past 30 years in desert (9 cut), Mediterranean (6-7 cut), and Intermountain (3-4 cut) environments.  Partial economic returns due only to variety choice varied between nil and over $500 ha per year.  Additional seed cost of up to $3 kg of seed were largely insignificant in affecting the returns from variety selection.  Within-year trends in yield may provide economic advantages to specific lines that yield more during first and second cuttings, which provide improved returns due to high prices for those harvests.   While differences due to lack of pest management, irrigation mistakes, soil fertility limitations, and cutting schedules sometimes mask differences due to variety, nevertheless variety selection is a critical economic factor, providing opportunities for improved profitability.    Information from variety testing program is worth an estimated $120 million in California each year.  These estimates are based only upon yield advantages – additional economic returns may be due to pest resistance, quality, and biotechnology traits  While difficulties exist in differentiating varieties in small plot tests, and in transferring data to broader areas, performance, not seed cost is the most important economic factor for variety selection.