Alfalfa - UC-Impalo-WF


UC-Impalo-WF was developed by the University of California alfalfa breeding program lead by Dr. Larry R. Teuber and research associates Larry K. Gibbs and Kenneth L. Taggard.  Selection for resistance to the Silverleaf whitefly (Bemisia argentifolii), disease and pest resistance, and adaptation to Low Desert Production was conducted at the University of California Desert Research and Extension Center.  Selection for seed yield occurred in winter nurseries in Chile.  Funding for this project came from the Imperial County Whitefly Management Committee.


UC-Impalo-WF was developed from a broad based germplasm pool (UC-356) by four cycles of among-and-within half-sib family selection. UC-356 was developed from nine different source pools in the University of California alfalfa breeding program.  The component populations had previously been selected for resistance to saline soil conditions, root knot nematode (Meloidogyne sp.), Phytophthora root rot (Phytophthora megasperma), bacterial wilt (Clavibactor insidiosum), and Fusarium root rot (Fusarium oxysporum), blue alfalfa aphid (Acyrthosiphon kondoi), pea aphid (Acyrthosiphon pisum), spotted alfalfa aphid (Threioaphis maculata), and forage yield and adaptation in the low desert production area of California and Arizona.  The primary selection criterion in developing this cultivar were adaptation to low desert production conditions, resistance to and the silverleaf whitefly (Bemisia argentifolii) and high seed yield.  This germplasm pool is composed of:  0%, M. falcata: 0%, Ladak; 1%, M. varia; 8%, Turkistan; 0%, Flemish; 7%, Chilean; 1%, Peruvian; 15%, Indian; 35%, African; 10%, Arabian; and 23%, unknown sources of germplasm.


UC-Impalo-WF is very nondormant (fall dormancy group 9) with a Fall Dormancy Rating (FDR) of 8.7 based on University of California Fall Dormancy Trials, flower color is predominantly purple (>98%) with a trace of Variegated types (< 1%) and a trace of Cream (< 1%).  The Cultivar has been tested in the Imperial Valley and in the San Joaquin Valley of California, and Central Arizona.  It is adapted to Low Desert irrigated production areas, including the Imperial and Palo Verde valleys of California, and extreme southwestern Arizona and is intended for hay, haylage, greenchopor dehydration.


UC-Impalo-WF is highly resistant to Fusarium wilt (Fusarium oxysporum) and spotted alfalfa aphid (Threioaphis maculata). It is resistant to Phytophthora root rot (Phytophthora megasperma), blue alfalfa aphid (Acyrthosiphon kondoi), pea aphid (Acyrthosiphon pisum), and southern root knot nematode (Meloidogyne incognita).  It is moderately resistant to bacterial wilt (Clavibactor insidiosum) and has low resitance to southern anthracnose (Colletotrichum trifolii) (Race 1) and the Silverleaf Whitefly (Bemisia argentifolii).  Resistance of this cultivar to Verticillium wilt (Verticillium albo-atrum) and Aphanomyces root rot (Race 1) (Aphanomyces euteiches)  and stem nematode (Ditylenchus dispasaci) is unknown.


UC forage yield trial data can be found at:


Seed classes of UC-Impalo-WF are Breeder, Foundation, and Certified.  The University of California Foundation Seed Project, Davis maintains breeder and Foundation seed classes.  Foundation and Certified seed production are each limited to a 3-year stand life.  Seed production of both Foundation and Certified classes is limited to the San Joaquin Valley of California south of 37o25’N latitude and Riverside and Imperial counties of California south of 34o00’N latitude.  Certified seed was first offered for sale in 2000.


UC-Impalo-WF, was favorably reviewed by the National Alfalfa and Miscellaneous Small Legume Variety Review Board in December 2000.  Plant Variety Protection, Title V, was issued in June 2002, Certificate no. 200000353.  Under these protections, UC-Impalo-WF can only be sold in commercial seed channels as a class of certified seed.


Foundation seed of UC-Impalo-WF is distributed by the University of California Foundation Seed Program to licensed brokers and seed houses twice annually, fall and spring.  Off-cycle requests are considered on a case-by-case basis.

To obtain information and/or a license for UC-Impalo-WF contact the University of California, Davis Technology Transfer Center:

Clinton H. Neagley
Senior Intellectual Property Officer
University of California, Davis
Technology Transfer Center
1850 Research Park Drive
Davis, California 95616
Tel. (530) 757-3432
Fax (530) 758-3276