|Foster, M - TEXAS A&M UNIV, PECOS, TX|
|Nesmith, D - TEXAS A&M UNIV, PECOS, TX|
Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2007
Publication Date: October 1, 2007
Citation: Foster, M.A., Coffelt, T.A., Nesmith, D.M. 2007. Cold tolerance of guayule on the southern high plains. Association for the Advancement of Industrial Crops Conference, P. 26. Technical Abstract: Native guayule populations are scattered throughout 300,000 km2 of rangeland in the Chihuahuan Desert and surrounding regions. Indigenous U.S. stands occur in the Trans Pecos region of southwestern Texas which is important because it is the only native stand in the U.S., and it is the most northern extension of the plant’s habitat. Maximum air temperatures of over 38oC are frequent, and minimum temperatures of -23oC have been recorded. The objective of our study was to determine if guayule production could be successful farther north on the Southern High Plains near Plainview, TX. Seed used in the experiment included four released lines, AZ-1, AZ-2, AZ-3, and AZ-4; a released USDA cultivar (11591); and three unreleased breeding lines, N9-3, N6-5, and N13-1. Seeds were obtained from T.A. Coffelt, USDA, ARS Arid Lands Agricultural Research Center, Maricopa, AZ, and planted March 14, 2006, in the greenhouse at the Texas A&M University Agricultural Research Station near Pecos. Guayule seedlings were transplanted on May 18, 2006, at the Texas A&M University Agricultural Research Station at Plainview. The experimental design was a randomized complete block with four replications. Plots were single rows (each containing 18 plants of each line) spaced 1 m apart and 6 m long. Plant height was measured November 7, 2006, and June 6, 2007. Guayule cold damage was estimated June 6, 2007, using the following index: (1) no damage, (2) slight – injury of terminals to 6 cm, (3) moderate – 2/3 of plant volume injured, (4) severe – all aerial portions killed but resprouting, and (5) complete – beyond recovery with no regrowth. Plant height measured on November 7, 2006, varied from 31 cm in 11591 to 56 cm in AZ-1. Only one line had increased in height when measured on June 6, 2007: 11591 had increased from 31 to 38 cm. Line N6-5 remained the same while all other lines decreased in height. The cold damage index ranged from 1.2 in line 11591 to 3.8 in line AZ-1. The maximum and minimum air temperatures recorded during the study were 38oC and -14oC, respectively. Line 11591 had the least cold damage and holds promise for establishment and rubber production on the Texas High Plains. Guayule grown here will not produce the biomass of those cultivated in the Southwest, but certain production criteria may make the Plains an additional production site: annual rainfall averages 46 cm, irrigation water salinity is less than 1 E.C. and is pumped from only 90 m, and center pivots are available for establishing guayule by direct-seeding.