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a USDA-ARS, Forage and Range Res. Lab., Utah State Univ., UT 84322-6300
b US Army Corps of Engineers, Engineering Research and Development Center, Cold Regions Research and Engineering Lab. (ERDC-CRREL), Hanover, NH
* Corresponding author (kevin{at}cc.usu.edu).
‘FirstStrike’ slender wheatgrass [Elymus trachycaulus (Link) Gould ex Shinners] (Reg. No. CV-29, PI 643910) was developed by a research team at the USDA-ARS Forage and Range Research Laboratory at Utah State University, Logan, UT, in collaboration with the U.S. Army Engineer Research and Development Center, Hanover, NH. FirstStrike was released on 16 Oct. 2006. In field trial evaluations as part of the Strategic Environmental Research and Development Program (SERDP) project CS-1103 to identify resilient plant characteristics and develop wear-resistant plant cultivars for use on military training lands, FirstStrike was designated a SERDP-select slender wheatgrass. FirstStrike was chosen for persistence and overall plant vigor in response to drought. FirstStrike is a multi-origin composite of three collections from Colorado and Wyoming. Seedling establishment of FirstStrike was equal or better than other commercially available cultivars as determined from extensive evaluation on rangeland sites in western portions of the USA.
The 20 source plants of FirstStrike originated from seed of three germplasm collections: Ruth 21, Fort Carson Training Center, CO (53–54 [N/S], 15–16 [E/W]); Ruth 26, Fort Carson Training Center, CO (71–72 [N/S], 14–15 [E/W]); and Ruth 31, 10 mi. north of Rawlings, WY. A fourth collection, Ruth 37, originating at Gillette, WY, between Wyoming Hwy. 14-16 and Railand was evaluated, but this population did not contribute to the parentage of FirstStrike. A source nursery was established in 1995 at the Fort Carson Training Center near Pueblo, CO. Collections of Ruth 21, 26, 31, and 37 were planted in a space-planted nursery with 10 plants per plot and eight replications (320 plants). Based on persistence and overall vigor, selections were made from Ruth 21 (seven plants), Ruth 26 (nine plants), and Ruth 31 (four plants) in 1997.
Vegetative sprigs (clones) from the 20 plants selected were established at a nursery near Stone, ID (Curlew Grasslands), in 1998. This nursery was composed of two plants per plot with five replications. In 2000, seed from each line was bulked in equal quantities by weight to form the Breeder seed. A Foundation seed field was established in North Logan, UT, in 2001, and Foundation seed was harvested in 2002, 2003, and 2004.
Rapid seedling establishment is the key to a successful revegetation planting in the western USA. In seeded trials at Yakama Training Center, Yakima, WA (established fall 2002), Camp Guernsey, Guernsey, WY (established spring 2004 and 2005), Fillmore, UT (established fall 2003 and 2004), and Malta, ID (established fall 2004), FirstStrike had significantly (P < 0.05) more seedlings per unit area (m2) than the cultivar Pryor in the establishment year when planted at a rate of 1 seed cm–1 pure live seed in rows spaced 25 cm apart,. At Fillmore, UT, and Malta, ID, initial stand and persistence of FirstStrike were similar to the cultivar San Luis. FirstStrike was similar to or better than Pryor and San Luis for persistence. At Guernsey, WY, dry matter yield was 27% greater (P < 0.07) in FirstStrike than Pryor. Seed germination of FirstStrike averaged 5 d earlier than Pryor on three different soil types (sandy loam, loam, and sandy).
Amplified fragment length polymorphisms (AFLP) were used to compare FirstStrike with other cultivars of slender wheatgrass (Vos et al., 1995). Pairwise comparisons of the average similarity between cultivars yielded lower coefficients than within cultivars. The fewest similarities occurred between a rhizomatous breeding line and Pryor (36.5%), while the greatest similarity was detected between FirstStrike and Pryor at 67.1%. The relative amounts of variation apportioned among cultivars were all greater than 20%. FirstStrike can be distinguished from the other cultivars by the presence or absence of several AFLP markers.
Breeder, Foundation, and Certified seed classes will be recognized. Breeder seed will be maintained by the USDA-ARS Forage and Range Research Laboratory at Logan, UT. Protection under the U.S. Plant Variety Protection Act of 1994 will be applied for, with the requirement that seed of FirstStrike can be marketed only as a class of Certified seed. Contact the corresponding author for all seed requests. No seed will be distributed without written permission for 20 yr from the date of release by the USDA-ARS, at which time seed will also be available from the National Plant Germplasm System.
Footnotes
All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.
Received for publication November 2, 2007.
References
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