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a USDA-ARS Western Wheat Quality Lab., E-202 Food Sci. & Human Nutrition Facility East, Washington State Univ., Pullman, WA 99164-6394
b Dep. of Food Science & Human Nutrition, Washington State Univ., Pullman, WA 99164-6376
* Corresponding author (morrisc{at}wsu.edu).
‘Waxy-Pen’ soft white spring waxy wheat (Triticum aestivum L.) (Reg. No. CV 1006, PI 637779) was released by the USDA-ARS in 2006. Waxy-Pen was developed by Dr. Craig F. Morris, USDA-ARS, Western Wheat Quality Laboratory. Waxy-Pen was released due to its fully "waxy" starch composition (<1% amylose) and unique end-use quality, and its potential for broad adaptation to U.S. Pacific Northwest (PNW) environments.
Waxy-Pen is a backcross-five derivative (Penawawa *6/‘Wx2–2a’) of the soft white spring wheat variety ‘Penawawa’. Penawawa (PI 495916; ‘Potam 70’/‘Fielder’) was developed by Dr. Calvin Konzak while at Washington State University (WSU), Pullman, WA, and was released in 1985 by WSU and the USDA. Penawawa is null for the granule-bound starch synthase (GBSS) (Waxy) gene on chromosome 4A (haplotype = Wx-A1a, Wx-B1b, Wx-D1a) and has an apparent amylose content of 19.9% (Zeng et al., 1997). The donor of the two additional GBSS null alleles (Wx-A1b, Wx-D1b) was the soft red spring wheat germplasm line WQL6K107-BHWX 2-2a (PI 612545), which has the pedigree ‘Kanto 107’(PI 631445)/‘Bai Huo’ (PI 606717) (Morris and Konzak, 2001). A tentative name assignment of ‘Penawawa-X’ was approved by the Seed Regulatory & Testing Branch, USDA-Agricultural Marketing Service in 2003 but was changed to Waxy-Pen in 2006.
Breeder seed of Waxy-Pen was derived by bulking seed from 27 BC5F3–derived F5 field plots grown near Bozeman, MT, in 2004. The BC5F3 plants were derived from 10 randomly selected BC5F2 spikes that had been assayed for homozygous waxy trait using I2/KI (stock solution of 0.1 M of each; working dilution in the range of 5–10 mM) on several kernels each. The kernels had a small portion of the distal brush end removed with a razor blade, and the exposed endosperm was stained with iodine. Rust color, as opposed to dark purple color, was indicative of waxy starch. The waxy endosperm trait was confirmed on the BC5F5 seed.
Waxy-Pen was evaluated in 2005 in the WSU Extension Uniform Cereal Variety Testing Program (WSU Ext. UCVTP) as ‘WA7996’, by John Burns, extension agronomist; and in the Western Regional Uniform Cooperative (WRN Coop) Wheat Nurseries, Dr. Kim Garland Campbell, ARS research geneticist, coordinator, as ‘WQL7PENWX-2’. In general, Waxy-Pen is morphologically and developmentally indistinguishable from Penawawa except for the waxy endosperm trait. Across 18 WSU Ext. UCVTP locations, Waxy-Pen had significantly lower grain yield (lower at 15 of 18 sites; 1620 vs. 1730 kg ha–1, respectively, difference significant at P = 0.01), slightly lower test weight (712 vs. 718 kg m–3, difference significant at P = 0.05), and similar grain protein contents (125 and 126 g kg–1, difference not significant at P = 0.05) compared with Penawawa.
Like Penawawa, Waxy-Pen is susceptible to the stripe rust (Puccinia striiformis f. sp. tritici Westend.) race(s) currently prevalent in the Pacific Northwest. Due to intense stripe-rust incidence in 2005, Waxy-Pen and Penawawa yielded from lows of 457 and 511 kg ha–1, respectively, up to 3736 and 3863 kg ha–1, respectively, across the 18 WSU Ext. UCVTP locations. In the WRN Coop Wheat Nurseries, grain yield of Waxy-Pen ranged from 1340 to 8528 kg ha–1 (data not shown).
Due to the unique amylose-free composition of Waxy-Pen starch, several end-use quality traits are dramatically altered. The following mean (± sd) end-use quality traits of ‘Alpowa’ and Waxy-Pen, respectively, were obtained from single replicate samples from Lamont, Lind, Pullman, St. John, and Moses Lake, WA, Western Regional Uniform Cooperative Wheat Nurseries (Alpowa was the check variety for the soft white spring WRN Coop Wheat Nurseries; Penawawa was not included): test weight, 804 (15) and 767 (13) kg m–3; Single Kernel Characterization System kernel hardness, 34 (3) and 36 (5); wheat protein, 124 (9) and 128 (11) g kg–1; L-DOPA polyphenol oxidase activity (Anderson and Morris 2001), 1.17 (0.10) and 1.20 (0.23) A475; flour yield, 661 (12) and 594 (18) g kg–1; break flour yield, 505 (12) and 445 (14) g kg–1; flour ash, 4.1 (0.2) and 5.4 (0.3) g kg–1; milling score, 78.9 (1.9) and 62.7 (3.2); flour protein, 109 (10) and 116 (13) g kg–1; flour swelling volume, 19.9 (0.6) and 26.5 (0.4) mL g–1; carbonate Solvent Retention Capacity (SRC), 789 (41) and 1166 (75) g kg–1; water SRC, 563 (12) and 723 (18) g kg–1; sucrose SRC, 1063 (57) and 1505 (91) g kg–1; mixograph water absorption, 558 (26) and 625 (15) g kg–1; and cookie diameter, 9.18 (0.27) and 7.72 (0.18) cm. Consequently, Waxy-Pen must be strictly segregated from other soft white wheat grain.
Waxy-Pen received protection under U.S. Plant Variety Protection (PVP Certificate No. 200600005) and has been exclusively licensed to the WSU Research Foundation (WSU RF), 1610 N.E. Eastgate Blvd., Pullman, WA, 99163. Licensing or commercialization inquiries should be directed to the WSU RF; small quantities of seed for crossing, research, and other noncommercialization activities are available on written request from the corresponding author. It is requested that appropriate recognition be made if this cultivar contributes to research or the development of germplasm or cultivars. Genetic material of this release has been deposited in the USDA National Plant Germplasm System, where it will be available after the expiry of the Plant Variety Protection for research purposes, including development and commercialization of new cultivars.
Acknowledgments
The authors acknowledge the excellent cooperation and advice provided by John W. Burns, Washington State Univ., and Dale Clark, WestBred LLC.
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 August 31, 2006.
References
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