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a Dep. of Plant Sciences, North Dakota State Univ., Fargo, ND 58108-6050
b Dep. of Plant Pathology, North Dakota State Univ., Fargo, ND 58108
c Dep. of Soil Science, North Dakota State Univ., Fargo, ND 58108. Research supported by grants from the North Dakota Soybean Council
* Corresponding author (Ted.Helms{at}ndsu.edu).
ABSTRACT
‘Ashtabula’ soybean [Glycine max (L.) Merr.] (Reg. No. CV-500, PI 655938) was first tested as ND02-2367 and was released in January 2009 by the North Dakota Agricultural Experiment Station, North Dakota State University to provide producers with a Maturity Group 0 conventional cultivar (0.4), generally adapted as a full-season cultivar from 46 to 48° N latitude. Ashtabula was evaluated by the North Dakota State University soybean breeding program in advanced yield trials for a total of 24 location-years that included 2005 to 2008. Testing for iron deficiency chlorosis (IDC) was conducted in 2005 at four sites located in eastern North Dakota, based on three replicates per site. Screening for resistance to race 4 of Phytophthora sojae (M.J. Kaufmann & J.W. Gerdemann) was conducted using the hypocotyl-injection method. Ashtabula was released because it has resistance to race 4 of Phytophthora sojae, high yield in North Dakota environments, lodging resistance, and tolerance to iron deficiency.
Abbreviations: IDC, iron deficiency chlorosis • NDSU, North Dakota State University
‘Ashtabula’ soybean [Glycine max (L.) Merr.] (Reg. No. CV-500, PI 655938) was developed by the North Dakota Agricultural Experiment Station, North Dakota State University (NDSU) and was first tested as ND02-2367. Ashtabula was released in January 2009 as a Maturity Group 0 conventional cultivar (0.4), generally adapted to full-season production from 46 to 48° N latitude. Ashtabula was released because it has resistance to race 4 of Phytophthora sojae (M.J. Kaufmann & J.W. Gerdemann), high yield in North Dakota environments, lodging resistance, and tolerance to iron deficiency. Ashtabula is intended to replace the conventional cultivar Barnes (PI 614831; Helms et al., 2001). Barnes is less tolerant to iron deficiency chlorosis (IDC) and lower in yield than Ashtabula.
Methods
Parent Choice and F1 Development
Ashtabula is an F4–derived line, originally designated ND02-2367, with the pedigree ND95-952 x ‘Council’ (PI 587091; Helms and Halvorson, 1996). ND95-952 is a line developed by NDSU that has the pedigree ND88-800 x ‘Pioneer 9061’. ND88-800 was never released as a named cultivar. The pedigree of ND88-800 is ‘Evans’ (PI 548560) x ‘Maple Amber’ (PI 548592) (Lambert and Kennedy, 1975; Bernard et al., 1995). Pioneer 9061 has the pedigree ‘Wells’/‘Rampage’//‘Corsoy’ (PI548630, PI548609, PI548540, respectively) (Wilcox et al., 1973; Weber and Fehr, 1970a,b). The objective of the cross was to develop high-yielding, IDC-tolerant, phytophthora-resistant experimental lines. The cross leading to Ashtabula was made in the summer of 1999 at Casselton, ND. The F1 plants were grown in the 1999–2000 Chile winter nursery, which is provided by Agricola Greenseed Company, near Rancaqua.
Early Generation Population Development
The F2 population was grown in the summer of 2000 and advanced to the F3 generation by the single-pod bulk method (Fehr, 1991). One pod, with either two or three seeds per pod, was harvested from each of approximately 200 F2 plants. All of these pods were threshed together to form a bulk of approximately 500 seeds (two to three seeds per F2 plant), and approximately 200 seeds were selected at random for generation advancement. The F3 population was grown in the 2000–2001 Chile winter nursery and advanced to the F4 generation by the single-pod bulk descent method. Individual F4 plants were harvested from the Casselton, ND, nursery, without selection, and threshed in the fall of 2001. One hundred eighty-seven F4:5 plant-rows of the ND95-952 x Council population were evaluated in 2002 at Prosper, ND, using nonreplicated, single rows that were 3.3 m long.
Line Selection and Evaluation
Twenty-nine of the 187 plant-rows were selected (16%) on the basis of visual appearance for lodging resistance. Seed from each selected F4:5 row was bulked. These 29 plant-rows were tested for resistance to race 4 of Phytophthora sojae. Ashtabula was first tested for yield as ND02-2367 using three replicates of an 8 x 8 incomplete lattice design at Casselton, ND, in 2003. Ten out of 60 experimental lines from that particular experiment were selected for advanced, multiple-location yield tests for the 2004 cropping year. In all yield tests, the plots were planted as two rows 6.3 m long with 0.76 m between-row spacing and later end-trimmed to 4.2 m for harvest.
Ashtabula was evaluated by the NDSU soybean breeding program in advanced yield trials for a total of 24 location-years that included 2005 to 2008. Advanced yield testing of Ashtabula in North Dakota included four locations in 2005, seven locations in 2006, seven locations in 2007, and six locations in 2008. Lodging was rated on a 1 to 5 visual scale, with 1 the best and 5 the worst.
Testing for IDC was conducted in 2005 at four sites located in eastern North Dakota, based on three replicates per site. The four sites were classified as Aeric Calciaquolls, with a seasonal high water table and free CaCO3 on the surface. The four sites were selected on the basis of a past history of IDC symptoms. The experimental unit consisted of hills planted with eight seeds and thinned to three seeds per hill. Hills were spaced on a 0.76-m grid. Iron deficiency chlorosis was rated at the 2 to 3 trifoliolate stage and the 5 to 6 trifoliolate stage, using a 1 to 5 visual scale. In this scale, a rating of 1 represented no chlorosis, 2 represented a slight yellowing of the upper leaves of a general (not interveinal) nature, 3 represented interveinal chlorosis of the upper leaves without stunting or necrosis, 4 represented an interveinal chlorosis of the upper leaves with reduced growth or the beginning of necrosis, and 5 represented severe stunting, chlorosis, and damage to the growing point. Ratings were recorded ±0.5 chlorosis unit for each rating for each hill. Genotypes that are more susceptible to IDC on calcareous soils are lower yielding on calcareous soils. Froehlich and Fehr (1981) reported that yield decreased 20% for each one unit increase in IDC score (1 = best, 5 = worst) when the percentage yield decrease between calcareous and noncalcareous soil was compared for each of 15 cultivars averaged across five testing environments.
Screening for resistance to Phytophthora sojae was conducted using the hypocotyl-injection method developed by Haas and Buzzell (1976). The race 4 isolate was originally baited from North Dakota soils and previously tested for virulence on soybean (Nelson et al., 2008). Plants were inoculated when 8 to 9 d old with the unifoliate leaves unfolded. Plants were maintained in a growth room at 24 ± 2°C for 10 d and then evaluated as resistant and susceptible from a sample of 12 plants. Resistant plants survived and susceptible plants died. The cultivars Walsh (PI 615586; Helms et al., 2002) and LaMoure (PI 634813; Helms et al., 2005) were used as the resistant and susceptible checks, respectively. Walsh is resistant to races 3, 4, and 25. LaMoure is resistant to race 3 but susceptible to races 4 and 25 of phytophthora root rot, caused by P. sojae. Twelve seedlings were evaluated for each cultivar in each test. In both tests, all inoculated Ashtabula plants survived, while 90% of the susceptible plants died. Barnes and Ashtabula are both resistant to races 3, 4, and 25 of phytophthora root rot. The most common races of phytophthora root rot in North Dakota include race 4, which was found in 39% of fields, and race 3, which was found in 28% of fields (Nelson et al., 2008).
Protein and oil data are reported on a 130 g kg–1 moisture basis, based on data collected from USDA Uniform Regional Trials: Northern States (Abney, 2008). Seed composition was measured by the USDA–ARS National Center for Agricultural Utilization Research, Peoria, IL, using near infrared transmittance (Abney, 2008). For yield evaluation in the Uniform Regional Tests, plot length and between-row spacing varied among test participants.
Seed Purification and Increase
Purification of Ashtabula was initiated in 2006 by threshing 128 individual F4:9 plants. Seed of each plant was placed in a separate envelope and evaluated for uniformity of hila color and seed-coat luster between different envelopes. Seed of 80 plants that had yellow hila and dull seed-coat luster were selected for planting in 2007. Seed from each envelope was planted in a 3.3-m row with 40 rows grown at Prosper, ND, and 40 rows grown at Casselton, ND. In 2007, these purification rows (F9:10) were grown and inspected for uniformity of flower and pubescence color as well as maturity. Of the 40 purification rows grown at Prosper, ND, seed of 32 rows were selected for uniformity and blended to produce F4:10 Breeder seed. This seed was then sent to the 2007–2008 Chile winter nursery for seed to increase Breeder seed (F4:11). Foundation seed (F4:12) was increased at Casselton, ND, in summer 2008. Ashtabula was observed to be uniform and stable for a 2-yr period.
Statistical Analyses
Data were analyzed using SAS software (SAS Institute, Cary, NC). All data were analyzed as a randomized complete block design. Genotype was considered a fixed effect and environment was considered random. Analysis of variance was performed with 
= 0.05 level of Type I error.
Characteristics
Agronomic and Botanical Description
Ashtabula is an indeterminate cultivar with a relative maturity of 0.4. In USDA Uniform tests, Ashtabula matured 14 September, which is 3 d later than ‘Traill’ (PI 596541; Helms and Nelson, 1998) (Table 1
) and 7 d earlier than ‘Surge’ (PI 599300; Scott and Orf, 1998). Ashtabula has purple flower color, gray pubescence, brown pod color, yellow hila, and dull seed-coat luster. Ashtabula showed good lodging resistance compared with Surge. Plant height of Ashtabula was similar to Traill and Surge. When Ashtabula was evaluated for IDC in North Dakota, Ashtabula was classified as moderately resistant, with a mean score of 2.2, compared with Barnes (score of 3.3).
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Availability
Breeder seed of Ashtabula will be maintained by the Seed Stock Project of NDSU. A small sample of seed for research purposes can be obtained from the corresponding author for at least five years. Protection for Ashtabula under the U.S. Plant Variety Protection Act Title V is pending. Seed of Ashtabula was deposited at the National Center for Genetic Resource Preservation, Fort. Collins, CO, 80521-4500. Seed may be used for crossing or testing purposes by signing a Material Transfer Agreement with the North Dakota State University Research Foundation located at 1735 NDSU Research Park Drive, Fargo, ND 58108-6050.
Acknowledgments
Technical support was provided by Tracy Christianson, Dave Hanson, Larry Martin, and Brian Johnson. This research was supported by the North Dakota Soybean Council and NDSU.
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 March 16, 2009.
References
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