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a Texas AgriLife Research and Extension Center, 1102 E FM 1294, Lubbock, TX 79403
b Texas AgriLife Research and Extension Center, 10345 Agnes St., Corpus Christi, TX 78406
c Division of Agriculture, West Texas A&M Univ., P.O. Box 60998, Canyon, TX 79016
* Corresponding author (g-peterson1{at}tamu.edu).
ABSTRACT
The sorghum [Sorghum bicolor (L.) Moench] germplasm lines Tx2945 through Tx2952 and Tx2954 through Tx2961 (Reg. No. GP-645 to GP-660, PI 655260 to PI 655275) were developed and released by Texas AgriLife Research (formerly the Texas Agricultural Experiment Station), Lubbock, TX, in 2006. These lines are 3-dwarf (dw1Dw2dw3dw4) in height and possess unique combinations of tan plant color, agronomic traits, traits for resistance to head smut [Sphacelotheca reiliana (Kuhn) Clinton], rust [Puccinia purpurea (Cooke)], zonate leaf spot (Gloeocercospora sorghi Bain and Edgerton), bacterial leaf streak [Xanthomonas holcicola (Elliot) Starr and Burkholder], and bacterial leaf stripe [Pseudomonas andropogoni (E.F. Smith) Stapp], and biotype E greenbug [Schizaphis graminum (Rondani)] resistance.
The sorghum [Sorghum bicolor (L.) Moench] germplasm lines Tx2945 (Reg. No. GP-645, PI 655260), Tx2946 (Reg. No. GP-646, PI 655261), Tx2947 (Reg. No. GP-647, PI 655262), Tx2948 (Reg. No. GP-648, PI 655263), Tx2949 (Reg. No. GP-649, PI 655264), Tx2950 (Reg. No. GP-650, PI 655265), Tx2951 (Reg. No. GP-651, PI 655266), Tx2952 (Reg. No. GP-652, PI 655267), Tx2954 (Reg. No. GP-653, PI 655268), Tx2955 (Reg. No. GP-654, PI 655269), Tx2956 (Reg. No. GP-655, PI 655270), Tx2957 (Reg. No. GP-656, PI 655271), Tx2958 (Reg. No. GP-657, PI 655272), Tx2959 (Reg. No. GP-658, PI 655273), Tx2960 (Reg. No. GP-659, PI 655274), and Tx2961 (Reg. No. GP-660, PI 655275) were developed and released by Texas AgriLife Research, Lubbock, TX, in 2006. These lines are 3-dwarf (dw1Dw2dw3dw4) in height and possess unique combinations of tan plant color, biotype E greenbug [Schizaphis graminum (Rondani)] resistance, agronomic traits, and resistance to head smut [Sphacelotheca reiliana (Kuhn) Clinton], rust [Puccinia purpurea (Cooke)], zonate leaf spot (Gloeocercospora sorghi Bain and Edgerton), bacterial leaf streak [Xanthomonas holcicola (Elliot) Starr and Burkholder], and bacterial leaf stripe [Pseudomonas andropogoni (E.F. Smith) Stapp].
The lines were developed by crossing the resistance source ‘Capbam’ through Tx2783 to other elite breeding or released lines in the Texas AgriLife Research sorghum improvement program. Released or converted exotic lines used as parents include the following:
The remaining lines used as parents are unreleased from the Texas AgriLife Research sorghum improvement program. Lines with an "SC" designation are partially or fully converted exotic lines from the sorghum conversion program (Stephens et al., 1967). The stage of conversion is indicated by the underlined number. The resistance source in all lines is ‘Capbam’ through Tx2783 (Peterson et al., 1983) or a closely related Tx2783 derivative. Capbam is an introduction from Russia received from DeKalb Agricultural Research Inc. in 1971.
Methods
Crosses to develop populations for selection were made using the plastic bag emasculation technique (Schertz and Clark, 1967). All crosses were made at the Texas AgriLife Research and Extension Center, Lubbock, TX. Crossed seed was sent to a winter nursery in Isabela or Guayanilla, Puerto Rico, for selfing and selection of F1 plants. All lines were developed by the pedigree-breeding method. Agronomic practices used were those common to the respective location.
All F2 populations were grown at the Texas AgriLife Research station, Halfway, TX, and visually selected for plant color, grain color, and improved potential. Subsequent generations were visually selected for agronomic type (plant color and grain color), adaptation, disease resistance, and improved potential at Lubbock, Corpus Christi, or Beeville, TX.
Nurseries at Corpus Christi and Beeville are located in a region in which several sorghum diseases are commonly found. Visual selection was practiced at both locations for resistance to head smut, rust, zonate leaf spot, bacterial leaf streak, and bacterial leaf stripe, as well as insecticide phytotoxicity and grain weathering resistance. Progeny rows with any of the diseases present were discarded. Disease expression in the lines was visually scored over 2 yr using the methodology proposed by Frederiksen et al. (1991).
The lines were evaluated for resistance to biotype E greenbug in replicated seedling stage trials. Evaluations were conducted in greenhouses at Texas A&M University or at West Texas A&M University using the methodology proposed by Teetes (1980).
Characteristics
Pedigrees for each line are listed in Table 1 . Reaction to selected diseases and selected agronomic traits for each line are listed in Table 2 . Tx2945 through Tx2952 and Tx2954 through Tx2957 restore fertility (R-lines) in the A1 cytoplasm system. Tx2958 through Tx2961 do not restore fertility (B-lines) in the A1 cytoplasm system. Fertility restoration in other cytoplasmic systems is not known. All of the lines have tan plant color. Pericarp color of Tx2947, Tx2952, and Tx2957 through Tx2960 is white. Pericarp color of the remaining lines is red. All of the lines possess a thin epicarp, tan glumes, and normal endosperm. All of the lines are awnless except for Tx2948.
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Across environments, the lines reached 50% anthesis no later than and are generally 1 to 5 d earlier than Tx2783, RTx430 (Miller, 1984), and RTx436. The grain weathering resistance of each line is at least equal to and usually superior to that of Tx2783, RTx430, and RTx436. Reaction for insecticide phytotoxicity will vary with the line and location (1.0–3.5 on a scale of 1 = no leaf burn to 5 = 100% leaf burn) and each line is usually less damaged than Tx2783, RTx430, and RTx436.
Availability
Seed of Tx2945 through Tx2952 and Tx2954 through Tx2961 will be maintained by Texas AgriLife Research, Texas AgriLife Research and Extension Center, 1102 E FM 1294, Lubbock, TX 79403-6603. Seed will be available with a Materials Transfer Agreement (MTA) from the Office of Technology Commercialization, Texas A&M University System, 1700 Research Parkway, Suite 250, College Station, TX 77845-9548. Seed will be distributed with an MTA for a period of 20 yr following release.
Acknowledgments
Financial support from the INTSORMIL (International Sorghum and Millet) collaborative research support program funded by the U.S. Agency for International Development (USAID) was used in the development of this germplasm.
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 October 30, 2008.
References
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