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Cultivar · Sorghum inbred line

BTx623

BTx623 is a public grain sorghum inbred line developed at Texas A&M University and released in 1977 as a maintainer (B) line for hybrid breeding. It is the source of the sorghum reference genome and a standard genetic reference for the species.

Dated referenceLast reviewed: 2026-07-12Updated: 2026-07-12
Illustrative diagram · AgricultureID (original)

Record

Cultivar / variety
Variety of
Sorghum
Botanical taxon
Sorghum bicolor
Type
Inbred line
Breeding method
Pedigree breeding using sorghum conversion-program germplasm
Origin
Texas, United States
Released
1977
Breeder / institution
Texas Agricultural Experiment Station, Texas A&M University (developed by Fred R. Miller)
Registry status
Historical
Registries
  • USDA GRIN · United States · as of 2026-07-12BTx623 is maintained as a public grain sorghum inbred accession in the U.S. National Plant Germplasm System; specific record identifiers are not reproduced here.
Adaptation
Warm-season grain sorghum; short (combine-height) stature suits mechanized grain production. Adaptation and performance are environment-specific.
Intended use
Maintainer (B) parent line in hybrid grain sorghum breeding, Reference genome for sorghum, Genetics and genomics research

Registry listing or variety protection is jurisdiction- and date-specific and does not by itself indicate current commercial availability, universal cultivation approval, patent status, or a recommendation.

BTx623 is a public inbred line of grain sorghum developed at the Texas Agricultural Experiment Station (Texas A&M University) by Fred R. Miller and released in 1977. It was bred as a maintainer (B) line — used in the cytoplasmic male-sterility system to maintain a corresponding male-sterile (A) line — and it is a short-statured, combine-height grain type.

BTx623 was derived from the cross BTx3197 × SC170, the latter a line from the sorghum conversion program that introduced tropical (caudatum/Zera-zera) germplasm into short, early-flowering backgrounds adapted to temperate mechanized production. BTx623 is best known today as the source of the sorghum reference genome.

Background and development

BTx623 was released in 1977 from the Texas A&M sorghum breeding program. Its pedigree, BTx3197 × SC170, combines an adapted kafir-background maintainer line with a converted line (SC170) from the sorghum conversion program, which shortened and made photoperiod-insensitive otherwise tall, tropical germplasm so it could be used in temperate breeding.

As a maintainer (B) line, BTx623 is used in hybrid grain sorghum production alongside its corresponding male-sterile (A) line: hybrid seed production in sorghum relies on cytoplasmic male sterility, in which B-lines maintain the sterile A-lines that serve as seed parents.

Role as the sorghum reference genome

BTx623 was chosen as the genotype for the first sequenced and assembled sorghum genome, reported in 2009, making sorghum one of the early grass species with a reference genome. Because of this role, BTx623 has become a standard genetic and genomic reference and is used extensively in sorghum research, including as a parent of mapping populations.

Scope & limitations

Geographic scope: Developed in Texas, United States, for warm-season grain sorghum; used internationally as a reference genotype and breeding parent.

Climate context: Warm-season grain sorghum germplasm; adaptation and performance are environment-specific and evaluated in a breeding context.

  • BTx623 is a public inbred maintainer line and research reference, not a stand-alone commercial variety; its performance is not representative of the hybrids to which it contributes.
  • Pedigree notation for the SC170 parent is written slightly differently across sources; the general conversion-program background is well documented.

Sources

This article draws on the following authoritative sources. See our sources & methodology for how they are selected.

  1. [1]GRIN-Global / National Plant Germplasm System (opens in a new tab)

    USDA Agricultural Research Service (ARS)

    Authoritative

    Cited for: Maintenance of BTx623 as a public sorghum inbred accession

    Type:
    Official registry
    Jurisdiction:
    United States / Global
    Accessed:
    2026-07-12
  2. [2]USDA ARS — Agricultural Research Service (opens in a new tab)

    USDA Agricultural Research Service (ARS)

    Authoritative

    Cited for: Sorghum conversion-program germplasm and the BTx623 reference genome

    Type:
    Government agency
    Jurisdiction:
    United States
    Accessed:
    2026-07-12

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