{ "id": "the-timor-hybrid", "url": "https://coffearium.org/entries/the-timor-hybrid/", "license": "CC-BY-4.0", "title": "The Timor Hybrid", "summary": "A natural cross of arabica and robusta found on the island of Timor. It carries robusta genes against coffee leaf rust and is the parent of the Catimor and Sarchimor groups of varieties.", "domain": "botany", "kind": "Variety", "stage": "plant", "topics": [ "science", "history" ], "topicSections": {}, "lang": "en", "status": "verified", "reviewer": "Coffearium verification pass", "lastVerified": "2026-10-22T00:00:00.000Z", "updated": "2026-10-22T00:00:00.000Z", "added": "2026-10-22T00:00:00.000Z", "brief": [ "The Timor Hybrid (Híbrido de Timor, HdT) is a spontaneous cross of *C. arabica* and *C. canephora* found on Timor; most sources date the plant to 1927.1,3,6", "It crosses readily with arabica, so breeders made it the main donor of rust resistance genes.9,2", "The leaf rust resistance genes SH6–SH9 come from robusta and give the Timor Hybrid populations their resistance.1,2", "Crosses with Caturra gave the Catimor group, crosses with Villa Sarchi the Sarchimor group; each is a family of varieties, not one variety.1,11", "Trials show that cup quality varies line by line; selection can keep resistance without lower quality.7,8" ], "quickFacts": [ { "label": "Parents", "value": "C. arabica × C. canephora (spontaneous)" }, { "label": "Found", "value": "Timor, 1927 (1917 in one source)" }, { "label": "Key accessions (CIFC)", "value": "832/1, 832/2, 1343, 2570; 4106 (held to be the first plant)" }, { "label": "Rust resistance genes", "value": "SH6, SH7, SH8, SH9 (from C. canephora)" }, { "label": "Introgressed robusta DNA", "value": "7–11% of the genome in five derivatives (2024 genome study)" }, { "label": "Descendant groups", "value": "Catimor (× Caturra), Sarchimor (× Villa Sarchi)" } ], "aka": [ "Híbrido de Timor", "Hibrido de Timor", "Timor hybrid", "HdT", "HDT" ], "linkTerms": [ "Timor Hybrid", "Híbrido de Timor", "Catimor", "Catimors", "Sarchimor", "Sarchimors", "introgressed variety", "introgressed varieties" ], "related": [ "arabica-varieties", "coffee-leaf-rust", "coffee-berry-disease", "coffea-arabica", "coffea-canephora", "polyploidy-and-the-arabica-genome", "f1-hybrids", "the-arabica-bottleneck" ], "contested": [ "Year the plant was found: 1927 in a rust review, a cytogenetic study and the arabica genome study1,3,6; 1917, in a Typica plantation, in a 2020 Brazilian study citing a 1973 circular by A. Bettencourt published by the Instituto Agronômico de Campinas.4 A 2006 review speaks of its “discovery in the late 1950s”, which matches the date when the populations were recognised as hybrids.2,1", "Ploidy of the first plant: a 2006 review states that the Timor Hybrid has the same chromosome number as arabica and crosses fertilely with it2; a 2013 cytogenetic study proposes that accession CIFC 4106, held to be the first plant, is an allotriploid and that other accessions arose from it.3", "Group of Obatã, Tupi and IAPAR 59: a 2006 review lists them as regional names of Catimor2; the World Coffee Research catalogue gives Obatã (Obata Red) the parentage Timor Hybrid 832/2 × Villa Sarchi and files it as Sarchimor, and its T5296 entry names Obata (Red), Tupi and IAPAR 59 as similar selections from the Sarchimor population.15,11" ], "corrections": [ { "date": "2026-10-22T00:00:00.000Z", "change": "SH6–SH9 no longer described as found only in Timor Hybrid derivatives in the brief and body; the 2006 claim is now attributed and the 2017 review's wider statement (Timor Hybrid and other interspecific hybrids) added.", "reason": "The 2017 review cited for the claim says the genes occur in the Timor Hybrid and other interspecific hybrids; the coffee leaf rust entry gives the same." }, { "date": "2026-10-22T00:00:00.000Z", "change": "The 1917 date is now attributed to a 1973 circular by A. Bettencourt (Instituto Agronômico de Campinas), not to a CIFC report; the contested item giving 1967 for the start of breeding in Portugal was removed and the 1960 start of the CIFC programme added to the text.", "reason": "Setotaw et al. cite Bettencourt 1973, IAC Circular 23; 1967 rested on one Tier B source (a WCR history narrative), against a Tier A review giving 1960." }, { "date": "2026-10-22T00:00:00.000Z", "change": "Limani described as the name of the Sarchimor population in Puerto Rico, not as a selection from T5296; nematode resistance limited to some derived lines; Catimor 129 statement attributed to the WCR catalogue without the count of lines.", "reason": "Wording of the WCR T5296 page and of Bertrand et al. 2003; the count of lines rests only on a WCR history narrative." } ], "sources": [ { "id": "s1", "title": "The coffee leaf rust pathogen Hemileia vastatrix: one and a half centuries around the tropics", "authors": "Talhinhas, P.; Batista, D.; Diniz, I.; Vieira, A.; Silva, D. N.; Loureiro, A.; Tavares, S.; Pereira, A. P.; Azinheira, H. G.; Guerra-Guimarães, L.; Várzea, V.; Silva, M. C.", "year": 2017, "publisher": "Molecular Plant Pathology 18(8), 1039–1051", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC6638270", "doi": "10.1111/mpp.12512", "tier": "A", "quote": "HDT (Híbrido de Timor) populations were derived from a plant discovered on the island of Timor in 1927", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s2", "title": "Coffee resistance to the main diseases: leaf rust and coffee berry disease", "authors": "Silva, M. C.; Várzea, V.; Guerra-Guimarães, L.; Azinheira, H. G.; Fernandez, D.; Petitot, A.-S.; Bertrand, B.; Lashermes, P.; Nicole, M.", "year": 2006, "publisher": "Brazilian Journal of Plant Physiology 18(1), 119–147", "url": "https://www.scielo.br/j/bjpp/a/dTHqD9SqgdJtq9wHCf9Hp6R/?lang=en", "doi": "10.1590/S1677-04202006000100010", "tier": "A", "quote": "This interspecific hybrid has the same number of chromosomes as C. arabica and the crosses are fertile.", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s3", "title": "Following the track of “Híbrido de Timor” origin by cytogenetic and flow cytometry approaches", "authors": "Clarindo, W. R.; Carvalho, C. R.; Caixeta, E. T.; Koehler, A. D.", "year": 2013, "publisher": "Genetic Resources and Crop Evolution 60(8), 2253–2259", "url": "https://locus.ufv.br/items/822a744d-11c4-4133-a91f-72d7e28b79a5/full", "doi": "10.1007/s10722-013-9990-3", "tier": "A", "quote": "All HT CIFC 4106 plants exhibited the same 2C-value, AT% and chromosome number.", "abstractOnly": true, "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s4", "title": "Genome Introgression of Híbrido de Timor and Its Potential to Develop High Cup Quality C. arabica Cultivars", "authors": "Setotaw, T. A.; Caixeta, E. T.; Zambolim, E. M.; Sousa, T. V.; Pereira, A. A.; Baião, A. C.; Cruz, C. D.; Zambolim, L.; Sakiyama, N. S.", "year": 2020, "publisher": "Journal of Agricultural Science 12(4), 64–76", "url": "https://www.alice.cnptia.embrapa.br/alice/bitstream/doc/1125339/1/Setotaw-et-al-2020-1.pdf", "doi": "10.5539/jas.v12n4p64", "tier": "A", "quote": "Híbrido de Timor is the principal source for disease and pest resistance genes in C. arabica breeding program worldwide.", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s5", "title": "Molecular analysis of introgressive breeding in coffee (Coffea arabica L.)", "authors": "Lashermes, P.; Andrzejewski, S.; Bertrand, B.; Combes, M. C.; Dussert, S.; Graziosi, G.; Trouslot, P.; Anthony, F.", "year": 2000, "publisher": "Theoretical and Applied Genetics 100(1), 139–146", "url": "https://agritrop.cirad.fr/264024", "doi": "10.1007/s001220050019", "tier": "A", "quote": "obviously constitutes a considerable source of genetic diversity for Arabica breeding", "abstractOnly": true, "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s6", "title": "The genome and population genomics of allopolyploid Coffea arabica reveal the diversification history of modern coffee cultivars", "authors": "Salojärvi, J.; Rambani, A.; Yu, Z.; Guyot, R.; et al.", "year": 2024, "publisher": "Nature Genetics 56(4), 721–731", "url": "https://doi.org/10.1038/s41588-024-01695-w", "doi": "10.1038/s41588-024-01695-w", "tier": "A", "quote": "An introgressed region shared by all Timor hybrid lines was evident on chromosome 4", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s7", "title": "Impact of the Coffea canephora gene introgression on beverage quality of C. arabica", "authors": "Bertrand, B.; Guyot, B.; Anthony, F.; Lashermes, P.", "year": 2003, "publisher": "Theoretical and Applied Genetics 107, 387–394", "url": "https://publications.cirad.fr/une_notice.php?dk=523152", "doi": "10.1007/s00122-003-1203-6", "tier": "A", "quote": "Selection can avoid accompanying the introgression of resistance genes with a drop in beverage quality", "abstractOnly": true, "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s8", "title": "Calidad física y en taza de los componentes de la Variedad Castillo® y sus derivadas regionales", "authors": "Alvarado-Alvarado, G.; Moreno-González, E.; Montoya-Restrepo, E. C.; Alarcón-Suárez, R.", "year": 2009, "publisher": "Cenicafé 60(3), 210–228", "url": "https://www.cenicafe.org/es/publications/arc060(03)210-228.pdf", "tier": "A", "quote": "forman grupos de similitud por sus atributos en taza", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s9", "title": "The Coffee Tree – Genetic Diversity and Origin", "authors": "Herrera, J. C.; Lambot, C.", "year": 2017, "publisher": "In: Folmer, B. (ed.), The Craft and Science of Coffee, Academic Press, ch. 1, pp. 1–16", "url": "https://doi.org/10.1016/B978-0-12-803520-7.00001-3", "doi": "10.1016/B978-0-12-803520-7.00001-3", "tier": "B", "quote": "Therefore, most of the breeders decided to use the Timor hybrid (which is a natural hybrid between C. arabica and C. canephora), highly cross-compatible with Arabica, as the main source of resistant genes.", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s10", "title": "T5175", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/t5175", "tier": "A/B", "tierNote": "A for lineage, breeder and genetic group as catalogued; B for the history narrative", "quote": "In Honduras, additional selection of T5175 led to the creation of IHCAFE 90 and Lempira.", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s11", "title": "T5296", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/t5296", "tier": "A/B", "tierNote": "A for lineage and genetic group as catalogued; B for the history narrative (dates, transfers)", "quote": "was crossed with compact Villa Sarchi to create hybrid 361 (H361)", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s12", "title": "Costa Rica 95", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/costa-rica-95", "tier": "A", "quote": "confirmed through scientific evaluation to be susceptible to coffee leaf rust in Costa Rica", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s13", "title": "Lempira", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/lempira", "tier": "A", "quote": "Lempira has been confirmed through scientific evaluation to be susceptible to coffee leaf rust in Honduras", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s14", "title": "Catimor 129", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/catimor-129", "tier": "A/B", "tierNote": "A for lineage, breeder, release year and disease data as catalogued; B for the history narrative", "quote": "Of the five Catimor lines introduced, only one—Cat129—showed some resistance to CBD.", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s15", "title": "Obata (Red)", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/obata-red", "tier": "A/B", "tierNote": "A for lineage, breeder and genetic group as catalogued; B for the history narrative", "quote": "Timor Hybrid 832/2 x Villa Sarchi CIFC 971/10", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s16", "title": "Marsellesa", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/marsellesa", "tier": "A", "quote": "Pedigree selection made by ECOM-CIRAD in Nicaragua specifically for its rust resistance traits.", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s17", "title": "Herança da resistência do Híbrido de Timor UFV 443-03 à ferrugem-do-cafeeiro", "authors": "Capucho, A. S.; Caixeta, E. T.; Zambolim, E. M.; Zambolim, L.", "year": 2009, "publisher": "Pesquisa Agropecuária Brasileira 44(3), 276–282", "url": "https://doi.org/10.1590/S0100-204X2009000300009", "doi": "10.1590/S0100-204X2009000300009", "tier": "A", "quote": "Dois genes dominantes e independentes conferem a resistência genética do Híbrido de Timor UFV 443-03 à raça II e ao patótipo 001 de H. vastatrix.", "accessed": "2026-10-22T00:00:00.000Z" }, { "id": "s18", "title": "The population structure of Hemileia vastatrix in Brazil inferred from AFLP", "authors": "Maia, T. A.; Maciel-Zambolim, E.; Caixeta, E. T.; Mizubuti, E. S. G.; Zambolim, L.", "year": 2013, "publisher": "Australasian Plant Pathology 42, 533–542", "url": "https://doi.org/10.1007/s13313-013-0213-3", "doi": "10.1007/s13313-013-0213-3", "tier": "A", "quote": "This result suggested that H. vastatrix in Brazil behaves as a large undifferentiated population with a high level of genotypic diversity that is unstructured with regard to its geographic and host origins.", "accessed": "2026-10-22T00:00:00.000Z" } ], "markdown": "## A natural cross on Timor\n\nThe Timor Hybrid is a coffee plant that arose without human help. A *C. arabica* plant and a *C. canephora* (robusta) plant crossed on the island of Timor.1,6 Most sources date the plant to 1927.1,3,6 One study gives 1917 and says it grew in a plantation of Typica.4 In Portuguese it is called Híbrido de Timor; papers shorten it to HDT or HT, and this entry uses HdT.1,4\n\nThe plant came from the part of Timor that was then a Portuguese colony, now Timor-Leste.2 In the 1950s, its offspring were shown to be natural hybrids of the two species.1 Most of them resisted all or some of the known races of coffee leaf rust.2 A race is a form of the rust fungus that can overcome certain resistance genes.\n\nArabica itself is an old hybrid, with robusta as one of its two parents. How that happened is covered in Polyploidy and the arabica genome. The Timor Hybrid is a much younger, second meeting of the two species.6\n\n## Why breeders chose it\n\nRobusta carries ample resistance to leaf rust.1 Bringing it into arabica through direct crosses, which give triploid hybrids, is a long route.9 The Timor Hybrid has the same number of chromosomes as arabica, and crosses with arabica are fertile.2 According to a coffee science textbook, this made it the main source of resistance genes for most breeders.9\n\nThe resistance comes from robusta genes. Four rust resistance genes from robusta, SH6, SH7, SH8 and SH9, give the Timor Hybrid populations their resistance.1,2 The plant also carries a gene against coffee berry disease.2 Some lines derived from it also resist the root-knot nematode *Meloidogyne exigua*.7 How the SH genes work against the fungus is explained in Coffee leaf rust.\n\nThe Timor Hybrid is not one uniform plant. Its accessions carry different numbers of resistance genes.17 In a 2009 Brazilian study, two dominant genes controlled the rust resistance of one accession, UFV 443-03.17\n\n## From one plant to many varieties\n\nBreeders cross the Timor Hybrid with a good arabica variety. They then select for several generations. The aim is to keep the robusta genes for resistance and lose the rest of the robusta traits.5,7 The result is called an introgressed variety: arabica that carries some robusta DNA.5\n\nThe figure shows the idea on the chromosomes. Robusta segments (filled blocks) enter with the Timor Hybrid. Selection keeps some of them and loses others.5,6\n\n
\n
\n
    \n
  1. Arabica parent. A variety such as Caturra or Villa Sarchi, with no introgressed robusta DNA.1
    2. \n
  2. Timor Hybrid line. Robusta segments in large blocks, almost all on the arabica chromosomes that came from robusta’s side; one region on chromosome 4 is shared by all lines studied.6
    3. \n
  3. Selected line A. After crossing and selection, fewer robusta segments remain.5
    4. \n
  4. Selected line B. A sister line can keep different segments: lines differ in how much robusta DNA they carry.5,7
    5. \n
\n
Introgression of robusta segments, shown on the 11 chromosomes of arabica’s robusta-derived subgenome. Schematic, not to scale: block positions are illustrative, except the shared region on chromosome 4.5,6
\n
\n\n## Catimor and Sarchimor\n\nThe coffee rust research centre in Portugal, the Centro de Investigação das Ferrugens do Cafeeiro (CIFC), built its breeding programme on the Timor Hybrid, starting in 1960.2,1 It crossed two Timor Hybrid plants with dwarf arabica varieties.1 Caturra × HdT CIFC 832/1 gave the Catimor population. Villa Sarchi × HdT CIFC 832/2 gave the Sarchimor population.1 Colombia crossed Caturra with HdT CIFC 1343, and Brazil crossed Catuaí with HdT CIFC 2570.1\n\nCatimor and Sarchimor are not single varieties. Each is a group of distinct varieties with similar parentage.11 National programmes selected their own lines and gave them local names.2,11 As of 2017, these populations were the source of most rust-resistant varieties grown.1\n\n
\n
\n
    \n
  1. Catimor (CIFC H26). Caturra × HdT 832/1, selected further in Brazil and at CATIE in Costa Rica as T5175; IHCAFE 90 and Lempira were selected from T5175 in Honduras.10,1 Costa Rica 95, bred by ICAFE, has the same parentage.12
    2. \n
  2. Colombian Catimors. Caturra × HdT 1343.1 Catimor 129 is a selection of a Colombian line of this cross.14 Castillo is made of advanced lines of Caturra × Timor Hybrid; the source opened does not name the accession (dashed).8
    3. \n
  3. Sarchimor (CIFC H361). Villa Sarchi × HdT 832/2, designated T5296 at CATIE; Parainema and Cuscatleco came from further selection, and in Puerto Rico the Sarchimor population was called Limani.11
    4. \n
  4. Other Sarchimors. HdT 832/2 × Villa Sarchi CIFC 971/10: Obata (Red), selected by IAC in Brazil, and Marsellesa, selected by ECOM-CIRAD in Nicaragua.15,16
    5. \n
  5. Brazilian population. Catuaí × HdT 2570; no example variety from this cross was checked for this entry.1
    6. \n
\n
From Timor Hybrid accessions to the Catimor and Sarchimor groups and some of their varieties, as named in the World Coffee Research catalogue and a 2017 review. Selected examples, not a complete tree.1,10,11
\n
\n\n## Resistance that wears off\n\nRust races that overcome the Timor Hybrid genes have appeared. Some commercial varieties derived from it are gradually losing their resistance.2,1 World Coffee Research records that Costa Rica 95 and Lempira, both Catimors, have been confirmed susceptible to leaf rust in Costa Rica and Honduras.12,13 In Brazil, a rust isolate infected Oeiras, a cultivar from Caturra × HdT CIFC 832/1 released as resistant to race II.17 A 2013 study found the rust in Brazil highly diverse, with no separate populations on different hosts.18 The Coffee leaf rust entry follows the races and how resistance is lost.\n\n\n\n## What was introgressed\n\nIntrogression here means that robusta DNA was moved into the arabica genome by crossing and backcrossing. Arabica has two subgenomes, one from *C. canephora* and one from *C. eugenioides*.6 The 2024 arabica genome study sequenced five descendants of the original Timor Hybrid, obtained by backcrossing to arabica.6 Their robusta segments lay in large blocks, a sign of recent hybridisation, and covered 7–11% of the genome.6 Introgression occurred almost exclusively within the subgenome from robusta. One introgressed region on chromosome 4 was shared by all Timor Hybrid lines.6\n\nEarlier work measured the same thing with markers. A 2000 study used AFLP markers (amplified fragment length polymorphism) on 19 introgression lines (BC1F4) and two Timor Hybrid accessions.5 It found 178 markers that set the Timor Hybrid material apart from arabica. The introgressed markers in these genotypes were estimated at 9–29% of the *C. canephora* genome.5 Introgression involved recombination within chromosomes, not only the replacement of whole chromosomes.5 A 2020 Brazilian study with AFLP and SSR (microsatellite) markers concluded that introgression into the Timor Hybrid does not reach 30% of the *C. canephora* genome.4\n\nThe figures do not measure the same quantity. The marker studies give a share of the robusta genome detected in the lines. The genome study gives the share of the arabica genome covered by robusta blocks.5,6\n\n## Resistance genes and candidate loci\n\nNine rust resistance factors are known in coffee, SH1 to SH9.1,2 A 2006 review states that SH6, SH7, SH8 and SH9 were found only in Timor Hybrid derivatives.2 A 2017 review describes them as robusta-derived genes that confer the resistance of the Timor Hybrid populations and places them in the Timor Hybrid and other interspecific hybrids.1 Accession HdT CIFC 832/2 carries additional introgressions compared with other genotypes.1\n\nThe genome study reanalysed published gene-expression data from a resistant Timor Hybrid line and a susceptible cultivar after inoculation with rust. It found 723 differentially expressed genes, most of them associated with defence.6 In the shared introgressed region on chromosome 4 it names strong candidate genes: one homologue of *RPP8*, six of *CPR1* and one *LRK10L*.6 These are candidates, not confirmed SH genes.\n\nHow many genes act in one accession was tested in a 2009 Brazilian inheritance study. Catuaí Amarelo IAC 64 (SH5, susceptible) was crossed with HdT UFV 443-03; the F1 plant was selfed (246 F2 plants) and backcrossed to the resistant parent (87 plants) and to the susceptible parent (115 plants).17 Leaf discs were inoculated with race II (v5) and with pathotype 001, a single-pustule isolate from the cultivar Oeiras.17 With race II, the F2 split 235 resistant to 11 susceptible, which fitted both 15:1 and 61:3. The susceptible backcross split 80:35, which fitted 3:1 (χ² = 1.811, P = 0.178) and rejected 7:1.17 Pathotype 001 gave the same picture (F2 231:15; backcross 85:30). The authors conclude that two dominant, independent genes control the resistance of this accession to both inocula.17 The same paper reports earlier Brazilian work with one dominant gene in accession UFV 427-15 and three in six other accessions. It explains the difference by the heterogeneous origin of the accessions, plants collected on Timor by the CIFC in the 1950s.17\n\n## Rust variability and resistance breakdown\n\nThe 2009 study also showed the limits of race typing. Pathotype 001 reacted as race II on the CIFC differential set, yet it infected Oeiras and Icatu Vermelho, which race II did not.17 The authors read this as one or more virulence genes the differentials do not detect, possibly a new race.17 They cite earlier work in which isolates from Catimor, Sarchimor and the cultivar Colombia had been typed as race II but carried further virulence genes.17\n\nA 2013 study analysed 91 rust isolates collected in 2007 from *C. arabica*, *C. canephora* and Timor Hybrid or Icatu derivatives in Minas Gerais, Espírito Santo and São Paulo, Brazil, with 100 AFLP markers.18 Every isolate had its own multilocus genotype. Of the genetic variance, 99.56% lay within host groups and 0.44% between them (GST = 0.026).18 Random mating could not be rejected for the isolates from *C. canephora* (IA = 0.225, P = 0.123), which the authors take as support for sexual recombination.18 They argue that varieties bred from canephora × arabica hybrids share common resistance genes, which favours new, complex races able to infect both species.18 The paper notes that several cultivars from these hybrids have lost their resistance to new races, and that race XXXVII (v2,5,6,7,9) was first detected in Brazil in 2008.18\n\nAgainst coffee berry disease, the Timor Hybrid carries one gene at the T locus, with intermediate action.2 According to the World Coffee Research catalogue, of the Catimor lines introduced to Malawi only Catimor 129 showed some resistance to coffee berry disease.14\n\n## One plant or many\n\nBreeding lines trace back to accessions held at CIFC. Accession CIFC 4106 has been considered the first plant, found in 1927.3 A 2013 study measured nuclear DNA content, base composition and chromosome number in CIFC 4106 and five other accessions.3 All CIFC 4106 plants were alike; the other five differed in DNA content.3 The authors suggest that CIFC 4106 is an allotriploid, formed from a reduced germ cell of each species, and that the other accessions arose from it.3\n\nThis sits uneasily with the older account that the Timor Hybrid has arabica’s chromosome number.2 Both can be true if the first plant was triploid and the populations used in breeding are its tetraploid descendants. No study opened for this entry tested that sequence directly.\n\n## Cup quality in trials\n\nIntrogressed varieties have a reputation for lower cup quality. According to a coffee science textbook, the quality of some is debated; it names Costa Rica 95 as inferior to traditional varieties.9 Trials give a mixed picture, line by line:\n\n- **CIRAD and IRD, 2003.** A trial compared Timor Hybrid-derived lines and F1 hybrids with non-introgressed controls. Lines differed significantly in caffeine, chlorogenic acids, fat, trigonelline and sucrose, in acidity and in overall standard.7 Two lines were poorer than the controls in sucrose and acidity. Two highly introgressed lines did not differ from the controls.7 Lines carried 1–37 introgressed AFLP markers, and marker number was not correlated with chemistry or cup attributes.7\n- **Cenicafé, 2009.** A panel of five tasters scored 34 F5 and F6 component lines of Castillo against Típica, Borbón, Tabi and Caturra on 10 attributes.8 The progenies formed similarity groups with the traditional varieties, and some groups scored statistically higher than the controls on some variables.8\n- **Brazil, 2020.** A trial cupped 16 genotypes: three arabica, seven Timor Hybrid accessions and six Timor Hybrid × arabica cultivars.4 It found no significant differences in cup attributes between Bourbon and the cultivars derived from the Timor Hybrid.4\n\nThe trials agree on one point: quality depends on the line selected, not on the presence of robusta DNA as such. Selection can keep resistance without a drop in cup quality.7,9 No study opened for this entry compared Catimor and Sarchimor groups as wholes.\n\n## Reference values\n\n| Parameter | Value reported | Source |\n|---|---|---|\n| Parents | *C. arabica* × *C. canephora*, spontaneous | Talhinhas et al.1; Salojärvi et al.6 |\n| Year found | 1927 (1917 in one study) | Talhinhas et al.1; Clarindo et al.3; Setotaw et al.4 |\n| Recognised as interspecific hybrid | 1950s | Talhinhas et al.1 |\n| CIFC breeding programme started | 1960 | Talhinhas et al.1 |\n| Rust resistance genes | SH6, SH7, SH8, SH9 | Silva et al.2 |\n| Rust resistance genes in accession UFV 443-03 | 2, dominant and independent (race II and pathotype 001; Catuaí Amarelo IAC 64 × UFV 443-03, 246 F2, 115 susceptible-backcross plants) | Capucho et al.17 |\n| Rust population, Brazil (2007 isolates) | 91 isolates, each a distinct AFLP genotype; 99.56% of variance within host groups, GST = 0.026 | Maia et al.18 |\n| Coffee berry disease resistance | One gene at the T locus | Silva et al.2 |\n| Robusta DNA in derivatives | 7–11% of the genome (5 lines) | Salojärvi et al.6 |\n| Introgressed markers | 9–29% of the *C. canephora* genome (19 BC1F4 lines and 2 Timor Hybrid accessions) | Lashermes et al.5 |\n| Introgressed AFLP markers per line | 1–37 | Bertrand et al.7 |\n| Catimor parents | Caturra × HdT CIFC 832/1 | Talhinhas et al.1; WCR10 |\n| Sarchimor parents | Villa Sarchi × HdT CIFC 832/2 | Talhinhas et al.1; WCR11 |\n| Other breeding crosses | Caturra × HdT CIFC 1343 (Colombia); Catuaí × HdT CIFC 2570 (Brazil) | Talhinhas et al.1 |\n\n## Open questions\n\n- **Ploidy of the original plant.** Whether the first plant was triploid, and how the fertile breeding populations arose from it.3\n- **Which genes give resistance.** The genome study names candidate genes in the chromosome 4 region; which of them correspond to SH6–SH9 is not established.2,6\n- **Durable resistance.** With races overcoming several derivatives, breeders look for new resistance sources, including more robusta material.1 A 2013 Brazilian rust population study found high genotypic diversity and gene flow, which it links to a high potential of the fungus to adapt.18\n\n## Key studies\n\n
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Lashermes et al., 2000 – Measuring introgression. Used AFLP markers on 19 arabica introgression lines and two Timor Hybrid accessions. Robusta material made up a substantial share of the lines and had entered by recombination, not only as whole chromosomes.

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Theoretical and Applied Genetics 100(1), 139–146 · doi:10.1007/s001220050019

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Bertrand et al., 2003 – Introgression and beverage quality. Compared Timor Hybrid-derived lines with non-introgressed arabica for chemistry and cup. Some lines were poorer in sucrose and acidity, others matched the controls, and the amount of robusta DNA did not predict quality.

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Theoretical and Applied Genetics 107, 387–394 · doi:10.1007/s00122-003-1203-6

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Silva et al., 2006 – Resistance to leaf rust and coffee berry disease. A review from the CIFC and partners of how resistance is inherited and expressed. It sets out the SH genes, the resistance groups and the CIFC crosses with the Timor Hybrid that gave Catimor and Sarchimor.

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Brazilian Journal of Plant Physiology 18(1), 119–147 · doi:10.1590/S1677-04202006000100010

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Clarindo et al., 2013 – Tracing the first plant. Compared DNA content, base composition and chromosomes of six Timor Hybrid accessions. Proposes that the accession held to be the first plant is triploid and that the others derive from it.

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Genetic Resources and Crop Evolution 60(8), 2253–2259 · doi:10.1007/s10722-013-9990-3

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Salojärvi et al., 2024 – The arabica genome. Among wild and cultivated arabica, it sequenced five Timor Hybrid descendants. Their robusta blocks sit almost only on the robusta-derived subgenome, with one region shared by all lines, and the study names candidate rust-defence genes.

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Nature Genetics 56(4), 721–731 · doi:10.1038/s41588-024-01695-w

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