title: Improving salt tolerance of lowland rice cultivar 'Rassi' through marker-aided backcross breeding in West Africa.
abstract: Salt stress affects about 25% of the 4.4 million ha of irrigated and lowland systems for rice cultivation in West Africa (WA). A major quantitative trait locus (QTLs) on chromosome 1 (Saltol) that enhances tolerance to salt stress at the vegetative stage has enabled the use of marker-assisted selection (MAS) to develop salt-tolerant rice cultivar(s) in WA. We used 3 cycles of backcrossing with selection based on DNA markers and field-testing using 'FL478' as tolerant donor and the widely grown 'Rassi' as recurrent parent. In the BC3F2 stage, salt-tolerant lines with over 80% Rassi alleles except in the region around Saltol segment were selected. 429 introgression lines (Saltol-ILs) were identified as tolerant at vegetative stage, of which 116 were field-tested for four seasons at the reproductive stage. Sixteen Saltol-ILs had less yield loss (3-26% relative to control trials), and 8 Saltol-ILs showed high yield potential under stress and non-stress conditions. The 16 Saltol-ILs had been included for further African-wide testing prior to release in 6 WA countries. MAS reduced the time for germplasm improvement from at least 7 to about 4 years. Our objective is to combine different genes/QTLs conferring tolerance to stresses under one genetic background using MAS.
authors.affiliation: Africa Rice Centre, Sahel Regional Station, B.P. 96, Saint Louis, Senegal. Electronic address: k.bimpong@cgiar.org.
authors.forename: Isaac Kofi
authors.initials: IK
authors.lastname: Bimpong
authors.affiliation: Africa Rice Centre, Sahel Regional Station, B.P. 96, Saint Louis, Senegal. Electronic address: b.manneh@cgiar.org.
authors.forename: Baboucarr
authors.initials: B
authors.lastname: Manneh
authors.affiliation: Africa Rice Centre, Sahel Regional Station, B.P. 96, Saint Louis, Senegal. Electronic address: m.sock@cgiar.org.
authors.forename: Mamadou
authors.initials: M
authors.lastname: Sock
authors.affiliation: Africa Rice Centre, Sahel Regional Station, B.P. 96, Saint Louis, Senegal. Electronic address: f.Diaw@cgiar.org.
authors.forename: Faty
authors.initials: F
authors.lastname: Diaw
authors.affiliation: Africa Rice Centre, Sahel Regional Station, B.P. 96, Saint Louis, Senegal. Electronic address: n.amoah@cgiar.org.
authors.forename: Nana Kofi Abaka
authors.initials: NKA
authors.lastname: Amoah
authors.affiliation: International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines. Electronic address: a.ismail@irri.org.
authors.forename: Abdelbagi M
authors.initials: AM
authors.lastname: Ismail
authors.affiliation: International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines. Electronic address: g.gregorio@irri.org.
authors.forename: Glenn
authors.initials: G
authors.lastname: Gregorio
authors.affiliation: International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines. Electronic address: r.k.singh@irri.org.
authors.forename: Rakesh Kumar
authors.initials: RK
authors.lastname: Singh
authors.affiliation: Africa Rice Centre, 01 BP 2031, Cotonou, Benin. Electronic address: m.wopereis@cgiar.org.
authors.forename: Marco
authors.initials: M
authors.lastname: Wopereis
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000354:Africa, Western; D000483:Alleles; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D017343:Genes, Plant / Q000235:genetics; D018895:Microsatellite Repeats / Q000235:genetics; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D000069600:Plant Breeding / Q000379:methods*; D040641:Quantitative Trait Loci / Q000235:genetics*; D015203:Reproducibility of Results; D055049:Salt Tolerance / Q000235:genetics*; D000068618:Selective Breeding
keywords: High grain yield; Introgression lines; Lowland rice; Marker-aided backcross breeding (MABC); Salt stress; Saltol QTL