title: Quantitative trait loci associated with functional stay-green SNU-SG1 in rice.
abstract: During monocarpic senescence in higher plants, functional stay-green delays leaf yellowing, maintaining photosynthetic competence, whereas nonfunctional stay-green retains leaf greenness without sustaining photosynthetic activity. Thus, functional stay-green is considered a beneficial trait that can increase grain yield in cereal crops. A stay-green japonica rice 'SNU-SG1' had a good seed-setting rate and grain yield, indicating the presence of a functional stay-green genotype. SNU-SG1 was crossed with two regular cultivars to determine the inheritance mode and identify major QTLs conferring stay-green in SNU-SG1. For QTL analysis, linkage maps with 100 and 116 DNA marker loci were constructed using selective genotyping with F2 and RIL (recombinant inbred line) populations, respectively. Molecular marker-based QTL analyses with both populations revealed that the functional stay-green phenotype of SNU-SG1 is regulated by several major QTLs accounting for a large portion of the genetic variation. Three main-effect QTLs located on chromosomes 7 and 9 were detected in both populations and a number of epistatic-effect QTLs were also found. The amount of variation explained by several digenic interactions was larger than that explained by main-effect QTLs. Two main-effect QTLs on chromosome 9 can be considered the target loci that most influence the functional stay-green in SNU-SG1. The functional stay-green QTLs may help develop low-input high-yielding rice cultivars by QTL-marker-assisted breeding with SNU-SG1.
authors.affiliation: Department of Plant Science and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
authors.forename: Soo-Cheul
authors.initials: SC
authors.lastname: Yoo
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Cho
authors.forename: Haitao
authors.initials: H
authors.lastname: Zhang
authors.forename: Hyo-Chung
authors.initials: HC
authors.lastname: Paik
authors.forename: Chung-Hee
authors.initials: CH
authors.lastname: Lee
authors.forename: Jinjie
authors.initials: J
authors.lastname: Li
authors.forename: Jeong-Hoon
authors.initials: JH
authors.lastname: Yoo
authors.forename: Byun-Woo
authors.initials: BW
authors.lastname: Lee
authors.forename: Hee-Jong
authors.initials: HJ
authors.lastname: Koh
authors.forename: Hak Soo
authors.initials: HS
authors.lastname: Seo
authors.forename: Nam-Chon
authors.initials: NC
authors.lastname: Paek
mesh_terms: D002734:Chlorophyll / Q000032:analysis; D002874:Chromosome Mapping; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development; D040641:Quantitative Trait Loci / Q000235:genetics*
chemical_list: D002734:Chlorophyll