Quantitative trait loci associated with functional stay-green SNU-SG1 in rice.
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.
Yoo
Soo-Cheul
SC
Department of Plant Science and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
Cho
Sung-Hwan
SH
Zhang
Haitao
H
Paik
Hyo-Chung
HC
Lee
Chung-Hee
CH
Li
Jinjie
J
Yoo
Jeong-Hoon
JH
Lee
Byun-Woo
BW
Koh
Hee-Jong
HJ
Seo
Hak Soo
HS
Paek
Nam-Chon
NC
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*
D002734:Chlorophyll