title: Identification and fine mapping of quantitative trait loci for seed vigor in germination and seedling establishment in rice.
abstract: Seed vigor is an index of seed quality that is used to describe the rapid and uniform germination and the establishment of strong seedlings in any environmental conditions. Strong seed vigor in low-temperature germination conditions is particularly important in direct-sowing rice production systems. However, seed vigor has not been selected as an important breeding trait in traditional breeding programs due to its quantitative inherence. In this study, we identified and mapped eight quantitative trait loci (QTLs) for seed vigor by using a recombinant inbred population from a cross between rice (Oryza sativa L. ssp. indica) cultivars ZS97 and MH63. Conditional QTL analysis identified qSV-1, qSV-5b, qSV-6a, qSV-6b, and qSV-11 influenced seedling establishment and that qSV-5a, qSV-5c, and qSV-8 influenced only germination. Of these, qSV-1, qSV-5b, qSV-6a, qSV-6b, and qSV-8 were low-temperature-specific QTLs. Two major-effective QTLs, qSV-1, and qSV-5c were narrowed down to 1.13-Mbp and 400-kbp genomic regions, respectively. The results provide tightly linked DNA markers for the marker-assistant pyramiding of multiple positive alleles for increased seed vigor in both normal and low-temperature germination environments.
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Xie
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Tan
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Rongbao
authors.initials: R
authors.lastname: Xu
authors.forename: Laibao
authors.initials: L
authors.lastname: Feng
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Xing
authors.forename: Xiaoquan
authors.initials: X
authors.lastname: Qi
mesh_terms: D002874:Chromosome Mapping; D018525:Germination / Q000235:genetics*; D012275:Oryza / Q000235:genetics*; D040641:Quantitative Trait Loci; D036226:Seedlings / Q000502:physiology*; D012639:Seeds / Q000502:physiology*; D013696:Temperature
keywords: Conditional quantitative trait locus mapping; germination; rice; seed vigor; seedling establishment