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Volume 07
Advances in Crop Science and Technology
ISSN: 2329-8863
Agri 2019
August 15-16, 2019
conference
series
.com
August 15-16, 2019 | Rome, Italy
14
th
International Conference on
Agriculture & Horticulture
Page 54
Jianlong Xu, Adv Crop Sci Tech 2019, Volume 07
Jianlong Xu
Chinese Academy of Agricultural Sciences, China
Selective introgression lines-based QTL mapping and QTL-designed breeding in rice
A
dvances in re-sequencing and fast phenotyping technologies greatly facilitate gene mapping and favorable allele
mining of important agronomic traits from germplasms and mapping populations in crops. However, separation of
QTL mapping studies from breeding practice results in difficult use of most mapping results in breeding program due to
sensitivity of QTL to genetic background and environment. Here, we proposed a selective introgression line strategy to
tightly connect QTL mapping and QTL-designed breeding together. Using three sets of trait-specific introgression lines
(ILs) in a
Xian (indica)
variety Huanghuazhan (HHZ) background, we identified nine drought tolerance QTL (DT-QTL)
and seven low nitrogen tolerance QTL (LNT-QTL) by a segregation distortion approach and a genome-wide association
study, respectively. Based on performances of DT and LNT and genotypes at the detected QTL, two ILs M79 and M387
with DT and LNT were selected for cross-making to validate the identified QTL and to develop DT and LNT rice lines
by pyramiding two DT-QTL (
qDT3.9
and
qDT6.3
) and two LNT-QTL (
qGY1
and
qSF8
). Using four pairs of kompetitive
allele specific PCR (KASP) SNP markers, we selected 66 F
2
individuals with different combinations of the target DT- and
LNT-QTL favorable alleles and they showed expected improvement in DT and/or LNT, which were further validated by
the significant improvement in DT and/or LNT of their F
3
progeny testing. Based on evaluation of pyramiding lines in F3
lines under drought, low nitrogen (LN) and normal conditions, four promising pyramiding lines having different QTL
favorable alleles were selected, which showed significantly improved tolerances to drought and/or LN than HHZ and their
IL parents. Our results demonstrated that trait-specific ILs could effectively connect QTL mapping and QTL pyramiding
breeding, and designed QTL pyramiding (DQP) using ILs could be more effective in molecular rice breeding for complex
quantitative traits.
Recent publication:
1.
Ali J, Xu JL, Gao YM, et al (2017) Harnessing the hidden genetic diversity for improving multiple abiotic stress
tolerance in rice (Oryza sativa L.). PLoS One 12: e0172515.
2.
Cui Y, Zhang F, Xu J, et al (2015) Mapping quantitative trait loci in selected breeding populations: a segregation
distortion approach. Heredity 115, 538–546.
3.
Li ZK, Fu BY, Gao YM, X, et al (2005) Genome- wide introgression lines and their use in genetic and molecular
dissection of complex phenotypes in rice (Oryza sativa L.). Plant Mol Biol 59, 33–52.
Biography
Jianlong Xu got PhD degree on Crop Genetics & Breeding in 2001 in Zhejiang University, China.After finishing postdoctoral career of molecular rice breeding for
two years at IRRI, he joined the Institute of Crop Sciences, Chinese Academy Agricultural Sciences, focusing on gene mapping and favorable allele mining for
molecular rice breeding in high yield, high grain quality, abiotic and biotic stress tolerance. So far, he has published 70 papers in international journals, obtained
four provincial awards and 13 patents.
xujianlong@caas.cn