QTL pyramiding for improving of cold tolerance at fertilization stage in rice

Abstract

Vigorous cold tolerance at the fertilization stage (CTF) is a very important characteristic for stable rice production in cold temperature conditions. Because CTF is a quantitatively inherited trait, pyramiding quantitative trait loci (QTLs) using marker-assisted selection (MAS) is effective for improving CTF levels in rice breeding programs. We previously identified three QTLs controlling CTF, qCTF7, qCTF8 and qCTF12, using backcrossed inbred lines derived from a cross between rice cultivar Eikei88223 (vigorous CTF) and Suisei (very weak CTF). However, pyramiding of these QTLs for the application of MAS in practical rice breeding programs have not yet been elucidated. In this study, we examined the effect of pyramiding QTLs for improvement of CTF level using eight possible genotype classes from the 152 F3 population derived from a cross between Eikei88223 and Suisei. Increasing of CTF levels in combinations between qCTF7 and qCTF12 and between qCTF8 and qCTF12 were detected. Furthermore, we compared the haplotype pattern around the QTLs for CTF among the rice cultivars from Hokkaido. These results are useful for improvement of new cultivars with high CTF levels using MAS and identification of genetic resources with the novel QTL(s) for CTF.

Identification of main-effect quantitative trait loci (QTLs) for low-temperature stress tolerance germination- and early seedling vigor-related traits in rice (Oryza sativa L.)

“…Recently, Najeeb et al (2019) reviewed the LTS tolerance QTLs reported in rice at germination and seedling and booting stages while using different genetic backgrounds such as DHs, RIL S , BILs, BC 2 F 1 , F 2 , and F 8 as mapping populations. Among these populations, a few major QTLs have been identified by Andaya and Mackill (2003b), Fujino et al (2004), Lou et al (2007), Baruah et al (2009), Shinada et al (2014), Fig. 4 Depicted representation of the distribution pattern of lowtemperature stress (LTS) tolerance QTLs associated with phenotypic traits on 12 chromosomes, The total phenotypic variance explained (PVE) of different QTL indicates in the middle part with black color font, and percentage of number QTLs (%) distributed on 12 chromosomes were shown at the outter boundary of pie chart (Chr = chromosome; PVE = phenotypic variation explained; LTG = low-temperature germination; LTGS = low-temperature germination stress index; BMSI = biomass stress index; SL = shoot length; RL = root length; SLSI = shoot length stress index; RLSI = root length stress index; SGI = shoot growth index; SVI = seedling vigor index) Jiang et al (2017), andShakiba et al (2017).…”

“…Likewise, a few M-QTLs with relatively higher PV explained were consistently governing two stages, such as LTGS(II) and LTGS(III) (20.70 Mb) on chromosome 1 and LTGS(II) and LTGS(III) on chromosome 3. In earlier reports, Fujino et al (2008), Li et al (2013), Cui et al (2013), Shinada et al (2014), and Zhu et al (2015) mentioned a few stable QTLs across several environments under LTS. The importance of stable QTLs is that they have larger additive effects and are less affected by the environment.…”

Breeding for Low Temperature Stress Tolerance in Reproductive Stage of Rice (Oryza sativa L.)

“…They identified three QTLs for CTF and a clear effect by QTL, qCTF7, for increasing the level of CTF was validated using advanced progeny. Shinada et al, (2014) evaluated the effect of pyramiding QTLs for improvement of CTF level using eight possible genotype classes from the 152 F 3 population derived from a cross between Eikei88223 and Suisei. And they detected the increasing of CTF levels in combinations between qCTF7 and qCTF12 and between qCTF8 and qCTF12.…”

Deployment of cold tolerance loci from Oryza sativa ssp. Japonica cv. ‘Nipponbare’ in a high‐yielding Indica rice cultivar ‘93‐11’

“…() have reported the effects of pyramiding QTLs for cold tolerance at the booting stage. Shinada, Iwata, Sato, and Fujino () improved cold tolerance at the fertilization stage by combinations between QTLs qCTF7 and qCTF12 or between qCTF8 and qCTF12 . Endo et al.…”

“…For example, Kuroki et al (2011) have reported the effects of pyramiding QTLs for cold tolerance at the booting stage. Shinada, Iwata, Sato, and Fujino (2014) improved cold tolerance at the fertilization stage by combinations between QTLs qCTF7 and qCTF12 or between qCTF8 and qCTF12. Endo et al (2016) have reported the pyramiding of qCT-4 and qLTB3, resulting in an increase of~10% in seed fertility of rice exposed to cold-water treatment.…”