Characterization of Quantitative Trait Loci for Germination and Coleoptile Length under Low-Temperature Condition Using Introgression Lines Derived from an Interspecific Cross in Rice

Abstract

Previously, five putative quantitative trait loci (QTLs) for low-temperature germination (LTG) have been detected using 96 BC3F8 lines derived from an interspecific cross between the Korean japonica cultivar “Hwaseong” and Oryza rufipogon. In the present study, two introgression lines, CR1517 and CR1518, were used as parents to detect additional QTLs and analyze interactions among QTLs for LTG. The F2 population (154 plants) along with parental lines, Hwaseong and O. rufipogon, were evaluated for LTG and coleoptile length under low-temperature conditions (13 °C). Among five QTLs for LTG, two major QTLs, qLTG1 and qLTG3, were consistently detected at 6 and 7 days after incubation. Three minor QTLs were detected on chromosomes 8 and 10. Two QTLs, qLTG10.1 and qLTG10.2, showing linkage on chromosome 10, exerted opposite effects with the Hwaseong allele at qLTG10.2 and the O. rufipogon allele at qLTG10.1 respectively, in turn, increasing LTG. Interactions among QTLs were not significant, implying that the QTLs act in an additive manner. Near-isogenic line plants with the combination of favorable alleles from O. rufipogon and Hwaseong exhibited higher LTG than two introgression lines. With regard to coleoptile length, three QTLs observed on chromosomes 1, 3, and 8 were colocalized with QTLs for LTG, suggesting the pleiotropy of the single gene at each locus. According to the results, the introgression of favorable O. rufipogon alleles could hasten the development of rice with high LTG and high coleoptile elongation in japonica cultivars.

Screening Technique Based on Seed and Early Seedling Parameters for Cold Tolerance of Selected F2-Derived F3 Rice Genotypes under Controlled Conditions

“…Bertin [25] reported a positive correlation between early seedling cold tolerance with flowering stage cold tolerance. According to Akhtamov's findings [26], the insertion of advantageous O. rufipogon alleles might speed up the development of rice cultivars with high levels of coleoptile elongation and low-temperature germination (LTG) in japonica cultivars. The outcomes demonstrated that the effects of low temperature differed across genotypes investigated in both studies.…”

Quantitative Trait Loci Mapping Analysis for Cold Tolerance Under Cold Stress and Brassinosteroid-Combined Cold Treatment at Germination and Bud Burst Stages in Rice

“…Thus, the measurements of PH and FLL under cold stress set the data under normal-temperature condition as the control, whereas the measurements of PH and FLL under BR-combined cold treatment set the data under normal-temperature condition and cold stress as the controls, respectively. This was done to obtain more comprehensive QTLs ( Kim et al, 1999 ; Qiao et al, 2004 ; Akhtamov et al, 2020 ; Najeeb et al, 2020 ; Pan et al, 2020 ).…”

“…The evaluation of cold tolerance at germination and bud burst stages was conducted based on previous studies with minor changes ( Kim et al, 1999 ; Qiao et al, 2004 ; Akhtamov et al, 2020 ; Najeeb et al, 2020 ; Pan et al, 2020 ). Seeds of each accession from the BRILs were placed in a drying oven at 50°C for 72 h to break dormancy, and surface-sterilized in 1% NaClO solution for 10 min, followed by washing three times in sterilized distilled water.…”

QTL mapping and candidate gene analysis of low temperature germination in rice (Oryza sativa L.) using a genome wide association study

“…A total of 100 plumped seeds of each rice accession were extracted and spread on a round wet filter paper and kept at 15 °C and in darkness for germination. The number of germinated seeds was recorded daily from D6 to D10 with a seed shoot or root exceeding 0.1 cm considered a germinated seed ( Wang et al, 2018c ; Akhtamov et al, 2020 ; Najeeb et al, 2020 ). Seed germination rate = germinated seeds/100.…”