QTL Mapping of Cold Tolerance at the Seedling Stage using an Introgression Lines Derived from an Intersubspecific Cross in Rice

Abstract

Low-temperature stress is an important factor controlling the growth and development of rice (Oryza sativa L.) in temperate region. In this study, a molecular linkage map consisting of 136 SSR markers was employed to identify QTL associated with cold tolerance at the seedling stage. 80 recombinant inbred lines (RILs) from an intersubspecific cross between Milyang23 (O. sativa ssp. Indica) and Hapcheonaengmi3, a japonica weedy rice and the parents were evaluated for leaf discoloration and SAPD value of seedlings. Rice plants were grown for 15 days in the low-temperature condition (13/20°C day/night) and the control condition (25/20°C day/night) in the growth chamber. The degree of leaf discoloration showed a highly significant correlation with the SPAD value in the low-temperature plot (r =-0.708, P < 0.0001). A total of four QTLs for SPAD were identified and the phenotypic variance explained by each QTL ranged from 5.4 to 16.0%. Two QTLs detected in the control condition were located on chromosomes 2 and 5, respectively. Two QTL on chromosomes 1 and 4 were detected at the low-temperature condition and Hapcheonaengmi3 alleles increased the SPAD values at these loci. Substitution mapping was conducted to delimit the position of qSPA-4 using introgression lines derived from the same cross. Results indicated that qSPA-4 was located in a 810-Kb region flanked by RM16333 and RM16368. The results indicated that Hapcheonaengmi3 contains QTL alleles that are likely to improve cold tolerance of Indica rice.

Overexpression of BrCIPK1 Gene Enhances Abiotic Stress Tolerance by Increasing Proline Biosynthesis in Rice

“…For the cold bioassays, 20 2-weekold plants grown previously in the greenhouse were transferred into a growth chamber using a constant day and night temperature of 4°C with continuous full-light fluorescent bulbs, approximately 50-70 μmol m −2 s −1 photosynthetically active radiation (PAR) intensity. Leaf samples were collected at 0, 1, 3, 6, 12, 24, 36, and 48 h for biochemical analyses (Park et al 2013).…”

Optimization of Temperature Regime to Screen Cold Tolerant Rice Seedlings

“…The higher SPAD value, the more variety has tolerance to the discoloration (Kim et al 1989). For the quantitative trait locus (QTL) analysis about seedling CT, the SPAD value is utilized as indicator of discoloration (Park et al 2013).…”

QTL Mapping for Cold Tolerance at the Seedling Stage in Rice

“…The availability of saturated molecular maps enables scientists to work for betterment of the complex traits like cold tolerance using QTL (Price et al, 2002). The molecular linkage map for cold tolerance of rice at seedling stage has been reported (Park et al, 2013;Verma et al, 2014;Zhang et al, 2014). Breeders aim to develop rice germplasm that can produce high and stable yields in regions where low temperatures are found.…”

“…Priyanka et al (2015) 17 °C for 7 days Germination (%) and its speed Sthapit and Witcombe (1998) Park et al (2013) 12-h light (15000 LX) 12-h dark. The seedlings were initially exposed to 14 °C for 2 h followed by 12 °C for 4 h and 10 °C for 4 h. …”

“…qSPA-1 and qCTS-1 on chromosome 1 (Park et al, 2013;Liu et al, 2013;Juan et al, 2010); qCTS-2 on chromosome 2 (Lou et al, 2007;Liu et al, 2013); qCTS-12 on chromosome 12 Suh et al, 2013;Anandya et al, 2006). Likewise, Suh et al (2013);Verma et al (2014) also found approximately the same region of Chromosome 3 with LOD score greater than 3.…”