Quantitative Trait Loci for Cold Tolerance of Rice Recombinant Inbred Lines in Low Temperature Environments

Abstract

Low temperature is one of the major environmental stresses in rice cultivation in high-altitude and high-latitude regions. In this study, we cultivated a set of recombinant inbred lines (RIL) derived from Dasanbyeo (indica) / TR22183 (japonica) crosses in Yanji (high-latitude area), Kunming (high-altitude area), Chuncheon (cold water irrigation) and Suwon (normal) to evaluate the main effects of quantitative trait loci (QTL) and epistatic QTL (E-QTL) with regard to their interactions with environments for cold-related traits. Six QTLs for spikelet fertility (SF) were identified in three cold treatment locations. Among them, four QTLs on chromosomes 2, 7, 8, and 10 were validated by several near isogenic lines (NILs) under cold treatment in Chuncheon. A total of 57 QTLs and 76 E-QTLs for nine cold-related traits were identified as distributing on all 12 chromosomes; among them, 19 QTLs and E-QTLs showed significant interactions of QTLs and environments (QEIs). The total phenotypic variation explained by each trait ranged from 13.2 to 29.1% in QTLs, 10.6 to 29.0% in EQTLs, 2.2 to 8.8% in QEIs and 1.0% to 7.7% in E-QTL × environment interactions (E-QEIs). These results demonstrate that epistatic effects and QEIs are important properties of QTL parameters for cold tolerance at the reproductive stage. In order to develop cold tolerant varieties adaptable to wide-ranges of cold stress, a strategy facilitating marker-assisted selection (MAS) is being adopted to accumulate QTLs identified from different environments.

Identification of Heterosis QTLs for Yield and Yield-Related Traits in Indica-Japonica Recombinant Inbred Lines of Rice (Oryza sativa L.)

“…A total of 179 F8 RILs derived using the single-seed descendant method from a cross between Dasanbyeo (Tongil type, indica) and TR22183 (temperate japonica) developed by Seoul National University in Korea (DT-RILs) were used in this study (Chin et al 2011;Jiang et al 2011). Each RIL was crossed with Dasanbyeo as the female parent, and 178 BC1F1 lines (except for line 40) were produced (BC1F1 line).…”

Identification and validation of QTLs for cold tolerance at the booting stage and other agronomic traits in a rice cross of a Japanese tolerant variety, Hananomai, and a NERICA parent, WAB56-104

“…These traits are important in determining yield potential of rice and have been reported to be associated with cold tolerance ability of rice (Jiang et al, 2011;Mackill & Lei, 1997;Zeng et al, 2009). Spikelet fertility was only significantly correlated with panicle number, panicle weight, and culm length (Table 2).…”

“…Xu et al (2008) identified a QTL (qCTB-10-2) in another cross population in the same interval which explained 14.9% of the total phenotypic variance. Jiang et al (2011) detected a QTL (QTL 10.1) between markers S10001B and S10019 in the same interval which explained 15.9% of the phenotypic variation. The QTL qCTB-10 reported here explains more variation (33%) than qLTSPKST10.1, qCTB-10-2, and QTL 10.1 reported before in other studies.…”

“…Spikelet fertility after cold water irrigation has been widely used as an effective parameter for determining the cold tolerance of rice at the reproductive stage (Jiang et al, 2011; of different levels of cold water stresses. Spikelet fertility was determined as the number of fertile grains in percentage (%) and was calculated based on the number of filled spikelets divided by the total number of spikelets per panicle.…”

“…Some important agronomic traits such as culm length, heading date, panicle length, spikelets per panicle, spike length, grain weight, panicle number, panicle exsertion, and phenotypic acceptability are associated with cold tolerance and they may influence cold tolerance ability of rice (Jiang et al, 2011;Mackill & Lei, 1997;Zeng et al, 2009). These traits are also closely correlated with yield potential of rice thus important in determining yield outputs in rice.…”