A novel genetic map of wheat: utility for mapping QTL for yield under different nitrogen treatments

Abstract

BackgroundCommon wheat (Triticum aestivum L.) is one of the most important food crops worldwide. Wheat varieties that maintain yield (YD) under moderate or even intense nitrogen (N) deficiency can adapt to low input management systems. A detailed genetic map is necessary for both wheat molecular breeding and genomics research. In this study, an F6:7 recombinant inbred line population comprising 188 lines was used to construct a novel genetic map and subsequently to detect quantitative trait loci (QTL) for YD and response to N stress.ResultsA genetic map consisting of 591 loci distributed across 21 wheat chromosomes was constructed. The map spanned 3930.7 cM, with one marker per 6.7 cM on average. Genomic simple sequence repeat (g-SSR), expressed sequence tag-derived microsatellite (e-SSR), diversity arrays technology (DArT), sequence-tagged sites (STS), sequence-related amplified polymorphism (SRAP), and inter-simple sequence repeat (ISSR) molecular markers were included in the map. The linear relationships between loci found in the present map and in previously compiled physical maps were presented, which were generally in accordance. Information on the genetic and physical positions and allele sizes (when possible) of 17 DArT, 50 e-SSR, 44 SRAP, five ISSR, and two morphological markers is reported here for the first time. Seven segregation distortion regions (SDR) were identified on chromosomes 1B, 3BL, 4AL, 6AS, 6AL, 6BL, and 7B. A total of 22 and 12 QTLs for YD and yield difference between the value (YDDV) under HN and the value under LN were identified, respectively. Of these, QYd-4B-2 and QYddv-4B, two major stable QTL, shared support interval with alleles from KN9204 increasing YD in LN and decreasing YDDV. We probe into the use of these QTLs in wheat breeding programs. Moreover, factors affecting the SDR and total map length are discussed in depth.ConclusionsThis novel map may facilitate the use of novel markers in wheat molecular breeding programs and genomics research. Moreover, QTLs for YD and YDDV provide useful markers for wheat molecular breeding programs designed to increase yield potential under N stress.

QTL detection for wheat kernel size and quality and the responses of these traits to low nitrogen stress

“…The plant materials included a set of 188 recombinant inbred lines (RILs) derived from Kenong 9204 (KN9204) × Jing 411 (J411) (denoted by KJ-RIL) (Cui et al 2014a;Fan et al 2015). The 188 kJ-RILs and their parents were grown from 2011 to 2012 in Shijiazhuang (L1); 2012-2013 in Shijiazhuang (L2), Beijing (L3) and Xinxiang (L4); and 2013-2014 in Shijiazhuang (L5).…”

“…An LN treatment and an HN treatment were applied in each trial for a total of ten environments (year × location × treatment), designated as E1, E2, E3, E4, E5, E6, E7, E8, E9, and E10. The N treatments, field arrangements and experimental designs of L1 to L4 are detailed in our previous reports (Cui et al 2014a;Fan et al 2015). T5 followed the above trial design and was carried out from 2013 to 2014 in Shijiazhuang.…”

“…A linkage map of the KJ-RIL population has been previously established (Cui et al 2014a). In this study, 11 functional markers of kernel size and quality-related traits were used to saturate the KJ-RIL-derived genetic map, with the aim of estimating whether the QTLs were co-localized with known genes.…”

“…An adequate quantity of nitrogen (N) and an appropriate time of application can improve yield and quality; however, the use of N fertilizer leads to an increased cost as well as environmental consequences, such as groundwater pollution due to nitrate leaching (Laperche et al 2007(Laperche et al , 2008Suprayogi et al 2009;Cui et al 2014a). Wheat varieties that maintain a high yield and quality under moderate or even severe N deficiency can be adapted for use in low-input management systems.…”

“…An understanding of the genetic basis of N deficiency tolerance is essential for the breeding of such varieties. However, few QTLs for both yield/quality and their responses to N deficiency in wheat under field conditions have been documented to date (Habash et al 2007;Laperche et al 2007Laperche et al , 2008Cui et al 2014a). Favorable QTL alleles that decrease differences in yield and/or quality between high N (HN) and lower N (LN) conditions are of value in wheat breeding programs designed to increase N deficiency tolerance (Cui et al 2014a).…”