Structural chromosome variations from Jinmai 47 and Jinmai 84 affected agronomic traits and drought tolerance of wheat

Structural variation is an important source of genetic variation in wheat and have been important in the evolution of the wheat’s genome. Few studies have examined the relationship between structural variations and agronomy and drought tolerance. The present study identified structural chromosome variations (SCVs) in a doubled haploid (DH) population and backcross introgression lines (BC5F3) derived from Jinmai 47 and Jinmai 84 using fluorescence in situ hybridization (FISH). There are one simple translocation, 10 present/absent variations (PAVs), and one copy number variation (CNV) between Jinmai 47 and Jinmai 84, which distributed in 10 chromosomes. Eight SCVs were associated with 15 agronomic traits. A PAV recombination occurred on chromosome 2A, which was associated with grain number per spike (GNS). The 1BL/1RS translocation and PAV.2D were associated with significant reductions in plant height, deriving from the effects on LI2-LI4, LI2-LI4 and UI, respectively respectively. PAV.2D was also contributed to an increase of 3.13% for GNS, 1BL/1RS significantly increased spikelet number, grain length (GL), and grain thickness (GT). The effect of PAV.4A.1 on GL, PAV.6A on spike length (SL) and thousand-grain weight (TGW), PAV.6B on SL, GT and TGW were identified and verified. PAVs on chromosomes 2A, 6A, 1D, 2D, and a CNV on chromosome 4B were associated with the drought tolerance coefficients. Additive and interaction effects among SCVs were observed. Many previously cloned key genes and yield-related QTL were found in polymorphic regions of PAV.2B, PAV.2D, and CNV.4B. Altogether, this study confirmed the genetic effect of SCVs on agronomy and drought tolerance, and identification of these SCVs will facilitate genetic improvement of wheat through marker-assisted selection.