Detecting QTLs controlling chlorophyll fluorescence parameters in Iranian wheat recombinant inbred lines

Measurement of chlorophyll fluorescence is one of the methods to detect a disorder in the photosynthetic system, which reflects the photochemical state of the plant. Identification of the genetic structure of chlorophyll fluorescence parameters can provide useful solutions for breeding varieties with higher potential. The present study was conducted with the aim of identifying quantitative loci (QTL) related to chlorophyll fluorescence parameters in an Iranian RILs wheat population. One hundred and twenty F8 RILs of wheat derived from crossing Kohdasht (KHD) and Gonbad (GND) cultivars in the form of an alpha lattice design were studied in 2019 and 2020. The analysis of QTLs was performed in the software R using the package QTL.gCIMapping.GUI v2.0. The genetic map was constructed with 423 SSR markers, 21 CBDP markers, 58 ISJ markers, and 19 SCoT markers (521 polymorphic alleles) distributed on 21 wheat chromosomes. This map covered 3167.9 cM of the wheat genome and had an average marker spacing of 6.1, 6, and 6.2 cM for the A, B, and D genomes, respectively. Thirteen of the fourteen QTLs discovered in 2019 and four of the nine QTLs discovered in 2020 had an explanatory coefficient greater than 15% and were considered major QTLs. In 2019, pleiotropic QTLs were found at position 1.79 cM on chromosome 3A and between two markers Xwmc11-3A and BARC1177. In 2020, two QTLs, qABS/ RC 1B and qTRo/ RC 1B were located at position 36.80 cM 1B and between two markers Xgpw4331-1B and Xgpw5162-1B, and two QTLs, qETo/ RC-5D and qREo / RC-5D were located at position 63.25 cM chromosome 5D and correspond to the position of marker cfd266. Pleiotropic QTLs as well as major QTLs can be used in marker-assisted selection for chlorophyll fluorescence traits in wheat breeding projects.