Dynamic QTL mapping for plant height in the hybrid population of Agropyron Gaertn.

Abstract

Plant height (PH) plays a very important role for plant breeding and also serves as a model trait to dynamic development study. The dynamic quantitative trait locus (QTL) analysis for PH of Agropyron Gaertn. was carried out in a cross‐pollination (CP) hybrid population of A. Gaertn. based on the phenotypic data of PH at different developmental stages in four year‐sites and the constructed single‐nucleotide polymorphism (SNP) genetic map. The results showed that 69 QTL and nine major QTL were detected by unconditional QTL mapping. A total of 107 QTL and 13 major QTL were found using conditional QTL mapping. Forty‐seven QTL were detected by two methods. Two unconditional QTL, Qph2‐5 and Qph3‐4, were expressed as major and stable QTL for PH. Four major stable conditional QTL for PH, cQph4‐1, cQph4‐8, cQph6‐2 and cQph6‐7, were detected. Two conditional PH QTL, cQph3‐5 and cQPh3‐7, were identified in four environments over multiple stages. The gene/QTL controlling PH was expressed in a certain spatiotemporal manner. These results could also provide a reference for genetic and breeding research of related plant.

Four-Year and Five-Developing-Stage Dynamic QTL Mapping for Tiller Number in the Hybrid Population of Agropyron Gaertn.

“…For example, the QTL controlling TN of rice also controls the number of leaves ( Liu et al, 2009 ). Also, on the interval of Marker11517–Marker14862 of the QTL qTN2-2 on chromosome 2 with a conditional QTL that controlled PH at several developmental stages in two environments, the high genetic variation of PH was explained ( Che et al, 2020 ), as well as on the interval of Marker10138–Marker53481 of qTN3-5 / cQTN3-5 on chromosome 3 with a QTL affecting ear stem length (ESL) in different years and environments ( Che et al, 2018 ). These regions may contain several QTLs controlling TN, PH, and ESL, respectively, or one QTL affecting these traits meantime.…”

“…When a chromosome interval met the above conditions, it was considered that there was a QTL affecting TN. When a QTL was detected with a contribution rate >10% in different environments, it was regarded as a major QTL, and the QTL that was detected in at least three different environments was defined as a stable QTL ( Fan et al, 2015 ; Che et al, 2020 ). The name of the unconditional QTL is “q + TN + chromosome number + serial number” ( Mccouch et al, 1997 ).…”

“…constructed using a CP population that contains 1,023 markers on seven linkage groups, with a total of 907.8 cm and an average distance of 1.5 cm between adjacent loci (Zhang et al, 2015). Based on this map, the major and stable QTL for plant height (PH; Che et al, 2020) and QTL for other characteristics of the spike (Che et al, 2018) in A. Gaertn. have been detected.…”