AUTHOR=Che Yonghe , Song Nan , Yang Yanping , Yang Xinming , Duan Qingqing , Zhang Yan , Lu Yuqing , Li Xuqing , Zhang Jinpeng , Li Xiuquan , Zhou Shenghui , Li Lihui , Liu Weihua 

TITLE=QTL Mapping of Six Spike and Stem Traits in Hybrid Population of Agropyron Gaertn. in Multiple Environments

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 9 - 2018

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01422

DOI=10.3389/fpls.2018.01422

ISSN=1664-462X

ABSTRACT=Most of species in Agropyron Gaertn. are excellent sources of forage. The derivative lines of wheat-Agropyron cristatum show elite agronomic traits, and some are valuable for wheat breeding. The species of Agropyron Gaertn. was mainly recognized by the spike morphology in traditional taxon. Six traits, including spike length (SL), ear stem length (ESL), the second internodes length (SIL), spikelet number per spike (SNS), floret number per spikelet (FNS) and grain number per spikelet (GNS), are vital to morphology study and also influence the forage crop yield. To elucidate the genetic basis of spike and stem traits, a quantitative trait locus (QTL) analysis was conducted in a CP (cross pollinated) hybrid population derived from a cross between two diverse parents, Agropyron mongolicum Keng Z2098 and Agropyron cristatum (L.) Gaertn. Z1842, evaluated across three ecotopes (Langfang, Changli and Guyuan of Hebei, China) in three years (from 2014 to 2016). Construction of a high-density linkage map was based on 1023 SNP markers, covering 907.8 cM of the whole Agropyron genome. A total of 306 QTLs with single QTL in different environments explaining 0.07 to 33.21% of the phenotypic variation were detected for study traits. Seven major-effect QTLs were identified, including one  for ESL on chr. 3, one for SIL on chr. 5, three for SL (two on chr. 2 and one on chr. 4), and two for SNS on chr. 3 and chr. 7. As well seven stable QTLs, including four for ESL, one for SL, one for GNS and one for FNS were mainly mapped on chromosome 2, 3, 4, 5 and 7, respectively, elucidating 0.25% to 14.98% of the phenotypic variations. On the use of Agropyron CP hybrid population to identify QTL determining spike and stem traits for the first time, these QTLs for six traits would provide a theoretical reference for the molecular marker-assisted selection in the improvement of forage and cereal crop species.