Hybridization Domestication and Molecular Cytogenetic Characterization of New Germplasm of Thinopyrum intermedium with smGISH at Northeastern China

Abstract

Abstract Thinopyrum intermedium (2n = 6x = 42, StStJrJrJvsJvs), a perennial relative of wheat, is resistant or tolerant to biotic and abiotic stresses, making it an important genetic material for breeding perennial crops. It is also known as intermediate wheatgrass (IWG). The morphological performance, chromosome composition, and yield components of 24 newly developed perennial germplasm, designated 19HSC-Q and 20HSC-Z lines, were investigated from 2019 to 2022. Six lines of 19HSC-Q had higher values of yield component traits, such as thousand-kernel weight, grains per spike, and tiller number than that of Th. intermedium. 19HSC-Q14, 19HSC-Q18 and 19HSC-Q20 had the best agronomic traits with grain number per spike and thousand-kernel weight of 115, 97, and 102 and 7.674, 7.516, and 7.371 g in 2022, respectively. Three 20HSC-Z lines had been growing for two years that the grain number per spike was 116, 88, and 81, and the thousand-kernel weight was 7.146, 6.523, and 5.916 g, respectively. The results of sequential multicolor GISH analysis revealed that the Jvs-subgenome of Th. intermedium were divided into two karyotypes, type-I Jvs with 3 pairs of chromosomes and type-II Jvs with 4 pairs of chromosomes. Both IWG and 24 perennial germplasm had the similar chromosome composition but the translocation between subgenome chromosomes were detected in some lines with prominent comprehensive agronomic traits, such as 19HSC-Q6, 19HSC-Q11, 19HSC-Q18, and 20HSC-Z. The chromosome aberration could be distinguished into two types: the large fragment translocation with Jr-St, Jvs-St, Jr-IIJvs, and Jvs-Jr and the small fragment introgression of St-IJvs. Results of this study provide important materials for the next breeding cycle of cold resistant perennial wheatgrass.