Chromosome Karyotype and Stability Identification of New Synthetic Hexaploid Wheat

Abstract

Synthetic hexaploid wheats offer breeder ready access to potentially novel genetic variations in wild ancestral species. In present study, we used MY3478 (2n = 4x = 28, AABB) as female crossing with SY41 (2n = 2x = 14, DD) of stripe rust resistant as male through natural chromosome doubling to constructed the new hexaploid wheat line NA0928. Agronomic traits and cytological analysis were characterized in NA0928 of S8-S9 generations. The major study and results were described as follows, agronomic character variation coefficient in NA0928 of S8 generation showed that the effective tiller number (55.3%) > spike length (15.3%) > number of spikelets (13.9%) > plant height (8.7). It is suggested that the effective tiller number and spike length have great utilization value in breeding. Cytological observation and fluorescence in situ hybridization (FISH) results showed that the chromosome number and configuration have rich variations in S9 of NA0928. Chromosome number variation range of 36–44. Numerous chromosome karyotype variations were almost detected in A and B subgenomes. In addition, more diverse types of chromosomal structure variations were observed in the stripe rust resistant strains with more excellent performance than susceptible strains in agronomic traits. Especially, the tillering number of the resistant strains were much higher. Here, Meiosis stage of pollen mother cells and multicolor-GISH (Mc-GISH) results showed that two new synthetic hexaploid wheat lines were obtained, which showed genetic stability, one line was resistance to stripe rust, and the other one line was susceptible stripe rust, at the same time, there had two excellent characteristics with high 1000-grain weight and multiple tillers. They will be valuable germplasm materials in wheat breeding utilization.