Identification, Characterization, and Evaluation of Novel Stripe Rust-Resistant Wheat–Thinopyrum intermedium Chromosome Translocation Lines

Stripe rust is an important disease in wheat, and development of genetic resistance in cultivars is an effective approach to control the disease. Wild species of wheat, such as Thinopyrum intermedium, are an excellent gene source for wheat improvement. In this study, two stripe rust-resistant wheat–Th. intermedium chromosome translocation lines, CH4131 and CH4132, were characterized by cytogenetic and pathological methods. The introgressed chromosome fragment was tagged using amplified fragment-length polymorphism-derived sequence-characterized amplified region (SCAR) markers and intron targeting markers, indicating that CH4131 and CH4132 both possess a homologous group 3 chromatin of Th. intermedium. Genomic in situ hybridization results suggested that a very small Th. intermedium chromosome segment was translocated to the terminal region of wheat 1BS for both lines, forming a configuration of T3Ai-1BS.1BL. The two translocation lines were resistant to stripe rust, and the resistance gene, temporarily designated YrCH-1BS, was likely derived from Th. intermedium. The translocated chromosome fragments have no genetic linkage drag to agronomic performance. The grain quality indexes of these two translocations were higher than local wheat varieties. Therefore, CH4131 and CH4132 could be used as potential gene sources in wheat improvement programs. The SCAR markers are useful to select stripe rust resistance from Th. intermedium.

Alien chromosome addition in durum wheat. II. Advanced progeny

Alien chromosome addition in durum wheat was accomplished by backcrossing and selling an amphiploid derivative F10 strain of Triticum turgidum L. var. durum × Agropyron intermedium (Host) Beauv. The number of chromosome pairs increased from an average of 10.4 bivalents in the B1F1 to 18.5 bivalents in the B1F7 generation. Stabilization of chromosome pairing was improved as expressed in the range of bivalents (0–21 in the B1F1 and 16–21 in the B1F7 generation). Backcrossing to the durum wheat parent resulted in the elimination of some Agropyron chromosomes and in others becoming pairs. A hexaploid Agrotriticum with the constitution AABBII resulted. The I genome consists of a group of seven chromosome pairs from A. intermedium.Key words: Agrotriticum, Agropyron intermedium, chromosome pairing.