Registration of four durum wheat lines carrying Sr13 alleles for resistance to stem rust

Abstract

Four durum wheat (Triticum turgidum ssp. durum) lines Rusty-KLB (Reg. no. GP-1098, PI 705448), Rusty-14803 (Reg. no. GP-1097, PI 705447), Rusty-ST464C1 (Reg. no. GP-1099, PI 705449), and CAT-A1 (Reg. no. GP-1096, PI 705446), which carry stem rust resistance gene Sr13 alleles Sr13a, Sr13b, Sr13c, and Sr13d, respectively, are released by USDA-ARS. These alleles originated from cultivated emmer wheat (T. turgidum ssp. dicoccum) landrace Khapli (CItr 4013), T. turgidum ssp. polonicum accession CItr 14803, durum landrace ST464 (PI 191365), and durum line Camadi Abdu tipo #103 (PI 192168), respectively. Rusty-KLB, Rusty-14803, and Rusty-ST464C1 are near-isogenic lines with the pedigrees Rusty*7/KL-B, Rusty*4/3/Rusty/CItr 14803//2*Rusty, and Rusty*7/ST464-C1, respectively. KL-B, ST464-C1, and CAT-A1 are monogenic lines with the pedigrees Marruecos 9623//Khapli/Marruecos 9623, Marruecos 9623*2/ST464, and Marruecos 9623*2/Camadi Abdu tipo #103, respectively. Sr13 can be detected by perfect markers including Kompetitive allele specific polymerase chain reaction (KASP) marker KASPSr13 and semi-thermal asymmetric reverse polymerase chain reaction (STARP) markers rwgsnp37. Specific alleles can be identified via STARP markers rwgsnp38, rwgsnp39, and rwgsnp40. The Sr13 alleles provide a moderate level of resistance, typically an infection type 2, to a broad spectrum of stem rust races. Sr13c was effective against all 15 stem rust races tested while Sr13a was ineffective only against race TCMJC. Sr13b was ineffective against JRCQC, QCCJC, QFCSC, and TTRTF. Sr13d is notable in being the only Sr13 allele ineffective to TTKSK (Ug99) and TKTTF. These lines are useful for studying the host-stem rust pathogen interactions, identifying new genes, and breeding durum and bread wheat cultivars with stem rust resistance.