Detection of Key Brown Rust Resistance Gene, Bru1 , in 200 Sugarcane ( Saccharum L.) Ancestral Species and Landraces Using a Four-Primer Molecular Marker

Sugarcane brown rust is a fungal disease with global distribution that is caused by Puccinia melanocephala, and is responsible for severe yield and sucrose losses in sugarcane production. The most effective strategy of controlling the disease is breeding and cultivating resistant varieties. Bru1 is a major gene that has been demonstrated to confer resistance to P. melanocephala strains from different parts of the globe. R12H16 and 9O20-F4 are two molecular markers that have been previously reported to be closely associated with Bru1, and are often used in brown rust resistance identification during sugarcane germplasm evaluation activities. In the present study, a novel type of molecular marker based on four primers is used to detect Bru1 among 200 sugarcane ancestral species and landraces from the China National Germplasm Repository of Sugarcane (NGRS). According to the results, among the 200 tested materials, 125 materials, such as 51NG63, Katha, and Uba, Bru1 could be detected based on bands corresponding to those in POJ2878, indicated that the 125 (62.5%) materials contained Bru1, and the detection rates of Bru1 in 69 sugarcane ancestral species and 131 landraces were 73.9% and 56.5%, respectively. These results indicated that the sugarcane ancestral species and landraces conserved in the China NGRS contain abundant brown rust-resistant materials, which could provide resources that could facilitate the breeding of brown rust-resistant sugarcane varieties.