Identification of potential donors and QTLs for resistance to false smut in a subset of rice diversity panel

Abstract

False smut of rice caused by Ustilaginoidea virens (Cooke) Takahashi (teleomorph Villosiclava virens) has emerged as a serious concern in rice production. While variation for resistance exists in rice germplasm, most of the cultivated varieties are susceptible to false smut. A total of 125 diverse lines from global rice diversity panel were screened for resistance to false smut along with susceptible checks GSR123 and PR116, under natural hot spot for 3 years at two different locations and artificial inoculation conditions in a fourth consecutive year. False smut resistance was recorded based on infected panicles per plants (IPP), number of smut balls per plant (NSBP) and a disease score (DS). Of 125, 21 germplasm lines showed high level of resistance in all the years under natural hot spot as well as artificial inoculation conditions whereas 31 germplasm lines showed moderate resistance. Genome wide association study for false smut related traits identified significant associations on chromosomes 2, 3, 6, 9 and 11 for IPP. Similarly, significant associations for NSBP were identified on chromosomes 3 and 8 and DS on chromosomes 3, 4 and 11. Most of these QTLs were found to be associated with all the traits. The study highlights the potential donors for resistance to false smut that could be utilized in rice breeding programme. The identified QTLs could be the potential candidate regions for further studying the false smut resistance.