Improvement of Cercospora leaf spot and powdery mildew resistance of mungbean variety KING through marker-assisted selection

Abstract

The development of resistant mungbean varieties is one of the most efficient strategies to control major diseases such as Cercospora leaf spot (CLS) and powdery mildew (PM). The objectives of this study were to pyramid a CLS resistance gene and two PM resistance genes from the donor parent D2 into a susceptible variety KING through marker-assisted backcrossing (MABC) and to evaluate their agronomic traits and disease resistance under field conditions. Five markers linked to the resistance genes were used for foreground selection, while two marker sets [Set A containing 15 polymorphic simple sequence repeat (SSR) and expressed sequence tag-SSR (EST-SSR) markers and Set B containing 34 polymorphic inter-simple sequence repeat (ISSR) loci] were also used for background selection. Two pyramided backcross (BC) lines, namely H3 and H4, were homozygous at all five marker loci when confirmed in BC4F4 and BC4F5 generations. Their recurrent parent genome (RPG) recovery ranged from 96.4 to 100.0%, depending on the marker sets. During field evaluation, a moderate to high level of CLS and PM resistance was observed in both BC lines compared to the susceptible recurrent parent KING. One of these BC lines (H3) had all agronomic traits similar or superior to the recurrent parent KING at all environments, and had a higher yield than KING (18.0–32.0%) under CLS and PM outbreaks. This line can be developed into a new resistant mungbean variety in Thailand in the future. These results substantiate the usefulness of MABC for transferring multiple resistance genes into an elite variety.

Thirty Years of Mungbean Genome Research: Where Do We Stand and What Have We Learned?

“…Marker-assisted backcrossing (MABC) was practiced to introduce VrPGIP2 from V2802 and VrMLO12 from V4718 to mungbean cultivar "Chai Nat 84-1" to improve resistance to bruchids and powdery mildew, respectively (Jittawimon, 2021). Papan et al (2021) enhanced the CLS and PM resistance of mungbean cultivar "KING" via MABC using qCLSC72V18-1 (VrTAF5?) from V4718 CLS, and qPMC72V18-1 from V4718 and qPMC72V85 from V4785 for PM.…”