Origins of Susceptibility to Insect Herbivores in High-Yielding Hybrid and Inbred Rice Genotypes

Area of Science:

• Agricultural Science
• Entomology
• Plant Breeding

Background:

• Hybrid rice often exhibits increased susceptibility to insect herbivores compared to inbred rice.
• Understanding the genetic and phenotypic factors influencing this susceptibility is critical for crop improvement.

Purpose of the Study:

• To investigate whether hybrid rice susceptibility to key insect pests is linked to plant type or rice phylogeny.
• To identify traits and genetic factors associated with herbivore resistance in rice genotypes.

Main Methods:

• Evaluated 20 hybrid and 12 inbred rice genotypes against brown planthopper (BPH), white-backed planthopper (WBPH), and yellow stem borer (YSB).
• Conducted greenhouse and screenhouse bioassays, alongside field monitoring of herbivore populations.
• Utilized single nucleotide polymorphic (SNP) markers to analyze genetic relationships among genotypes.

Main Results:

• Hybrids and inbreds formed distinct genetic clusters, irrespective of their origin.
• Rice hybrids showed greater susceptibility to yellow stem borer (YSB), with plant biomass being a key predictor.
• Plant origin significantly influenced susceptibility to brown planthopper (BPH) and white-backed planthopper (WBPH), more so than plant type.

Conclusions:

• Herbivore resistance in rice hybrids is achievable through strategic breeding, as evidenced by the identification of resistant hybrids and susceptible inbreds.
• Selecting appropriate genotypes and considering plant origin are vital for managing planthopper pests (BPH, WBPH) in rice.
• Integrating knowledge of genotype-specific resistance into breeding programs is essential for effective, sustainable rice pest management.