The green rice leafhopper (GRH),
Nephotettix cincticeps Uhler, is a serious insect pest of cultivated rice (
Oryza sativa L.) in temperate East Asia. Six GRH-resistance genes (
Grh1,
Grh2,
Grh3,
Grh4,
Grh5, and
Grh6) and one quantitative trait locus (QTL;
qGRH4) have been identified. We selected near-isogenic lines (NILs) carrying
Grh1,
Grh2,
Grh4,
Grh5,
Grh6, and
qGRH4 with the
japonica genetic background (Taichung 65 cultivar) by means of marker-assisted selection using new simple sequence repeat markers flanking the GRH-resistance genes and QTL. We also developed three pyramided lines (PYLs;
Grh2/Grh6-PYL,
Grh4/Grh6-PYL, and
Grh5/qGRH4-PYL) using each NIL that carried a GRH-resistance gene or QTL. The NILs, PYLs, and donor parents were evaluated by using an antibiosis test. The resistance of
Grh1-NIL and
Grh5-NIL did not differ significantly from those of the donor parents, whereas the resistances of
Grh2-NIL and
Grh6-NIL were significantly lower than those of the donor parents.
Grh4-NIL and
qGRH4-NIL were highly susceptible. The resistance levels of the pyramided lines for
Grh2 and
Grh6,
Grh4 and
Grh6, and
Grh5 and
qGRH4 demonstrated a gene pyramiding effect that significantly increased their resistance. The developed NILs and PYLs should be useful genetic resources for rice improvement and deployment of the resistance genes.
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