Abstract:

Two restorer lines “Shuhui 162” and “Miyang 46” were crossed with one set of the wide-compatible, homonucleus-heteroplasmic (HN-HP) cytoplasmic male sterile (CMS) lines containing 6 different types of cytoplasm and two sets of homoplasm-heteronuclear (HP-HN) CMS lines containing the cytoplasmic types of wild abortion (WA) and Indonesia paddy rice (IPR), generating F1 hybrids. Resistance to Chilo suppressalis was investigated in greenhouse and rice field with percentage of larval survival, larval body weight and percentage of rice dead heart (DH). Genetic effects of cytoplasm, nucleus, and nucleoplasmic interaction (NPI) on the resistance to C. suppressalis were analyzed. Insect resistance bioassays revealed that in the HN-HP CMS lines, the larval body weight on the dwarf-abortive “Guoguang 2A”, D-type “Guoguang 4A” (G-4A), Indonesia paddy rice “Guoguang 5A” (G-5A) and K-type “Guoguang 6A” were significantly lower than those on the wild abortive “Guoguang 1A” and Gang-type “Guoguang 3A”. The percentages of (DH) in G-4A (12.9%) and G-5A (14.1%) were significantly lower than those in the rest of the HN-HP CMS lines. Significant difference was found in the DH percentage between the WA and IPR in HP-HN CMS lines. Analysis of genetic effects indicated that there were no effects of cytoplasm and nucleoplasmic interaction on larval survival rate both in the HN-HP CMS lines and in the IPR HP-HN CMS lines. On the HN-HP CMS lines, larval body weight was mainly affected by NPI (47.1%) and cytoplasmic effect (CE) (29.4%), and DH percentage affected by nuclear effect (NE) (76.0%), CE (12.1%), and NPI (10.4%). On the WA HN-HP CMS lines, larval body weight was mainly affected by NE (78.5%) and CE (17.7%); NE (58.5%) and NPI (35.7%) affected DH percentage. NPI affected both larval body weight and DH percentage, with 26.5% and 66.9% in the IPR HN-HP CMS lines, respectively. Larval body weight was also affected by NE (50.7%) and CE (21.9%).

Key words: Homonucleus-heteroplasmic CMS line, Cytoplasmic effect, Genetic effect, Insect resistance, Chilo suppressalis, Rice