Abstract:

【Objective】To introgress insect-resistance gene cry1C* into 9311, an elite indica rice variety, for developing new rice lines and hybrids which are resistant against rice stem borers and leaffolders.【Method】T1C-19 harbouing cry1C*, a transgenic rice material, was used as donor of insect-resistance in the study. cry1C* was introgressed into the genetic background of 9311 by hybridizing, backcrossing and MAS. Improved new lines and hybrids were carried out for identifying insect-resistance in field, testing protein content of CRY1C*, evaluating yield, main agronomic traits, growth duration and rice quality in improved lines and hybrids.【Result】Eight near-isogenic lines (improved lines) with genetic background of 9311 and insect-resistance gene cry1C* were developed and 56 crosses were made. Identification in field showed that the levels of stem borer- and leaffolder-resistance were the same as that of the donor parent T1C-19. Improved new breeding lines and T1C-19 were not damaged by leaffolders, compared to the twenty percents in damage in 9311 in the same field. The expressing protein contents of CRY1C* in improved lines were the same as T1C-19. The expressing protein contents of CRY1C* of hybrids were lower than that of their male lines at tillering stage, but higher at elongation stage. The growth duration, main agronomic traits and rice quality of improved lines were the same as 9311, but the grain yield per plant was higher. Three insect-resistant combinations with long growth duration were screened for one cropping with higher yield over check hybrid Yangliangyou 6. Five insect-resistant combinations with higher yield and quality over check hybrid Q-you 6 were selected for one cropping with medium growth duration. One insect-resistant combination with the same yield and growth duration as check hybrid Jinyou 207 was selected for second cropping. 【Conclusion】 The insect-resistance gene cry1C* has been introgressed into the genetic background of 9311 by hybridization, backcrossing and MAS. The developed lines with insect-resistance have the same characters as 9311 in growth duration, yield, main agronomic traits, rice quality and combining ability. Several insect-resistant hybrids were selected for one or second cropping.

Key words: indica rice, cry1C*, insect-resistance, rice hybrids