Establishment And Genetic Evaluation Of Waxy Hybrid Rice Breeding Technology System

Approximately 0.5kg dried seeds of parents of hybrids (including maintainer lines,photoperiod (temperature) sensitive genic male sterile lines and restorer lines) were treated with ⁶⁰Co Y -rays at the dosage of 250Gy and 350Gy respectively, a group of waxy mutants with different genetic background were obtained in their M₂ brown rice population, then waxy CMS lines, restorer lines and hybrids were developed, and corresponding breeding system of waxy hybrid rice had been established. For genetic analysis, allelic relationship, dosage efficiency as well as mutation reversion of induced waxy gene had been studied. The main biology characteristics of waxy parents and waxy hybrids had been studied. The nutrition components including crude protein content, the amino acid content, the mineral elements content and the fatty acid composition and some of the cooking and eating quality of waxy hybrids had been analysed. The main results were as following:1. The frequency of waxy mutation in parents of hybrids was 0 12.81 × 10^-4, the average was 3.18 × 10^-4. Under the suitable dosage scope, the bigger dosage (350Gy) had the higher mutation frequency than that of the smaller (250Gy) one, and there existed difference among varieties. The seedling rate of waxy mutants could be effectively improved by using embryo rescuing technology, 50.00% 86.21% of seedling rate and averaged 74.80% had been achieved. It was indicated by genetic analysis that waxy mutation genes newly obtained by radiation were allelics to the known waxy gene, the waxy characteristic of the mutation was dominated by a pair of recessive gene wxwx, whose dominant alle was Wx and was responsible for nonwaxy, and there existed obvious wx dosage efficiency, that amylose content reduced while the dosage of the waxy gene increased. It was discovered that the reversion mutation from induced waxy mutant (wx) to wild nonwaxy (Wx) type, the frequency of waxy mutant reversion was 0 6.34x10-5, the averaged was 3.74x10-5.2. A group of waxy CMS lines, restorer lines and hybrids had been developed by using the waxy hybrid rice breeding technology system. 7 waxy CMS lines including LongtepuwxA, Gang46wxA, II-32wxA, D62wxA, Jin23wxA, Zhong9wxA and SE21wxS had passed the technical appraisal. 8 waxy restorer lines including Minghui77wxR, Minghui63wxR, Minghui86wxR, Nanhui175wxR, Shuhui527wxR, Fuhui838wxR, Xianghui288wxR and 402wxR had been developed. And one waxy hybrid rice named Twx63 which had passed the cultivar examination and approval had been developed.3. Studied of biological characteristic of waxy rice indicated that:(l) waxy and...