| Rice blast, caused by the ascomycete fungus Magnaporthe oryzae. is one of the most serious rice diseases over the world. Breeding and planting resistant cultivars is the most effective, economical, and eco-friendly approach for controlling diseases. However, the blast resistance cultivars is easy to lose resistance in 3 to 5 years due to the rapid evolution of the fungus. So.it is a vital part of the rice breeding research in the coming a few years to keep working on the new combine cultivars. Rong 18A is characterized with large panicles,high combining ability.good grain quality and strong blast resistance in Chengdu Academy of Agricultural and Forestry Sciences. Derived from Rong 18A,a large number of F1 hybrids have been registered and released to commercial production by Sichuan Provincial Crop Variety Appraisal Committee.Nowadays the Rong 18 hybrid combinations have been widely applied in production.The purpose of this experiment was to evaluate the blast resistance of Rong 18A and their combinations by identification of rice blast resistance in field and measuring of indoor blast resistance frequency:confering the blast resistance gene of Rong 18A by means of molecular biology technique;screening the utilization Prospect of anti rice blast, high quality,high yield new combination by evaluating the main agronomic traits of Rong18A combinations and their blast resistance identification results.The results were as follows:1. Inoculating 231 isolates isolated from samples can be drawn the rice blast disease resistance frequency of Rong 18A is 96.53%.The field resistance of Rong 18A series were indentified,and the results indicates Rong 18A is resistant to rice blast.Therefore we can say The Rong 18 A has a larger the scope of the use of alternative.2. The field resistance of F1 generation of Rong 18A testcross were indentified,and the results indicates that:Rong 18A has a lasting, broad-spectrum blast resistance and its resistance gene is dominant; the blast resistance of F1 generation is closely related to their paternal blast resistance.3.20 complete diallel hybrid rice combinations were identified in blast disease nurseries located at Ya’a. The results show the difference of CMS anti-rice blast resistance has a certain influence on the blast resistance of the combination.The blast resistance of distributive combination under the different circumstances shows that the Blast Resistance of Hybrid combinations were effected by both sterile and restorer lines, when sterile line is the same in different restorer.4. The main agronomic traits of 9 testcross combinations of Rong 18A were deteemined,the results indicated that:the number of days from sowing seeds to heading was between 143 to 151 days.Most maturitiesare for late maturing combinations,plant height 100.9～114.6cm,panicles per 7.1～9.3 spike, panicle length 23.23～25.93cm, grain weight 29.18～32.83g,grains per panicle 167.8-202.3,seed Setting rate 68.2～83.1%, grain density 4.9～5.9,per mu yield 365.82～486.05 kg.mu-1.Yield rate -7.84～7.68%.The result shows that the combinations of Rong 18A provide a better choice for breeding.The resistance Frequency of 10 combinations consisting of our own recovery were determined, that shows the blast resistance of these combinations of Rong 18A is good.and has an important significance on breeding new varieties of rice blast resistance.5. Here we applied RT-PCR detection and inoculating 10 rice monogenic lines in blast diseasenurseries of Ya’an.The result found that the blast resistance gene Pia,Pi-k,Pi-kp Pita,Pib.Pit,and Pish have been lost resistance in Sichuan province,and indicated the blast resistance gene Pid2 and pi9 might contribut greatly to the blast resistance of Rong 18A. |
PDF Full Text Request