| Rice is an important food crop in China,and rice production has long faced problems such as reduced arable land,poor quality,and variety degradation.At the same time,the occurrence of rice blast disease seriously threatens rice production and national food security.Practice has proven that breeding and planting disease-resistant varieties are the most economical,environmentally friendly,and effective measures for controlling rice blast disease.Therefore,breeding new rice varieties with disease resistance,high quality,and high yield is still the main focus of rice breeding,and the excellent traits of hybrid rice come from parents.Therefore,it is crucial to create new parents with disease resistance,high quality,and high combining ability.In this paper,67 new rice restorer lines created by the Rice Disease Research Group of the College of Agriculture of Sichuan Agricultural University were taken as the research objects.First,through the identification of rice blast resistance,agronomic character evaluation,and external rice quality testing of the materials,new restorer lines with disease resistance and quality were preliminarily screened.Then,incomplete diallel cross and test cross were conducted,and the blast resistance,agronomic character Conduct a comprehensive evaluation of the characteristics and characteristics of appearance,rice quality,and yield.The main results are as follows:1.The results of blast resistance identification showed that 2 out of 67 newly restored lines showed high resistance to leaf blast,18 showed resistance to leaf blast,13 showed moderate resistance to leaf blast,13 showed moderate sensitivity to leaf blast,15 showed sensitivity to leaf blast,and 6 showed high sensitivity to leaf blast.In addition,13 out of 67 newly restored lines showed resistance to ear neck blast,19 showed moderate resistance to ear neck blast,16 showed moderate sensitivity to ear neck blast,15 showed sensitivity to ear neck blast,and 4 showed high sensitivity to ear neck blast;Among them,23 showed moderate or above resistance to both leaf blast and ear neck blast,which is of great value for the breeding of new resistant hybrid rice varieties.2.The results of agronomic traits investigation showed that 67 new restorer lines had rich genetic diversity in agronomic traits: the sowing period was 97-112 days,the plant height was 101.7cm～133.8cm,the effective panicles per plant were 7.6-14.6 panicles,the panicle length was 20.7cm～30.0cm,the thousand grain weight was 19.1g～35.2g,the number of grains per panicle was 81.4～269.4,the number of grains per panicle was 70.8～220.8,the seed setting rate was 63.9%～96.2%,the density of grains per panicle was 3.6～10.8,and the weight of grains per plant was 19.9g～63.1g.Based on the main indicator of grain weight per plant,the new restorer line has a grain weight of over 40.0g per plant.There are 25 materials with strong yield,including CR46,CR27,and CR57.3.The evaluation of appearance rice quality showed that the grain length and width of 67 newly restored lines varied from 5.8mm to 7.5mm,1.8mm to 2.5mm,71.3% to 81.4% for brown rice rate,67.3% to 76.9% for polished rice rate,42.7%to 72.8% for whole milled rice rate,0.1% to 28.4% for chalky rice rate,and 0.1%to 11.2% for chalkiness rate.According to the "NY/T593-2021 Quality of Edible Rice Varieties" standard,19 of the materials reached the ministerial level 1 of high-quality,14 of the materials reached the ministerial level 2 of high-quality,19 of the materials reached the ministerial level 3 of high-quality,and 15 of the materials did not reach the high-quality level.4.The analysis of combining ability showed that the new restoring lines CR57(11.5857),CR46(9.0062),CR53(6.6792),CR47(3.9465),CR45(3.7639),and CR59(2.7597)had higher general combining ability;The combination of CR63/Pinxiang A(7.9978),CR27/Huazhe 2A(10.237),CR65/Jincheng 2A(10.1276)and other 13 has high special combining ability.These new restoring materials and combinations have high application potential.5.Six new restorer lines with disease resistance,high quality and high combining ability were inoculated in vitro by leaf scratch inoculation and spray inoculation with 150 isolates of Magnaporthe grisea collected from different rice regions in Sichuan.The results showed that the disease resistance frequency of the six new restorer lines was more than 65%,showing a wide resistance spectrum,and the resistance spectrum frequency of CR53 and CR46 was more than 92%;From this,it can be seen that these 6 new restoring line materials have strong resistance to the Sichuan rice blast pathogen population and have high utilization value.6.The comprehensive evaluation of hybrid combinations shows that according to the "Sichuan Province Rice Approval Standards"(2022 version),there are 56 high and stable yield varieties and 40 green and high-quality varieties among 96 test crosses.Among them,23 green and high-quality varieties meet the approval standards,and 18 high and stable yield varieties meet the approval standards.A total of 19 new combinations with disease resistance,high quality,and high yield were selected based on factors such as field blast resistance(resistance level 0-3),rice appearance quality(high quality level 3 or above),yield advantage(increased yield per mu by ≥ 5% compared to the control),and comprehensive evaluation of variety types(green and high-quality varieties).These combinations can be promoted and applied after multiple experiments in the future.Especially the mid maturity combinations CC74,CC87,and CC89 have high resistance to rice blast,high-quality grade 3 rice,short growth cycle,and obvious advantages in yield increase,with yield increases of 18.2%,7.2%,and 14.2% respectively compared to the control;The late maturing combinations CC17,CC23,CC62,and CC65 have high resistance to rice blast,and the rice quality is classified as Grade 2high-quality by the Ministry.The rice quality performance is excellent,while the yield advantage is strong.The yield per mu has increased by 11.6%,7.6%,7.3%,and 10.9% compared to the control variety. |
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