Evaluation Of Blast Resistance And Agronomic Characters Of New Rice Restorer Line Yahe And Its Combinations

Rice is one of the most important ration crops in our country.Its stable and high yield is directly related to the food security of our country.Rice blast is the main disease of rice,which poses a great threat to the safety of rice yield.It has been proved that breeding and popularizing resistant varieties is the most economical,effective and environmental protection measure to control rice blast.With the continuous development of economy,people are paying more and more attention to satiety,and the demand for rice quality is also higher and higher.Therefore,breeding new rice varieties with disease resistance,high quality and high yield is the main goal of rice breeding.Yahe is a New Indica Restorer line created by the rice disease research group of Agricultural College of Sichuan Agricultural University.In order to fully explore its utilization value,this paper systematically evaluated the blast resistance,quality and agronomic characters of Yahe and its series of combinations.The main results are as follows:（1）Main characteristics of YaheThe height of Yahe plant is 119.1cm,the number of leaves in the main stem is15-16,the average effective ear of a single plant is 14.2 ears,the leaves are slightly curled upright,the leaf sheath,ear and edge are green,and the spikelet is yellow.The length of ear is 24.1cm,the number of grains per ear is 128.6,the number of grains per ear is 116.0,the average density of grains per ear is 5.3 grains/cm,the seed setting rate is 90.2%,the weight of 1000 grains is 29.9g,and the ratio of grain length to width is 2.9.Yahe was planted in the first ten days of April in Chongzhou City,Sichuan Province,with a sowing and drawing period of about 111 days and a full growth period of about 145 days.It has a large amount of pollen and a long flowering period,so it is suitable for seed production.The brown rice rate of Yahe is 79.3%,the milled rice rate is 68.6%,the whole milled rice rate is 59.0%,the length of rice grain is 6.5 mm,the length width ratio of rice grain is 2.9,the chalkiness rate is 11%,the chalkiness degree is 1.7%,and the appearance rice quality reaches level 1 of national standard for high quality rice.（2）Combining ability analysis of YaheThrough 7×5 incomplete diallel cross test,the general combining ability of Yahe（R7）was 1.1122,the special combining ability of A4×R7（18fa8041/Yahe）was 3.1266,the special combining ability of A5×R7（18a8035/Yahe）was 4.2247,and the special combining ability was high.The results showed that the general combining ability and the special combining ability of Yahe were both high,and it was expected to produce high-yield hybrid rice combinations.（3）Determination of blast resistance of YaheThe results showed that Yahe leaf blast 1 and ear neck blast 0 were resistant to leaf blast and ear neck blast.The results of indoor anti-spectrum test showed that the frequency of resistance to 55 monospora strains of Magnaporthe grisea was 100%and the resistance spectrum was wide.（4）Preliminary study on blast resistance gene of YaheBy RT-PCR analysis,it was found that Pi2,Pi5-1,Pid2,Pib,Pia-RGA4 and other five R genes were highly expressed in Yahe,and Pid2,Pia-RGA4 were highly expressed in LTH.Referring to the research results of Li Deqiang^[57]on blast resistance of single gene lines,Pib,Pia-RGA4 and Pi5 had lost resistance in Sichuan,There was no difference in the expression of Pid2 between Yahe and LTH,so it can be inferred that the main anti blast gene in Yahe might be Pi2.In addition,by inoculating the rice blast strain Guy11,which was pathogenic to Pi2,Yahe still showed resistance to the disease.It is further speculated that in Yahe,in addition to Pi2,there are other R genes involved in the process of resistance to rice blast.（5）Screening of Yahe superior combinationThe evaluation results of the competitive advantage of Yahe series showed that the late maturing combinations of Medium Indica Rice:SW-3（Yixiang 1A/Yahe）,SW-4（Chuanzhong 3A/Yahe）,SW-6（Rong7A/Yahe）,SW-7（Jincheng 2A/Yahe）,SW-8（Yakang 1A/Yahe）,SW-36（Chuankang 606A/Yahe）showed outstanding performance,among which the converted per mu yield of SW-7（Jincheng 2A/Yahe）was 686.97 Kg,an increase of 8.18%compared with the control,the rice quality and appearance evaluation level reached level 1 of the national standard for high quality rice,resistant to rice blast,medium resistant to rice false smut,and the frequency of resistance to indoor inoculation reached 100%.The combination will be approved by the national level in the upper reaches of the Yangtze River in 2020.Mid season indica rice combinations:SW-17（Ya1A/Yahe）,SW-19（Taifeng A/Yahe）,SW-20（Luxiang 618A/Yahe）,SW-35（Yakang 3A/Yahe）showed outstanding performance,among which SW-17（Taifeng A/Yahe）converted per mu yield 629.18 Kg,with an increase of 3.67%compared with the control,the rice quality and appearance evaluation level reached level 1 of the national standard for high quality rice,resistant to rice blast and high resistance to rice false smut,and the frequency of resistance to indoor inoculation reached 92.7%.In 2020,it participated in the national regional trial and production test in the upper reaches of the Yangtze River.SW-37（Hongda A/Yahe）is the early maturing type combination of medium indica rice.The above 11combinations are competitive in yield,quality and resistance,and have a good prospect in production.