| Rice as the main food rations crop in China,the high and stable yield of rice is related to the national food security.As the growth of China’s population and the improvement of people’s living standards,the demand for rice yield and quality gradually increases.Rice blast is a major disease in rice production and its occurrence has a serious impact on rice production and quality.The selection and cultivation of disease-resistant varieties is the most economical and effective measure to control rice blast,and the creation of disease-resistant,high-quality,high-compatibility parents is the basis for the selection and breeding of new disease-resistant,high-quality,high-yielding hybrid rice varieties.Shunhe is a new rice restoretion line selected by Professor Huang Fu’s team at the College of Sichuan Agricultural University,using a cross between the highly-resistant and high-quality super rice restoration line Yahui 2115 and the high-quality and high-cooperativeness restoration line Chenghui727.In order to explore its utilization value,in this experiment,Shunhe and its series of combinations were systematically identified and evaluated Through technical means such as agronomic trait investigation,rice quality determination,rice plague resistance identification and compatibility determination,etc.The results showed that Shunhe is a new rice restoration line that combines high quality,disease resistance and high compatibility,and its series of combinations mostly exhibit characteristics of high quality,disease resistance and high yield.The main results are as follows:1.Evaluation of agronomic traits and plague resistance of ShunheShunhe plant were neat and consistent in the field,with a compact plant shape,erect leaves,green leaves,full growth period of 138 days,plant height 106.5cm,effective ear 9.8ears per plant,208.0 grains per panicle average,spike length 26.0cm,panicle average grain density 8.0 grains / cm,grain length 9.8mm,grain width 2.8mm,ratio of rice grain length to width 3.0,thousand grain weight 28.8g,seed setting rate 93.1%.The whole refined rice rate is 61.81%,the degree of chalkiness is 1.2%,the appearance quality reached the NY/T 593-2021 "Quality of Edible Rice Varieties" Ministry of Quality Rice Grade 2,and the rice quality is superior.The results of two consecutive years of plague resistance in Sichuan Ya’an Caoba Disease Nursery showed that Shunhe leaf blight grade 1 and spike neck blight grade 0,with high resistance to leaf blight and spike neck blight in the field.Use 224 effective single spore strains tested for indoor resistance to Shunhe,with a high resistance frequency of 90.2%,exhibits a broad spectrum of resistance,making it suitable for blending disease-resistant varieties.2.A preliminary investigation of plague resistance genes in ShunheIn order to explore the rice blast resistance genes in the newly restored line Shunhe,the single spore strain of Magnaporthe grisea was used to spray and inoculate Shunhe and LTH.The RNA was extracted at 0h,12 h,24h and 48 h,and the c DNA was amplified by reverse transcription.Using Actin as the internal reference gene,primers were designed with the cloned rice blast resistance gene sequence for RT-PCR analysis.It was found that Pi2,Pid2,Pi25 and Pib were expressed in Shunhe.Among them,the highest expression of Pid2 and Pi2 was the after 12 hours of inoculation,while Pi25 and Pib were slightly expressed,while Pib lost its resistance in Sichuan,Pid2 is only resistant to ZB15.Inoculation tests with Guy11,a strain pathogenic to Pi2,against LTH,Pi2 monogenic line,Shunhe and Yahui 2115 in isolated leaf scratch and spray inoculation showed no disease in Shunhe and Yahui 2115,presumably Pi2 and Pid2 act together in Shunhe resistance,and as the main rice blast resistance gene of Shunhe’s parent Yahui 2115 has been shown to be Pi2,it is presumed that Pi2 may also be the main rice blast resistance gene of Shunhe.The role of Pid2 and Pi25 in Shunhe needs to be further verified.3.Analysis of combining ability of ShunheThrough 6×7 NCII and designing three repeats,the general combining ability of 6restorer lines and the special combining ability of 42 combinations were analyzed according to the effect value and positive and negative.The results showed that among the 9 traits,Shunhe had the highest GCA value in filled grains per ear,grain number per ear and average grain density per ear,which were 6.28,5.00,9.83 respectively.Shunhe showed positive effects on effective panicle per plant,filled grains per panicle,grain number per panicle,average grain density per panicle,seed setting rate and yield.In terms of yield,the general combining ability effect value of Shunhe is 3.79,ranked second among the six restored lines,which was better than the parent Yahui 2115,it belongs to high combining ability rice restorer line.4.Screening of Shunhe’s superior hybrid rice combinationsAgronomic trait analysis of a total of 70 hybrid rice combinations tested and mated by Shunhe from 2021 to 2022 found that the fruiting rate ranged from 76.2% to 97.3%,with an average fruiting rate as high as 90.38%,indicating that Shunhe is more resilien.With reference to the ministerial standards of “NY/T 593-2021 Quality of edible rice varieties”and the 2022 revised version of “Sichuan Provincial Variety Validation Standards”,the comprehensive yield advantage(yield increase of ≥5% per mu compared with the control),field resistance to plague(resistance grade 0～3),comprehensive evaluation of variety type(green and high-quality varieties)and rice appearance quality(variety quality grade 2 or above),indoor resistance spectrum determination of disease resistance frequency RF ≥65%.A total of 10 high-quality,high-yielding,disease-resistant hybrid rice combinations were screened : six late maturing combinations(20A7035/Shunhe,Yuexiu A/Shunhe,Jincheng 2A/Shunhe,Rongxiang A/Shunhe,Yulong 1A/Shunhe,Jincheng 3A/Shunhe)and four medium maturing combinations(Huasheng A/Shunhe,Xiehe A/Shunhe,Taifeng A/Shunhe,Deyue 729A/Shunhe).Indicating that these combinations have potential to be exploited and deserve further focused testing. |
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