| The rice restorer line R221 bred by Shanghai ZKW Molecular Breeding Technology has elite agronomic traits and strong resilience,and contains excellent genes such as Gn1 a,LAX1,GS3,Xa26,SCM2.Gn1 a is a gene positively correlated with total grain number.LAX1 can increase the grain length.GS3 can promote stigma exposure.BPH29 can resist brown planthopper infectation.Xa26 can resist Xanthomonas oryzae infectation.SCM2 is a gene positively correlated with lodging resistance.However,its resistance to rice blast is poor,which limits its application in the field of rice breeding to a certain extent.Wushansimiao is a rice variety with strong rice blast resistance.In this study,through the mensuration and observation of rice blast resistance and resistance spectrum,agronomic traits and quality traits,part DUS traits and growth period of improved restorer lines WAH23(Pigm,Pi25,Pi2,Pid2),WAH112(Pigm,Pi25,Pi2),WAH114(Pigm,Pi25,Pid2),their characteristics and breeding application value were identified.The main findings are as follows:1.The results of artificial inoculation test showed that the incidence of leaf blast of R221 was 90%,while the incidence of leaf blast of three improved restorer lines ranged from 6% to 12%.The results of natural induction test showed that the blast resistance of R221 with leaf blast score 8,neck blast incidence rate score 9,neck blast loss rate score 5,and resistance score susceptible is poor,while the blast resistance of three improved restorer lines with leaf blast score 2 or 3,neck blast incidence score 1or 3,neck blast loss rate score 1,and resistance score resistant is strong.Besides,The resistance score of the hybrid combinations of three improved restorer lines reached resistance or medium resistance.Identification results of leaf blast resistance spectrum showed that the resistance frequency of the three improved restorer lines ranged from92.7% to 94.1%,which was significantly broadened compared with R221.2.The results of main agronomic traits and quality traits showed that the agronomic traits of the three improved restorer lines were close to R221,and the quality traits were different,and only WAH114 reached the quality grade 3 according to the national standard for high-quality indica rice.The three improved restorer lines had strong resilience,and the fertility of spikelets of 39 hybrid combinations ranged from66.9% to 88.1%,and the average fertility of spikelets of every improved restorer lines was above 75%.The results of part DUS trait mensuration showed that the three improved restorer lines were significantly different from R221,but their traits were basically consistent under different sowing dates.The observation results of the growth period showed that the growth speed and the total number of main stem leaves of the three improved restorer lines was basically the same.The growth speed of the main stem leaves was one leaf growing every 4-5 days,and the total number of main stem leaves was 15-17.Under different sowing dates,the full period,the heading period and the effective accumulated temperature of the full period and the heading period of the three improved restorer lines were basically the same and the value of them was between R221 and Wushansimiao.In addition,combined with the main agronomic traits and quality traits,three excellent combinations were selected,including211S/WAH112,Huke1A/WAH114 and Quanxiang 12A/WAH114.The yield of each line was higher than 59 g,and the quality of each line reached the quality grade 3 or above.3.The results of combining ability analysis showed that the traits of hybrid combinations is closely related to the general combining ability of parents.WAH23 can be used to breed varieties with more panicles,long period,high head rice rate.WAH112 can be used to breed varieties with more total grain number,high fertility of spikelets and high yield.WAH114 can be used to breed varieties with high brown rice rate,milled rice rate and alkali spreading value or varieties with low chalky grain rate and chalky degree. |
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