Characteristics And Applied Basic Research On The Male Sterile Line Of Rice-hang 17S By Space Mutation

Breeding of excellent male sterile line rice is one of the key factors to improve the heterosis and quality of two-line hybrid rice.The Hang 17S is a new male sterile line-obtained by space mutation Pei’ai 64S dry seeds with the"No.8"agricultural satellite launched in September 2006 in C hina,after the ground cultivation and tracking,directed screening,pressure selection of critical terility induc ing temperature,it has the characteristics of low amylose content(AC)and low critica l terility induc ing temperature.In this study,Pei’ai 64S was used as a control to study the main agronomic traits,flowering habits and growth characteristics of Hang 17S,critical terility induc ing temperature,rice quality,and the combination of the Heterosis and combining ability analysis.The main results were listed as follows:1.Except flag leaf width,the main agronomic traits of the Hang 17S were close to the protospecies-Pei’ai 64S,the plant type was distributed well,the stems were thicker,the total number of leaves was less,the leaves were fast,the tillers were strong,spike grain number was moderate,accord with the standard selection of agronomic traits of male sterile lines rice.2.The overall outcrossing characteristics of the Hang 17S is good,the flowering period is long,the flowering period is concentrated,the flowering rate is high at the beginning of the afternoon,and the choice rate is higher when the flowering period is arranged.In addition,the exposed rate of stigma is high,especially the bilateral exposed rate is higher,which is favorable for accepting foreign pollen,to improve the quality and yield of hybrid seed production.3.The microsatellite polymorphism analysis of Hang 17S and protospecies-Pei’ai 64S,it was found that the protospecies was insensitive to the spatial environment at the DNA level,and it was not easy to cause the mutation of the gene locus.Wx Multiple alleles sequence analysis showed that the low AC of Hang 17S was mainly affected by Wx major gene.The specific reason is that the first base G mutation of T at the 5’end of the first intron of Wx gene and the first intron cleavage site upstream 55bp(CT)_n repeat number of18.4.Hang 17S critical terility inducing temperature is below 23℃,in line with the NY/T1215-2006;the range of DSH variation is the biggest,the effective accumulative temperature was minimun,the effective accumulated temperature was stable,it shows that the Hang 17S is a TGMS line,at the same time,it has the characteristics of stable fe rtility and good reproduction,it is an excellent two-line male sterile line.5.The combination of Hang 17S with super parent and control heterosis(including the combination of Pei’ai 64S with the corresponding conditions)were obvious,mainly in the 4characters,such as yield per plant,number of productive ear,Thousand Kernel Weight and plant height.6.Hang 17S had higher general combining ability(GCA)in yield per plant,number of productive ear,seed setting rate,plant height,Thousand Kernel Weight and so on.The combination of Hang-17S/1H1124 and Hang-17S/1179,which is an ideal hybrid combination of comprehensive traits.7.A simple correlation analysis between yield and other agronomic traits showed that number of productive ear,the total number of grains per panicle,the seed setting rate were significantly positively correlated with the yield per plant,and Thousand Kernel Weight was not significant.The path analysis showed that the direct path coefficient of the yield per plant and the 4 yield components reached a very significant level,the direct effect of the effective panicle number and grain number per panicle were the most obvious,Thousand Kernel Weight had an indirect effect on the number of productive ear and the number of grains per panicle.8.Analysis of rice quality showed that the Hang 17S combination is excellent in milling quality,the appearance and cooking quality were unable to meet the overall national quality rice standard because of the higher chalkiness degree and low AC,and this is a major challenge in terms of two-line hybrid rice grain quality.This study shows that:the new type of male sterile line Hang 17S,which was bred by space mutation,has good agronomic characters,good outcrossing characteristics,low critical terility inducing temperature and low AC,its combination of hybrid has good advantages,good combining ability,high yield;it also has a huge application to enhance the space in the rice quality.With the gradual application of the Hang 17S in breeding practice,we will write a strong essay for the hybrid rice breeding in our province.At the same time,we will use the space mutation technology to select the new male sterile line rice,which will enrich the genetic background of the male sterile line rice,and will guide the two lines of hybrid rice breeding.