Molecular Mapping Of Fertility Restoring Gene Rf₃ And The Abortion Characters Of T763A,a Male Sterile Line With Triticum Timopheevi Cytoplasm

Wheat is one of the world's three major food crops,which has an immeasurable planting area in the world.The male sterile lines of wheat have high utilization value in hybrid breeding and great significance to increasing wheat yield.Among all the male sterile wheat,T-type cytoplasmic male sterility is researched most frequently and deeply.In order to make the morphological and cytological characteristics of T763 A clearly,as well as provide reliable basis for the selection of restorer lines,we take an in-depth study of the abortion characteristics and the restoration of fertility against T763 A,which is a T-type cytoplasmic male sterile wheat line.At the same time,we identified the karyotype of all the materials,onducted genetic analysis,and mapped the gene localization of nRf₃,which was used to reveal the genetic characteristics of male sterile wheat.The results are shown below:1.T763 A,a wheat male sterile line,763 B,its maintainer line,and Tm3315 B,Tm504B and TP731 B,its restorer lines,were used as the test materials to observe their external morphological phenotypes and the pollen grains production?acetic acid magenta staining,I2-KI staining and DAPI staining?.Anthers and microspore,which were under trinucleate stage,were investigated by scanning electron microscope analysis.We found that the abortion type of pollen from T763 A was classical abortion and spherical abortion,the mature pollen grains was small and dried up compare with 706 B.Moreover,the outer epidermal cells of anthers were irregularly arranged,and the inner epidermal cells were uneven,which had little ubisch body.The pollen grains were crimpled with little contents.Meanwhile,the pollen grains were sterileand the abortion of T763 A occurred between late uninucleate and binucleate stage.2.The 1B/1R karyotype of all the materials?sterile lines T763 A and T504A;maintainer line 763 B and 504B;restorer line Tm3315 B,Tm504B and Tp731B?were simultaneously identified by molecular marker technology and A-PAGE,with CS?Chinese Spring?and Rye as control materials.In addition,we conducted a comparative research of the recovery capability of the three restorers.The results showed that all the materials were non 1BL/1RS;the restoration capability of the three restorers were high,and among them,Tm504 B was the best restorer line against T763 A,the reasons for this might in connection with the gene counts of the restorer lines.3.The separation of fertility in F2?T763A/Tm504 B and T504A/Tm504B?and BC1?T763A//Tm504B/763 B and T504A//Tm504B/504B?from crosses between sterile lines,maintainer lines and restorer lines were statistically analysed.The results indicated that the abortion type of T763 A and T504 A were sporophyte abortion.Fertility restoration to T763 A was involved by a pair of restorer gene,two pairs of genes for T504 A.So it is conferred that the fertility restoration of different male sterile lines has different genetic modes,which has a complicated genetic mechanism.4.By mapping the fertility restoring gene Rf₃,we discovered that Rf₃ was located in 1BS.Sat18-0.50-1.00 of wheat,and the molecular marker Xfba329,BE425889 and Xmwg68 were linked to Rf₃ at genetic distances were 2.4cM,1.7cM and 4.7cM respectively.Here,we constructed the genetic linkage map of Rf₃,which will lay the foundation for further understanding of molecular genetics fertility restoring gene.