Identification And Distribution Of Self-incompatible S Alleles In Radish

Radish(Raphanussativus L.)is a cruciferous vegetable with an annual supply and plays an important role in people’s daily life.Radish is affected by self-incompatibility in breeding,which often leads to inefficient reproduction and hinders the breeding process,and is controlled by the S locus(also called S haplotype)complex allele.Currently,dozens of S haplotypes have been identified in radish by different groups at home and abroad,but the naming of S haplotypes is confusing,while the distribution of S haplotypes in Chinese radish is not very clear.In this study,67 radish materials from different sources in China were used as experimental materials,and the S locus genes(SRK and SLG)were analyzed by PCR amplification,T-A cloning,sequencing,and comparative analysis fragments were studied,and S haplotypes of all experimental materials were identified,named and classified.In addition,two radish self-incompatibility lines with high self-cross affinity were screened by field experiments.The main findings are as follows:1 Radish high generation self-incompatibility lines were used as experimental materials and specific primers were designed to amplify their S-locus genes.Thirty-seven autogamous materials were found to have amplified class I S haplotype target fragments,and 35 autogamous materials were found to have amplified class II S haplotype target fragments.The obtained target fragments were subjected to monoclonal sequencing,and the analysis identified 18 class I S haplotypes and 9 class II Shaplotypes,for a total of27 S haplotypes,including 3 new S haplotypes.The S locus gene sequences obtained in this study were analyzed by detailed comparison with published sequences,and S haplotypes with nucleotide sequence similarity of 98% or more were identified as the same S haplotype.By comparing the results,the haplotypes published by different groups were named uniformly,and the affinities of S haplotypes were further analyzed by constructing a phylogenetic tree.2 Using self-pollination experiments in the field sleeve and after calculating the affinity index,two resources of self-compatible radish for breeding needs were identified as ’B1243’ and ’B1267’.By pollen tube germination test,the germination morphology of pollen tubes after selfing was observed by fluorescence microscopy,and it was found that pollen of the two affinity selfing materials could germinate normally on their own stigmas,and pollen tubes passed through the stigma tissue in large quantities without callus production,which proved that both materials had thorough selfing affinity.The S haplotypes were further characterized and found to be Rs SRK3 and Rs SRK6 for ’B1243’and ’B1267’,respectively.A genetic segregation population was constructed based on the affine material ’B1243’ and the unaffine material ’B499’,and the selfing affinity of single plants in the F2 segregation population was investigated and found that the selfing affinity of ’B1243 The self-cross affinity of’B1243’ was controlled by a pair of genes and the affinity was recessive compared with the unaffinity.In summary,this study identified the distribution of S haplotypes in domestic radish resources and unified the nomenclature.Two self-incompatible radish resources were screened,and the genetic pattern of the affine material ’B1243’ was initially analyzed through genetic experiments.The development of this study will lay the foundation for research on the molecular mechanism of self-incompatibility and breeding applications in radish.