| Tomato yield is greatly affected by fruit size and fruit number,and the main factors affecting fruit number are the number of inflorescences per plant and the number of flowers in each inflorescence.Self-pruning tomatoes are limited by the number of inflorescences,resulting in lower yields.Therefore,breeding high self-pruning tomato varieties can not only increase tomato yield,extend the supply period,but also reduce labor costs.In this experiment,tomato strain lines AXF and GXF with different pruning positions were used as the test materials.The differences in phenotypic traits,fruit traits,soluble sugars,enzyme activities,and endogenous hormones were studied and High-throughput resequencing technology were used to detect for variation and analysis on the genome,thereby providing assistance for the selection of high self-pruning tomato varieties and molecular marker-assisted breeding.The main findings are as follows:1.The study of phenotypic traits showed that the plant height,first flower node position,number of self-pruning inflorescences,leaf number and node spacing of GXF were 191.47 cm,6.43 length,12.67 piece,23.2 piece and 8.68 cm,which were significantly higher than AXF 37.49 cm,4.67 length,2.77 piece,8.60 piece and 4.92 cm.Moreover,the leaf type,leaf traits,growth habits,inflorescence interval nodes,fruit color,ripeness,fruit traits,fruit shape index and single fruit weight between GXF and AXF were consistent.2.Physiological index research showed that the soluble sugar content and free amino acid content of GXF leaves were higher than that of AXF at the same period,indicating that with increase of leaf number in high self-pruning plants lead to a large amount of nutrients accumulation,which was beneficial to plant growth,promoted flower bud differentiation,and delayed plants pruning.The SOD enzyme activity in GXF leaves was higher than that of AXF,indicating that high SOD enzyme activity in high self-pruning plants leaves was beneficial to the production of flower buds,which might be one of the factors that delayed plant pruning.Plant endogenous hormone was an important factor that affected the flowering of tomatoes,and had a closerelationship with tomato pruning.ABA,CTK,IAA,GA contents in GXF and AXF leaves were all significant differences.The content of ABA,CTK,IAA and GA of GXF were higher than that of AXF,and the content of ABA was higher than other hormones,indicating that high content of ABA was beneficial to the differentiation of flower buds.Cytotaxins could promote the flower buds,and the CTK content of GXF was significantly higher than AXF.3.The results of genomic variation detection showed that the number of SNPs detected in the AXF and GXF genomes were 2 496 666,2 540 062,and the number of Indels were 198 036,197 549.The changes of the genome were mostly single nucleotide mutations,and the conversion type was the main type.Through KEGG enrichment analysis and gene function annotation,10 738 variant genes were annotated,of which the most variant genes involved in signal transduction and carbohydrate metabolism.KEGG enrichment analysis of nonsense variant SNP and Indel showed that the zeatin biosynthetic variation was present in both types of mutations;Genetic screening based on the KEGG enrichment revealed that the genetic variation mainly existed in cytokinin anabolic metabolism. |
