Biological Characterization Of Diploid Regenerated Plants Of S. Verrucosum

Potato cultivars are tetraploid,with high heterozygosity,self-incompbility,and sharp separation of offspring.This problem could be solved using diploid material by chromosome reduction.Simplified genetic background can help with exploring and utilizing the excellent genes in diploids.However,diploid potato materials with self-compatibility and homozygous properties have not been reported.In this study,we evaluated and analyzed the agronomic characters of theregenerated potato plants produced by anther culture of S.verrucosum including diploids（SVA4、SVA7、SVA22、SVA23、SVA32、SVA33）and haploid（SVA19）.The main characters we focused are ploidy,self-compatibility,homozygosity,plant vigor,etc.The main findings as follows:All six regenerated potato plants were identified as dilpoids by root tipchromosome counting and the flow cytometry.Homozygosity was investigated and confirmed by 35 pairs polymorphicInDel markers developed near the centromere and telomere of 12 chromosomes of potato.PAGE results showed that the genotypes of the six regenerated potato plants were homozygous and the homozygous probability of the six regenerated potato plants was 1-（1/2）³⁵>0.9999.The morphological characteristics of the above ground parts of the plantsshowed that four of regenerated diploids SVA4,SVA22,SVA23,SVA33 and haploid（SVA19）were erect type identical with parents plants,while SVA7 and SVA32showed developed type.The length of compound leaves of three regenerated plants,SVA7,SVA22,SVA33,were significantly shorter than parents plants.For the leaf margin,most of the regenerated diploids were flat,except for SVA33.SVA33 was slightly wavy.The shape of top leaflet for both parents and regenerated plants were narrow,while the basal parts were heart shape.The self-compatibility was confirmed by pollen vitality,berry setting andseed setting.The results indicated that the pollen vitality of SVA4,SVA7,SVA32,SVA33 were over 75%,no significant difference with parents（P>0.05）.While the other two regenerated plants and haploid showed lower pollen vitality.For the berry setting,SVA4 and SVA32 could berry.The berry number of these plants were 48.8,48.8,averagely.Other regenerated diploids had no berry.Seed shape of SVA4 and SVA32 were identical with the parent plants,the ratio of length and width were 1.6and 1.3,respectively.Evaluation of tuber characters was preformed,including shape,number andweight.The results of tuber shape showed that most regenerated diploids and haploid had no significant difference with parent plants,except for SVA33.The tuber shape index for SVA33 was 1.7,higher than parents.The results of tuber shape showed that most regenerated diploids and haploid had no significant difference with parent plants,except for SVA32.The tuber shape index for SVA33 was 1.7,higher than parents.The SVA32,SVA4,SVA7 were no significantly different from the parent plants in the the number of tubers per plant,but significantly higher than that of the haploid.The number of tubers per plant of SVA22 and SVA33 were 12.3 and 5.7,respectivel,ywhich were significantly lower than that of the parent plants.The yield per plant of SVA4 and SVA23 were 120g and 160.6g,respectively.And there was no significant difference compared with the parent.The yield of other regenerated diploid materials was significantly lower than that of the parent plants.Except for SVA33,the yield of the other 5 regenerated materials was significantly higher than that of the haploid material.The average tuber weight of SVA22 and SVA33 were5.5g and 5.9g,respectively,which was significantly higher than that of the parent.There was no significant difference between other regenerated diploid materials and the parent plants.The solanine content of all regenerated diploid and parent and haploid potato peel was significantly higher than that of flesh,and there was no significant difference in the solanine content of peel in each materials.Compared with the parent,most of the diploid materials have higher solanine content of flesh,but they have not reached significant difference.The number of parents’buds was 8and the number of SVA4 buds was slightly higher than that of their parent.The number of buds of the other regenerated diploid materials and haploid materials were lower than that of their parent,but there were no significant difference（P>0.05）.Through the above experiments,the homozygous diploid materials SVA4and SVA32 with self-compatibility and high seed setting rate were identified,which can be used as model materials for potato basic research and have important application value for potato breeding.