Study On Genetic Diversity Of 11 Species (Cultivar) From Verbena Linn.

Verbena Linn.plants,the vast majority produced in tropical to temperate America.Among them,three species of Verbena bonariensis L.,Verbena tenera Spreng.,and Verbena hybrida Voss have begun to emerge in garden applications in China with their excellent ornamental characteristics and wide adaptability.They have begun to be used in flower-seeking lawns,flower beds,flower arrangements,potted plants and land.Being planted,people are gradually recognized,accepted,and loved.However,in the current research,it mainly focuses on the aspect of planting conservation,and its systematic research is almost a blank.This paper selected 11 representative varieties of the above three species,in the morphology,palynolog,and karyotype study.The genetic diversity of the three aspects of the model was studied and it is hoped that it will provide further insights and lay the foundation for the application of gardening and cross breeding.The main results are as follows:1.Through planting observation,the phenophases of 11 species(cultivars)were highly uniform during the vegetative growth stage,and there were significant differences after entering the flowering stage.The Verbena bonariensis L.and Verbena tenera Spreng.are far longer than Verbena hybrida Voss;From the bud stage to the bud stage,the three species of plants grow more slowly.The bud stage grows to the initial flowering stage.From the beginning of the flowering stage,the three species of plants have different performances.The Verbena bonariensis L.and Verbena tenera After flowering,there is still a short period of continuous growth,and the height of the plants does not change after the Verbena hybrida Voss enter the flowering stage.2.Through the observation of 22 morphological traits,as a whole,the difference between species was greater than among species,and greater than within species.The average coefficient of variation for all traits was 10.61% and 25.90%,and the average coefficient of variation for all phenotypic traits was between 2.35% and 43.60%.Several traits are the main factors leading to differences in Verbena plants.There was abundant genetic diversity among species(cultivars),with the variation ranged from 16.11% to104.79%,with the largest variation in the amount of planting and plant height;the diversity of phenology period,plant height,flower type,and flower color in breeding.All have a higher use value.According to the class-average UPGMA clustering method,the clusters of eleven species(races)of genus Verbena Linn.can be divided into three categories according to their phenotypes,and all varieties of Verbena hybrida Voss can be clustered into five categories.The clustering results show that the genetic distance In terms of distance and species,species can be differentiated to some extent.3.The pollen of 9 species(cultivars)scanned by electron microscope existed in the form of single grains.The side view of the pollen was elliptical,the polar surface was nearly triangular,and the surface was a smooth surface structure with small holes.The surface decoration belongs to the more primitive type,the Verbena tenera Spreng.and Verbena hybrida Voss rejuvenate the hole,the Verbena bonariensis L.only has the germination ditch,belongs to the simple germination hole.In contrast,Verbena bonariensis L.is more primitive than Verbena tenera Spreng.and Verbena hybrida Voss.All pollens have 3germination holes and are evenly arranged on the equator.4.The karyotype analysis of 10 Verbena tenera Spreng.and Verbena hybrida Voss varieties was performed using radicle root tip cells.The results showed that all varieties were diploid,the chromosome base number was x=5,and the chromosome number was 2n.=2x=10.Two kinds of chromosomes(m,sm)are present,and at the same time there are st-type chromosomes,consisting essentially of three chromosomes(m,sm,and st),and a single satellite appears in some species.The ratio of the longest arm to the shortest arm of the Verbena hybrida Voss is between 1.17 and 1.46,and the Verbena tenera Spreng.is between 1.21 and 1.52.The proportion of chromosomes whose arm ratio is greater than 2:1is between 0% and 20%.Verbena tenera Spreng.are between 20% and 40%.The nucleus of Verbena hybrida Voss is divided into 1A and 2A.The Verbena tenera Spreng.are 2A.The karyotype asymmetry coefficient is between 55.54% and 62.33%,and the karyotype symmetry is high.The above research provides theoretical basis and data support for scientific and rational garden application and cross breeding.