Genetic Diversity Analysis And Preliminary Studies Of Chemical Male Sterilizing Of Viola×wittrockiana Inbred Lines

Pansy (Viola×wittrockiana) which is in great demand in the market nowadays is very important bed flowers and potted flowers in early spring. Most of the cultivars of pansy were hybrids which were imported with high price from abroad. It is very important to breed new quality cultivars with our own intellectual property. We have many inbred lines developed for years that can be used in heterosis breeding. We want to analyze genetic diversity among them in order to match combinations with comparative advantages. On the other hand, there were no male sterility lines in pansy and it is very hard to get genetic male sterility by transgenosis because the regeneration are difficult, so we want to use chemicals to induce male sterility physiologically.1. Genetic diversity analysis of pansy inbred linesWe selected20morphological parameters to analyze the genetic diversity of19pansy inbred lines which have great variations. The results of principal analysis showed that floral organ traits are principal factors affecting the classification of pansy by morphological markers, the second are plant type, leaf and calyx shape. All19inbred lines were clustered into4groups based on morphological traits, the litter flower inbred lines are clearly separated from the middle flower inbred lines by cluster analysis based on morphological markers.170sets of SRAP primer combinations were tested on preliminary tests, of which13sets of primer combinations with abundant polymorphism were screened out to analyze the well-defined and stable amplification products. A total of249bands were observed, of which219bands were polymorphic (88%). The principal coordinates analysis based on SRAP showed that19inbred lines of pansy have large genetic distance between each other. The grouping produced by the cluster analysis based on SRAP marker has correlations with flower diameter and flower color. The Mantel-test indicated that there was a significant correlation (r=0.5949) between the morphological traits and SRAP markers, but SRAP has greater sensitivity to separate inbred lines with similar morphological features. 2. Preliminary studies of chemical male sterilizing of pansyThe effects of four sulfonylurea chemicals including tribenuron-methy1、 pyrazosulfuron-ethy1、bensulfuron-methyl and nicosulfuron-methyl on male sterility inducing ability of pansy were investigated by spraying chemicals onto leaves of pansy at first flowering stage. Among these chemicals, Tribenuron-methyl was screened out with the best effect of inducing male sterility at the concentration of0.3-0.6μg mL-1. Pyrazosulfuron-ethyl and bensulfuron-methyl also can induce male sterility of pansy at the concentration of0.6μg mL-1in some way. Nicosulfuron-methyl has not male sterility-inducing ability in pansy at the concentrations we set. Tribenuron-methy1、 Pyrazosulfuron-ethy1、Bensulfuron-methyl do have side effects on pansy vegetative growth at concentrations inducing male sterility by suppressing plant height development, leaves and flowers growth and branches increase. Considering the little harm or no harm these chemicals do to pistil fertility and the universality of side effects of CHA, it is expected to have a broad prospect of tribenuron-methyl in inducing male sterility of pansy.Microscopic observations of development of sterile pollens revealed that the cytologic features especially the tapetum of male sterility induced by tribenuron-methyl were very different from the contrast during any development stage of the pollen. There were no pollen grains or litter deformity pollen grains in the anther when pollen grains reach maturity of male sterility.