Selection Of High-quality Inbred Lines Of Zinnia Elegans And The Dwarfing Effect Of Different Treatments

Zinnia elegans, it usually was used in flower bed and flower board due to its characters of colorfulness, many kinds of flower pattern and long flower phase. We got more than20inbred lines of fine quality, majority of which are medium height, otherwise less are small, after many years breeding and collection. The first part of our experiment was to breed inbred lines of high quality including dwarf, narrow-leaf and popular-color types and male sterility two-type lines. And then we observed and analyzed the growth law of6inbred lines; based on this observation, the second part is to dwarf plants and find the best treatment of dwarfing, through exposing plant growth inhibitors and pinchings to plants of J6series. The third part was The results are follo wings:1. Breeding of inbred lines of high quality.(1) using the four kinds of F1series named Dream land including rose red series, scarlet series, yellow series and ivory series as material, self-pollination of3generations was carried out to get the dwarf lines of high quality named MAf2through pedigree method and extreme selection.(2) Using the same ways, we got a series named MAh3with a stably yellow flower.(3) Using the narrow-leaf series named A3N as the selfing materials, we got a stably narrow-leaf series, which leaf is same long as normal but narrower since seedling stage, at the same time, and we predict the gene controlling narrow leaf is recessive.2. The growth law for6inbred lines of Zinnia elegans. The trend in which6inbred lines’height varied along time is very close to S-curve, so the whole growth process can be categorized into3stages:early growth period, fast-growing period, and last growing period. It comes into fast-growing period after showing up3-4pairs of leaves, in term of beginning point of fast-growing period, length of faster-growing period and plants height, these6inbred lines can be categorized into2types:(1) the first type includes A3, J7J and J10with characters of early speeding point, short faster-growing period and less than50cm height;(2) the second includes S5, J6and J17having a later speeding point, long fast-growing period and more than50cm height. The growth law also demonstrated that beginning point of fast-growing period is around a weed later than early bud period and the ending point is just very close to early flower period, in term of this, fast-growing period can be inferred by observing its development.3. The effect of plant growth inhibitors and pinchings on height of plants:(1) paclobutrazol, chlormequat chloride and pinching all have dwarfing effect, which of paclobutrazol is the most strong, chlormequat chloride is the second strong, pinching is last strong. The effect of high concentration and high frequency of pinching is more apparent, However, when high concentration of chlormequat chloride (2000mg/L and2500mg/L) is sprayed into leaves, its phytotoxicity appeared, otherwise paclobutrazol did not. The results showed the effect of the application through soil is not apparent as spraying onto leaves. After considering dwarfing effect, economic cost and environmental security, the best treatment is a combination of paclobutrazol which concentration is800mg/L with one time pinching, the second best is the combination of paclobutrazol which concentration is800mg/L with no pinching.