The Inflorescence Development And Inhibition Of Lawn Type Bermudagrass [Cynodon Dactylon(L.) Pers.] By Heredity Improvement And Management

Bermudagrass [Cynodon dactylon(L.) Pers.]is the most widely uesd warmseason turfgrass,with the characteristic of dwarfness,fineness,stress resistance.however the longer flower and fruit period—generally from the April keep on up to November—was a problem both for lowing turf quality and cost of turf management.Mowing could resolve this problem to a certain degree, caused other problems again to some extent, more money spending on the manegement, the wound resulted in diseases and insect pests more easily.Therefore, it is important to study on the inflorescence development and suppression of bermudagrass inflorescence by heredity improvement and culture management for the development of high quality and low cost bermuda turf in the further.For the moment,there was few reports about of bermudagrass in domstic and abroad. There were some reports on the inflorescence in hibition by plant growth regulaters in 80's abroad,but the results were not effiective.There was not report about this in domestic.In the paper, florescence of Chinese native bermudagrass accessions was investigated, and the inflorescence development of C299 was observed.The inflorescence density variation ploidy lever and SSR marker of the bermudagrass C754 by radiation-induced mutation was comprehensively analyzed.In the end,mowing, nitrogen fertilizer and plant growth regulators were comprehensively used to try to find the best management measure for the inflorescence densitycontrol.the main results were showed as follows:1 Florescence and inflorescence development processThe florescence of 39 native bermudagrass accessions were investigated both in 2005 and 2006, the results showed that florescence of accession 13 only appears in spring, the others appears both in spring and autumn;No relation was found between the florescence of 39 native accessions and longitude and latitude of their collecting site.The inflorescence development process of C299 was observed, the result showed that the inflorescence differentiation of C299 could be preliminarily divided into eight stages, i.e., the vegetative growth stage,the development of raceme number stage,the single ridge stage, the double ridge stage, spikelet differentiation stage, floret differentiation stage, roecium and gynoecium differentiation stage, and development of glume, lemma and palea.2 The effect of The ⁶⁰Co-γradiation-induced mutation on inflorescence inhibition of C754The inflorescence density and other charactersitics of C754 and the mutants including C75403 MI-1, C75403 MI-I-1, C75403 M1-2, C75404 M2-2-1 was oberved,the result showed the obvious difference was existed between C754 and it's mutants. ⁶⁰Co-γsignificantly reduced the inflorescence density of C754, whereas no significantly difference was found between other morphological charactersitics of C754 and it's mutants. Chromosome numebers of C754 and it's mutants were studied in this experiment,the preliminary result showed that the mutants had more aneuploid than the parent.The results of SSR marker, also showed the obvious difference between C754 and it's mutants.3. Management measure to inhibite the inflorescence density of C299The effect of plant growth regulators on inflorescense The result showed that the inflorescences density inhibitition was ranked as 6-BA＞NAA＞GA; but 6-the BA will bring certain harm to lawn, aggravating with the concentration increasing.The effect of nitrogen fertilizer on the inflorescence density were increased with the applied amount from 40g/m² to 70g/m².Based on the experiment in 2005,mowing, the plant growth regulators and nitrogen fertilizer were used to control the inflorescence density of C299,the result showed that, the mowing + 40g/m² nitrogen fertilizers + 400mg/m²Â·kg 6-BA were the best treats with the least injury to tufgrass and the highest turf quality.