Aging Process And Reproductive Characters Of Experimental Clones Of Elymus Excelsus In The Songnen Plains Of China

Large samples of experimental Elymus excelsus clones in five different established years were rapped at the maturing period and last growing period of 2010 and 2009, aging process and the differences in quantitative characteristics of E.excelsus clones, and the relationships between quantitative characteristics and increased years of growth. At the same time, reproductive tillers of E. excelsus population were randomly marked with labels every other four days at the early earring stage, and the samples marked at five times were harvested together at the dough stage, and analyzed the differences in quantitative characteristics of reproductive tillers, and the relationships between quantitative characteristics and shortened time of reproductive growth. The results showed that:At the maturing period, with the growth year increased, the number and biomass of reproductive tillers, the biomass of tillers, RA decreased 90.4%, 98.1%, 81.3%, 85.3% respectively in 2010, and the above indexes decreased 71.5%, 69.2%, 53.8%, 33.7% in 2009. The number and biomass of vegetative tillers increased 62.5%, 64.5% in 2009.The decreased reproductive tiller numbers and the increased then decreased vegetative tiller number both reflected that Elymus excelsus clones showed the aging process with increased years of growth.At the last growing period, with the growth year increased, the number and biomass of reproductive tillers, the biomass of tillers decreased 93.4%, 98.4%, 82.2% in 2010, the number of reproductive tillers and tillers, the biomass of reproductive tillers and tillers decreased 59.8%, 20.3%, 73.4%, 64.4% in 2009. For dormancy module, the number of winterness buds, winterness seedlings and dormancy module decreased 65.8%,48.5%,57.1% in 2009, the number of winterness seedlings decreased 65.9%. Reality clones and potential clones both showed aging process with increased years of growth.At the maturing period, quantitative characteristics of reproductive tillers of E. excelsus population showed the different variation trend with the growth year increased. The reproductive tiller height, spike length, tiller biomass, spike biomass decreased 25.2%, 22.1%, 46.8%, 47.6% respectively in 2010, the above indexes decreased 17.8%, 15.0%, 45.1%, 37.0% respectively in 2009. The quantitative characteristics of reproductive tillers showed aging process with increased years of growth.Quantitative characteristics of reproductive tillers decreased with shortened time of reproductive growth which was bad for reproductive growth and allocation, fruting of reproductive tillers. In 2010 and 2009, at the time of reproductive growth shortened by 16 days, grain biomass decreased 75.1% and 99.4%, setting percentage decreased 60.5% and 98.8%, RAⅠdecreased 29.2% and 54.3%, RAⅡdecreased 66.7% and 99.2%, respectively. All the quantitative characters had a significant difference with the shortened time of reproductive growth expect number of florets and tiller biomass in 2010, all the quantitative characters decreased exponentially with shortened time of reproductive growth expect tiller and spike biomass, number of florets decreased logarithmically.