Comparative Study On The Characteristic Of Pollination Ecology For Grape "Cabernet Gernischt" And Two Seedless Varities

Taking grape Cabernet Gernischt and two seedless varieties as the research materials,the dynamic process of flowering,morphological characteristics of pollen and stigma,pollen vigor and fertility,stigma receptivity,pollination insects species,breeding system and pollination behavior were observed and measured.Meanwhile,the effect of expanding agent on fruit setting of seedless grape was studied.The main results were as follows:The single flowering period of grape is about 5-8 days,and the flowering period of population is about 13 days.Cabernet Gernischt,Venus Seedless and Ruby Seedless whose the flower order of grape inflorescence is from top to bottom.Temperature of 22 ? and 29 ?,relative humidity 40% to 70% is the most suitable for grapes.The flowering of cultivated grapes in the vineyard was greatly affected by the temperature of the previous day,and the suitable temperature on the previous day would cause the flower to open on the second day.In 2017,the three varieties of grapes entered the beginning of flowering earlier than 2016.Different flowering stages are mainly affected by temperature.The pollen grains of Cabernet Gernischt are long and flat ellipse,the polar view is triangular,the furrow is long,almost reaches the two poles,the two ends are more pointed,the three groove type,the surface smooth has the reticulate pattern;the pollen grains of Venus seedless and Ruby seedless grape are both long oval,the polar view is round,the two ends are flat,the surface is flat,and the grain is reticulate.The three varieties of grape have different stigma morphology and changes in different flowering stages,the stigma was the highest on the day before flowering,the second day after flowering,the Venus seedless and Ruby seedless grape stigma was reduced to 0;the pollen vigor of Cabernet Gernischt increased first and then decreased with the increase of flowering time,the pollen vigor of Venus seedless and Ruby seedless grapes decreased with the increase of flowering time.The experiment of pollen storage showed that the pollen vigor decreased with the prolongation of storage time,and the higher the temperature,the faster the pollen vigor decreased.Therefore,grape pollen should be preserved in low temperature environment,and it is not suitable for storage for more than 3 months.Through the observation of the behavior of visiting flowers,it was found that Cabernet Gernischt were 10 kinds of flower visitors,which ran through the whole flowering process;the Venus seedless grapes had the phenomenon of ovary enlargement on the day of flowering,and there was no visitor to the flower during the observation,this proves to some extent that Venus seedless grapes is only a self-pollination plant,relying on its own pollen stimulation to form fruit;after the ruby seedless grape blossoms,only one kind of flower visitor was observed.The two seedless grapes had few visitors,which may indicate that nectar secreted by the nectar gland of the seedless grape is not enough to attract the flower visitor.It is also a basis for self-pollination of seedless grapes.During the peak period of two flower visitors,the main factors affecting the frequency of flower visit were light and temperature.In one day,when the temperature was 22 ? to 30 ?,the frequency of flower visiting was positively correlated with the temperature,and when the temperature was higher than 30 ?,there was a positive correlation between the frequency of flower visit and the temperature.The frequency of flower visiting was negatively correlated with temperature.Under the same temperature,the frequency of flower visiting is obviously higher when there is direct sunlight than when there is no direct sunlight.Therefore,the frequency of flower visiting can be increased when there is sufficient sunshine.The experiment analysis of grape breeding system shows that the pollination of grape by wind as a pollinating medium has little effect on grape.The analysis of OCI and P/O showed that the breeding system of the three varieties was different,which was the same as the behavior of flowering insects.Through the artificial pollination test of the bag,it was shown that Cabernet Gernischt was mainly self-pollinated,and the insect pollination was supplemented,Venus seedless and Ruby seedless grapes are self-pollinated,need pollen to stimulate the stigma to sit fruit.Spraying expanding agent can increase the fruit weight of seedless grape,increase the yield of grape and enhance the taste of grape.