Preliminary Study On Biological Characters And Fruit Qualities Of Introduced Grapefruit

The grapefruit (Citrus paradisi Macf.) a species belonging to the family Rutaceae, is one of the main four citrus groups in the world. In order to amend the structure of the citrus varieties and enrich the fresh fruit resources in China and then find out the excellent varieties suitable for Yunnan growing, we studied preliminarily the grafting propagation, growth and development characters, blossom and fruiting characters and fruit qualities of nine grapefruit varieties introduced from the United States by use of Randomized Experimental Design study ways , and combining with field investigation and observation and laboratory experiment. The results are as follows:1. It is much better to graft the most grapefruit varieties in spring than in autumn. The difference of the survival rate between grapefruit varieties are little on the C. aurantium Linn. Rootstock, but contrary to the local C. grandis Osbeck rootstock. Henderson Ruby and Reed Marsh can be initially determined as having better compatibility if we take the two trees as rootstocks in production and practice. Scion should be grafting as fresh as possible in order to put up the survival rate of graftage.2. The phonological periods of introduced vareities are not changed on the whole, but contrsting with the origin, the phonological periods of grapefruit planted in Puwen is advanced slightly. All the introduced varieties show that they have good ecological adaptation—the fruit are larger, the flesh of fruit is soft and juicy, and the fruit characters are excellent. Make introduced varieties comprehensive assessment, the results showed: Perlist, Reed Marsh, Rio Red, Ray Ruby and Henderson Ruby and Hudson Foster have good adaptation and economical characters. These varieties can be extended in the similar ecological regions; by reason of poor comprehensive nourishment quality, Flame and Star Ruby can be collocation as pollenizers; Genetic Dwarf can not be extended because the vegetative growth period is too long.3. The introduced grapefruit varieties sprout three times in one year. The quantity of treetops sprouted in spring is most largest and the treetops sprouted in spring are the main twigs of bearing fruit. The quantiy of treetops sprouted in summer is fewer than in spring and the twigs and treetops growth is unregular. The quantity of treetops sprouted in fall is also fewer than in spring, but the sprouting time is more indentical. There is a significance of difference in the length of the spring and summer sprouts, but is no significent...