Influence of the Number of Reserved Fruit on Fruit-bearing Branch of Early-maturing Citrus unshiu Marc. on Fruit Growth and Development

In order to provide theoretical references for early-maturing Citrus unshiu Marc. in terms of fruit thinning, timely fertilization and harvesting, as wel as for for-mulation of of Early-maturing Citrus unshiu Marc. Cultivation Technique Standards in Guizhou Province, the dynamic changes of fruit longitudinal diameter and trans-verse diameter of 11-year-old and 12-year-old early maturing Citrus unshiu Marc. were tested in two consecutive years and the effects of single-fruit bearing branch on fruit growth and development were compared. The results showed annual varia-tion of longitudinal and transverse diameter of the fruit in Guizhou grew faster at the beginning and then slowed down gradual y, maintaining a slow-growth period after October; the growth curve final y was flat in mature stage. General y, the growth and development stage of fruit showed four growth peaks, showing an in-creasing S-shape curve and fruit net increase also had four growth peaks with a double S-shape curve. Specifical y, longitudinal diameters growth alternated with transverse diameter growth and the former proved much stronger. In terms of ef-fects of single-fruit bearing branch on longitudinal and transverse diameter growth, the number of reserved fruits had direct effects on the growth, net increase of weight, time of growth peak, fluctuation and the number of growth peak. The growth and development, and quality of fruits in the treatments with two or three fruits re-served on single fruit-bearing branch proved better compared with the control with four left fruits. It suggested that early June and early July are the best time for fer-tilization of early-maturing Citrus unshiu Marc. in Guizhou Pprovince and would have better effect if combined with foliage spraying. The suitable harvest time is in the end of October. The preferred number of reserved fruit on single fruit-bearing branch is 2-3. In actual production, the implementation of flower and fruit thinning should also takes tree age, balance of tree vigor, strength of fruit bearing branch, alternate bearing phenomenon and other factors into consideration.

Study on the Control Technique of "On" and "Off" Years of Early Maturing Citrus unshiu

In order to change the universal phenomenon of alternate bearing of early- grown Satsuma orange （Citrus unshiu Marc.） in north Guizhou province, and provide references for setting scientific cultivation techniques and rational management mea- sures for Satsuma orange gardens, cultivation techniques for controlling alternate bearing of the early-grown Satsuma orange were tested and optimized for 7 years （2005 to 2011）. The results showed that production of local early-grown Satsuma or- ange orchards could be significantly improved through the application of cultivation techniques such as rational trimming, strengthening soil, fertilizer and water manage- ment, conducting flower and fruit management pertinently, effective and comprehen- sive control of disease and insects. The yield difference between ＂on＂ and ＂off＂ years was 10%-15%, and the orchards with serious alternate bearing phenomenon were changed into the one with high and stable yield. Meanwhile, the commercial rate of early-grown Satsuma orange fruit enhanced, leading to good economic benefits.