ISHS Acta Horticulturae 403: International Symposium on Cultivar Improvement of Horticultural Crops. Part 2: Fruit Crops
GENETIC STUDY AND ARTIFICIAL REGULATION OF JUVENILE PERIOD OF CITRUS SEEDLING |
| Authors: | C. Ligeng, C. Keling, Z. Guangyan |
| Abstract:
For many years investigations and statistical analysis were carried out among 4789 individual seedlings, which originated as nucellar seedlings from 14 cultivars and as hybrid seedlings from 21 cross combinations, aiming to learn the genetic backgrounds and the regulation methods of the juvenile period of Citrus seedlings. It was shown that the juvenile period varies with different parent species and cultivars, and the length of juvenile period is a quantitative character controlled by multigenes. Seedlings begin to bear fruit on a definite sequence of branching, and it is 12th for mandarins and 15th for sweet oranges. So the first flower bearing branch sequence is also a genetic character and can be used as morphological information for determining whether the transition from juvenile to adult reaches or not. Among the artificial methods for shortening juvenile period the most efficient was grafting the buds of one year old seedlings on adult fruit bearing trees, which could reduce the juvenile period for 2 to 4 years. It was futile applying the plant growth regulators to seedlings under age of 3 to shorten the juvenile period. To some extend the seedlings could begin to blossom earlier if they were girdled and treated with regulators after age 4. | |
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