Study on poliination characteristics and hybrid offspring analysis on hickory (Carya cathayensis)

摘要

Hickory (Carya cathayensis) is an important ornamental tree in China. Crossbreeding is carried out with hickory as female parent, pollinating with pecan (C. illinoensis) pollen and other different types of pollen treatments. Fruit set percentage, fruits and seeds characters, pollen germination in vitro and situ and identification of seedling using AFLP and RAPD are studied in order to get pollination characteristics on hickory. The results showed that hickory and pecan pollens were not germination on 14 different components media. Hickory pollens start germinating on the female flower stigma pollinated after 8 h and universal after 24 h using Scanning electron microscopy (SEM). There is a small amount of fruits under cover treatment, without-pollination treatment and 2, 4-D treatment. The rate of fruit setting is the biggest up to 42.2% when female flowers are pollinated with mixed pollen within populations on hickory. Among harvested fruits and seeds, fruit phenotypic characteristics show large variation when pollinating with pecan. Fruits and seeds weight and size are significant difference comparing with the control. The frequency of polyembryony is about 9.04%. Offsprings of C. cathayensis × C. illinoensis are not true hybrids using AFLP and RAPD analysis. The variation of fruits is due to xenia effect. These results suggested that apomixis mechanism might exist on hickory.