Study On Molecular Identification And Main Physiological Characteristics Of The Early Ripening Mutation In Gala Apple

The morphological characters, fruit quality, photosynthesis characteristics and endogenous hormone content of an early ripening bud mutation in Gala apple were studied with Gala as control. The results were as follows:1. DNA of the early ripening bud mutation and Gala was analyzed based on AFLP data of 80 pairs of primer. And 2945 bands were amplified including 3 polymorphic bands, and 0.101% of the total bands were polymorphism bands. The genetic similarity index between bud mutation and maternal plant was 0.9995, and their genetic distance was 0.0005.2. Biological characteristics of the early ripening bud mutation were studied compared with Gala as the control. The results indicated that the phenological period of the early bud mutation was mainly consistent with Gala but the mature period about 25 days earlier.The bud mutation had shorter tree bodies, more branches and lower growth rate of trunk diameter. The length of internode, the width and thickness of leaf were 1.07, 1.15 and 1.16 times than the control, respectively. There was no difference in the length of branch, leaf and petiole. The length and width of petal, lengthways and transverse of anther diameter, length and diameter of anthocaulus, germination rate of anther, and the size of corolla were 0.87, 1.15, 0.94, 1.14, 0.63, 1.49, 0.70 and 0.87 times than the control, respectively. The average fruit weigth was 206.2 g, which was 25.3% higher than the control. The content of soluble solid, soluble sugar and soluble acid were 13.87%, 5.55% and 0.1%, which was 4%, 9% and 66.6% lower than the control, respectively. The sugar acid ratio was 56, which was 267% higher than the control. The fruit surface was covered with striped red equably. In conclusion, the early bud mutation was a excellent variety with bigger fruit size and higher sugar acid ratio,compared with other varieties matured in the same period.3. Study on photosynthesis characteristics indicated that diurnal changes of net photosynthetic rate, stomatal conductance, transpiration rate and carbon dioxide concentration presented a single peak curve both in the early maturing bud mutation and Gala, and the highest values appeared at 10:00, 10:00, 12:00 and about 12:00, respectively. The whole day net photosynthetic rate, stomatal conductance, transpiration rate were 10.5%, 40%, 25.5% higher than the control, respectively. And the carbon dioxide concentration was 6.2% lower than the control. 4. Study on endogenous hormone content indicated that the content of ABA、ZRs、GAs and IAA in leaf of the early ripening bud mutation were 5.5%, 12.3%, 16.7% and 16.6% lower than those in the control. And the ratio of(IAA+GAs+ZRs)to ABA was 10% lower than the control.