ISHS Acta Horticulturae 636: XXVI International Horticultural Congress: Key Processes in the Growth and Cropping of Deciduous Fruit and Nut Trees
FRUIT DEVELOPMENT IN DECIDUOUS TREE CROPS AS AFFECTED BY PHYSIOLOGICAL FACTORS AND ENVIRONMENTAL CONDITIONS (KEYNOTE) |
| Authors: | L. Corelli-Grappadelli, A.N. Lakso |
| Keywords: | fruit growth, cell division, cell expansion, modelling, carbon balance, temperature, light, apple, peach |
| Abstract:
This paper focuses on the processes occurring in the fruit between the stages of fertilization and harvest, with particular emphasis on some physiological, energetic and modelling aspects affecting the growth of this organ. As fruits transition from flower to actively growing fruitlets, cell division sets the basis for final fruit size, which is the result of the product cell number x cell volume. If cell volume is relatively constant, a fruit with more cells should be larger at harvest. The importance of the cell division phase has been confirmed in apples, which show some degree of correlation between fruit growth during this early stage and final fruit size. Fruit growth rates have in turn been correlated to daily temperature regimes: warmer temperatures can induce faster growth in the initial stages, and can thus result in larger fruit at harvest. Cell volumes may also vary in fruits adding variation to final size. The interplay of length of season and temperature regimes needs to be integrated with other factors that influence fruit development; in particular the type of leaves that support fruit growth, light microclimate, crop load, vegetative growth and changes in the fruit anatomy/physiology. Along with endogenous hormones, nutrients and water relations involved in the control of fruit growth, the plant carbon balance plays a major role. The energy required for fruit growth can be expressed by its cost of production per gram of fruit, which is often fairly constant during most of the growing season. The cost of production of organs provides a useful expression for comparison with photosynthetic energy production. In conclusion, there are many factors capable of influencing the growth of the fruit, and also the quality attributes that the fruit attains after harvest. Knowledge and integration of these factors is important if the goal is to produce large amounts of top quality fruit. | |
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