INFLUENCE OF LEAF SHADING AND DEFOLIATION ON OIL SYNTHESIS AND GROWTH OF OLIVE FRUITS

The relative growth rate (RGR) of the endocarp was higher than that of the mesocarp until mid August, then it was clearly lower. The growth of the seed was high during the first fruit growth stage, then it remained at the level of mesocarp growth with a large reduction during the last two months. As a consequence the flesh/pit ratio (d.w./d.w.) was reduced to 0.5 at mid August and afterwards it increased to the final value of 1.2. The oil synthesis was continuous from the end of July to January. The shading of main branches for a month from the first days of July caused a very large fruit and leaf drop and a reduction in endocarp dry weight while increased the flesh/pit ratio and the percentage of oil in the fruits. The shading from July to October caused similar effects on fruit growth, but with little difference in the flesh/pit ratio. The flesh/pit ratio and the oil content drastically dropped with shading through December or for different periods from August onwards. The defoliation of main branches, carried out at the end of July, reduced the flesh/pit ratio in spite of the reduction in endocarp weight. The variation of "source" level, even in a restricted zone close to the fruit, influences the growth of fruit tissues that exhibit the most intense growth, changing the ratio between the fruit parts with the possibility of enhancing the assimilate repartitioning towards organs more useful for production. It is necessary to apply treatments that have no negative collateral effects.

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