Measurement of physiological parameters with respect to yield
1993
Hadley, P. | Yapp, J.H.H. (Reading Univ., Reading (United Kingdom). Horticulture Dept.)
Presents a framework for analysing yield development in cocoa based on light capture, photosynthetic efficiency and the partitioning of dry matter between vegetative, reproductive and storage components of the tree. This is contrasted with traditional methods for assessing yield potential of cocoa genotypes. Seeks to establish the physiological determinants of growth in juvenile cocoa and yield development in immature and mature cocoa stands. Large variation was detected in net photosynthetic activity of non-bearing cocoa genotypes measured under field conditions. Fast growing clones expressed higher photosynthetic rates: For young, bearing cocoa precocity and yield were linearly related to fractional light interception. For cocoa planted at high density in which canopy closure had occurred yield was related to light distribution through the canopy quantified as light extinction coefficient (K). Canopies with lower K values permitted greater light penetration allowing the lower shade leaves to make a greater photosynthetic contribution to dry matter production. These results are discussed in relation to developing a more rational approach to parental selection for yield potential.
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