Foliar Indicators and Sweet Cherry Production Efficiency in Central Leader and Kym Green Bush Training Systems in Chile

Canopy development and production efficiency variations were evaluated in four sweet cherry (Prunus avium L.) cultivars: 'Bing', 'Lapins', 'Sweetheart' and 'Regina', grafted on different vigor rootstocks: 'Colt', 'Cab-6P, 'Maxma-14' and 'Gisela-12', and conducted in two training systems: Central Leader (CL) and Kym Green Bush (KGB), growing in Chile. Leaf indicators were calculated after tree defoliation. A principal components analysis (PCA) was conducted to select indicators that explain the variation among the combinations. Results showed that leaf size and number varied between different cultivar/rootstock combinations and training systems. By means of two principal components, the model employed could explain 72% of the data variability. The most relevant indicators for the PC1 were: leaf weight per hectare (0.98) and leaf area index (0.97), with a significant training system effect, whereas for the PC2 they were: leaf weight per leaf area (0.85) and production per leaf area (0.72), mainly for productive efficiency. In 'Lapins'/'Colt', the KGB system presented a higher weight and leaf area than CL, with almost double the leaf weight per hectare and leaf area index, due mainly to a 37% leaf area per tree and 20% higher tree number/ha in KGB. However, average production per leaf area reached 0.49 kg m(-2), without distinction between training systems.

Automated summary

Leaf size and number varied between different cultivar/rootstock combinations and training systems, with a model explaining 72% of the data variability through two principal components. Relevant indicators for the first component were leaf weight per hectare and leaf area index, showing a significant training system effect, while for the second component they were leaf weight per leaf area and production per leaf area, mainly for productive efficiency.