Tree Growth, Productivity, and Fruit Quality Attributes of Pear Grown Under a High-Density Planting System on Heavy Soil. A Case Study

Abstract

During two consecutive years (2014 and 2015) we investigated tree vigour, productivity, and the main physicochemical attributes of Carmen, Kieffer, Santa Maria, and Williams pears grafted on quince BA.29. Results showed that trunk cross-sectional area (TCSA), yield per tree (Y), yield efficiency (YE), and number of fruits per tree (NFT) were significantly affected by cultivar and years, whereas the interaction of cultivar × year influenced only Y and YE. Carmen and Kieffer had the largest trees and Williams the smallest. Santa Maria and Williams had the best productivity attributes (Y, YE, and NFT). In 2015, TCSA and Y were better, whereas YE was higher in 2014. Kieffer had superior fruit weight, fruit width, and surface area, whereas Carmen had the highest fruit length and flesh firmness. Year-by-year variations of physical properties were not significant, with the exception of length/diameter (L/D) ratio and flesh firmness, whereas the interaction of cultivar × year significantly influenced fruit physical properties, except for L/D ratio. Soluble solids content was not influenced by cultivar, year, or their interaction. Titratable acidity and maturity index were highest in fruits of Santa Maria and lowest in Carmen and Kieffer, respectively. Mean acidity content was higher in 2015, whereas maturity index was higher in 2014. The interaction of cultivar × year affected only acidity content. Significant correlations were found among some pear tree, yield, and fruit quality properties. Principal components analysis showed that there are large variations among varieties in terms of agronomic and fruit quality attributes. It can be said that in terms of positive traits of the tree, productivity, and fruit, Williams and Santa Maria can be singled out, while Carmen and, especially, Kieffer are recommended for growing on a small scale in similar conditions.