Leaf Chlorophyll Contents in Some European Pear Cultivars Grafted on Different Rootstocks and Its Relation with Growth and Yield

Abstract

Aim of study: To investigate the effect of different combinations of pear rootstocks and cultivars on the contents of leaf photosynthetic pigments and their relation with some growth and yield characteristics. Area of study: Ondokuz Mayis University, Samsun, Turkiye, in two years, 2021 and 2022. Material and methods: The pear cultivars 'Santa Maria', 'Williams', and 'Deveci' were grafted on eight rootstocks: two quince clonal rootstocks (BA29 and QA), five pear clonal rootstocks (FOX9, FOX11, OHxF333, OHxF87, FAROLD40) and Pyrus communis L. seedlings. Growth and yield attributes were calculated and chlorophyll and carotenoid contents were determined by the spectrophotometric method, using 99.8% methanol solvent for chlorophyll (chl) extraction. Main results: Chl a/b in the case of rootstocks, chl a and total carotenoids in the cultivars were found statistically significant; the ratio chl a/b ranged 1.71-2.30 in the case of rootstocks; in the case of cultivars chl a ranged from 17.77 (cv. 'Santa Maria') to 19.88 (cv. 'Deveci') mu g mL(-1), and carotenoids ranged 0.21-0.95 mu g mL(-1). Under the main impact of cultivars, rootstocks and their combinations, a significant difference was seen in the growth and yield attributes. Research highlights: A negative correlation coefficient was observed between photosynthetic pigments and morphological characteristics; however, the correlation coefficient was positive for canopy volume and annual shoot growth. Canopy management, especially with the use of rootstocks and cultivars that result in weaker growth, is helpful for improving chlorophyll content and yield performances.