Morphological and chemical markers associated with Acyrthosiphon pisum tolerance in hybrid pea lines

Abstract

Aim of study: Determining morphological and chemical markers in hybrid lines of winter forage pea (Pisum sativum subsp. arvense L.) associated with Acyrthosiphon pisum tolerance for breeding programs.Area of study: The experimental field of the Institute of Forage Crops, Pleven, Bulgaria, during the 2016-2018 period.Material and methods: Six hybrid lines of winter forage pea were studied for tolerance to A. pisum. The field trial was conducted using a long-plot design and a natural background of soil (leached chernozem) supplied with major nutrients. An entomological net for sweeping was used once a week for aphid number recording. Stem height and leaf number were recorded and chemical composition was determined at the flowering stage. The coefficient of variation concerning aphid density was calculated and the stability and adaptability of lines was evaluated.Main results: Hybrid lines 6 and 12A were stable, widely adapted to the changing environmental conditions and the aphid density was statistically the lowest (31.1 and 36.8 individuals/m2, respectively). A significant positive interaction was found between aphid density and plant height, leaf area, protein, and phosphorus content. Lines 6 and 12A had lower stems (74.7 and 82.5 cm), smaller leaf areas (571.13 and 657.39 cm2/plant), lower protein and P contents, and these markers defined them as aphid tolerant.Research highlights: Incorporation of plant markers of pea lines, less preferred by aphids, is an efficient tool for improving breeding programs for aphid resistance.