Screening of peach rootstock hybrids for resistance to root-knot nematode

Abstract

Two peach genotypes ‘Sharbati’ and ‘Flordaguard’ were crossed to develop F1 hybrid rootstocks and subsequently tested for resistance against root-knot nematode. Minimum reduction in plant height after 120 days of nematode inoculation was recorded in Flordaguard (11.07%), it was followed by Sharbati × Flordaguard (16.73%). Sharbati × Flordaguard seedlings inoculated with nematode juveniles had high plant height, root length, leaf chroma, ‘b’ values, hue angle, leaf size and leaf area. Flordaguard seedlings had higher shoot dry weight, ‘a’ value, spad values, petiole length and leaf number but, lower plant height, leaf area, leaf size, chroma values, hue angle. Hybrid seedlings from both the cross combinations had dark red coloured young leaves, a trait from Flordaguard. Number of juveniles penetrated the root system was negatively correlated with shoot dry weight, internodal length, leaf number, petiole length, spad values, ‘a’ value shoot dry weight and positively correlated with ‘L’value, ‘b’ value, chroma and hue angle. The highest number of juvenile penetration per root system was recorded in Sharbati with (38 juvenile per roots system) followed by seedlings of Sharbati × Flordaguard (15 juvenile per root system) and Flordaguard × Sharbati (11 juveniles per root system). Shoot dry weight, internodal length, petiole length, spad values, ‘a’ value, and hue angle vary among the hybrid seedlings with lower nematode population and root penetration whereas higher nematode population and root penetration were abserved among the seedling population. These characters can be used to assess nematode tolerance/resistance in peach hybrid seedlings.