Peach Flower Reaction to Inoculation with Monilinia Fructicola(Wint.) Honey

Abstract

Brown rot, caused by Monilinia fructicola(Wint.) Honey, is one of the main fungal diseases of stone fruit ( Prunusspp.). Flower infection can cause significant damage to the trees, reducing the number of flowers, decreasing fruit set, and also providing a source of spore inoculum for fruit infection. The objective of this work was to study the reaction of peach flowers from different genotypes to M. fructicola; identify possible sources of resistance; and determine the frequency of distribution of seedlings from several progenies in different classes of infection incidence. Six cultivars, one selection, and six progenies, originated by crosses among them, were tested in 2001 and 2002. Flowers were inoculated with 0.1 ml of a 5 × 10 ⁴spores/ml suspension and maintained under controlled environment at 24°C ± 2°C, 75 to 85% relative humidity, and 12 hour photoperiod. The percentage of infected blossoms (showing petals with necrotic spots) was evaluated 72 hours after inoculation. Cultivars Magno and Leonense were infected the least; eleven seedlings within the tested progenies also showed good resistance levels (≤ 10%). However, further studies are needed for final conclusions. A transgressive inheritance was observed in the studied progenies. The broad sense heritability for blossom blight due to M. fructicolawas relatively low (H = 0.30 - 0.42).