Uncommon disorders and decay in near-isogenic lines of melon and reference cultivars

Abstract

uring recent years, melon export f r o m B r a z i l h a s i n c r e a s e d dramatically in terms of quantity and cultivar diversity (Sales et al., 2004; Souza et al., 1994; Nunes et MARTINEZ JA; JOWKAR MM; OBANDO-ULLOA JM; VARÓ P; MORENO E; MONFORTE AJ; FERNÁNDEZ-TRUJILLO JP. 2009. Uncommon disorders and decay in near-isogenic lines of melon and reference cultivars. Horticultura Brasileira 27:505-514. Uncommon disorders and decay in near-isogenic lines of melon and reference cultivars ABSTRACTPostharvest disorders and rots can produce important economic losses in fruits stored for long time for exportation. The genetic and physiological basis of some disorders in melon (Cucumis melo L.) are unknown and particularly the possible relation with climacteric behavior. A collection of melon near-isogenic lines (NILs) (SC3-5 and seven more showing climacteric and two non-climacteric ripening pattern) were analyzed to study genetic and physiological aspects of fruit disorders and rots. Two non-climacteric (Nicolás; Inodorus Group; and Shongwan Charmi PI161375, Conomon Group) and two climacteric cultivars (Fado, Reticulatus Group; Védrantais, Cantaloupensis Group) were used as reference. The field was divided in eight blocks containing one three-plant replication for each NIL, two for the parental cultivar Piel de Sapo and one or two for the reference cultivars. Replications evaluated were more than six in the cultivars studied. Plant problems included aphids, powdery mildew, and leaf wind injury. Preharvest fruit disorders included whole fruit cracking in cultivar Védrantais and NIL 5M2, and stylar-end cracking in cultivar Fado. Climacteric NILs with yellow skin were particularly affected by over-ripening, stylar-end cracking, and sunburn during cultivation. At harvest, two NILs showed slight placental tissue necrosis which was inherited from SC and were also detected after storage. Other uncommon disorders seen at harvest or 30 days after storage at 8 o C included warted skin (scarring), flesh discoloration (light brown or translucent areas), hollow flesh disorder, and deep furrow netting inherited from SC. Less common rots included grey mould, bacterial soft rot, Penicillium rot, cottony leak and internal Cladosporium rot. Stylar-end hardness below 20 N·mm -1 was associated with cracking and softening. The incidence of the disorders and rots was too low to confirm that the genetic component played a role in their development.

Pre- and Postharvest Muskmelon Fruit Cracking: Causes and Potential Remedies

“…1L and 3G) containing introgressions in linkage groups (LG) VII or X of melon. Round-shaped melons also tend to be less susceptible to splitting than the oblong-types (Martínez et al, 2009).…”

“…Splitting is an extreme form of cracking in which the cracks penetrate deep into the flesh (Opara, 1997). Melon fruit cracking or splitting around the distal (blossom-end) or at the peduncle (stem-end) has been visually documented in historical paintings (Janick and Paris, 2006), where fruit cracking at blossom-and stem-ends is apparently associated with postclimacteric senescence, as a seed dispersal mechanism (Corbacho et al, 2013;Fernández-Trujillo et al, 2008;Martínez et al, 2009;Vrebalov et al, 2009). Usually moderate to severe symptoms of blossom-end breakdown (Fig.…”

“…4A) (Fernández-Trujillo et al, 2007). Deep suturing is a heritable trait in melons and is frequently expressed in progeny when sutured cultivars are crossed with nonsuturing cultivars (Martínez et al, 2009). Ample field observations have shown that some NILs for suturing tend to be more susceptible to splitting compared with the parental controls such as the PStypes, SC7-2 (Figs.…”

“…4H) are more susceptible to blossom-end cracking ( Fig. 5F and G) due in part to dehiscence (Martínez et al, 2009). Also, the former NILs contained quantitative trait loci (QTLs) in LG III and VI that induce climacteric ripening and also interact epistatically to induce advance in ethylene biosynthesis (Vegas et al, 2013).…”

“…Other melon cultivars have also been shown to be susceptible to splitting (Corbacho et al, 2013;Martínez et al, 2009;Schultheis and Jester, 2005). These include: 'Arava' [C. melo Reticulatus Group (Syngenta/Zeraim Gedera, Revadim, Israel)], Charentaistype melons (Fig.…”