摘要
Fusarium wilt is a major disease of watermelon (</span><i><span style="font-family:Verdana;">Citrullus</span></i> <i><span style="font-family:Verdana;">lanatus</span></i><span style="font-family:Verdana;">) caused by </span><i><span style="font-family:Verdana;">Fusarium</span></i> <i><span style="font-family:Verdana;">oxysporum</span></i><span style="font-family:Verdana;"> f. sp. </span><i><span style="font-family:Verdana;">niveum</span></i><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">Fon</span></i><span style="font-family:Verdana;">). Use of host resistance is the most </span><span style="font-family:Verdana;">effective management strategy for the disease, and a major objective for breeding programs. Screening assays rely on the ability to discriminate resistant and susceptible genotypes in segregating populations. However, complex</span> <span><span style="font-family:Verdana;">interactions between </span><i><span style="font-family:Verdana;">Fon</span></i><span style="font-family:Verdana;"> and the soil environment can influence symptom development and disease severity rating. In the current study, severity of Fusarium wilt (race 1) in sand-peat (1:1 v/v), sand-perlite (1:1), sand-peat-vermiculite (4:1:1), </span></span><span style="font-family:Verdana;">peat-perlite (1:1) and Fafard 3B potting media was compared among five watermelon cultivars: Calhoun Gray (resistant), </span><span style="font-family:Verdana;">SunSugar (resistant), Allsweet (moderately resistant), Sugar Baby (susceptible) and Charleston Gray (susceptible). Plant biomass (average dry weight/plant) was lowest in peat-perlite (1.67</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">g) </span><span style="font-family:""><span style="font-family:Verdana;">and sand-peat (2.16 g), and was significantly different (</span><i><span style="font-family:Verdana;">α</span></i><span style="font-family:Verdana;"> = 0.05) from that of sand-perlite (3.48 g), sand-peat-vermiculite (4.94 g) and Fafard 3B (6.90 g). Conversely, disease severity [area under disease progress curve (AUDPC)] across cultivars was significantly higher in peat-perlite (AUDPC = 62.96) and sand-peat (AUDPC = 40.87), than in sand-perlite (AUDPC = 11.55), sand-peat-vermiculite (AUDPC = 10.67) and Fafard 3B (AUDPC = 9.29). Consistent discrimination (</span><i><span style="font-family:Verdana;">α</span></i><span style="font-family:Verdana;"> = 0.05) of resistant and susceptible cultivars was realized in sand-peat-vermiculite and Fafard 3B, but was not possible in peat-perlite, sand-peat and sand-perlite. Collectively, these findings support suitability of sand-peat-vermiculite and Fafard 3B for routine screening of Fusarium wilt resistance in watermelon.
Fusarium wilt is a major disease of watermelon (</span><i><span style="font-family:Verdana;">Citrullus</span></i> <i><span style="font-family:Verdana;">lanatus</span></i><span style="font-family:Verdana;">) caused by </span><i><span style="font-family:Verdana;">Fusarium</span></i> <i><span style="font-family:Verdana;">oxysporum</span></i><span style="font-family:Verdana;"> f. sp. </span><i><span style="font-family:Verdana;">niveum</span></i><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">Fon</span></i><span style="font-family:Verdana;">). Use of host resistance is the most </span><span style="font-family:Verdana;">effective management strategy for the disease, and a major objective for breeding programs. Screening assays rely on the ability to discriminate resistant and susceptible genotypes in segregating populations. However, complex</span> <span><span style="font-family:Verdana;">interactions between </span><i><span style="font-family:Verdana;">Fon</span></i><span style="font-family:Verdana;"> and the soil environment can influence symptom development and disease severity rating. In the current study, severity of Fusarium wilt (race 1) in sand-peat (1:1 v/v), sand-perlite (1:1), sand-peat-vermiculite (4:1:1), </span></span><span style="font-family:Verdana;">peat-perlite (1:1) and Fafard 3B potting media was compared among five watermelon cultivars: Calhoun Gray (resistant), </span><span style="font-family:Verdana;">SunSugar (resistant), Allsweet (moderately resistant), Sugar Baby (susceptible) and Charleston Gray (susceptible). Plant biomass (average dry weight/plant) was lowest in peat-perlite (1.67</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">g) </span><span style="font-family:""><span style="font-family:Verdana;">and sand-peat (2.16 g), and was significantly different (</span><i><span style="font-family:Verdana;">α</span></i><span style="font-family:Verdana;"> = 0.05) from that of sand-perlite (3.48 g), sand-peat-vermiculite (4.94 g) and Fafard 3B (6.90 g). Conversely, disease severity [area under disease progress curve (AUDPC)] across cultivars was significantly higher in peat-perlite (AUDPC = 62.96) and sand-peat (AUDPC = 40.87), than in sand-perlite (AUDPC = 11.55), sand-peat-vermiculite (AUDPC = 10.67) and Fafard 3B (AUDPC = 9.29). Consistent discrimination (</span><i><span style="font-family:Verdana;">α</span></i><span style="font-family:Verdana;"> = 0.05) of resistant and susceptible cultivars was realized in sand-peat-vermiculite and Fafard 3B, but was not possible in peat-perlite, sand-peat and sand-perlite. Collectively, these findings support suitability of sand-peat-vermiculite and Fafard 3B for routine screening of Fusarium wilt resistance in watermelon.
作者
Geoffrey Meru
Cecilia McGregor
Geoffrey Meru;Cecilia McGregor(Horticultural Sciences Department and Tropical Research & Education Center, University of Florida, Homestead, FL, USA;Institute of Plant Breeding, Genetics & Genomics and Department of Horticulture, University of Georgia, Athens, GA, USA)
