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Fruit melanotic ringspot (FMRS) – a disease of resistant Capsicum genotypes infected with Tomato spotted wilt virus (TSWV) on the fruits
64-69Views:64Etiology of pepper fruit melanotic ringspot (FMRS) disease (Salamon, 2009) was studied on fruit samples collected in forced pepper populations. It was noticed that in spite of heavy thrips (Frankliniella occidentalis) infestations and of TSWV epidemy detected in the forcing houses, FMRS occurred only in plants having healthy foliage. Symptomatological surveys strongly suggested that FMRS appeared exclusively in specific pepper genotypes. The size of melanotic ringspots has been observed to grow at room temperature during postripening of diseased fruits. A mechanically transmitted plant virus was isolated from symptomatic parts of 9 white pepper fruits affected by FMRS. On test plants each of the virus isolates caused systemic symptoms characteristic to TSWV. Using cDNA/PCR technique and TSWV N-gene specific primers a ca. 300 bp long DNA fragment has been amplified from total nucleic acid extracted from symptomatic tissues but never from asymptomatic parts of the fruits showing FMRS. Plant progenies grown from seeds of FMRS diseased fruits segregated in respect of resistance and/or susceptibility to TSWV infection. TSWV was also detected in and isolated from three fruits showed non-melanotic yellow rings (one of them was infected with a tobamovirus, too). Seedlings derived from these fruits proved to be susceptible to TSWV. Based on the above results we could conclude that the FMRS disease developed on fruits of “cecei” type white peppers that carry a TSWV resistance gene, most likely the Tsw gene in heterozygous form. These fruits were infected with thrips transmitted TSWV and FRMS appeared as a hypersentive reaction (HR) manifested in fruits.
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Rheological evaluation of industrial tomato
137-140Views:119Today, tomato has the second largest harvesting area globally, and the fourth largest in Hungary. The importance of industrial tomato is growing year by year, and one of the most important tasks is to satisfy the needs of the industry. To meet these needs, the producer has to find the proper genotype, which can achieve up to 100 t ha-1 crop yield. This quality has high importance to be researched.
The experiment was carried out in the Botanical and Exhibition Garden of the University of Debrecen, with 3 examined genotypes. The planting date was 3 of May 2018. The harvesting was two-threaded. On 27 of July the physical parameters – fruit shape index (length/diameter), firmness (kg cm-2), water-soluble dry matter content (Brix%) and weight of the berries (g) – were evaluated. On 15 of August the rheological parameters were examined – the force needed to tear the skin – bioyield point (g) and flesh firmness (g).
The fruit shape index was oval (between 1.19 and 1.24) for all the examined genotypes. The firmness was between 0.92 (UG1122713 F1) and 1.05(Prestomech F1) kg cm-2, which compliance the needs of the industry. The water-soluble dry matter content was suitable, with a value between 4.49 (Prestomech F1) and 4.65 (UG1122713 F1) Brix%. The weight of the berries was between 45.94 (UG989 F1) and 49.37 (Prestomech F1) g per piece.
The bioyield point was between 76.00 (UG1122713 F1) and 85.16 (UG989 F1) g. The flesh firmness was between 33.68 (UG1122713 F1) and 42.81 (UG989 F1) g.
Finally, we can conclude based on the obtained data that the UG989 F1 hybrid was the most proper for the applied cultivation conditions. This genotype can be recommended for the farmers even in extreme weather conditions.