• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.212-217
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• 2019

Bacterial wilt caused by Ralstonia solanacearum is a major disease that affects tomato plants widely. R. solanacearum is a soil born pathogen which limits the disease control measures. Therefore, breeding of resistant tomato variety to this disease is important. To identify the susceptible variety, degree of disease resistance has to be determined. In this study, micro sap flow sensor is used for accurate prediction of resistant degree. The sensor is designed to measure sap flow and water use in stems of plants. Using this sensor, the susceptibility to bacterial wilt disease can be identified two to three days prior to the onsite of symptoms after innoculation of R. solanacearum. Thus, this find of diagnosis approach can be utilized for the early detection of bacterial wilt disease.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.557-567
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• 2012

This study was conducted to achieve basal information for the development of tomato cultivars with disease resistances through marker-assisted backcross (MAB). Ten inbred lines with TYLCV, late blight, bacterial wilt, or powdery mildew resistance and four adapted inbred lines with superior horticultural traits were collected, which can be useful as the donor parents and recurrent parents in MAB, respectively. Inbred lines collected were evaluated by molecular markers and bioassay for confirming their disease resistances. To develop DNA markers for selecting recurrent parent genome (background selection) in MAB, a total of 108 simple sequence repeat (SSR) primer sets (nine per chromosome at average) were selected from the tomato reference genetic maps posted on SOL Genomics Network. Genetic similarity and relationships among the inbred lines were assessed using a total of 303 polymorphic SSR markers. Similarity coefficient ranged from 0.33 to 0.80; the highest similarity coefficient (0.80) was found between bacterial wilt-resistant donor lines '10BA333' and '10BA424', and the lowest (0.33) between a late blight resistant-wild species L3708 (S. pimpinelliforium L.) and '10BA424'. UPGMA analysis grouped the inbred lines into three clusters based on the similarity coefficient 0.58. Most of the donor lines of the same resistance were closely related, indicating the possibility that these lines were developed using a common resistance source. Parent combinations (donor parent ${\times}$ recurrent parent) showing appropriate levels of genetic distance and SSR marker polymorphism for MAB were selected based on the dendrogram. These combinations included 'TYR1' ${\times}$ 'RPL1' for TYLCV, '10BA333' or '10BA424' ${\times}$ 'RPL2' for bacterial wilt, and 'KNU12' ${\times}$ 'AV107-4' or 'RPL2' for powdery mildew. For late blight, the wild species resistant line 'L3708' was distantly related to all recurrent parental lines, and a suitable parent combination for MAB was 'L3708' ${\times}$ 'AV107-4', which showed a similarity coefficient of 0.41 and 45 polymorphic SSR markers.