Watermelon breeding for root-knot nematode resistance (Meloidogyne incognita) / Rabia Ramadan Ali Ali Elhawagry ; Supervised Khaled Elsayed Ali Abdelati , Abbas Mohamed Kheir , Mohammed Aboulfotouh Mohammed Selim

Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Vegetable

This study was conducted in research facilities of theVegetable Crops Department andDepartment of Zoology and Agricultural Nematology, Faculty of Agriculture, Cairo UniversityandHorticultural Research Instituteduring the period from 2010 to 2016 to evaluate 21 genotypes of Citrullusspp. for level of resistance to root-knot nematode (RKN), Meloidogyne incognita, to evaluate selected genotypes and their intervarietal hybrids, and to identificate nature and inheritance of RKN resistance.The evaluation results showed thatthe five citron PIs 482303, 482379, 270563, 482338 and 500347 of C. lanatus var. citroides had the highest resistance level against M.incognita, while the cultivatedvarieties Sugar Baby, Charleston Gray 133 and Giza 1 were reacted as susceptible hosts to M.incognita. Based on these results, the five resistant accessions (C. lanatus var. citroides) (as male parents) were crossed with the three cultivated watermelon varieties, Sugar Baby, Giza 1 and Charleston Gray 133 (as female parents) in one direction.These 15 F1 hybrids and their parents were evaluated along with the F1 hybrid Aswan as a control during the 2015 and 2016 summer seasons under pot conditions and natural infection in infested and non infested fields.Results showed that the citron PIs 482303 and 482379 were good sources of resistance against the RKN, M.incognita for the development of resistance in watermelon cultivars. The crosses Sugar Baby {u00D7} PI 482303, Sugar Baby {u00D7} PI 482379 and Charleston Gray 133 {u00D7} PI 482379 were rated as resistant hosts against the RKN

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