Abstract
This study was carried out to develop and produce cucumber inbred lines possessing high level of resistance to the root knot nematodes, Meloidogyne spp. combined with highly commercially acceptable characters. The study was performed under micro-plot and field conditions extending for three successive years (2012-2015) as a complementary phase to a previous breeding program to satisfy the goal of this study. Evaluation for resistance was estimated based on four nematode parameters, viz., root gall index, number of galls, number of egg masses and number of eggs (fecundity). The study included five host cycles in two phases. The first phase included two generations grown in two successive cycles under micro-plot conditions with artificial nematode infestation. The second phase included three generations in three field growing cycles (natural infestation) in Gezerit El-Dahab location, Giza, Egypt. Results showed that level of resistance was gradually increased with the progress in the inbreeding program by selecting the most resistant plants to nematode infection, which were 77.93, 81.35, 97.37, 97.56 and 98% for F-2, F-3, F-4, F-5 and F-6, respectively. The last advanced step in the breeding program yielded three inbred lines, highly resistant to Meloidogyne spp. compared with local variety Beit Alpha. The best inbred line was characterized by outstanding values of flowering characters as number of days to first female flower (33.83 days) compared with (49.93 days) for Beit Alpha. As to yield character, it was 4.83 kg/plant compared with 2.38 kg/plant for Beit alpha. These inbred lines are potentially promising as a good source for producing new hybrids characterized by high nematode resistance level and good yield quantity and quality.