Breeding Cucumber (Cucumis sativus L.) for Spotted Spider Mite (Tetranychus urticae) Resistance

Tetranychus urticae (Koch) is important pests of cucumber (Cucumis sativus L.). In this context, the aim of this study was finding resistance sources in ten cucumber accessions from different genetic resources (3 from Gene bank in Netherland, 4 from Nord Gene bank in Sweden and 3 from Main Vegetables and Hybrids Production Project in Egypt). The evaluation of resistance to T. urticae (Koch) and bitter taste in the inbred lines was carried out under greenhouse in the Department of Vegetables Crops, HRI, Dokki, Giza, during April - May 2017. INDIA-110, CHINA-86 and EGY-118 inbred lines showed the least number of eggs and adults and less damage for T. urticae infection per leaf, EGY-112, EGY-114 and CHINA-117 inbred lines showed low infection and resistance. The other inbred lines showed highly infection. The evaluations for bitter showed that foliage of five inbred lines were bitter, INDIA-110 and CHINA-86 (high resistance), EGY-112 and CHINA-117 (resistance) and GUTA-105 (susceptible). The other inbred lines were bitter free where two of them were high resistant and resistant, (EGY-118 and EGY-114, respectively. INDIA-110, CHINA-86 and EGY-118 were selected as resistant parents to produce 6 hybrids using half-diallel mating design during July 2017. The results indicated that CHINA-100 and its hybrids were highly infected. On the other hand, INDIA-110, CHINA-86 and EGY-118 as well as their hybrids were high resistant. These results refer that the crossing between resistant × resistant is good specific combiner. The results of bitter taste showed that bitterness is dominance in all resistant hybrids. The other genetic studies for horticultural traits showed that EGY-118 inbred line appears good general camping.