Effects of grafted seedling on plant growth, yield and quality of watermelon and histological investigation of grafting point

ABSTRACT PhD THESIS EFFECTS OF GRAFTED SEEDLING ON PLANT GROWTH, YIELD AND QUALITY OF WATERMELON AND HISTOLOGICAL INVESTIGATION OF GRAFTING POINT Halit YETİŞÎR DEPARTMENT OF HORTICULTURE INSTITUTE OF NATURAL AND APPLIED SCIENCES UNIVERSITY OF ÇUKUROVA Supervisor : Prof. Dr. Nebahat SARI Year: 2001, Pages: 179 Jury : Prof. Dr. Nebahat SARI Prof. Dr. Kazım ABAK Prof. Dr. Ruhsar YANMAZ Prof. Dr. Sinan ETİ Assist. Prof. Dr. Mustafa PAKSOY The studies were carried out between 1999 and 2001. In this study, effects of different rootstocks on plant growth, plant nutrition uptake, yield and quality and effectiveness of grafting on different rootstocks against Fuasitm wilt were investigated. In this study, 5 open pollinated and 7 Fj hybrids were used as rootstocks. Crimson Tide watermelon cultivar was used as scion. In addition to this, graft compatibility of these rootstocks with watermelon was studied. According to results of three years studies, it was determined that Lagenaria type rootstocks had high level of affinity (95 %) with watermelon. The affinity rates decreased to 60 % Cucurbita type rootstocks. All grafted plants grew faster than control plants, and they had also much more biomass than control. Depending on vegetative growth, it was determined that grafted plants had 200 % more yield than control. When the Fusarium wilt was present, 400 % yield increase was determined in grafted plant. In quality analysis, any significant difference was not found between control and grafted plant except fruit size. According to leaf analysis results, total nutrition uptake was higher in grafted plant than control in all macro and micro elements (specifically in Fe). Rootstocks, scion and grafted plants were tested against known three races of Fusarium oxsyporum f. sp. niveum and it was found that all grafted plant and rootstocks were resistant to all races. On the other hand, C. Tide was found as susceptible to race 2. In histological studies, incompatibility did not found in Lagenaria type rootstocks, in contrast, in grafted plants on C. maxima, C. moschata and their interspecific hybrids, abnormal swelling at grafting point and coiling in vascular bundle were determined. In plants without affinity problem, number and diameter of vascular pipe increased. In the last year of the study, effect of plant density on yield and quality was investigated in grafted watermelon on three bottle gourds and it was found that economical yield could be obtained by 4000 - 5000 plants/ha. Key Words: Rootstocks, grafting incompatibility, resistance to Fusarium, plant growth II