小果番茄(Solanum lycopersicum L.)嫁接茄砧及乾旱處理對生育之影響

Abstract

Grafting tomato (Solanum lycopersicum L.) scions onto specific eggplant rootstocks enhances resistance to soil-borne diseases and tolerance of waterlogging stress of plants. However, study on the effects of grafting on fruits under greenhouse environment was limited. Commercial cherry tomato (T) cultivar ‘Jade Girl’ grafted onto ‘EG203’ eggplant (E) were subjected to be investigated for the effects of grafting and drought on plant growth and fruit quality and production. The effects of calcium chloride (CaCl2) solution spray on fruits were also studied. Plant materials used were tomato/eggplant grafted (T/E) in addition to the two controls, tomato self-rooted (T/T) and ungrafted (T) plants. Drought treatment was watered biweekly (D) relative to weekly (CK). When immature fruits were visible, a weekly 30 mL 50 mM CaCl2 spray per plant on fruiting trusses was applied, whereas control plants received none. Grafting had little effect on shoot biomass of young plants, but young T/E plants had smaller leaves with higher chlorophyll meter reading (CMR).The scion base showed overgrowth in flowered T/E plants. T/E plants also had shorter plant height and leaf length, and the lower leaves of T/E abscissed later than T/T and T.Fruit total soluble solids (TSS) and titratable acidity (TA) were increased by grafting for 0.6oBrix and 0.09%, respectively. Grafting had no significant effect on fruit cracking incidence, but it led to lower production, of which the extent of reduction differed between trusses.Drought treatment caused reduction in plant height, leaf length, and leaf relative water content, and increase in CMR of flowered tomato plants. Drought also promoted fruit TSS by 0.6o Brix, having no effect on TA; moreover, fruit cracking incidence and production were both reduced under drought. Drought treatment didn’t significantly affect plant height, leaf length, leaf CMR and relative water content of T/E plants; however, drought yet caused production reduction in T/E plants.According to higher degree of methylene blue dye stagnation below graft union, water transport rate might be slow, causing T/E scion to experience mild drought. CaCl2 spray lowered fruit TA and fruit cracking incidence, increasing marketable production.In corporation with drought treatment, CaCl2 spray reduced cracking incidence from 36% to 8%in T plants; however, fruit cracking in T/E could not be significantly reduced by the treatment.