| The resistance of tomato commercial cultivars and rootstocks to common soil-borne diseases was studied. The control efficacy of grafted tomato on root-knot nematode (Meloidogyne spp.) disease and the soil -borne disease was investigated in field experiment and the economic benefit of this technology was evaluated. The main results were as following.(l)Three tomato commercial cultivars (cv. Cuore Di Bue, Tropic VF, Marmande RAF) were susceptive to these pathogens, Rhizoctonia solani. Sclerotium rolfsii, Phytophthora nicotianae Verticillium dahliae, Fusarium oxysporum f.sp.radicis lycopersici Fusarium oxysporum f.sp.lycopersici.(2)Sixrootstocks (Energy, Spirit, He Man, Beaufort, AX105, AL1612 )were resistant to pathogens, Verticillium dahliae .Fusarium oxysporum f.sp.radicis lycopersici Fusarium oxysporum f.sp. lycopersici and susceptive to pathogens, Rhizoctonia solani, Sclerotium rolfsii . Phytophthora nicotianae.(3)The local tomato cultivar-Maofen 802 was the most sensitive to root knot nematodes (Meloidogyne incognita) and medium sensitive to Fusarium wilt (Fusarium oxysporum f.sp. lycopercisi), cv. Jasia was resistant to root knot nematodes but sensitive to Fusarium wilt, cv. FA-516 was tolerant to root knot nematodes and medium sensitive to Fusarium wilt. The tomato rootstock - Beaufort was tolerant to root knot nematodes and Fusarium wilt, He Man and energy were resistant to root knot nematodes and Fusarium wilt. The root exudates of rootstocks-Energy and Beaufort could restrain the growth of the mycelia of Fusarium oxysporum f.sp. lycopercisi ,and the percent of inhibition were 17.35% and 23.14%.(4)The disease indices of tomato root knot nematode was the highest while the soil water percentage was 8.98% and then decrease while the soil water percentage was higher than 26.27%. Tomato could be infected by root knot nematodes at low level of soil water (<3.90%),but that need longer time (about 2 months) with a lower disease indices.(5)There was a significant difference between the nematode disease index of grafted tomato with resistant rootstock and that of no grafted tomato. The grafted tomatoes with resistant rootstock beaufort (Lycopersicon lycopersicum x L. Hirsutum) could resist the root-nematode( Meloidogyne spp.). Disease indices of grafted tomatoes in the 5 plots (MB, MS , MB+VIF MS+VIF and SS+BCA) were zero. The disease index of grafted tomato (8.4%) was far lower than that of no grafted tomato (95%). There was no significant difference in disease indices among the four chemical fumigation approaches. The yield of no grafted tomato in chemical fumigation plot was higher than in CK plot.(6) At the same treatment plot, the yield of grafted Maofen was 22.0%-102.0% higher than that of Maofen. Compared with Maofen, the yield of grated Maofen at control plot increased 102.0% to 50,756kg/hm2, at SS + BCA plot it increased 101.4% to 50,539kg/ hm2, at MB and MB + VIF plots the yield of grafted Maofen increased 22.0% and 24.9% to 19,577kg and 21,319kg respectively. And at the other two plots of MS and MS+VIF, the yield of grafted plots increased 25.0% and 22.1% to 20,566kg/hm2 and 18,401 kg/hm2.All the treatments of MS, MS+VIF, MB, MB+VIF could control the root knot nematodes significantly, the crop yields of these treatment increased more than 30,000kg/hm2, increased production rate was about 40%. On the contrast, the effect of SS+BCA treatment to control root knot nematode was relatively low, crop yield just increased 0.2%, increased production was 75 kg/hm2.(7)The tomatoes grafted on the rootstocks-beaufort which has resistance to root-knot nematode were shorter and stronger and more orderly and had higher flowering rate than no grafted tomatoes. There was no significant difference between total soluble solid (TSS) of grafted tomato and no grafted tomato. The average fruit weight, similarly, had no significant difference between treatments from Jan. to Mar. for both cultivars respectively. However it was found that in the second harvesting stage (from April to May), a... |
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