Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
Vegetable Grafting for Managing Soil Borne Diseases
Narayan Chawda
VNR Seeds, Village Gomchi (Near nandan Van), P.O. Tendua, Raipur- 492 099 (Chattisgarh)
Growing grafted vegetables was first launched in Japan & Korea in the late 1920s by
grafting water melons to gourd root stocks. After the first trial, the cultivated area of grafted
vegetables, as well as the kinds of vegetables being grafted, has been consistently increased. At
present, most of the watermelons (Citrullus lanatus), melons (Cucumis melo), green house
cucumbers (Cucumis sativus), and several solanaceous crops are grafted before being
transplanted in the field or in green house. The purpose of grafting also has been greatly
expanded, from reducing infection by soil borne diseases caused by pathogens such as Fusarium
oxysporum to increasing low- temperature and soil and wet-soil tolerance, enhancing water and
nutrient uptake, and increasing plant vigour and extending the duration of economic harvest time
among other purposes. Growing grafted vegetables, compared to growing grafted trees, was
seldom practiced in the United states or in other western countries where land use is not intensive,
i.e., proper crop rotation is being practiced. However, it is highly popular in some Asian and
European countries where land use is very intensive and the farming area is small.
DAMAGE FROM CONTINUOUS CROPPING: Under continuous cropping were caused by soilborne
diseases and nematodes. Since soil sterilization can never be complete, grafting has
become an essential technique for the production of repeated crops of fruit-bearing vegetables.
OBJECTIVES OF VEGETABLE GRAFTING: The main objective of vegetable grafting is to avoid
soil-borne diseases such as Fusarium wilt in Cucurbitaceae (Cucumber,melons etc.) and bacterial
wilt in Solanaceae (Tomato,pepper etc.).
Grafting's early purpose was to avoid or reduce the soil borne disease caused by F.
Oxysporum, but the reasons for grafting, as well as the kinds of vegetables grafted, have
increased dramatically. Watermelons, other melons (Cucumis spp.), cucumbers, tomatoes
(Lycopersicon esculentum Mill.) and eggplants (Solanum melongena L.) are commonly grafted to
various rootstocks. Numerous rootstocks also have been developed. Watermelons are commonly
grafted to gourds (Lagenaria siceraria) or to inter-specific hybrids (C.maxima x C. Moschata).
Cucumbers are frequently grafted to Figleaf gourd (C. Ficifolia) or inter-specific hybrid (C. Maxima
x C. Moschata)
Eggplants and relatives can be used as rootstocks for tomato. The Asian Vegetable
Research and Development Centre (AVRDC) develops S. melongena rootstock resistant to water
logging as well as bacterial wilt and other soil borne diseases for grafting tomatoes. However,
many rootstocks having distinctive characteristics are available today, and growers select the
rootstocks, they think are the most suitable for their growing season, cultivation methods, (field or
green houses) soil type and the type of crops and cultivars. For example, cucumber grown in
green houses during the cool season, should be grafted onto Figleaf gourd; however, those grown
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