1. Drainage Requirements in Tomato NextPreviousEnd

2. NextPreviousEnd Introduction: For tomato, irrigation should be so arranged that the soil remaining moderately moist. Any thing above 30 cm irrigation depth significantly reduced the yield as well as quality. Alvino et al (1986) found that high irrigation levels do not increase the yield of tomato but depress the quality. During summer irrigation at intervals of 3-4 days is necessary while in winter 10-15 days interval is sufficient. Excessive moisture in soil induces the plant to vine and drop off the blossoms.

3. NextPreviousEnd Rudich et al., (1977) found that frequent irrigation at the time of fruit expansion had an adverse effect on fruit expansion had an adverse effect on quality of tomato fruits by significantly reducing the TSS viscosity and increasing the acidity of fruit juice. Most vegetables are highly sensitive to flooding and genetic variation with respect to this trait is limited particularly in tomato (Dela Pena and Hughes 2007). Just like other vegetables the production of tomato also is limited during rainy season due to excessive moisture brought about by heavy rains.

4. NextPreviousEnd In general damage to the crop by flooding is due to reduction of oxygen in root zone which inhibits aerobic process. The rapid development of epinastic growth of leaves is a characteristic response of tomatoes to water logged conditions and the role of ethylene accumulation has been implicated. Low oxygen levels stimulated an increased production of an ethylene precursor 1- amino cyclo propane 1- carboxylic acid (ACC) in the roots. Flooded tomato plants accumulate endogenous ethylene that causes damage to the plants (Drew 1979).

5. NextPreviousEnd The severity of flooding symptoms increases with rising temperature; rapid death of tomato plants is usually observed following a short period of flooding at high temperature (Kuo et al.,1982). It was observed that many accessions of egg plant are highly tolerant of flooding (Midmore et al., 1997). In as much as generic variability for tolerance of excessive soil moisture is limited or inadequate to prevent yield loss in tomato, at AVRDC Research work was taller up to screen egg plant germ plasam for flood tolerance.

6. NextPreviousEnd So the centre developed grafting technique to improve flood tolerance of tomato using egg plant rootstocks which were identified with good grafting compatibility with tomato and high tolerance to excess soil moisture. In addition to protection against flooding some egg plant genotypes are drought tolerant and such of those egg plant root stocks can therefore provide protection against limited soil moisture stress also. Tomato scions grafted on to egg plant root stocks grow well and produce acceptable yields the rainy season (Midmore et al., 1997).