The Journal of Horticultural Science & Biotechnology
Vol. 87 No: 3
Inheritance of resistance to root-knot nematode (Meloidogyne incognita race 1) in tomato (Solanum lycopersicum L.) 'Pusa 120'
S. SHRESTHA, R. KUMAR, T.K. BEHERA and H.K. SHARMA
The inheritance of resistance to root knot nematode (RKN; Meloidogyne incognita race 1) in progeny of the tomato (Solanum lycopersicum L.) cultivar ‘Pusa 120’ was studied.
Twenty-eight diverse genotypes of tomato were screened for resistance against M. incognita (race 1). Two susceptible tomato genotypes (‘La-Bonita’ and ‘Selection N-5’) used as pollen donors, were crossed with the more resistant ‘Pusa 120’ as the seed parent to obtain F1 and F2 generations, and two backcross generations.
After 60 d of exposure, the numbers of root knots and egg masses per plant root system were counted.
A chi-square (χ2) test of the frequency distribution based on the root-knot index (RKI) of the F2 progenies of the two crosses (resistant × susceptible) showed the best-fit to a 3(R):1(S), Mendelian ratio.
The monogenic dominant model was further confirmed by the 1(R):1(S) ratio found to be the best-fit for the backcross generation (B2) with the susceptible pollen donor parent.
These results confirmed that resistance to RKN (M. incognita race 1) is controlled by a single dominant resistance gene (R-gene) inherited from the resistant parent, ‘Pusa 120’. ‘Pusa 120’ can therefore be used to develop high yielding varieties, or hybrids, of tomato with improved RKN resistance.
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