Comparison of migration, penetration, development and reproduction of Meloidogyne graminicola on susceptible and resistant rice genotypes

Abstract

Migration, penetration, development and reproduction of the rice root-knot nematode, Meloidogyne graminicola, in the resistant African rice genotypes TOG5674, TOG5675, CG14 and RAM131, and in the susceptible Asian rice genotypes IR64 and UPLRi-5 were studied and compared. The number of second-stage juveniles (J2) that had migrated horizontally and vertically towards the rhizosphere at 48 h after inoculation was comparable in both resistant and susceptible rice genotypes. Penetration of J2 was significantly lower in the resistant rice genotypes compared with the susceptible rice genotypes at 3 and 7 days after inoculation (DAI). Nematode development in the resistant rice genotypes was slower than in the susceptible rice genotypes. Nematode reproduction was significantly lower in the resistant rice genotypes, which supported fewer eggs per g of roots and eggs per female. A significantly higher percentage of egg-laying females was found in the susceptible rice genotypes. Mature females that had developed in the resistant rice genotypes were significantly smaller than the ones in the susceptible rice genotypes. The resistant rice genotypes had significantly fewer galls than the susceptible rice genotypes.