GENETICS OF 2 MECHANISMS OF RESISTANCE TO MELOIDOGYNE-NAASI (FRANKLIN) IN AN AEGILOPS-VARIABILIS EIG ACCESSION

Accession No. 1 of Aegilops variabilis has complete resistance to the root knot nematode, Meloidogyne naasi. F2 segregation in a cross between this and two susceptible accessions showed that one dominant gene named Rkn-mn1 prevented development of galls on the roots and consequently of female nematodes. The study of the numbers of females in galls on the F2 plants allowed detection of a recessive gene, Rkn-mnAv, suppressing development of J2 larvae into females. The presence of Rkn-mnAv also resulted in a decrease of the level of galling. Rkn-mn1 has already been introduced into wheat. Thc interest in transferring also Rkn-mnAv is discussed in relation to extending durability of the nematode resistance.