Process of infection and histological changes with Ascochyta blight of chickpea caused by A. rabiei (Pass.) Labr. were studied by light microscopy. Germ tubes from conidia of the fungus penetrate the stem tissue at the juncture of two epidermal cells and form subepidermal aggregates until the fourth day. On the sixth day, yellowing and necrotisation of host tissue coincides with formation of mature pycnidia. Fungus causes extensive damage to cellulosic cell walls of parenchymatous cortical and pith tissues in advance of invading hyphae indicating involvement of cell wall degrading enzymes. Lignified tissues, particularly xylem tracheary elements, remain intact.

Three lentil genotypes resistant to Fusarium oxysporum f.sp . lentis viz . Pant L 234, JL 446 and LP 286 were crossed with two susceptible ones . The hybrid plants were all resistant in the eight crosses evaluated . Segregation pattern for wilt reaction in F2, BC(P), BC(P2) and F3 generations in field and glasshouse conditions indicated that resistance to Fusarium wilt is under the control of two dominant duplicate genes in Pant L 234 and two independent dominant genes with complementary effects in JL 446 and LP 286 . A third dominant gene complementary to the dominant genes in JL 446 and LP 286 is present in two susceptible lines . Allelic tests suggest the presence of five independently segregating genes for resistance . Duplicate dominant genes in Pant L 234 are non-allelic to two dominant genes with complementary effects in LP 286 and JL 446 and the third gene complementary to the two genes in JL 446 and LP 286 in susceptible lines JL 641 and L 9-12 . Gene symbols among parental genotypes have been designated .

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