Inheritance of Non-Parasitic Leaf Spot and Leaf Blotch of Barley

The inheritance of two patterns of non-parasitic lesions on leaves, viz., leaf spot as exhibited by the barley variety decorticatum and leaf blotch as developed on N.P. 13 and C. 138-2 has been reported.

A single recessive gene, np₂, conditioned leaf spot of decorticatum in crosses with the non-spotted varieties, Egypt 4 and C. 138-2.

The simultaneous presence of two recessive genes lbl and lbl₂ appears to condition leaf blotch in N.P. 13 and C. 138-2 with both varieties carrying the same two genes. The non-blotched varieties, Quinn, Chevron and E.B. 410 were homozygous for the dominant allele at both loci while C. 251, B.R. 22, Egypt 4 and decorticatum carried dominant alleles at one of these loci and recessive alleles at the other.

The gene, np₂, for leaf spotting was linked (30.9 per cent. crossover) with one of the two genes for leaf blotching, and was inherited independently of V v (I), Bb (II), Nn (III and VII) and S s (V), Hs hs (leaf sheath hairiness), G₂g₂ G₃g₃ (teeth on lemma) and El el El₂ el₂ (lemma elongation).

The two genes, lbl and lbl₂, for leaf blotching showed independent segregation from ne (ear nodding), se (ear shattering) da da₂ (awn dehiscence) and leaf rust resistance. The gene lbl also showed no linkage with V v (I), B b (II), Nn (III and VII) and S s (V).