Inheritance of leaf hairiness in Gossypium hirsutum L. cotton and its relationship with jassid resistance

Summary Two pairs of genes indicated by H ^P ₁ and H ^A ₂ appear to play a part in the genetic control of pubescence of leaves in the crosses of Pak51 x Empire Red leaf, L11 x Empire Red leaf, AC134 x Empire Red leaf, AC134 x Acala 1517D and L11 x Acala 1517 D. H ^P ₁ seems to induce hair of sufficient length and density and is completely dominant to h ^p ₁.H ^A ₂ allele, seems to induce hairiness but to a smaller degree. It acts additivily to H ^P ₁ giving profusely hairy plants. H ^P ₁ gene is present in the local varieties Pak51, L11 and AC134 producing hair of such length and density as to confer jassid resistance in them. Compared with these, the exotic types viz., Empire Red leaf and Acala 1517D possess H ^A ₂ giving sparsely hairy plants.The exotic variety Deltapine Smooth leaf possesses another gene, E ^A, which displays an epistatic effect on H ^A ₂ gene. The gene E ^A has only a minor effect on the H ^P ₁.Apart from this, the presence of certain intensifying or modifying genes seem to affect the density and length of hair resulting in deviations even in individual groups.M. Sc. Student, Professor and Head, and Reader, respectively of the Dept. of Plant Breeding and Genetics.