GENETIC STUDIES OF SOME ECONOMIC CHARACTERS IN THE GOSSYPIUM BARBADENSE L. CROSS GIZA 77 x PIMA S6

The inheritance of some economic cotton characters of the par­ents, F₁ and F₂ for the cross (Giza 77 x Pima 56) showed that the po­tence ratio estimates were in the range of partial dominance for lint per­cent and fiber strength. Whereas, over dominance was reported for boll weight and fiber fineness. Highly significant positive M.P. heterosis for boll weight and significant for fiber fineness were found. Moreover, high­ly significant positive B.P. heterosis was reported for boll weight and fi­ber fineness also, while lint percent showed highly significant negative heterosis for "B.P." and insignificant for "M.P". Highly significant inbreeding depression was found for boll weight, fiber fineness and fiber strength only, while lint percent showed only significant value for inbreeding depression. Reliable moderate heritability estimates were found for fiber fine­ness, boll weight and lint percent and low heritability estimate for boll weight. The expected genetic advance upon selection ranged from 1.84% for fiber strength to 13.03% for fiber fineness. These results led to the conclusion that, an effective breeding method wihtin this material for improving those economic cotton char­acters would lead towards the production of varieties rather than hy­brids. Moreover, the heritability estimates indicated that, such hybrid should be evaluated in several environments before any clear breeding decisions could be made.