The purpose of this study is to investigate the relative efficiency of single~
seed descent, pedigree and bulk population selection procedures in improving
economical traits in cotton and in the same time maintaining genetic variation.The
genetic materials used in the present study included five cation varieties. These
varieties were Giza 45, Giza 85, Giza 88, TNB1, and karshanseky ( Kar.2 ). All these
varieties belong to Gossyp < /em>ium barbadens L. The different selection procedures were
practiced on three crosses [(Giza 88 X TNB1), (Giza 85 X TNB1) and (Giza 45 X
Kar.2)] in order to comparing the efficiency of these methods for improvement of
Egyptian cotton traits. The results could be summarized as follows:
Tests of significance of the mean squares cleared that the differences
among lines derived by pedigree procedure were significant for all the studied traits
except for fiber strength for. the lines derived from second cross (Giza 85 X TNB1).
Although the mean squares of lines derived frorrr first cross (Giza 88 X TNB1} and
third cross (Giza; 45 X Kar.2) by bulk population (BP) procedure wer.e significant in an
stodiedtraits, it was siqnificant in the cases of lint percentage %, boll weight, seed
index, lint index, fiben IEmgtl:l at 2~5% Span length, fiber flnerress and fiber strength
traits for the lines selectedl from the second cross (Giza 85 X TNB1). While, the
differences among lines derived b)l tine single seed descent procedure were not
significant for most of studied traits with respect tb·tI'rettrre-e populations.
Lines selected by the pedigree method (PO) exhibited a wide ranges for all
studied traits compared to the ranges of the bulk population selection method (BP)
and the single seed descent method (SSO) lines should the some trend~t for
number of the opening bolls/plant and uniformity ratio, which gave a wide rangeS-1ft-
the bulk population selection method (BP).
The best ratio of superior lines over the mid-parents for mo~iie stu i
traits in the 1 st and 3rd crosses was detected in the pedigree selection procedure (PO)
and the bulk population selection procedure (BP). With respect to the cross (Giza 85
X TNB1) the percentage values of this parameter was low or equal to zero in the
populations derived by either SSO or PO procedures. This result indicated that the
bulk population procedure (BP) is more efficient in the improvement of most yield
component traits with respect to this cross.
The relative number of superior lines derived by each procedure than the
standard variety (Giza 88) in the three crosses recorded that the PO procedure is
more efficient in the improvement most as traits with respect to, the first cross (Giza
88 X TNB1). On the other hand, BP procedure exhibited superiority over the other
procedures in the improving lint yield/plant and seed cotton ield/plant.
Highly significant values of genotypic variance (0 g) were detected in the
pedigree selection procedure (PO) than in the bulk population selection procedure
(BP) and single seed descent procedure (SSO), for most studied traits in the three
crosses.