statistics, concisely depicting a one-dimensional
probability distribution (variance). In our
experiments, we drew three boxes in one table - these
are distributions obtained for one trait in one year
from three different regions. The left box is the
distribution of the trait in the Tashkent region, the
middle box is the distribution of the trait in the
Fergana region, and the far-right box is the
distribution of the trait in the Kashkadarya region.
The group sizes do not differ; hence, they are
comparable (Juraev et al., 2023, Juraev et al., 2023,
Juraev et al., 2022, Alimova et al., 2022, Juraev et al.,
2023).
3 RESULTS AND DISCUSSION
In 2018-2020 Four hybrid combinations of cotton F2-
F4 were studied, obtained by crossing introgressive
lines adapted to local conditions with high-yielding
varieties of foreign selection.
Figures 1-3 show the results of variability in fiber
yield for three generations of the F2-F4 hybrid
combination [(L-247 x S-484) x L-248]. It shows that
the greatest variability of the trait occurs in the third
generation of hybrids tested in the Fergana region: the
range was 8.9%. In the second and fourth generations,
the variability of the trait ranged from 2.6 to 5.6%.
The smallest range of variability in fiber yield for this
combination was observed in the Tashkent region
from 2.6 to 3.2%. In the Kashkadarya region, the
range of variability of the trait was from 2.6 to 5.2%.
This combination is also characterized by high
average fiber yields of 38.5-40.4%.
The hybrid combination [(Bukhara 6x L-h) x L-
247) x (L-247 x S-6593)] had the greatest variability
in fiber yield in the Kashkadarya region: in F2, F3 and
F4, respectively 6.2, 5. 1 and 7.1% (Fig. 4 - 6). In the
remaining two areas, the amplitude of the trait
variability was significantly less, from 2.8 to 5.1%.
Due to selections among this hybrid population, it
was possible to increase the average fiber yield.
The average fiber yield of the hybrid combination
[L-248 x (L-243 x S-2552)] was relatively low,
ranging from 33.8 to 38.3. However, in different
generations and in different regions there were forms
with a fiber yield of 39 – 41.8%. The highest
amplitude of variability of the trait, 8.8%, was
observed in the Kashkadarya region in the third
generation. In the remaining two regions, the
variability of the trait ranged from 3.4 to 4.5% (Fig.
7-9).
For the hybrid combination L-248 x S-2016, with
the exception of the fourth-generation experiment in
the Kashkadarya region, where the variability in fiber
yield was 10.7%, the range of variability in the
experiments was relatively narrow - from 1.7 to 4.7%.
The average fiber yield for this combination also
varied between years (Fig. 10-12).
The results of a three-year trial showed significant
differences in fiber yield both between hybrid
combinations and between groups in the regions.
Analysis of variance of hybrids showed that the share
of the influence of the genotype on the variability of
the trait in F2 was equal to 72%, in F3 - 41%, in F4 -
40.1%. The influence of the environment on the trait
in F2 was 11.3%. In F3, the influence of the
environment on the trait turned out to be unreliable,
since the P-value for the environmental factor was
greater than 0.05. The contribution of the
environment to the manifestation of the trait in F4 was
12.6%. In F4, the hybrid combination F4 [(F8 L-247
x S-484) x L-248] was highlighted, which showed
stability of the trait over the years, while its average
fiber yield in different regions reached 39-40%.
4 CONCLUSIONS
To summarize, it can be noted that in all years of
testing, regardless of the hybrid combination, the
widest range of variability in fiber yield appeared in
the Kashkadarya region. Moreover, both right-sided
and left-sided transgressions were observed. Analysis
of phenotypic variability in fiber yield in hybrids of
different genetic origins showed that the magnitude
of variation in the value of the trait largely depends
on the contribution of the genotype.
As V.V. Syukov writes, molecular genetic studies
in recent years confirm that phenotypic variability
includes, in addition to paratypic and genotypic
variability, also genotype-environment interactions,
which are mainly epigenetic in nature (Syukov et al.,
2010). A.H. Paterson et al (Paterson et al., 1991)
found in tomatoes that different QTLs appear for the
same trait under different environmental conditions.
Similar results were obtained by C.W. Stuber et al
(Stuber et al., 1992) on corn, M.C. Ungerer et al
(Ungerer et al., 2003) on Arabidopsis, Zh. Jiang et al
(Jiang et al., 2001) on soybeans, as well as A. Börner
et al (Börner et al., 2002), Yu.V. Chesnokov and
colleagues (Chesnokov et al., 2008, Chesnokov et al.,
2012), V.V. Syukov et al. (Syukov et al., 2012) on
wheat.
Our previous studies have shown that genotypic
variability makes a fairly significant contribution to
the formation of fiber yield, ranging from 42.9 to
60.7%. External conditions influenced the trait from