الفهرس 
Effect of locations and growing seasons on cotton genotypesOnly 14 pages are availabe for public view
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Abstract
The present investigation was designed to evaluate the performance and estimate stability of six cotton genotypes (3 commercial cultivars and 3 promising lines) grown in four locations viz. El-Mahala (El- Gharbia) Dekernes (El-Dakahlia),Sedi Salim (Kafr El-Sheikh) and Kafr Saad (Damietta), Agriculture Research Stations, Cotton Research Institute at Giza.
During two years of 2011/2012 for some agronomic, fiber and yarn quality traits. It is also targeted determining the superior strains which can be used as a useful genetic source for improving both yield potential and yield stability in cotton breeding programs.
The experimental design was a randomized complete block design with four replications at each location. Some traits, however, were estimated in three replications (fiber and yarn quality traits). The sowing dates were from 10 to 15 April for the two seasons. While, the picking dates were from1to 15 October for the two seasons. The plot size was 78 m2 and each plot contained thirty ridges of four meters long and 65 cm wide. Distance between hills was 25 cm apart. The plants were thinned to two seedlings per hill after six weeks.
Statistical analyses for Randamize Complete Block Design was carried out for each location, as well as combined analyses over the four locations in each season according to Snedecor and Cochran (l982).Analyses of phenotypic stability was done using the method of Eberhart and Russell (1966) to determine the stability of six genotypes over 8 environments (4 locations × 2 seasons).
The obtained results can be summarized as follows:
I-Performance of genotypes under different environments:
Analyses of variance illustrated that, mean squares of the main sources of variation, i.e. genotypes (G) and locations were highly significant in the two seasons for most studied traits, suggesting the
presence of wide range of differences between genotypes and environments. Growing years were significant and highly significant for all traits except seed index, fiber elongation,and yarn evenness it was not significant.
Most of the first order Y ×L, Y ×G, L×G interactions as well as the second order (Y × L ×G) interactions between different factors were significant for most studied traits except(Y×G و((L×G) for boll weight,seed index,lint percentage,and yarn elongation.
Effect of the studied factors on each trait are presented as follows:
Agronomic traits:
1-Boll weight (g): Gharbia location was superior over the other locations in the first year followed by Damietta and Kafr El-Sheikh which means 2.80, 2.78 and 2.75g, respectively .While, in the second year the same location was superior over the other locations followed by Kafr El-Sheikh and Dakahlia with means 2.80, 2.77 and 2.60 g, respectively. Insignificant differences were found between genotypes in the first and second years.The strain 10229 × Giza86 showed superiority in Y1, Y2 and combined analyses with means 3.02, 2.84 and 2.93g, respectively followed by Giza86 with means 2.96, 2.79 and 2.87g. On the other hand, strain Giza77 × pima S6 gave the lowest boll weight (g) at Y1, Y2 and combined analyses with means 2.45, 2.30 and 2.37g, respectively.
2-lint percentage (%): Gharbia location gave the highest mean value for lint percentage in the first year followed by Dakahlia and Kafr El-Sheikh locations which means 39.08, 38.95 and 38.32%, respectively. In the second year Damietta location recorded the highest mean value of lint percentage followed by Gharbia and Kafr El-Sheikh with means 38.90, 38.13 and 37.68 %, respectively. Insignificant differences were found between genotypes in the first and second years.
The strain 10229 × Giza86 showed superiority in Y1, Y2 and combined analyses with means 41.32, 41.17 and 41.25%, respectively followed by Giza86 with means 39.80, 39.38 and 39.59%, respectively.
3-Seed index (g): Damietta location surpassed the other locations in the first year (10.50g) followed by Dakahlia (10.37g), Gharbia (10.35g) and Kafr El-Sheikh (10.06g) locations. In the second year, Dakahlia location was superior the other locations followed by Gharbia and Kafr El-Sheikh with means 10.80, 10.64 and 9.78 g, respectively. The strain 10229 × Giza86 showed superiority in Y1, Y2 and combined analyses with means 11.60, 11.30 and 11.45g respectively followed by Giza86 and Giza88 with means 10.51, 10.19, 10.35, 10.23, 10.07 and 10.15g. On the other hand, strain Giza77 × Pima S6 gave the lowest seed index (g) at Y1, Y2 and combined analyses with means 9.21, 9.03 and 9.30 g, respectively. The Y × L interaction revealed that in the two years strain 10229 × Giza86 gave the best seed index at Gharbia 11.85g and Dakahlia 12.06 g locations while, strain Giza77 × pima S6 gave the lowest value of seed index at Kafr El-Sheikh (9.21g) and Damietta (9.03 g) locations.
4 -Seed cotton yield (Ken/fed): Gharbia location gave the highest mean value for seed cotton yield (11.43 ken/fed) followed by Kafr El-Sheikh (9.64 ken/fed) and Damietta (9.40 ken/fed). In the second year, the highest mean value was obtained from Kafr El-Sheikh location followed by Gharbia and Dakahlia by 10.17, 9.11, and 5.74 ken/fed, respectively.The strain 10229 × Giza86 showed superiority in Y1, Y2 and combined analyses with means 10.84, 9.10 and 9.97 ken/fed, respectively. On the contrary, strain Giza77 × Pima S6 gave the lowest seed cotton yield at Y1, Y2 and combined analyses with values 8, 6.87 and 7.43 ken/fed, respectively. The Y × L ×G interaction revealed that in the two years strain 10229 × Giza86 produced the best seed cotton yield
at Gharbia in the first year(12.52 k /f)and Kafr El-Sheikh in the second year(12.04 k/f), while Giza77 × Pima S6 gave the lowest value of seed cotton yield (6.24 ken/fed) at Dakahlia location in the first year.
5-Lint cotton yield (Ken/fed): Gharbia location surpassed the other locations in the first year followed by Kafr El-Sheikh and Damietta locations with means 14.11,11.74 and 10.78 ken/fed, respectively, in the second year the highest mean values were obtained from Kafr El-Sheikh location followed by Gharbia and Damietta with means 12.03, 11.00 and 6.51 ken/fed, respectively. The strain 10229 × Giza86 showed superiority in Y1, Y2 and combined analyses with means14.13, 11.77 and 12.95 ken/fed, respectively followed by Giza86 with means 12.13,9.39 and 10.76 k/f ,respectively while, Giza77 × Pima S6 recorded the lowest lint cotton yield with means 8.85, 7.35 and 8.10 ken/fed, respectively. The Y × L ×G interaction showed that the same strain 10229 × Giza86 produced the highest lint cotton yield at Gharbia (16.50 k/f) in the first year and Kafr El-Sheikh (15.51 k/f) in the second year, while Giza77 × Pima S6 gave the lowest value of lint cotton yield at Dakahlia location in the first year (7.07k/f) and combined analyses (8.10 k/f). In the second year, Giza 88 gave the lowest value of lint cotton yield (4.73 ken/fed) at Damietta.
6-Earliness percentage (%): Dakahlia location recorded the highest mean value for earliness percentage in the first year followed by Gharbia and Damietta locations with means 80.98, 68.58 and 57.24%, respectively. In the second year Kafr El-Sheikh location recorded the highest mean value of earliness% followed by Gharbia and Damietta. Strain 10229 × Giza 86 was earlier than the other studied genotypes in Y1 and combined analyses. In the second year strains Giza77 × Pima S6 and 10229 × Giza86 were earlier than the other studied genotypes followed by Giza 92 which averaged 79.66, 75.77 and 75.43,respectively, while Giza86 was the latest genotype at Y1, Y2 and combined analyses with means 56.68, 68.83 and 62.76, respectively.
The Y × L ×G interaction illustrated that the same genotype Giza 92 gave the highest earliness percentage (90.75%) at Dakahlia in the first year and atGharbia (86.20%) in the second year,while strain {G84 (G70xG51b)} x S62 gave the lowest value of earliness percentage at Kafr El-Sheikh (46.80%) in the first year and in the second year Giza 86 gave the lowest value (62.80%) of earliness percentage at Damietta.
Fiber properties:
1-Upper half mean length (mm): upper half mean length was higher in Kafr El-Sheikh location (35.47mm) in the first year followed by Damietta (35.30mm), Dakahlia (35.18mm ) and Gharbia locations (35.06mm),while in the second year Dakahlia location (34.98mm ) recorded the highest mean value of upper half mean followed by Gharbia (34.54mm), Kafr El-Sheikh (34.22mm) and Damietta (33.97mm) locations . The promising strain Giza77 × Pima S6 showed superiority (36.98 mm) in Y1. Giza 88 recorded the tallest fiber lengthin Y2 and combined analyses with means 36.45 and 36.11 mm,respectively. On the other side, Giza86 recorded the shortest fiber length (34.05 mm) in the first year and combined analyses (33.70mm). In the second year, the promising strain 10229 × Giza86 recorded the lowest mean value (33.20mm) of upper half mean.The Y × L ×G interaction showed that strain Giza77 × Pima S6 gave the highest upper half mean (37.80mm) at Damietta location in the first year and Giza88 in the second year (36.80mm) at Dakahlia location, whereas in the first year the shortest fiber length was obtained by Giza 86 (33.80mm) in Gharbia location and Giza 92 in the second year (31.50) at Gharbia location.These results indicated that genotypes Giza88 and Giza77 × Pima S6 were the longest cotton fiber in comparison with the other genotypes while Giza86 was the shortest.
2-Fiber strength (g/tex): The locations recorded the same arrangement in the two years. Damietta surpassed the other locations in the first year(47.37 g/tex) followed by Kafr El-Sheikh (45.23 g/tex), Gharbia (44.88 g/tex) and Dakahlia locations (44.58 g/tex).In the second year, the same location (Damietta) showed the highest mean values forfiber strength (43.99 g/tex) followed by Kafr El-Sheikh (43.59 g/tex), Dakahlia (43.53 g/tex) and Gharbia (43.18 g/tex)locations. Genotype Giza 92 showed superiority in Y1, Y2 and combined analyses with means 48.73,44.83 and 46.78 g/tex, respectively,while the promising strain 10229 × Giza86 gave the lowest Fiber strength in Y1,Y2 and combined analyses with means40.15,40.55 and 40.35 g/tex respectively. The Y × L ×G interaction revealed thatin the first year,genotypes Giza 92 and Giza77 × Pima S6 gave the highest fiber strength at Kafr El-Sheikhand Damietta locations (49.90g/tex). Genotype Giza92 gave the highest fiber strength at Gharbia location (47.90 g/tex) in the second year,while the promising strain 10229 × Giza86 recorded the lowest fiber strength at Dakahlia location(37.80 g/tex) and Gharbia location (38.80g/tex)in the first and second year,respectively .
3- Fiber elongation (%):Insignificant differences were found between locations in the first year. Dakahlia location surpassed the other locations (7.48 %)in the second year followed by Kafr El-Sheikh location (7.42%), Damietta location (7.30%) and Gharbia location (7.16%). Insignificant differences were found between genotypes in the first year. Giza 86 showed the first rank (7.47%) in Y1, whereas the promising strain10229 × Giza 86 showed the first rank in Y2 and combined analyses with means 7.39 and 7.42%, respectively. The Y × L ×G interaction showed that in the first and second years,genotypes 10229 × Giza 86 and Giza 88 were the best genotypes for fiber elongationat Kafr El-Sheikh location with means 7.53 and 7.80%, respectively.
4-Micronaire value: Kafr El-Sheikh location surpassed the other locations in the first year (3.65) followed by Gharbia location (3.77) , Damietta (3.83) and Dakahlia location (3.85), while in the second year insignificant differences were found between locations. The promising strain Giza77 × Pima S6 produced the lowest mean values of micronaire and showed thesame ranking and superiority in Y1, Y2 and combinedanalyses with means 2.98, 3.03 and 3.00, respectively followed by Giza 92 with means 3.75,3.53 and 3.64, respectively , while Giza86 gave the lowest micronaire value in Y1, Y2 and combined analyses with mean 4.53. The YLG interaction was not significant in the two years.
5-Maturity ratio (%):Fiber maturity percentage was higher in Damietta location (73.95%) followed by Kafr El-Sheikh(72.73%), Dakahlia(71.97%) and Gharbia (71.37%)locations in the in the first year,while in the second year, Dakahlia location (72.37%) was the first followed by Gharbia(72.00%), Kafr El-Sheikh(71.87%) and Damietta(71.48%) locations. Genotype Giza 86 showed the same ranking and superiority in Y1, Y2 and combined analyses with means 77.15, 75.55 and 76.35%, respectively. Genotype Giza 92 gave high fiber maturity in Y1, Y2 and combined analyses and genotype Giza 88 gave high fiber maturity in Y1, Y2 and combined. Conversely, the promising strain {G84 (G70xG51b)} x S6 recorded the lowest mean values in Y1, Y2 and combined analyses with means 70.23, 70.75 and 70.49%, respectively.The Y × L × G interaction indicated that in the first and second years, genotype Giza 86 gave the best fiber maturity (79.50%) at Kafr El-Sheikh location, while promising strains 10229 × Giza 86 and {G84 (G70xG51b)} x s6 produced the lowest value of fiber maturity at Gharbia location (69.00%) in the first year and Damietta and Kafr El-Sheikh locations(70.00%) in the second year.
6-Brightness (Rd %): the locations recorded the same arrangement in the two years. In the first year,Gharbia location surpassed the other locations (73.26%) followed by Kafr El-Sheikh (73.17%), Dakahlia (72.61%) and Damietta (71.92%)locations.
In the second year, the same location Gharbia recorded the highest mean value of Brightness followed by Kafr El-Sheikh, Damietta and Dakahlia with means 72.62, 72.47, 71.75 and 70.03%, respectively.The promising strain 10229 × Giza 86 showed the same ranking and superiority in Y1, Y2 and combined analyses with means 76.41, 75.33 and 75.87%, respectively. Conversely, genotype Giza 88 recorded the lowest mean value in Y1, Y2 and combined analyseswith means 66.92, 66.30 and 66.62%, respectively. The Y × L ×G interaction showed that the promising strain 10229 × Giza 86 was the best genotype in the first (78.57%) and second (79.50%) years at Kafr El-Sheikh location , while Giza 88 produced the lowest value of Rd% at Damietta location (66.23%) in the first year and Kafr El-Sheikh location (63.20%) in the second year.
7-Yellowness(+b): Damietta surpassed the other locations in the first year followed by Gharbia , Kafr El-Sheikh and Dakahlia locations with means 10.33, 10.17 , 9.92 and 9.90, respectively and in the second year the same location surpassed the other locations followed byDakahlia, Gharbia and Kafr El-Sheikh locations with means10.35, 10.28 , 10.27 and 10.05, respectively.The promising strain Giza77 × Pima S6 showed the same ranking and superiority (11.65) in Y1, Y2 (11.70) and combined analyses (11.68) on the other side, Giza 92 recorded the lowest mean values in Y1, Y2 and combined analyses with means 8.95, 8.35 and 8.65, respectively.The Y × L × G interaction revealed that in the first and second years promising strain Giza77× Pima S6 was the best genotypes for yellowness with means 11.90 and 11.70 at Damietta location, while Giza 92 produced the lowest value foryellowness 8.20 at Dakahlia in the first year and in the second year the same genotype gave the lowest value 8.10 at
Kafr El-Sheikh and Damietta locations.Yarn properties:
1-Single yarn strength (cN/tex)
a- Ring spinning system: The locations recorded the same arrangement in the two years. In the first year Damietta surpassed the other locations followed by Kafr El-Sheikh, Gharbia and Dakahlia locations with means 20.81, 20.21, 20.08 and 19.38 cN/tex, respectively.In the second year, the same location surpassed the other locations followed by Kafr El-Sheikh, Gharbia and Dakahlia locations with means19.87, 19.82, 19.48 and 19.41 cN/tex, respectively.Genotype Giza 92 gave the same ranking and superiority in Y1, Y2 and combined analyses
with means 22.29, 22.10 and 22.20 cN/tex, respectively. Conversely, Giza 86 recorded the lowest mean values in Y1, Y2 and combined analyses with means 17.72, 18.25 and 17.99 cN/tex, respectively. The Y × L × G interaction revealed that in the first and second years genotype Giza 92 gave the best single yarn strength 23.11 and 23.12 cN/tex, respectively at Kafr El-Sheikh location, while Giza86 recorded the lowest value (16.56 cN/tex ) at Dakahlia location in the first year and Gharbia location (17.11 cN/tex ) in the second year.
b-Compact spinning system: the locations recorded the same arrangement in the two years. In the first year, Damietta surpassed the other locations 21.66 cN/tex followed by Kafr El-Sheikh 21.11 cN/tex, Gharbia 21.07 cN/tex and Dakahlia locations20.17 cN/tex. In the second year, the same location Damietta recorded the highest mean value of yarn strength followed by Kafr El-Sheikh and Dakahlia locations with means 20.85, 20.67 and 20.26 cN/tex, respectively. Genotype Giza 92 showed the same ranking and superiority in Y1, Y2 and combined analyses with means 23.30, 22.74 and 23.02 cN/tex. Conversely, Giza 86 recorded the lowest mean value 18.74 cN/tex inY1 and18.99 cN/tex in combined analyses. The promising strain 10229 × Giza 86 recorded the lowest mean value 19.19 cN/tex in Y2. The Y × L × G interaction revealed that in the first, second years and combined analyses, genotype Giza 92 gave the best single yarn strength with means 24.76, 24.05 and 24.41 cN/tex, respectively at Kafr El-Sheikh location, while Giza86 recorded the lowest value 17.44 cN/tex at Dakahlia location in the first year and Gharbia location17.86 cN/tex in the second one.
2-Yarn elongation (%)
a-Ring spinning system:Insignificant differences were registered between locations in the first and second years.Also,insignificant differences were found between genotypes in the first and second years.The genotype Giza 92 gave the highest yarn elongation in Y1, Y2 and combined with means4.96, 4.68 and 4.82 % respectively, while genotype
Giza88 recorded the lowest mean values 4.09% in Y2 and 4.19% in combined analyses. The ranks of interactions Y × L, L × G and Y × L ×G were not significant except Y × G in combined analyses. In the first year, Giza 92 recorded the highest yarn elongation 5.42% while the promising strain Giza77 × Pima S6 produced the lowest value (3.95%). In the second year, the same genotype Giza 92 gave the highest yarn elongation (4.84%), while Giza 88 produced the lowest value (4%).
b- Compact spinning system: Insignificant differences were found between locations in the first and second years. Also,insignificant differences were found between genotypes in the first and second years. The genotype Giza 92 showed the first rank in Y1, Y2 and combined analyses with means 5.22, 4.90 and 5.06 %, respectively. Conversely, the promising strain Giza77 × Pima S6 gave the lowest mean value in Y1 with mean 4.44% and Giza 88 recorded the lowest mean values in Y2 and combined analyses with means 4.51 and 4.57%, respectively. The ranks of interactions Y × L, Y × G, L × G and Y × L ×G were not significant in combined analyses.
3- Yarn evenness (%)
a-Ring spinning system:In the first season, Kafr El-Sheikh location recorded the highest mean value of yarn evenness followed by Damietta, Dakahlia, and Gharbia locations with means 21.10, 21.17, 21.57and 21.59%, respectively. In the second year, Gharbia location recordedthe highest mean value of yarn evenness followed by Dakahlia, Damietta, and Kafr El-Sheikh locations with means 21.11, 21.26, 21.38 and 21.39 %, respectively. Insignificant differences were found between genotypes in the first and second years. The Y × L × G interaction showed that genotype Giza 86 gave the lowest yarn evenness (24.35%) at Dakahlia location, while the promising strain Giza77 × Pima S6 produced the highest value (18.04%) at Damietta location. In the second year Giza 86 gave the lowest value (22.70%) at Kafr El-Sheikh location, while the promising strain Giza77 × Pima S6 produced the highest value (19.54%) at Dakahlia location.
b- Compact spinning system: Kafr El-Sheikh surpassed the other locations in the first year followed by Damietta, Dakahlia and Gharbia locations with means 20.27, 20.32, 20.45 and 20.70%. In the second year, Gharbia location recorded the highest mean value 20.13% followed by Kafr El-Sheikh (20.18%), Dakahlia (20.24%) and (20.75%) Damietta locations. Insignificant differences were found between genotypes in the first and second years. The Y × L × G interaction showed that in the first year genotype Giza 86 gave the lowest yarn evenness (23.52%) at Dakahlia location, while genotype Giza 92 produced the highest value (17.81%) at Dakahlia location. In the second year, the lowest yarn evenness (22.11%) was obtained at Damietta location by Giza 86, while the promising strain Giza77 × Pima S6 produced the highest value (18.62%) at Dakahlia location.
Effect of spinning systems on yarn properties
In general, the performance of all yarn properties was higher in the first year with significant differences between years. Compact spinning yarns were better than the ring yarns.The strength of yarn improved by average of 2% and elongation by 2.9%, meanwhile the yarn imperfections (CV %) were reduced by 2% in compact spinning.
II- Stability analyses
Phenotypic stability of genotypes across eight environments was computed according to Eberhart and Russell (1966). The results indicated that no individual genotype showed stability for all traits. Some genotypes displayed good stability in many or some traits. from the six genotypesthe promising strain 10229 × Giza86 showed stability in five traits viz, earliness percentage, fiber elongation, lint cotton yield, yellowness and brightness.The promising strain {G84 (G70xG51b)} xS62 showed stability in four traits i.e., seed cotton yield, lint cotton yield, micronaire value and upper half mean length.
The Genotype G86 showed stability in the five traits i.e., seed cotton yield, fiber elongation, Micronaire value, fiber maturity and yarn unevenness (ring). The Genotype Giza 92 showed stability in the four traits i.e., lint cotton yield, fiber strength, upper half mean length and yarn strength (ring).The promising strain Giza 77 × Pima S6 showed stability in the two traits i.e.,earliness percentage and yarn strength (ring).The genotype Giza 88 showed stability in four traits i.e., micronaire value,yellowness, yarn unevenness (ring) and yarn strength (compact).