الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 145 |  |  |
| | | from | 145 | | |
Abstract
The title of this study: Family selection in sugarcane populations as affected by genotypes X environments interaction.
The present investigation included two experiments were carried out during three growing seasons (2011/12 to 2013/14) at three locations, i.e. Kom Ombo Agricultaral Research Station, Aswan Governorate latitude 24° 15o N (L1), Mattana Agriculture Research Station, Luxor Governorate latitude 25o 36o N (L2) and Shandweel Agricultural Research Station, Sohag Governorate latitude 26o 33o N (L3).
I- First experiment (base populations):
The basic materials used in this study consisted of five sugarcane populations consisted of 206 clones, were G.85-37 X self. (population I) number of clones 41, G.85-37 X Phil.8013 (population II) number of clones 27, G.85-37 X Bo.3 (population III) number of clones 51, Cp.57-614 X G.85-37 (population IV) number of clones 48 and EH.94-181-1 X Cp.31-294 (population V) number of clones 39 to select the best clones that could outyield the commercial check cultivar GT. 54-9 at two locations i.e. Shandweel and Kom-Ombo in 2011/2012 growing season.
Based on the results obtained from the first experiment (base populations) a total of sixteen clones of five populations were selected as follows: population I (2 clones); population II (4 clones); population III (2 clones); population IV (6 clones) and population V (2 clones) and planted in the second experiment.
II- Second experiment (selected clones):
Three experiments were planted on March, 10, 14 and 20th 2012 at Shandweel, Mattana and Kom-Ombo, respectively, to test the sixteen selected clones and their performance as plant crop and first ratoon through the 2012/2013 and 2013/2014 seasons, respectively. A randomized complete block design of three replications was used.
The obtained results could be summarized as follows:
I- First experiment (base populations):
A- Studies characters:
1. Stalk number per m2:
Most of the clones gave higher stalk number at Shandweel and the other gave opposite results. Furthermore, some clones were greatly affected by location. The differences among clones were highly significant in all populations except population IV was significant only.
On the other hand, the interaction between clones and locations was highly significant in the five populations such significant response is attributed mainly to clones effect.
Estimates of variance components indicated that σ2e was low. Likewise, σ2G was negative in population I and other populations its low and its ratio to phenotypic variance (heritability) was 80.62, 84.95, 77.66 and 82.60% for populations II, III, IV and V, respectively. Otherwise; clones x locations interactions (σ2GL) were high in the five populations and played the major part of the phenotypic variance. Estimates of expected genetic advance were obtained for population III (22.5%) and population V (23.6%).
2- Stalk height:
Locations mean squares of stalk height were highly significant for all populations and most of the clones gave high stalk height at Shandweel and the other gave opposite results. Furthermore, some clones were greatly affected by location. The differences among clones were highly significant in all populations.
On the other hand, the interaction between clones and locations was highly significant in the five populations such significant response is attributed mainly to clones effect.
Estimates of variance components indicated that σ2e was very low. Otherwise, σ2G was high in all populations. Regarding, clones x locations interactions (σ2GL) it was higher in the five populations comparing with σ2e and σ2G.
3- Stalk diameter:
Locations mean squares of stalk diameter were highly significant for three populations (I, III, IV), while it’s insignificant in pop. II and V and most of the clones gave higher stalk diameter at Kom-Ombo and the other gave opposite results except most of the clones in pop. I gave higher stalk diameter at Shandweel. The differences among clones were highly significant in all populations.
On the other hand, the interaction between clones and locations was highly significant in the five populations such significant response isattributed mainly to clones effect.
Estimates of variance components indicated that σ2e was low. However, σ2G were high and positive in all populations. On the other hand, clones x locations interactions (σ2GL) were high in the five populations. The low estimate of σ2GL in population II was the main cause of high heritability estimates which were obtained for stalk diameter.
4- Single stalk weight:
Locations mean squares of stalk weight were highly significant in all populations except population III was significant only and most of the clones gave higher stalk weight at Shandweel and the other gave opposite results. The differences among clones were highly significant in all populations except population IV was significant only.
On the other hand, the interaction between clones and locations was highly significant in the five populations such significant response is attributed mainly to clones effect.
Estimates of variance components indicated that σ2e was very low. Otherwise, σ2G were positive in all populations, its ratio to phenotypic variance (heritability) was 63.6, 71.4, 78.9, 69.8 and 47.6% for populations I, II, III, IV and V, respectively. However, clones x locations interactions (σ2GL) were higher than σ2e in the five populations. The low estimate of σ2GL in population III was the main cause of high heritability estimates which were obtained for stalk weight. Estimates of expected
genetic advance were obtained from population II (23.7%) and population IV (24.4%).
5- Brix:
Locations mean squares of Brix were significant in populations I and II, while it’s insignificant in populations III, IV and V and most of the clones gave higher Brix at Kom-Ombo except pop. IV most of the clones gave higher Brix at Shandweel and the other gave opposite results. The differences among clones were highly significant in all populations.
On the other hand, the interaction between clones and locationswas highly significant in the five populations, such significant response is attributed mainly to clones effect.
Estimates of variance components indicated that σ2e was low. However, σ2G were positive in all populations, and its ratio to phenotypic variance (heritability) was 73.3, 77.1, 75.0, 87.2 and 71.3% in populations I, II, III, IV and V, respectively. Likewise, clones x locations interactions (σ2GL) were higher than σ2e in the five populations. Estimates of expected genetic advance were obtained from population IV (17.47%) and population V (18.2%).
from results of this experiment, it could be concluded that clones number 2 and 22 (population I); 8, 12, 16 and 18 (population II); 4 and 13 (population III); 4, 5, 6, 9, 13 and 32 (population IV); 4 and 31 (population V) were most greatly superior to the other clones in the three traits (stalk number/m2, single stalk weight and Brix%) compared with check variety.
II- Second experiment (selected clones):
The effectiveness of selection depends not only on heritability but also genetic advance. The high broad sense heritability coupled with high on genetic advance for stalk number/m2, single stalk weight and Brix% indicates that these traits are influenced by additive genetic effects and highlights the usefulness of selection based on phenotypic performance
A- Growth characters:
1- Stalk height:
Mean squares of locations, clones and clones x location interaction were highly significant in the plant cane and first ratoon crops for the selected clones of the five populations, except for location in the 1st ratoon crop in population III, which was insignificant. The clone xlocation interaction mean squares was larger than that of clones in the plant crop and the opposite was true in the first ratoon crops in population I. In pop. II, III, IV and V the magnitude of mean squares due to locations was larger than that of clones and clones x locations interaction together. Meanwhile, the mean squares attributed to clones varied in the five populations from the plant to the first ratoon crops.
The effect of locations was clear on stalk height in which Shandweel location gave the tallest plants compared to Mattana and Kom-Ombo for the five populations either in the plant or first ratoon crops. When the performance at Mattana is considered, another trend was observed as two clones (6 and 13 in pop. IV) were taller than C9 in plant cane. Whereas, clones number 6 and 32 same population were tallest in 1st ratton.
2- Stalk diameter:
Location mean square was significant or highly significant in the plant crop, and first ratoon crops of the selected clones from the five populations except for the first ratoon in pop. IV, which was insignificant.The differences among the selected clones were highly significant in the five populations except for the plant crop in pop. V which was significant.
Average stalk diameter of the selected clones in the five populations indicated that no selected clone has stalk diameter larger than that of the check cultivar in the five populations.
3- Stalk weight:
Mean squares of locations, clones and their interaction were highly significant for the five populations in the plant crop and first