الفهرس 
MATERIALS AND METHODSOnly 14 pages are availabe for public view
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Abstract
This study was carried out at the experimental farm of the Rice Research and Training Center (RRTC), Sakha, Kafrelsheikh, Egypt and laboratories of Genetics Department, Faculty of Agriculture, Kafrelsheikh University, during the two growing seasons 2004 and 2005. Three cytoplasmic male sterile lines wild abortive (WA) type; IR 58025 A, IR 69625 A and IR 70368 A were tested using ten testers; Giza 178 R, Giza 181 R, Giza 182 R, IR 69137-34-1-3-1, Hayat, Aricombo, Estrela, IR 3894-40D-PN-S-1, Arabi and Blue Belle, and produced 30 crosses to study the morphological, floral and yield and its component characters and the correlation between these characters and hybrid vigor.
The obtained results can be summarized as follows:
1- A wide range in mean performance for the morphological characters was recorded. The mean values for testers and lines were ( 109.62, 107.92, 42.51 and 30.95 ) for plant height, days to heading, flag leaf area and flag leaf angle, respectively. For the floral characters were (65.67, 120.487, 0.567, 1.966, 0.873, 24.67, 1.31, 1.105, 1.80 and 3575.36) for duration of floret opening, the angle of ovary, style length, pistil length, stamen length, angle of floret opening, stigma length, stigma exsertion, anther length and quantity of pollen grains per anther. In additional, yield component and its characters were (23.61, 3.93, 14.82, 153.15, 25.05, 27.51 and 79.37) for panicle length, panicle weight, number of panicle per plant, number of grains per panicle, 1000-grain weight, grain yield per plant and seed set percentage, respectively.
2- A wide range in mean performance for the morphological characters. The mean values for crosses were ( 107.78, 105.47, 35.07 and 32.80 ) for plant height, days to heading, flag leaf area and flag leaf angle, respectively . For the floral characters were ( 39.43, 122.89, 0.672, 2.27, 0.886, 25.62, 1.58, 1.36, 1.86 and 3460.61 ) for duration of floret opening , the angle of ovary, style length, pistil length, stamen length, angle of floret opening, stigma length, stigma exsertion, anther length and quantity of pollen grains per anther. In addition, yield and its component characters were ( 24.19, 3.28, 18.55, 165.63, 26.15, 39.69 and 69.57 ) for panicle length, panicle weight, number of panicle per plant, number of grains per panicle, 1000-grain weight, grain yield per plant and seed set percentage respectively.
3- The hybrid IR 69625 A / Giza 178 R showed the desirable heterosis values for most studied traits and IR 69137 -34-1-3-1 was a good maintainer to develop new CMS lines.
4- In contrast, positive heterosis was recorded for the remaining characters, these results referred to the majority of crosses which may be partial maintainers or restorers and controlled by additive and dominance gene effects.
5- The analysis of variance revealed highly significant differences among the 43 genotypes (30 hybrids; ten testers and three lines) tested for all studied characters.
6- For general combining ability effects, the IR 69625 A was a good combiner for panicle weight and grain yield / plant. The varity Giza 178 R was the best general combiner for grain yield / plant and seed set percentage.
7- The GCA effects of lines, revealed significant differences among them. Among three CMS lines tested, IR 69625 A was the best combiner for stigma exsertion and opening flower angle and IR 58025 A was the best combiner for flag leaf angle.
8- Moreover, Giza 178 R was the best general combining ability variety for grain yield per plant and seed set percentage, the variety IR 69137-34-1-3-1 was the best general combiner for length of filament plus anther, 1000-grain weight, number of grains per panicle and panicle weight.
9- The data on stigma exsertion of female lines revealed the length of stigma especially for IR58025A line. The general combining ability (GCA) analysis showed that GCA / SCA ratio for lines and testers was more than unit, indicating that additive gene effect plays an important role in genetic control for all these traits.
10- For specific combining ability effects, the best combiners for 1000-grain weight were IR 69625 A / Giza 178 R and IR 58025 A / Blue Belle. But, for panicle weight, the best combiner was IR58025A/Arabi.
11- Heritability estimates in broad sense were high for floral traits, while, heritability estimates in narrow sense were relatively low. As well as, heritability estimates in broad sense were high for all yield and its component characters, while, heritability estimates in narrow sense were relatively low.
12- For histology analysis, the stigma length in CMS lines is further affected by stigma structure, indicating that , IR 58025 A was longer than other CMS lines such as IR 69625 A and IR 70368 A in stigma length. In contrast, IR 69625 A and IR 70368 A were bigger than IR 58025 A in stigma size.
13- The genetic behavior for floral traits of the three cytoplasmic male sterile rice lines, ten testers and their thirty crosses was studied. The results showed that the mean performance values were confirmed with the heterosis values for floral traits of male and female lines with their F1 crosses.
14 - Moreover, the cross IR 69625 A / IR 69137-34-1-3-1 was similar to the female parent IR 69625 A in stigma size and stigma length, while, the cross IR 58025 A / IR 69137-34-1-3-1 was similar to the female IR 58025 A in stigma size and length. These results suggest that, the stigma size and stigma length have maternal effect, so IR 69625 A could be used as a good donor to improve the stigma size and IR 58025 A to improve stigma length. Stigma of female parent should be long and it should exert out of floret after the initiation of floret opening.
15- With regard to correlation coefficient, in general, yield potentiality was mainly attributed to the number of grains per panicle, panicle weight and 1000-grain weight. All these components caused heavy weight of panicles and high yielding ability.
16- For esterase zymogram, a complex of sub-patterns was observed among the different tested genotypes. Description of esterase isozyme patterns of the three CMS lines and the four testers showed that IR 58025A line exhibited No. of bands (five bands), IR69625A ( six bands ) and IR 70368A line ( six bands ) .The bands No.1,2,7 were absent in IR 58025A line and the bands No.2,7,9 were absent in IR 69625A line and The bands No.2,7,9 were absent in IR 70368A line. On the other hand, all testers were differed in the activity and number of bands
17- The band No. 7 was absent in the cytoplasmic male sterile line that related to restoring ability and fertility percentage. Also, band No. 1 in IR 58025 A was absent and was present in IR 70368 A, IR 69625 A, these band responsible of heavy grains and style length.
18- For peroxidase zymogram, the line IR69625A showed eight bands, as well as, their crosses IR 69625 A / Giza 181 R and IR69625 A / IR 69137-34-1-3-1. But the crosses IR 69625 A / Giza 178 R and IR 69625 A / Giza 182 R exhibited nine bands.
19- The band no 10 was absent in. the varieties Giza 178 R, Giza 181 R and Giza 182 R and exhibited in IR 69137-34-1-3-1, the results suggested, the band number ( 10 ), my be related to maintaining ability. These data may be confirmed with some of the phenotypic traits under field conditions.