الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 146 |  |  |
| | | from | 146 | | |
Abstract
Summary
This study was carried out at the Genetic Department, Faculty of Agriculture, Ain Shams University and Botany Department, Faculty of Science, Benha University during the period from 2011 to 2018. The field experiment of this study was performed in the greenhouse of the Genetics Department. This study was performed for two selected wheat cultivars for time of flowering (earliness), crosses was carried out to obtain F1 cross in the following season, selfing to select the contrasting group of F2 generation for genetic studies depending on earliness.
The objective of this study was to obtain molecular markers associated with earliness for wheat using some molecular techniques such as RAPD, ISSRs and SSRs which could be useful for breeding programs and save time and cost.
The main finding of this study:
1. For wheat varieties was closer according to days to flowering from P84, Sakha93, Gmmeiza10 to Gmmeiza9 in ascending order. P84 and Gemmeiza9 were the earliest and latest respectively.
2. F2 individual were divided into two contrasting groups according to days to flowering (earliness) early flowering group and late ones.
3. Molecular analysis techniques, used in this study succeeded in obtaining molecular marker linked to earliness in wheat. A total of 377 amplified fragments were obtained, showing 42.4%polymorphism.
4. Eighteen arbitrary RAPD primers were used, out of them fourteen generated 257 fragments with 51.6% polymorphism the highest number of fragments were produced by primers OP-B15 and OP- O19.
5. RAPD-PCR revealed a total of twenty six markers for earliness. Eleven were regarded as positive marker for earliness in most of earliest group and fifteen as negative markers.
6. Primers OP-B17 and OP-D04 produced the highest number of fragments associated with earliness.
7. Twelve ISSR primers were used to screen each group and exhibited polymorphic pattern and a total of 141 Fragments were obtained with 26.9% polymorphism.
8. Ten ISSR primers produced a total number of 12 fragments regarded as molecular markers associated with time of flowering out of them five were positive and seven were negative one.
9. The higher number of ISSR marker were obtained by primers HB04 and HB10.
10. Primers HB15 and17898B showed no molecular marker associated earliness
11. Twenty two pairs of SSRs primers exhibited a total of 117 fragments with 48.7% polymorphism.
12. With SSR- PCR analysis, the highest number of fragments was obtained by primers Xgwm608.
13. Eleven SSR primers were successful in producing twelve molecular markers able to distinguish the earliest group from the latest one, Out of them, seven were associated with earliness and were considered as positive markers, while five negative markers as they appeared in the most of the late group.
14. All of the molecular technique used in this study succeeded in providing markers associated with earliness in wheat.
15. In general, a total of 377 fragments obtained out of them 50 fragments were regarded as molecular markers associated with flowering time (earliness), out of them 23 were considered as positive which appeared in most of earliest group and 27could be regarded as a negative ones.
16. These molecular markers can be used in plant breeding programs and may be valuable tools to reduce time and cost production.