الفهرس 
HeterosisOnly 14 pages are availabe for public view
 |  | from | 147 |  |  |
| | | from | 147 | | |
Abstract
The present study was carried out in the Agronomy Department, Faculty of Agriculture, Kafr El-Sheikh, Tanta University. The field experiments were conducted in the experimental farm, Faculty of Agriculture, Kafr El-Sheikh, Tanta University during the 1996, 1997 and 1998 seasons. The objective of this investigation was to study the performance of ten cytoplasmic male sterile lines in breeding rice hybrids in Egypt at the location of investigation; Kafi- El-Sheikh and to study the possibility to use the Egyptian high yielding cultivars as restorers in hybrid rice breeding. The genetic materials used in the present investigation included two ~~OLIPoSf rice germplasm. The first group consisted of ten pairs of lines; each CMS line and its ~naintainern amely: IR67701 A G46A AUCO A IR6770 1B G46B AUCO B The second group contained six local (4 genotypes) and introduced (2 genotypes) tester lines; namely: Giza 177, Giza 178, Sakha 101, Sakha 102, Suweon 287R and IR35366-62-1-2-2-3R. The CMS lines were used as lines, while the tester lines were used as testers in the experimental design (lines x testers analysis). All possible combination crosses were done (excluding reciprocals) in a factorial mating design (line x tester) in summer 1996 and 1997 seasons to produce 60 F1 seeds. Ten hybrids made in 1996 were cultivated in 1997 to produce plants of 10 F1 hybrids and the F2 seeds. The evaluation experiment was grown in summer 1998, in a complete randomized block design with four replications. Ten characters were studied in this investigation, viz. days to 50% heading, plant height, flag leaf area, panicle length, number of spikelets per panicle, sterility percentage, number of panicleslplant, number of filled grainslpanicle, 1000-grain weight and grain yield. However, an exception was the use of the inaintainer lines instead of their CMS lines in estimation of the whole parameters for 1000-grain weight and grain yield. Therefore, the genetic materials included in the statistical analysis were 10 cytoplasmic inale sterile lines, 6 tester lines, 60 I;, hybrids and 10 F2 hybrids. I-leterosis, combining ability and the inbreeding depression were estimated for the different studied traits. The obtained results could be summarized as follows: 1. Genetic differences among genotypes were highly significant for all st~~dietrdai ts indicating the presence of adequate genetic variability. 2. Meterosis was obtained in all the studied traits.