الفهرس 
Salinity ToleranceOnly 14 pages are availabe for public view
 |  | from | 287 |  |  |
| | | from | 287 | | |
Abstract
Soil salinity is one of the most constrains to rice productioli in millions of hcctarcs in tropics and subtropics. Jtice production in saline soils can be increascct considerably if salinity tolerant varieties zrc dcvclopcd. Studying the gerlctic background and components of salinity tolerant gcnotypes is an important tools in brecding for that character. The objcctivcs of this rescarch were to study 1) the effects of salinity on a group of growth and yicld cllaractcrs of rice varieties and its pl~enotypic zuld genotypic parameters; 2) the mode of inheritance and type of’ gene action governing salt tolerance under saline conditions at vegetative and reproductive stage; and 3) the identification of the most desirable genotypes as combiners in future breeding programmes. Performance espcrimcnls were carried out in two locations, Sakha has normal soil and El-Sirw has saline affected soil; to evaluate the pcrfornlance of a collcclio~lo f 70 rice pcnotypcs in 1989. Thir~yv iuictics wcrc ~clcclctlf or more accurate evaluation under norinal and saline conditions in the field and in the Lysimcter in 1990 and 1991 seasons. Besidcs, two Lysimcter experiments were conducted during 1991 and 1992 containing rnatcrials with a complete diallel set of eleven rice varieties. Thrce tolcrant varieties (Gi7z1 159, TCCP 266-2-49-B-B-3 and CSR lo), fivc moderately tolerant (Giza 175, Giza 176, GZ 587-2-1, GZ 1368 S-5-4, and IET 14-44) and three sensitive (Giza 181, IR 28, and Mi-48) were chosen as parents. The salinity lcvels were developed by using NaCl -I- CaCl2 in the ratio of 2: 1 by wcight. Salinity levels were fixed at 6000 ppm in 1991 to evaluate salt tolerance characters and 4000 ppm in 1992 to evaluate the rcst of them, in addition to the control (Tap water) which Lave an EC, of 10.6, 8.0 and 0.7G mnihos/cm at 25 OC respectivcly. Five groups of characters; i.e. salt tolerance; agronomic; yield and its components; panicle charactcrs; :tnd grain dimensions am! sllupc cluwclcrs wac incasurcd. The results indicated that solilc varictics showed high and moderate dcgree of tolerance such as Giza 159, GZ 261 1-4-1, BG 35-2, TCCP 266-2-49-B-B-3, and GZ 1368 S-5-4. .These varictics cudd be uscd as c&varsor as donors in a breeding for salinity program. Some chalactcss could bc uscd as good indicators for tolerance .