ABSTRACT Salinity is a main obstacle of rice (Oryza sativa L.) cultivation. Selecting rice genotypes for salinity tolerance based on phenotypic characteristics alone is inefficient and less reliable, finally will delay progress in rice breeding program. The recent advantages of molecular markers such as simple sequence repeat (SSR) could be used to detect associated salt tolerance markers in rice. This study was conducted to detect genetic variation within some rice genotypes using SSR markers and to identify salt tolerance in the studied genotypes. Forty-five rice genotypes were evaluated for their agro- morphological characteristics under non-stress and saline conditions for two growing seasons in 2018 and 2019. Using 21 SSR primers located on chromosome 8, only 18 SSR primer generated polymorphic patterns with a total of 76 alleles, whereas the other 3 primers were monomorphic. The number of alleles per locus ranged from 2 to 6 alleles with an average of 4.22 alleles per locus. The polymorphic information content (PIC) values varied from 0.30 (RM342) to 0.71 (RM6976) with an average PIC of 0.49. Out of the 18 polymorphic markers only 5 primers (RM 6976, RM7631, RM 5556, RM152 and RM342) perfectly distinguished rice genotypes. The best preforming genotypes under salinity stress were N22, IR 63731-1-1-4-3-2, GZ 7112-1-2-1-4, FL 478, TCCP 266-1-3B-10-2-1, IR 65600-127-6-2, IR 68011-15-1-1 and IR 66160-5-2-3-2. Thus, SSR markers are effective to detect high polymorphisms and variations among the rice genotypes, which could facilitate improving salt tolerance of commercial Egyptian rice varieties exhibiting high yield potential. In addition, the selected genotypes might be integrated into breeding programs for salinity tolerance.

ABSTRACT A study was conducted to evaluate the effects of exogenous enzymes supplementation in high protein (Hi-Pro) corn DDGS-based diets on broiler growth performance, intestinal health, and nutrient digestibility. A total of 200 one-day-old broiler chicks were randomly allocated to four dietary treatments with five replicates of 10 birds each. A basal diet (CON) was formulated (CP: 20%; ME: 2900 Kcal/kg) containing 15% of dietary crude protein share from Hi-Pro corn DDGS. Three experimental diets were developed using basal diets; diet one was supplemented with protease (CON-P), diet two with an enzyme mix of mannanase and xylanase (CON-MX) and diet three with a protease and enzyme mix of mannanase and xylanase. A digestibility assay was carried out using Celite (insoluble acid ash), from day 29 to day 35. On day 35, four birds from each replicate were picked randomly and killed by cervical dislocation to collect ileal digesta. In addition, duodenum, jejunum and ileum lengths were measured, and tissue samples were collected from midpoints of jejunum to note villus height and crypt depths. Feed intake, body weight gain and feed conversion ratio were not affected by dietary treatments during the entire study period (p>0.05). Likewise, no difference in carcass characteristics, soft organ weight, intestinal morphology, apparent amino acids digestibility and visible ileal digestible energy was observed by the dietary treatments (p>0.05).Supplementation of exogenous protease and enzyme mix (mannanase and xylanase) had no effect on growth performance, intestinal integrity and nutrient availability of broiler chickens fed Hi-Pro DDGS-based diets.