فهرست مطالب f. darvish

Chromosomes counting and flow cytometry method were used for assessing the ploidy level of various Aegilops cylindrica Host (2n=4x=28, CCDD) accessions of the National Plant Gene Bank of Iran (NPGBI). About 100 different accessions of Ae. cylindrica were estimated in flow cytometry analysis by using Ae. tauschii as a control sample. All the studied accessions fitted in 4x ploidy level. Chromosomes counts and flow cytometry data led to the same results. There was significant diversity in DNA index among Ae. cylindrica accessions. Cluster analysis was used for the classification of Ae. cylindrica based on their DNA content. Interestingly, accessions with smaller and larger DNA index had smaller and larger chromosome length, respectively. Also, the study of the relationship of DNA content and geographical distribution in Iran showed that there is diversity in DNA content of Ae. cylindrica for different areas of Iran.

In order to examine the responses of proso millet (Panicum miliaceum) to drought stress at different growth stages, four breeded genotypes and a local one of proso millet were selected and planted in a split-plot design with five irrigation treatments and three replications.This experiment was conducted in two locations, Birjand and Sarbisheh. Irrigation treatments included well - watered, drought stress at vegetative stage, ear emergence stage, seed filling stage and vegetative and seed filling stages which were considered as main- plots. The first five mentioned genotypes were considered as sub-plots. Drought stress. caused a great reduction in grain yield and WUE at ear emergence stage. This reduction represented itself in the number of seed per ear and the weight of seeds, but it didn’t have any effects on the number of ear. At ear emergence stage, the drought stress increased the floret death and loss of weight of seeds which resulted in the reduction in the harvest index of both ear per plant and seed per plant. Comparison of genotypes indicated that since K-C-M.4 had a greater number of ears and K-C-M.9 had heavier seeds that had higher grain yield. These two genotypes had the highest WUE and their harvest indices were relatively higher. Due to the salinity of water and infertility of soil in Birjand, the grain yield was lower compared with Sarbisheh. In summary, it can be said that genotype K-C-M.4 proved to be more suitable for both areas.

The effects of growth of two strains of lactic acid bacteria on microbial flora of ground beef after packaging in air permeable packs were studied under workshop conditions. The strains isolated from dairy products were added to ground beef at a density of 104 CFU/g after identification and antibiosis test against indicator bacteria (Escherichia coli and Staphylococcus aureus). The two strains were Lactobacillus casei subsp. casei 102, and Lactococcus lactis subsp. lactis var. diacetylactis 202. Inoculated and control samples were stored for up to five days under aerobic conditions in cold storage facilities with a temperature fluctuation between of –1°C to 5°C). Enumeration of different bacterial groups (total aerobic microorganisms, lactic acid bacteria, Pseudomonas spp., coliforms, Staphylococcus aureus, fungi) and detection of Escherichia coli were carried-out during storage period. The number of lactic acid bacteria in samples inoculated with lactobacillus casei subsp. casei 102 (treatment 1) increased during storage period, whereas total number of aerobic microorganisms, Pseudomonas spp., coliforms, and yeasts reduced. In samples inoculated with Lactococcus lactis subsp. lactis var. diacetylactis 202 (treatment 2), the number of yeasts decreased considerablely. As a result, Lactobacillus casei subsp. casei 102 can be used as a suitable antagonist of spoilage and pathogenic bacteria in ground beef under aerobic Conditions in cold storage facilities with a temperature variation between –1°C to 5°C.