The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes (F_3:6) derived from various crosses as a prerequisite for GWAS and genomic selection. Genotyping-by-sequencing provided 25,566 high-quality SNPs. The polymorphism information content (PIC) across chromosomes ranged from 0.09 to 0.37 with an average of 0.23. The distribution of SNPs markers on the 21 chromosomes ranged from 319 on chromosome 3D to 2,370 on chromosome 3B. The analysis of population structure revealed three subpopulations (G1, G2, and G3). Analysis of molecular variance identified 8% variance among and 92% within subpopulations. Of the three subpopulations, G2 had the highest level of genetic diversity based on three genetic diversity indices: Shannon’s information index (I) = 0.494, diversity index (h) = 0.328 and unbiased diversity index (uh) = 0.331, while G3 had lowest level of genetic diversity (I = 0.348, h = 0.226 and uh = 0.236). This high genetic diversity identified among the subpopulations can be used to develop new wheat cultivars.

Wheat (Triticum aestivum L.) is one of the most important crops in the world. Four spike-related traits, namely, spike weight (SW), spike length (SL), the total number of spikelets per spike (TSNS), total kernels per spike (TKNS), and thousand-kernel weight (TKW), were evaluated in 270 F_3:6 Nebraska winter wheat lines in two environments (Lincoln and North Platte, NE, USA). All genotypes in both locations exhibited high genetic variation for all yield traits. High positive correlations were observed among all yield-related traits in each location separately. No or low correlation in yield-related traits was observed between the two environments. The broad-sense heritability estimates were 72.6, 72.3, 71.2, 72.3, and 56.1% for SW, SL, TSNS, TKNS, and TKW, respectively. A genome-wide association study (GWAS) was used to identify SNPs associated with yield traits. In the Lincoln environment, 44 markers were found to be significantly associated with spike-related traits (SW, SL, TSNS, TKNS, and TKW), while 41 were detected in North Platte. Due to the strong significant genotype x environment, no common SNP markers were found between the two locations. Gene annotation of the significant markers revealed candidate genes encoded for important proteins that are associated directly or indirectly with yield traits. Such high genetic variation among genotypes is very useful for selection to improve yield traits in each location separately.

In vitro direct and indirect propagation of blackberry (Rubus sp.) were studied. Blackberry explants are easily oxidized, so the uses of the running tap water for washing about one hour before sterilization allowed avoiding the oxidation. The disinfection process was represented using different concentrations of Clorox (10, 15, 20%) with exposure times (5 and 10 min.), the best treatment being achieved by the concentration of (10% for 5 min.) for shoot tips and (5% for 5min) for leaves disinfectant. A normal growth and development occurred only in the BA of the multiplication, but at Kin or TDZ decreased in the shoots growth was induced. Maximum volume of callus induction and callus % were produced at TDZ or 2mg/l NAA or 2,4-D each alone from leaf explants. Addition of 2.0mg/l TDZ into media increased the callus induction from in vitro leaves than ex vitro leaves and having the best response. The highest responses of organogenesis obtained from In-vitro leaves than ex vitro leaves. The increased rooting of shoots appeared when MS reduced to ½ salts strength and produced highest leaves number, plant length (cm) and roots number. While, MS reduced to ¼ salts strength resulted in tallest of roots (2.72 cm). The rooting of plants derived from ½ MS salt strength medium give highest leaves number, plant length, roots number and roots length than other strengths of MS after two months from acclimatization in greenhouses.