Morphological, Physiological, Biochemical and Molecular Responses of Wheat vs Drought Stresses: A Review

Drought stress is becoming a serious challenge for international food security. Prevailing climate change, complex nature of genetic response to drought and multifaceted character of drought-associated traits make drought more pronounced. Drought severely impairs plant growth and development, production and performance of crop plants. It causes significant yield reduction and brings shrinkage of farmlands compared to other abiotic factors. Worldwide, wheat is the most important food crop contributing one fifth of total dietary calories and proteins. However, recurrent drought associated with climate change is among the principal constraints to global productivity of wheat (Triticum aestivum L.) and T. durum L.). Based on genetic variability within and among wheat species, there is morphological, physiological, biochemical and molecular attributes against water stress. This review illustrates, change in these attributes in wheat and functional genomics through transgenic wheat as drought tolerance mechanisms in wheat. Potential challenges and associated opportunities in drought tolerance development in wheat are also highlighted. Keywords: Climate change, drought tolerance, genetic variability, transgenic wheat

Laboratory Biosafety Status in Ethiopia

Globally biosafety during laboratory work and transfer of laboratory materials from one place to another is critical to prevent unintentional exposure to pathogens and toxins, or their accidental release in to the environment. Biosafety program plays pivotal role in the control of potentially harmful biological agents. There is enormous gap in biosafety use and applications between developed and developing nations. The aim of the present study is to review status of laboratory biosafety in Ethiopia. In the country, laboratory biosafety issues have been given less attention to safely conduct. The review was carried out using resources such as Pub-med, Google and Google scholar data bases. Additionally, Reports and Manuals from laboratories and libraries were explored. In Ethiopia, concerning biosafety, the following basics are lacking or not appropriately functioning and need serious attention. Standard biosafety devices and consumables, appropriate personal protective equipment, and appropriate or qualified biosafety officer in each laboratory are a top priority to ensure laboratory biosafety. Regular training on biosafety for biosafety officers, researchers and regulatory bodies is very demanding. Enforcing the existing biosafety rules and regulation, and coping with the international standards need due attention in the country. Establishment of standard national level biohazard waste disposal is required. Generally, to address the biosafety issues, proper attention and contribution from policy-makers, researchers, laboratory technologists, custodians, and other stakeholders are highly recommended

Genetic diversity in Ethiopian field pea (Pisum sativum L.) germplasm collections as revealed by SSR markers

Field pea is an ancient legume crop grown mainly for food in Ethiopia. Even though, there are over one thousand five hundred field pea collections, only a few studies has been conducted on the magnitude and pattern of genetic diversity at molecular level particularly with SSR markers. In this study, genetic diversity of 142 contrasting Ethiopian field pea germplasm were investigated using SSR markers. Euclidean Distance Matrix clustered the collections into seven distinct groups. There were 20 collections in Cluster I, 11 in Cluster II, 5 in Cluster III, 41 in Cluster IV, 17 in Cluster V, 18 in Cluster VI and 30 in Cluster VII. The first, second and third principal components accounted for variation of 76.85%, 6.89% and 6.06%, respectively. There was no definite relationship between pattern of molecular diversity and collection zones, enlightening high levels of intra and inter-genetic diversity of the germplasm. The SSRs used in this study showed relatively higher polymorphic information content (PIC), ranging from 0.33 to 0.95. This indicates that markers used in this study would be useful for genetic diversity analysis of pea. The study exposed that there is wealth of genetic diversity in the gene pool to exploit in field pea breeding and conservation endeavors

Genetic diversity of Ethiopian durum wheat landraces.

Genetic diversity and population structure assessment in crops is essential for marker trait association, marker assisted breeding and crop germplasm conservation. We analyzed a set of 285 durum wheat accessions comprising 215 Ethiopian durum wheat landraces, 10 released durum wheat varieties, 10 advanced durum wheat lines from Ethiopia, and 50 durum wheat lines from CIMMYT. We investigated the genetic diversity and population structure for the complete panel as well as for the 215 landraces, separately based on 11,919 SNP markers with known physical positions. The whole panel was clustered into two populations representing on the one hand mainly the landraces, and on the other hand mainly released, advanced and CIMMYT lines. Further population structure analysis of the landraces uncovered 4 subgroups emphasizing the high degree of genetic diversity within Ethiopian durum landraces. Population structure based AMOVA for both sets unveiled significant (P < 0.001) variation between populations and within populations. Total variation within population accessions (81%, 76%) was higher than total variation between populations (19%, 24%) for both sets. Population structure analysis based genetic differentiation (FST) and gene flow (Nm) for the whole set and the Ethiopian landraces were 0.19 and 0.24, 1.04, and 0.81, respectively indicating high genetic differentiation and limited gene flow. Diversity indices verify that the landrace panel was more diverse with (I = 0.7, He = 0.46, uHe = 0.46) than the advanced lines (I = 0.6, He = 0.42, uHe = 0.42). Similarly, differences within the landrace clusters were observed. In summary a high genetic diversity within Ethiopian durum wheat landraces was detected, which may be a target for national and international wheat improvement programs to exploit valuable traits for biotic and abiotic stresses

Genome wide association study of Ethiopian barley for terminal drought stress tolerance under field and climate chamber conditions

In order to detect markers for drought stress tolerance, field experiments in Ethiopia were conducted for three years at two naturally drought-prone locations and two optimum moisture locations using 239 Ethiopian barley landraces and 21 barley breeding lines. Furthermore, a climate chamber experiment applying drought stress at different water regimes (70% soil water capacity (WC) for control and 20% WC for drought stress conditions) after flowering was conducted for selected 196 accessions. Results revealed reduced grain biomass by 47% and 80% under field and climate chamber conditions, respectively, as well as significantly (p < 0.05) reduced days to maturity and plant height, in both experimental designs. Based on 10,644 SNP markers, GWAS was conducted to identify marker trait associations (MTA) for drought stress tolerance. For days to maturity, relative chlorophyll content, plant height, number of seeds per spike, thousand kernel weight, and harvest index under field and climate chamber drought stress treatments, 58 significant MTAs were identified. In total, 41.4% of the MTAs were located on chromosome 2H, of which one is very close to the Ppd-H1 flowering locus. These findings underpin the importance of this genome region for drought tolerance. Another MTA on chromosome 1H was detected for days to maturity under field drought stress treatment in the vicinity of the known flowering time ELF3 gene. Additionally, 13 and 3 Ethiopian landraces that tolerate severe and moderate drought stress in climate chamber and field experiments were identified, respectively, using drought indices. The results highlight the tolerance of Ethiopian landraces to different levels of drought stress as well as their potential to be considered in future barley improvement programs