Molecular genetic diversity study of Lepidium sativum population from Ethiopia as revealed by inter simple sequence repeat (ISSR) markers

Abstract

Lepidium sativum L. (family Brassicaceae), is an underutilized medicinal plant with worldwide distribution. In Ethiopia, L. sativum occurs in all regions and agro-ecologies at different altitudinal ranges. The study was conducted to assess the genetic diversity of L. sativum population from Ethiopia using inter simple sequence repeat (ISSR) marker. Molecular data generated from ISSR bands recorded was used for computing gene diversity, percent polymorphism and Shannon diversity index and AMOVA. Moreover, the ISSR data was used to construct unweighted pair group method with arithmetic mean (UPGMA) and principal coordinated analysis (PCO) plot using Jaccard's coefficient. Tigray and Amhara population showed higher gene diversity (0.24) and Shannon information index (0.35). All UPGMA, neighbor-joining (NJ) and PCO analysis showed very weak grouping among individuals collected from the same regions. Generally, Tigray and Amhara regions showed moderate to high diversity in ISSR analysis. Different geographical regions of Ethiopia, showed different level of variation; thus conservation priority should be given for those regions that have high genetic diversity. This result also indicates the presence of genetic diversity that can be exploited to improve the productivity of L. sativum in Ethiopia.

Multivariate Analysis of Genetic Diversity in the Ethiopian Garden Cress (Lepidium sativum L.) Genotypes

“…Similarly, a high degree of variation for days to flowering, days to maturity, plant height, pods per plant and seed yield per plant were reported for the Ethiopian lentil germplasm [34]. The results of this study were also partly in agreement with that of Said [10] which showed that genotypes from Amhara and Tigray Regional States had higher performance in grain yield than other Regional States. Genotypes from Somali Regional State scored relatively low grain yield/ha as they were lowland types and hence low yielding under the two testing sites of Kulumsa and Haramaya.…”

“…Hence, there has been no improved variety cultivated in the country. The cultivation of these landraces has declined in recent years due to high disease incidence and poor productivity [10]. In addition, lack of adequate information on garden cress genotypes has led to inefficient use for both conservation and utilisation of its desirable traits.…”

“…Among these, agromorphological characterisation is considered as the initial step [11,13] for designing breeding program. Temesgen et al [14,15] and Said [10] on the study of 49 and 85 accessions, respectively reported the presence of broad based genetic variations of garden cress landraces in Ethiopia. It was known that there could be many genetic and environmental effects on the crop variation [16].…”

Correlation and path coefficient analysis of yield and quality components of garden cress (Lepidium sativum L.) genotypes in Ethiopia

“…Grain yield is the result of a number of complex morphological and physiological processes that interact with each other and with the environment at different growing stages (Semahegn, 2011). The improvement of landraces for grain yield is not only dependent on the nature and extent of genetic variability, heritability and genetic advance in the base population but also on the association of yield and yield-related traits with desirable biochemical composition (Said, 2012;Temesgen et al, 2013a;Sabaghnia et al, 2015). Since sufficient variability is available in the Ethiopian garden cress (Said, 2012;Temesgen et al, 2013a,b), initiating a robust breeding program with this economically important but under-utilized crop will substantially contribute to its genetic improvement, cultivation and utilization.…”

“…It specifies the cause and effect relationship and measures the relative importance of each variable; therefore, path coefficient would provide a more meaningful interpretation of such association (Dewey and Lu, 1959;Mondal et al, 2011;Malek et al, 2014). It is, therefore, worthwhile to consider a large number of garden cress genotypes to make observations at several locations So far, the study of interrelationships among yield and yield related components characterized with small number of accessions and/or in non-ideal environment of single location (Temesgen et al, 2013a;Said, 2012) make characterization inefficient demanding a large number of genotypes tested in two suitable apparent locations enable the genotypes to discharge its full potential. Therefore, the present study was undertaken to determine the degree and nature of associations among seed yield and seed quality related characters.…”