Understanding the Phenotypic Diversity and Ecological Distribution of Noug (Guizotia abyssinica) for Its Improvement and Conservation

Noug (Guizotia abyssinica) is an important oil crop to Ethiopia where it has been cultivated as source of edible oil since antiquity. Despite the country harbors ample genetic resources of noug, diversity and ecological information useful for its improvement and conservation is very limited. The aim of this study was to assess noug phenotypic diversity along with its ecological distribution based on morphological characters and environmental data. During 2009/10 cropping season, one hundred noug accessions which were collected from different parts of Ethiopia were planted augmented with four standard checks at two testing sites namely Holetta and Ginchi. Diversity and correlation analysis followed by principal component analysis were conducted for agro-morphological traits using statistical software package R v. 2.10.0/1.17-3. Non-metric multidimensional scaling (NMDS) analysis was made to understand which environmental variable that drives phenotypic diversity. Ecological niche modeling using Maxent software programme was also employed to comprehend the agro-ecological niche of noug. According to diversity analysis of phenotypic data, most traits showed considerable diversity within and among populations. The correlation analysis revealed that the number of seeds per plant and number of heads was positively correlated with the number of primary or secondary branches. A significant positive correlation was also obtained between the number of heads and number of seed per plant, and 1000 seed weight and the number of seed per plant. Seven noug populations (N07027, N07028, N07001, N08009, N08002, N08048 and N07009) were found to be unique populations. NMDS analysis showed precipitation was the most important environmental factor that drives noug phenotypic diversity. Ecological niche modeling indicates that the northern and western parts of Ethiopia were found to be the dominant noug niches which accounts > 80% of the total noug growing areas. Kenya followed by Eritrea were other African countries where the crop was grown in some pocket area. A number of noug populations useful for breeding efforts were also identified. In conclusion, noug populations variable for many traits have been identified and such variability is useful for its improvement and ex situ conservation effort of the crop. Keywords: - Noug (Guizotia abyssinica), genetic diversity, noug improvement and conservation. DOI: 10.7176/JNSR/9-5-06 Publication date:March 31st 201

Embryogenic callus induction and regeneration in anther culture of noug (Guizotia abyssinica (L.F) Cass.)

Two released noug varieties, Shambu and Fogera, were used for this experiment. Initially, two experiments were conducted to identify the appropriate morphological stage of capitula (buds) for harvesting maximum number of responsive anthers and to study the optimum cold pretreatment duration for callus induction from the anthers. Three culture media, MS, B5 and NN, were employed for callus induction. MS medium, with nine different combinations of KN and IAA, was used for shoot regeneration study. Three different concentrations of IBA and growth regulator-free MS medium were used for the rooting experiment. The results showed that capitula, fully or slightly covered by sepal having whitish-green or greenish-yellow anthers, were the optimum stages of harvesting capitula; callus was efficiently induced when the capitula were pre-treated at 4°C for 24 hours. The types of calli induced significantly (P≤0.05) varied among the three media. Embryogenic calli were mainly produced in NN and B5 media, while varying in texture and colour. High percentage of embryogenic calli (80%) was induced on NN medium from the variety Shambu, followed by b5 medium showing 40% inductions for both varieties. Among nine different KN and IAA combinations, 2 mg/l KN combined with 1 mg/l IAA, was the most efficient for shoot regeneration. It was also found that 0.5 mg/l IBA was optimum for root induction. In the growth room as well as in the glasshouse, the survival rate of regenerants was generally better for the variety Shambu than for Fogera

Genetic Diversity and Population Structure in Ethiopian Mustard (<i>Brassica carinata</i> A. Braun) as Revealed by Single Nucleotide Polymorphism Markers

Ethiopian mustard (Brassica carinata A. Braun) is currently one of the potential oilseeds dedicated to the production for biofuel and other bio-industrial applications. The crop is assumed to be native to Ethiopia where a number of diversified B. carinata germplasms are found and conserved ex situ. However, there is very limited information on the genetic diversity and population structure of the species. This study aimed to investigate the genetic diversity and population structure of B. carinata genotypes of different origins using high-throughput single nucleotide polymorphism (SNP) markers. We used Brassica 90K Illumina InfiniumTM SNP array for genotyping 90 B. carinata genotypes, and a total of 11,499 informative SNP markers were used for investigating the population structure and genetic diversity. The structure analysis, principal coordinate analysis (PcoA) and neighbor-joining tree analysis clustered the 90 B. carinata genotypes into two distinct subpopulations (Pop1 and Pop2). The majority of accessions (65%) were clustered in Pop1, mainly obtained from Oromia and South West Ethiopian People (SWEP) regions. Pop2 constituted dominantly of breeding lines and varieties, implying target selection contributed to the formation of distinct populations. Analysis of molecular variance (AMOVA) revealed a higher genetic variation (93%) within populations than between populations (7%), with low genetic differentiation (PhiPT = 0.07) and poor correlation between genetic and geographical distance (R = 0.02). This implies the presence of gene flow (Nm > 1) and weak geographical structure of accessions. Genetic diversity indices showed the presence of moderate genetic diversity in B. carinata populations with an average genetic diversity value (HE = 0.31) and polymorphism information content (PIC = 0.26). The findings of this study provide important and relevant information for future breeding and conservation efforts of B. carinata

Rapid and Non-Destructive Determination of Fatty Acid Profile and Oil Content in Diverse Brassica carinata Germplasm Using Fourier-Transform Near-Infrared Spectroscopy

Brassica carinata is one of the oilseeds in the Brassicaceae family, possessing seed quality traits such as oil with various fatty acid profiles suitable for many industrial applications. Determination of such quality traits using conventional methods is often expensive, time-consuming, and destructive. In contrast, the Near-Infrared Spectroscopic (NIRS) technique has been proven fast, cost-effective, and non-destructive for the determination of seed compositions. This study aimed to demonstrate that NIRS is a rapid and non-destructive method for determining the fatty acid profile and oil content in diverse germplasms of B. carinata. A total of 96 genetically diverse B. carinata germplasms that include accessions, advanced breeding lines, and varieties were used in this study. Reference data sets were generated using gas chromatography and the Soxhlet oil extraction method for fatty acid profile and oil content, respectively. Spectra data were taken from the wavenumber range of 11,500 to 4000 cm-1 using the Fourier-transform near-infrared (FT-NIR) method. NIRS calibration equations were developed using partial least square (PLS) regression with OPUS software, version 7.5.1. Higher coefficient of determination (R-val(2)) and ratio of performance to deviation (RPD) > 3 were obtained for oleic acid (R-val(2) = 0.92, RPD = 3.6), linoleic acid (R-val(2) = 0.89, RPD = 3.2), linolenic acid (R2val = 0.93, RPD = 3.8), erucic acid (R2(val) = 0.92, RPD = 3.5), and oil content (R-val(2)= 0.93, RPD = 3.6). Thus, the NIRS calibration models for the aforementioned fatty acids and oil content were found to be strong enough for prediction. However, the calibration models for palmitic acid (R-val(2) = 0.78, RPD = 2.1) and stearic acid (R-val(2) = 0.75, RPD = 2.0) showed relatively smaller R-val(2) and thus became weaker in their prediction capacity. Despite their relatively lower R2, the calibration equations for palmitic and stearic acids could be used for approximate estimation and rough screening purposes. In conclusion, the calibration models that we have developed will be useful in applying NIRS as a high-throughput, non-destructive method for the screening of large germplasms in terms of their fatty acid profiles and oil content during the oil quality breeding efforts conducted on B. carinata

Genetic Diversity and Population Structure in Ethiopian Mustard (<i>Brassica carinata</i> A. Braun) as Revealed by Single Nucleotide Polymorphism Markers

Ethiopian mustard (Brassica carinata A. Braun) is currently one of the potential oilseeds dedicated to the production for biofuel and other bio-industrial applications. The crop is assumed to be native to Ethiopia where a number of diversified B. carinata germplasms are found and conserved ex situ. However, there is very limited information on the genetic diversity and population structure of the species. This study aimed to investigate the genetic diversity and population structure of B. carinata genotypes of different origins using high-throughput single nucleotide polymorphism (SNP) markers. We used Brassica 90K Illumina InfiniumTM SNP array for genotyping 90 B. carinata genotypes, and a total of 11,499 informative SNP markers were used for investigating the population structure and genetic diversity. The structure analysis, principal coordinate analysis (PcoA) and neighbor-joining tree analysis clustered the 90 B. carinata genotypes into two distinct subpopulations (Pop1 and Pop2). The majority of accessions (65%) were clustered in Pop1, mainly obtained from Oromia and South West Ethiopian People (SWEP) regions. Pop2 constituted dominantly of breeding lines and varieties, implying target selection contributed to the formation of distinct populations. Analysis of molecular variance (AMOVA) revealed a higher genetic variation (93%) within populations than between populations (7%), with low genetic differentiation (PhiPT = 0.07) and poor correlation between genetic and geographical distance (R = 0.02). This implies the presence of gene flow (Nm > 1) and weak geographical structure of accessions. Genetic diversity indices showed the presence of moderate genetic diversity in B. carinata populations with an average genetic diversity value (HE = 0.31) and polymorphism information content (PIC = 0.26). The findings of this study provide important and relevant information for future breeding and conservation efforts of B. carinata

Noug phenotypic data

This file contains phenotypic data collected on the level of individuals (sheet: Noug_Individual_Data), accessions (sheet: Noug_Pooled_Data) and environmental data of the collecting sites (sheet: Environmental_Data)

Data from: Patterns of domestication in the Ethiopian oil-seed crop Noug (Guizotia abyssinica)

Noug (Guizotia abyssinica) is a semi-domesticated oil-seed crop, which is primarily cultivated in Ethiopia. Unlike its closest crop relative, sunflower, noug has small seeds, small flowering heads, many branches, many flowering heads, indeterminate flowering, and it shatters in the field. Here we conducted common garden studies and microsatellite analyses of genetic variation to test whether high levels of crop-wild gene flow and/or unfavorable phenotypic correlations have hindered noug domestication. With the exception of one population, analyses of microsatellite variation failed to detect substantial recent admixture between noug and its wild progenitor. Likewise, only very weak correlations were found between seed mass and the number or size of flowering heads. Thus, noug's ‘atypical’ domestication syndrome does not seem to be a consequence of recent introgression or unfavorable phenotypic correlations. Nonetheless, our data do reveal evidence of local adaptation of noug cultivars to different precipitation regimes, as well as high levels of phenotypic plasticity, which may permit reasonable yields under diverse environmental conditions. Why noug has not been fully domesticated remains a mystery, but perhaps early farmers selected for resilience to episodic drought or untended environments rather than larger seeds. Domestication may also have been slowed by noug's outcrossing mating system