Noug (Guizotia abyssinica) is a semidomesticated 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, and 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.

ABSTRACT: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, BB 5 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 pretreated 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 B 5 °B media, while varying in texture and colour. High percentage of embryogenic calli (80%) was induced on NN medium from the variety Shambu, followed by BB 5 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.