|Wehner, Todd - North Carolina State University|
|Perkins, Penny - North Carolina State University|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2016
Publication Date: 7/5/2017
Citation: Wehner, T., Naegele, R.P., Perkins, P. 2017. Heritability and genetic variance for citrulline, arginine and lycopene content in a diverse set of watermelon cultigens. HortScience. 52(7): 936-940.
Interpretive Summary: Citrulline, a precursor of the amino acid arginine, has a beneficial effect on plant growth and human health. In mammals, citrulline improves cardiovascular health, antioxidant capacity, and lowers inflammation. This compound is naturally present in high quantities in watermelon, but concentrations in the fruit have been shown to vary among cultivars. Lycopene, an antioxidant, is also found in watermelon and has a beneficial effect on human health. Heritability for lycopene and arginine was found to be high, indicating that breeding for increased levels will result in higher success than breeding for increased levels of citrulline, pH, or brix, which had low heritability.
Technical Abstract: Citrulline, arginine, and lycopene are naturally occurring compounds found in watermelon, Citrullus lanatus (Thumb) Matsum & Nakai, with beneficial effects on plant growth and human health. This study evaluated seven commercial cultivars and one breeding line for citrulline, arginine, and lycopene content in mature fruit grown at two locations in North Carolina. Correlations among these compounds and fruit quality traits (% soluble solids and flesh pH) were evaluated. Watermelon cultigens evaluated were chosen for their diversity of fruit traits. 'Yellow Doll' and NC-517 had the highest citrulline and combined concentration of citrulline and arginine of all cultigens evaluated. Lycopene content was highest in 'Dixielee', followed by 'Sugar Baby' and 'Allsweet', each of which have different shades of red flesh color. Location and its interaction with genotype had no significant effect on arginine or lycopene concentration. Broad-sense heritability was estimated for each trait. Arginine content (89%) and lycopene content (99%) had very high heritability. Citrulline content (41%) and % soluble solids (46%) had moderate heritability, and flesh pH had high heritability (61%). Lycopene was positively correlated with flesh pH and negatively correlated with % soluble solids. Arginine content had a weak negative correlation with flesh pH, and was not correlated with % soluble solids.