Morphological traits of quinoa (Chenopodium quinoa) grains as indicators of nutritional quality

Localization of the main seed storage compounds inside the seeds of quinoa is known to have a marked compartmentation: Proteins are located mostly in the embryo and almost all the total saponin amount in seeds is located in the pericarp. Breeding programs till now have mainly focused on the development of better environmentally adapted varieties rather than to increase seed nutritional properties. Therefore the main aims of the study described in this presentation were: 1-Testing of the assumption of quinoa nutrients compartmentation by means of two different X-ray micro CT approaches, one based on bulk scanning of many grains at one time, the other one scanning a single quinoa grain at time, considering four quinoa varieties with contrasting nutritional properties. 2-Providing novel morphological traits to help breeders in enhancing quinoa nutrient profile. After univariated and multivariated statistical analysis of the morphometric parameters obtained by image analysis pf micro CT images, the findings could be summarised as follows: X-ray micro-CT on quinoa grains can provide a large amount of novel morpho-densitometric traits. Bulk scan approach is more suitable for representativeness and statistical significance of the results. Single seed scan approach allows very accurate internal structure grain characterization. Results from both scan approaches confirm the localization of the proteins mainly in the embryo. Traits from bulk seed scan are sufficient for a good discrimination among the varieties. Single seed scanning results agree with hypothesis that the saponins are predominantly present in the papillose cells of the pericarp.