Image phenotyping of inbred red lettuce lines with genetic diversity regarding carotenoid levels

Abstract Developing biofortified foods is a goal of genetic breeding programs. However, analysis costs and the time required for leaf sampling in the field are hindrances to this process. The objectives of this study were to evaluate the genetic diversity in red leaf lettuce germplasm and to evaluate the use of image phenotyping for the identification of carotenoid-rich genotypes. The experiment was carried out in 2018 at the Vegetable Experiment Station of the Federal University of Uberlândia-Monte Carmelo campus. Thirty inbred lines of red leaf lettuce were evaluated. All inbred lines resulted from the hybridization of the Belissima and Uberlândia 10000 cultivars and six successive selfings, carried out from 2013 to 2017. The genealogical method or pedigree is a working procedure used by plant breeders working with plant species whose reproductive system is autogamous and presenting cleistogamy. This method was used to obtain the treatments of the experiment. The cultivar Belissima (red lettuce) was used as a control, totaling 31 treatments. A conventional method and an aerial image phenotyping using Phantom 4 unmanned aerial vehicle (UAV) were used to evaluate six different agronomic characteristics and carotenoid levels of each treatment. The results showed substantial genetic diversity within the germplasm bank. Furthermore, high performance image phenotyping was highly correlated with the traditional methodology (r = -0.8732, coefficient of determination = 76.25%) and can therefore be considered an alternative for identifying different genetic backgrounds within a germplasm bank. Unmanned aerial vehicle (UAV) might also be used to monitor biofortification levels in crops.