Agronomic and digital phenotyping evaluation of sweet sorghum public varieties and F1 hybrids with potential for ethanol production in Spain


Sweet sorghum is receiving a lot of attention as a potential crop for bioethanol production in the Mediterranean area. Its advantages are a combination of high productivity and good response to abiotic stresses. There is a lack of information on adaptation of sweet sorghum cultivars to Mediterranean conditions. This investigation was undertaken to explore the adaptation and agronomic traits of a group of international varieties of sweet sorghum, to identify the best candidates to initiate a breeding program for this species in Spain. Sixteen varieties, chosen based on passport, evaluation and genetic data from the USDA GRIN database, were sown in 2011 in an irrigated field plot in Zaragoza, Spain. Several agronomic traits, like fresh weight were determined in the field. Juice samples were analyzed for Brix and POL score of the juice of the stalks. Some of the varieties, particularly Sugar Drip, MN2826, Smith, Ramada and Dale, offer good prospects to initiate a breeding program for Spanish conditions, due to a combination of good agronomics, high sugar content and spread of flowering dates. At the same time, these varieties were used as pollinators to produce hybrids in crosses with either sweet A-lines or grain sorghum populations. The potential to use F1 hybrids in this species was explored by analysing the growth of five of the most representative F1 hybrids (three F1 sweet sorghum hybrids and two crosses of grain sorghum by sweet sorghum) and their parents through a digital phenotyping analysis. Plant size was monitored on a daily basis. The sweet sorghum varieties apparently revealed different heterotic behaviour when crossed to sweet or grain female parents. Mid-parent heterosis for plant growth was detected, but suffered variations over time, which may be related to the experimental system.


sweet sorghum; breeding program; sucrose content; flowering date; Brix; POL; digital phenotyping; heterosis

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Maydica - A journal devoted to maize and allied species

ISSN: 2279-8013