Sweet sorghum ideotypes: genetic improvement of stress tolerance

Abstract

Stress tolerance is a prerequisite for the success of biofuel production, which normally requires the use of marginal lands and nonfood biofuel feedstocks. Sorghum is known for its ability to withstand stress conditions, however, terminal stresses threaten its growth and development negatively impacting yield and sugar accumulation. It is crucial, therefore, that research aimed at developing sorghum resistance to stress factors should be pursued to expand the range of its growth to marginal and barren soils to meet the needs of a growing population, changing diets, and biofuel production. In this context, the leaf architectural trait of stay-green drought tolerance, in addition to salinity, cold, and aluminium toxicity and biotic stress tolerance and their genetic basis discussed in this review are expected to be available in future sweet sorghum ideotypes. Also highlighted is the key role of effi cient management of farming systems, in particular the use of herbicides to control weeds, to ensure the sustainability of the sweet sorghum biomass productions. 4

Accumulation of stem sugar and its remobilisation in response to drought stress in a sweet sorghum genotype and its near‐isogenic lines carrying different stay‐green loci

“…The physiological mechanisms underlying the stay‐green trait include osmotic adjustment (Anami et al . ) and alterations in hormone levels and hormone signalling pathways (Thomas & Ougham ).…”

“…The stay-green sorghums were also reported to tolerate drought stress through modification of root architecture (Mace et al 2012), reduced tillering and increased leaf size (Borrell et al 2014), higher nitrogen use efficiency (van Oosterom et al 2010) and improved water use efficiency (Vadez et al 2011). The physiological mechanisms underlying the stay-green trait include osmotic adjustment (Anami et al 2015) and alterations in hormone levels and hormone signalling pathways (Thomas & Ougham 2014).…”

Sweet sorghum ideotypes: genetic improvement of the biofuel syndrome

“…For Northern China and high land Europe, chilling tolerance is a favorable trait for early seed germination and seedling growth. For tropical and subtropical regions, defining the right maturity to achieve three or four crops in a year to increase annual biomass yields and the development of perennial sweet sorghum cultivars that are more resilient to extreme environmental conditions would be the goal of breeding in addition to developing cultivars resistant to Striga parasitism (Anami et al 2015). For arid and semi-arid regions, breeding ideotypes with enhanced water use efficiency and adult plant drought tolerance would be essential.…”

“…Although, leaf stay green, abiotic, and biotic stress traits are important biofuel syndromes; they have been discussed in another review (Anami et al. ).…”

“…In addition, due to the relatively short history of sweet sorghum breeding, we consider the development of regional ideotypes adapted to various phenological requirements in order to optimize production of sweet sorghum with high stem sugars and higher biomass on marginal lands. Although, leaf stay green, abiotic, and biotic stress traits are important biofuel syndromes; they have been discussed in another review (Anami et al 2015).…”