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The purpose of this work was to assess biomass and grain yields, path modelling of yield components, and perenniality in 97 Sorghum bicolor x S. halepense (SB x SH) lines, and compare their biomass production to a series of 38 historic (1987–2015) biomass SB trials. Perenniality was evaluated as rhizome overwintering, while other traits were scored using standard procedures. Contrary to SB, several SB x SH lines developed rhizomes and overwintered, depending mostly upon increased dosage of SH genome in SB background. A few backcross-derived SB x SH lines overwintered, indicating that perenniality can be introgressed in sorghum using backcrossing approach. SB x SH lines were competitive in terms of grain and aboveground dry biomass yields compared to SB. SB x SH selections outperformed or were comparable to the best commercial biomass SB hybrid checks, and ranked among the best selections from the historic trials. Grain yield in SB x SH lines depended mainly on number of culms, whereas biomass yields depended mainly on plant height, dry mass and fiber mass fractions of dry material, and number of culms. We identified superior dual purpose SB x SH genotypes producing 5–11 and 38–45 t ha −1 of grain and aboveground biomass, respectively, most of which displayed satisfactory overwintering rates (56–100%) and high levels of fiber (61–69%) mass fraction. These lines represent high energy sorghums suitable for biofuel and food production. The best SB x SH crosses for developing perennial biomass and grain sorghums were represented by perennial/perennial, annual/perennial/perennial, and annual/perennial combinations. [ABSTRACT FROM AUTHOR]

Sorghum crop demonstrated high yield potential under drought and wet environments with a better energy balance than several cultivated plants. Sorghum biomass can contribute to solving the pressing issue of reducing reliance on fossil fuel. Africa and Asia are sorghum centers of diversity, and landraces therefrom can be of great breeding and production interests in the Mediterranean region. Several works evaluated biomass sorghums, but results on comparative performance between lines, landraces and hybrids are lacking. The objective of this work was to assess the performance of these genotypic groups for traits relevant for biofuel conversions, by carrying out a meta-analysis of data from twenty-four trials conducted in different Mediterranean locations in Italy over seven years. Obtained results showed sorghum hybrids as the best biofuel feedstock option as they outperformed landraces and lines for most traits including biomass yield. Landraces represented an attractive alternative to hybrids and lines as they outyielded lines and were second only to hybrids in terms of biomass production and cellulosic content. Biomass yield advantage was explained by increased plant tallness and cellulosic content in hybrids, and cellulosic content in landraces, and to a lesser extent, by plant maturity in hybrids and landraces. Based on biomass quality and quantity, hybrids and landraces can supply thermal, thermochemical and biochemical biofuel conversion industries. Sorghum lines could be better used in first generation biofuel and energy bioconversion technologies requiring lower lignin containing feedstocks. Landraces and lines could be targeted to areas where hybrid seed production industry is not developed. [ABSTRACT FROM AUTHOR]