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Sesame ( Sesamum indicum L.) yield response to nitrogen (N) application has been well documented, but the temporal dynamics of N accumulation and partitioning by sesame are poorly understood. Such knowledge is needed to better inform fertilization decisions and improve N use efficiency (NUE). The objective of this study was to characterize N and biomass accumulation, partitioning, and remobilization among diverse sesame cultivars grown in the humid southeastern USA. A two-year field study was conducted at the University of Florida Plant Science Research and Education Unit in Citra, Florida in 2013 and 2014. Four commercially available cultivars (S30, S32, S36, and S39) with variable maturity and branching characteristics were sampled at multiple growth stages and divided into vegetative (stalks plus leaves), reproductive (capsules plus seed), and root (only S30 and S36) components to determine biomass and N accumulation. Medium-maturing cultivars (S30 and S32) reached peak aboveground biomass accumulation at late-bloom stage and accumulated ∼5100 kg biomass ha −1 by dry down, while peak aboveground biomass accumulation for late-maturing cultivars (S36 and S39) was reached at physiological maturity and amounted to 8242–8739 kg biomass ha −1 at dry down. Cultivars reached peak N accumulation at mid-bloom (S30), late-bloom (S32 and S39), and physiological maturity (S36). Total N accumulated by cultivars ranged from70 to 99 kg N ha −1 in aboveground biomass, of which 33–60% was taken up during the reproductive growth phase. It was also estimated that 31–66% of aboveground vegetative N was remobilized to capsules and seed during reproductive growth. Root N accumulation peaked at mid-bloom stage, at which point S30 and S36 had accumulated approximately 4 kg N ha −1 . Removal of N with harvested seed amounted to 29–49 kg N ha −1 , with S36 removing more total N with harvest than both medium-maturing cultivars. This pattern of N accumulation suggests that plant available N has the potential to impact sesame reproductive nutrient allocation, but additional research is needed to determine if the impact of the timing of N fertilization differs among more diverse sesame maturity classes. [ABSTRACT FROM AUTHOR]

Sesame is a new crop for the southeastern USA, most recently being considered for this region because of frequent drought events in the historical farming area of the crop, that is, Texas and Oklahoma, and for overall expansion of its domestic production. Although sesame was introduced in the USA in the 19th century, its commercial cultivation was not possible before the 1990s with the release of non-dehiscent cultivars. The southeastern USA has been considered promising because of its greater annual precipitation as compared with the southwestern USA. In addition, sesame has some highly valuable agronomic characteristics that could make the crop a beneficial addition to crop rotations in the southeast. These crop characteristics include the following: nematode resistance potential, drought tolerance, nitrogen recovery ability, rotational suitability with the predominant agronomic crops in the region, and capacity to attract a wide variety of pollinators. Since very little United States-based literature is available on the crop, the objective of this review is to provide: 1) a sesame history in the USA; 2) a description of the botanical characteristics of the crop that make it suitable for mechanized production in the USA; and 3) an overview of the principal sesame production methods of interest for the southeastern USA. [ABSTRACT FROM PUBLISHER]

• Most sesame roots were present between 20 to 50 cm deep, and root diameter did not exceed 2 mm. • There was evidence of a lag in senescence between below- and aboveground parts of the plant. • Genotypic differences between non-dehiscent cultivars did not translate into strong rooting architectural differences. This study described sesame's rooting behavior and the relationship between above- and belowground biomass in architecture and senescence dynamics. Six non-dehiscent sesame cultivars, branched and non-branched, were grown for two years in North Central Florida's sandy soils in 2013 and 2014. The root systems were imaged in situ with a minirhizotron camera 5 times in 2013 and 7 times in 2014. Total root length, surface area and diameter were measured for each image, and roots were separated between alive, dying and dead. Leaf area index was recorded 5 times both years. Results showed that averaged maximum root diameter for all cultivars was <2 mm. Most roots were present between 20 to 50 cm deep, and a multivariate approach, namely a canonical discriminant analysis, showed that some cultivars tended to have more roots in the soil mid-depth ranges than others. However, these observations were not stable throughout the season. Leaf area index showed differences between cultivars, but these did not translate into contrasting yields. Results also highlighted a lag between leaf area index and total root length senescence, the former declining about 2 weeks before the latter. This study is among the first to describe sesame rooting characteristics in details. [ABSTRACT FROM AUTHOR]

Sesame (Sesamum indicum L.) is being considered for commercial production in the southeastern USA, but very little is known about its potential and the appropriate management practices required to achieve sustainable yield potential in the area. This study thus aims to determine the optimal planting date and row spacing for several sesame cultivars. Traits examined were yield, plant height, number of nodes on the main stem, number of branches, height to first capsule on the main stem, and number of plants per meter. A first trial investigated three planting dates in Citra, FL (May, June, and July); whereas a second one examined several row spacings at two locations: 19 and 38.1 cm in Citra; and 19, 38.1, and 76.2 cm in Live Oak, FL. The May planting date showed higher yields, number of nodes, and taller plants than the other dates. Accumulated air and soil growing degree days (GDDs), rainfall, and solar radiation values were calculated for each planting date in both years. Soil GDDs provided similar results to air GDDs; thus, either model would seem appropriate for predicting crop development in this region. Plant height, number of nodes with capsules, and number of branches were increased at wider row spacings in the Live Oak trials as compared with narrow rows. These two trials illustrated the potential of sesame for attaining economically sustainable yields in the southeastern USA, but further exploration and modeling of agronomic traits will be needed to reach the crop’s full yield potential in these regions. [ABSTRACT FROM AUTHOR]