This study was prompted by the special interest in sugar crops, at a time of high petroleum prices and fuel shortages, as potential renewable resources which would supplement non‐renewable fossil resources. Four to six sweet sorghum [Sorghum bicolor (L.) Moench] cultivars were evaluated 4 yr for fermentable sugar production potential at eight locations in the continental USA and at one location in Hawaii. Latitudes represented ranged from 21 to 47° N with the average number of frost‐free days ranging from 120 to more than 350. Data were collected for biomass yield, percent lignin, percent cellulose, stalk sugar yields, and other agronomic characters. Total sugar yield for the continental USA ranged from 4 Mg ha‐1 to 10.7 Mg ha‐1 during 3 yr of the study and up to 12 Mg ha‐1 at the Hawaiian location. Accordingly, theoretical ethanol production in the continental USA ranged from 2129 L ha‐1 to 5696 L ha‐1. Results of the study demonstrated that sweet sorghum is far more widely adapted than was anticipated for a plant of tropical origin and certainly has the potential for providing a good source of fermentable carbohydrates across a wide geographic area.

Sweet sorghum, Sorghum bicolor (L.) Moench, is a potentially renewable source of biomass, sucrose, and other fermentable sugars. Limited data are available on the influence of row width, plant arrangements within the row, and row width × plant arrangement within the row interaction on stalk and sugar yield. These field experiments were conducted from 1967‐1972 to determine the influence of row width and arrangement of plants within the row on gross and stripped stalk yield and juice quality of 'Rio' sweet sorghum. Four plant arrangements within each row, one, two, three, and four plants in hills spaced 15, 30, 45, and 60 cm, respectively, were planted on 52.5 and 105‐cm‐width rows. Narrow rows (52.5 cm) resulted in higher yields of gross and stripped stalks, and sugar per ha than conventional rows (105 cm). Plants from narrow rows were inferior to those from conventional rows in juice Brix, sucrose, purity, and yield of sugar per ton of stalks. Plants grown on narrow rows weighed less, contained less juice, and lodged more readily than those grown on conventional rows. Plant arrangement within the row did not significantly affect yield of gross stalk, stripped stalk, sugar per ton of stalks, and sugar per ha or juiciness, Brix, sucrose and purity. The width‐of‐row × plant arrangement interaction was highly significant only for stalk weight. Stalk weight was not affected by plant arrangement on narrow rows, but increased as the space between hills increased from 15 to 30, 45 or 60 cm on conventional rows. Since the narrow rows produced higher yields of stalks and sugar than conventional rows, planting sweet sorghum on narrow rows appears to be an effective method for increasing yield of total sugar per ha.