Many state seed laws have very close tolerences with regard to genetic purity of sorghum [Sorghum bicolor (L.) Moench] ✕ sudangrass [Sorghum sudanense (Piper) Stapf] hybrids. Genetic purity of sorghum ✕ sudangrass hybrid seed is difficult to maintain because of contamination by outcrossing with foreign pollen or selfing of supposedly cytoplasmic male sterile plants which have some fertility. The effect of reduced genetic purity on yield and quality, as evidenced by in vitro dry matter digestibility and protein content, was estimated by mixing various percentages of seed of a sorghum ✕ sudangrass hybrid and a grain sorghum. Treatments consisted of a hybrid (A Redlan ✕ Greenleaf); the grain sorghum (B Redlan); and 90:10, 80:20, 70:30, 60:40, and 50:50 mixtures of a hybrid and grain sorghum. The study was conducted 3 years in a randomized, complete block design. Dry matter forage yields were not significantly affected by the various mixtures of a grain sorghum and hybrid. The grain sorghum yielded significantly lower than all other treatments. Dry matter digestibility of all treatments was above 59%, indicating high quality forage, and was not significantly different among treatments within years. There was no difference in protein content between the hybrid and all mixtures within years. Protein content of the grain sorghum was higher than the other treatments and approached significance. The grain sorghum made slower regrowth and was more immature than all other treatments at each harvest date. The results of this experiment indicate that a small reduction of genetic purity in hybrids would not decrease total forage yields or lower quality of forage, as evidenced by in vitro dry matter digestibility or protein percentages.

Grain yields and water-use efficiencies were compared for conservation bench terraces, bench terraces, and common systems of dryland production of winter wheat (Triticum aestivum L.) and grain sorghum (Sorghum bicolor [L.] Moench). Grain production and water-use efficiency were highest on a bench terrace cropped in continuous grain sorghum. Conservation bench terraces and continuous grain sorghum grown on sloping land also had higher water-use efficiences and grain production than the common dryland systems of wheat-sorghum-fallow on graded terraces and continuous wheat or wheat-fallow on sloping land. The management factors greatly influencing water-use efficiencies were crop selection and land leveling to conserve potential runoff.

Crop residues of grain sorghum (Sorghum bicolor (L.) Moench) and corn (Zea mays L.) have attracted attention as an alternate economical forage resource for livestock utilization. There are little data available on agronomic production factors affecting yield and quality of crop residues. We evaluated the effect of rate and time of N fertilization on irrigated corn and grain sorghum grain and residue yields, grain N content, and forage quality of the residues. During 1972 and 1973 irrigated corn and grain sorghum plots were fertilized with O, 90, 180 and 270 kg/ha of N as a 32% N solution at planting or sidedress with two P levels (O and 22 kg/ha) incorporated prior to planting. Grain and residue samples were analyzed for grain N content, and residue crude protein and in vitro dry matter digestibility (IVDMD). Corn grain yields increased significantly with N applied at 90 and 180 kg/ha, while grain sorghum grain yields increased significantly only at the 90 kg/ha rate. Grain N content increased with N fertilization for both crops. Grain sorghum N content was generally equal to or greater than corn. Residue yields of both crops were increased significantly by 30 kg/ha with no further increase at the higher N rate. Corn grain/stover ratios increased with increasing N levels. Crude protein of grain sorghum residues was consistently higher than corn while IVDMD values were consistently lower in grain sorghum. Crude protein increased significantly in grain sorghum residue with each increasing N level while little increase occurred in corn. We conclude that N rate and time of application does affect yield and quality of row crop residues. This would have an affect on supplementation of livestock grazing row crop residues.

The need for an effective and nontoxic preharvest desiccant for grain sorghum (Sorghum bicolor (L.) Moench) has been recognized for many years. Studies were conducted to compare glyphosate [(N-phosphonomethyl) glycine] to sodium chlorate and paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) on hybrids RS 626 and Tophand. Glyphosate was more effective than sodium chlorate or paraquat in reducing grain, leaf, and stem moisture content. Glyphosate reduced grain moisture content to 13% or lower within 1 week after treatment from original grain moisture content of 20, 30 or 40%. Glyphosate prevented growth of axillary buds of grain sorghum and killed all established johnsongrass and Coloradograss in treated agreas. Lodging of grain sorghum was insignificant for 3 weeks following glyphosate treatment, despite heavy rainfall and high wind velocity. Germination of treated grain was not affected by glyphosate at rates of 0.56 and 1.12 kg/ha. The low mammalian toxicity and the absence of phytotoxicity from soil residue suggests that glyphosate may be a valuable preharvest grain sorghum desiccant.

Millet [Pennisetum typhoides (Burm.) Stapf and Hubbard] yields more forage than sorghum [Sorghum bicolor (L.) Moench] does in certain areas of the Southern Coastal Plain. Yield differences are associated with low soil pH in some instances. Experiments were conducted to elucidate the relation between soil pH, forage yield, and selected chemical composition of sorghum and millet. Management practices and plant nutrient applications were applied in a manner and at a level shown by other experiments to be adequate. The forage from both crops was analyzed for N, P, K, Ca, Mg, Al, and Mn. Upon completion of the experiment, soil samples were analyzed for P, K, Ca, Mg, Al, and Mn and soil pH was measured. Millet forage yield was unrelated to the soil pH in the pH range used. Sorghum forage yield increased 2,000 kg/ha when soil pH increased from 5.2 to 5.6. The concentration of Mg in sorghum forage was found to be greater at soil pH of 5.8 and above, while the concentration of Al and Mn decreased at a soil pH ≥ 5.2. The concentration of Ca increased more at soil pH ≥ 5.8; while the concentration of Al and Mn decreased at a soil pH ≥ 5.2. The concentration of Ca increased in millet forage at a soil pH ≥ 5.2; while P and Mg content increased at a soil pH ≥ 5.8. Based on this study, it is recommended that liming acid soils in the Southern Coastal Plain to increase soil pH increases sorghum forage yields and improves the mineral nutritional quality of both sorghum and millet forage.

Picloram (4-amino-3,5,6-trichloropicolinic acid) residues in soil may occur as a result of weed control practices on cropland and injure subsequent crops. This study was conducted to determine how soil residues of picloram affected the growth and dry matter production of sorghum (Sorghum bicolor (L.) Moench) ‘Topland’ and soybeans (Glycine max (L.) Merr.) ‘Hill’ grown in soil at various time intervals after picloram had been applied. The potassium salt of picloram was applied at 1.12 kg/ha and incorporated by disking into a Wilson clay loam soil 1 ½, 3, 6, 7, 12, 14, 16, 19, and 26 months before planting of sorghum and soybeans in the Spring of 1972 and 1973. Soil, sorghum, and soybeans were analyzed for picloram content at time of harvest. After maturing, crop plants were counted and harvested by clipping two rows, 4.1 m long at the soil level in each plot. Plants were weighed and oven-dried for dry matter determination. Germination tests were conducted with harvested sorghum seed. Sorghum was grown on picloram-treated soils 12 months after application without reduction in plant numbers, dry matter production, flowering, or germination. No picloram was detected in sorghum seed (immature and mature) produced by plants seeded 6 or 12 months after application of herbicide to the soil. Because soybeans were sensitive to small amounts of picloram in the soil, they should not be grown in a picloram-treated clay soil for at least 2 years after application. Earlier planting risks possible reduction in stand and dry-matter production in situations similar to this study.

In the semi-arid Great Plains yields of grain sorghum [Sorghum bicolor (L.) Moench] are almost always limited by lack of rainfall or soil moisture during some part of the growing season. The purpose of this study was to determine if minimal land shaping practices in combination with antitranspirant application would increase yield levels of dryland grain sorghum. Variables were width of watershed, width of growing bed, applied N, and foliarly applied antitranspirant combined in a central composite experimental design. Use of contoured, compacted bare micro-watersheds increased grain sorghum yields of adjacent growing beds considerably even in two relatively wet years. However, yields of the entire area (growing bed plus watershed) decreased. Atrazine (2-chloro-ethylamino-6-isopropylamino-s-triazine) as an antitranspirant at 0.2 to 0.3 kg/ha effectively increased sorghum grain yields under conditions of solid planting and adequate nitrogen. The antitranspirant-nitrogen interaction was especially positive under conditions of moisture stress. Since most grain sorghum is grown under conditions where moisture stress is likely, further work on the use of antitranspirants is warranted in order to establish the conditions of response.

En las investigaciones llevadas a cabo en las plantas de Sorghum vulgare var. Cuba C-102 y Pennisetum glaucum, de 1 a 7 meses de edad, sembradas en igualdad de condiciones y en suelo infestado con Helicotylenchus dihystera, H. erythrinae, Pratylenchus zeae, Xiphinema bassiri, Trichodorus sp. y Criconemoides sp. pudimos comprobar que el Sorghum es atacado fuertemente por H. erythrinae, H. dihystera, P. zeae y más levemente por X. bassiri y Criconemoides sp. observándose una fuerte necrosis y detención del desarrollo radical. Las raíces de Pennisetum no presenntaban lesión alguna, mostrando un desarrollo normal. Se recomienda no utilizar el Sorghum en las rotaciones con cultivos infestados por los nemátodos citados, pudiendo ser sustituido por Pennisetum, que no es tan susceptible. | In the research carried out in plants of Sorghum vulgare var. Cuba C-102 and Pennisetum glaucum, from one to seven months old, sowed in soil infected with the nematodes Helicotylenchus dihystera, H. erythrinae, Pratylenchus zeae, Xiphinema bassiri. Trichodorus sp. and Criconemoides sp. we observed that Sorghum vulgare was strongly attacked by H. erythhrinae, H. dihystera and P. zeae. Sorghum was attacked also, but less strongly, by X. bassiri and Criconemoides sp. The attack produced a strong necrosis and a detention of root development. Pennisetum roots showed no lessions, and those plants developed normaly. Due to the difference observed, we recommend not to use Sorghum in crop rotations with cultures susceptible lo the nematodes mentioned above.

En la región de Sabaneta, (Estado Barinas), Yaritagua, (Estado Yaracuy) y Maracay, (Estado Aragua), se encontraron plantas de sorgo, Sorghum bicolor (L.,) MOENCH, con una enfermedad caracterizada por bandas cloróticas, que luego se hacen necróticas y provocan la ruptura del tejido. Estas plantas generalmente no llegan a florecer. El organismo causante se encuentra en forma sistémica en la planta y es capaz de producir esporas sexuales y asexuales en el huésped. El patógeno fue identificado como el hongo Sclerospora sorghi WESTON y UPPAL, y es señalado por primera vez en Venezuela. Se encontró afectando también a la maleza conocida como "falso Johnson" Sorghum arundinaceum; la cual constituye una segura fuente de infección y perpetuación del patógeno. | SUMMARY Downy mildew of Sorghum, Sorghum bicolor (L.) MOENCH, caused by Sclerospora sorghi WESTON and UPPAL is first described in Venezuela. The disease was observed affecting seriously plants of sorghum and "false Jhonson", Sorghum arundinaceum STAPF. VEL AFF., at different locations: Sabaneta (Barinas), Guarabao (Yaracuy) and Maracay (Aragua). The diseased plants exhibit chlorotic areas in the leaves, parallel stripes of green and white tissues, which turn brownish and necrotic; later the leaf shred. Shredding of leaves is a very conspicuous symptom. The affected leaves soon become necrotic; they dry from the tip downwards to the base. The diseased plants remain stunted, fail to flower and produce grain. Oospores and conidia (sporangia) were extremely abundant in the shredded leaf tissue. S. arundinaceum is surely a common and constant source of inoculum. Some details about the morphology of the fungus, as well as about the behavior of different sorghum cultivars are given.

While many laboratory procedures have been proposed for estimating feeding quality of perennial grass and legume forages, none have been adequately tested for their potential in predicting quality of corn and sorghum silages. The objective of this phase of a comprehensive study was to assess the value of six biological procedures proposed for predicting forage digestibility of silages of corn (Zea mays L.) and sorghum (Sorghum bicolor (L.) Moench, S. sudanense (Piper) Stapf, and their hybrid). In vivo digestible dry matter (DDM) of 51 corn and sorghum silages (17 in each of 3 years) was determined using sheep in conventional feeding trials. A modified Tilley and Terry (1963) in vitro procedure (T-T DDM), gave the highest correlations with in vivo DDM (r = 0.83 for corn silages and 0.91 for sorghum silages). A “direct acidification” in vitro rumen fermentation procedure resulted in in vitro DDM which was also highly correlated with in vivo DDM (r = 0.50 and 0.91 for corn and sorghum silages, respectively). Within the corn silages, the correlation between direct avidification DDM and in vivo DDM of 18 entries with high grain percentages was only 0.19, while that for seven entries with low grain percentages was 0.93. Apparently, the combination of large amounts of available carbohydrates in the high grain entries and the phosphate buffer led to erratic growth and digestive action by the rumen bacteria. A 6-hour rumen fluid fermentation procedure gave DDM values which were 36 to 38% of the T-T DDM values and were poorly correlated with in vivo DDM. A cellulase-acid pepsin procedure gave DDM values for both corn and sorghum silages that were 56% of the T-T DDM values; however, cellulase-acid pepsin DDM was positively correlated with in vivo DDM of sorghum silages (r = 0.72) and negatively correlated with in vivo DDM of corn silages (r = −0.42). Two procedures that involved the neutral detergent extraction (Goering and Van Soest, 1970) and a 48-hour rumen fluid fermentation gave in vitro DDM values which were highly correlated with in vivo DDM (r = 0.73 to 0.90). A multiple correlation analysis revealed that little improvement of the simple correlation between specific laboratory procedures and in vivo DDM was attained by combining procedures. We developed simple regression equations to predict in vivo DDM from T-T DDM and direct acidification DDM for corn and sorghum silages.