The history, origins and classifiction of sorghum; Morphology and reproduction; Cytology and Genetics; Plant breeding; Hybrid and tetraploid grain sorghums, and colchicine effects; Physiology and Agronomy; The chemistry of the sorghum plant; The utilization of grain sorghum; Syrup, sorgos and sudangrass; Broomcorn; Witchweeds; Birds; Sorghum insect pests; Sorghum diseases.

Pearl millet, Pennisetum typhoides (Burn.) Stapf and C. E. Hubb.; foxtail millet, Setaria italica L.; and proso millet, Panicum miliaceum L. were evaluated for resistance to the C-biotype greenbug, Schizaphis graminum (Rondani), a recent serious pest of sorghum, Sorghum bicolor (L.) Moench. All trials were conducted in growth hambers at 27 C. Survival and reproduction of adult greenbugs confined to seedling and mature plants were greater on sorghum than on the millet species. The millets were also more resistant than sorghum on the basis of plant injury scores. Pearl millet seedlings were slightly more resistant than mature plants. Pearl millet supported the most greenbugs and proso the least in seedling trials with greenbugs confined to the three millet species individually and in all possible paired combinations. Since the millet species evaluated were highly resistant, they could serve as substitute crops for sorghum until greenbug-resistant sorghum cultivars become commercially available.

Palatability differences occurred among two sudangrass varieties (Sorghum sudanense (Piper) Staph.), four sorghum ✕ sudangrass hybrids (Sorghum bicolor (L.) Moench.) ✕ (Sorghum sudanense (Piper) Stapf.). The grazing preference of both cattle and sheep for these varieties was negatively correlated with HCN concentration. Leaf width, stem diameter, percent leaf, and percent dry matter were not associated with palatability in seven of eight trials. Total sugar concentration was never directly associated with palatability. The lack of association between percent leaf or sugar concentration and palatability did not agree with previous reports. The results suggest that selection for low HCN concentration to avoid prussic acid poisoning may also result in increased palatability.

Experiments were conducted at Lincoln, North Platte, and Alliance, Nebraska, during 1965 and 1966 to determine the effect of herbicides, herbicide incorporation, and rotary hoeing on ‘Nebraska 505’ sorghum [Sorghum bicolor (L.) Moench.] grown in 50.8-cm rows. Preplant soil incorporation and preemergence herbicide applications were superior to preemergence + shallow incorporation with a rotary hoe in weed control and grain yields. Postemergence rotary hoeing improved weed control and sorghum yields on herbicide treatments. The best treatments were atrazine (2-chloro-4-ethylamlno-6-isopropylamino-s-triazine) at 2.24 kg/ha and atrazine norea [3-(hexahydro-4,7-methanoindan-5-)y-ll, l-dimethylarea] at 0.84 + 1.68 kg/ha (1.12 + 2.24 kg/ha in 1965) + two rotary hoelngs at Lincoln, atrazine at 2.24 kg/ha at North Platte, and rotary hoeings but no herbicide at Alliance. Only at Lincoln did sorghum yields on herbicide-treated plots approach that on handweeded checks. On the low organic matter soils at North Platte and Alliance, atrazine injury limited sorghum yields.

Stubble heights of 8, 10, 15, and 25 un were imposed on ‘Gahi-1’ pearl millet (Pennisetum typhoides [Burm.] Stapf. and C. E. Hubb.), ‘Haygrazer’ and ‘Sudax SX-12’ sorghum-sudangrass hybrids (Sorghum vulgare Pers. ✕ Sorghum sudanense Stapf.), and ‘Trudan II’ sudangrass hybrid (Sorghum sudanense Stapf.) at either the first, second, or third harvest with other harvests being cut to a uniform height. Considering all cultivars tested, marked reductions in yields were obtained when they were defoliated to 8 cm as compared with 25 cm for 21 out of 24 harvests (87% of the harvest). Net gains in yield ranging from 1,203 to 2,039 kg/ha were realized within a 30-day growth period by raising the stubble height from 8 to 25 cm at a single harvest. Dry matter production was influenced more by variation in stubble heights at the second harvest than when these same variations were imposed at the first or third harvest. Gahi-1 pearl millet showed a different regrowth pattern than sorghum-sudangrass or sudangrass hybrids, as regrowth was more dependent on terminal buds and less on tillering. Regrowth from terminal buds increased for all the summer annual cultivars as the height of defoliation was raised from 8 to 25 cm. Basal and axillary tillering increased as the height of defoliation was lowered from 25 to 8 cm for the sorghum-sudangass hybrids. The nitrogen content of the forage was not reduced when the harvest height was lowered from 25 to 8 cm at the first or second harvest.

Reference is made to intervarietal variations in the biochemical composition of the leaves, stem and grain. Approximately 126 references are listed.

Screening sorghum (Sorghum bicolor (L.) Moench) varieties for seedling resistance to the sorghum shoot fly (Atherigona varia, Meigen) gave inconsistent results, and “recovery resistance” (tolerance) proved a better character. When levels of pest attack were high, infestation levels exceeded 90%, indicating that there was little worthwhile seedling resistance in the sorghums being tested. In contrast, good recovery resistance was shown by the cultivars ‘Serena’ and ‘Namatare,’ and more than 70% of the infested plants recovered and yielded normally. Recovery resistance was associated with good yield from tillers, and heritability was fairly high. ‘Namatare’ proved a successful parent, and grain sorghums with a combination of good shoot fly recovery resistance and yield were developed from crosses between Namatare and susceptible sorghums.