All anatomical components except the cuticle, trichomes, xylem, fibers, and bundle sheaths were digested after in vitro leaf digestion of Avena sativa L., Secale cereale L., Lolium multiflorum Lam., Poa pratensis L., Dactylis glomerata L., and Festuca elatior L. for 24 hours; Pennisetum typhoides (Burm.) Stapf and C. E. Hubb. for 48 hours; and Cynodon dactylon (L.) Pers. for 96 hours. Some breakdown of the bundle sheath in bermudagrass occurred. The outer thin‐walled parenchymatic bundle sheath but not the inner sheath of the cool‐season grasses was digested. The larger cells, less compact arrangement, and larger intercellular spaces of the mesophyll of cool‐season grasses as compared to bermudagrass or pearl millet appeared to allow the microorganism to be in contact with a larger surface area in a given time. These mesophyll characteristics may explain why the rate of digestion was faster in the cool‐season grasses than in pearl millet and bermudagrass.Observations on the arrangement of mesophyll in ‘Tift 18’ and ‘Tift 23’ pearl millet and on the patterns of digestion would indicate that digestibility could be increased by breeding for certain cell arrangements.

Native forages of the southern United States are frequently low in nutrients and poorly digestible, while improved pastures are the opposite. Since this area produces rapid growth of pines, which is a major use of the land, the integration of pines, pastures, and cattle seem to offer an efficient and economical form of management. Therefore, in a 20-year study Coastal bermuda (Cynodon dactylon), dallis (Paspalum dilatatum), and Pensacola bahia (P. notatum) grasses were grown in pastures with no trees, and with slash pine (Pinus elliottii) spaced 3.7 × 3.7 and 6.1 × 6.1 m. The trees were grown free of competition for 3 years, grasses were established during the 4th year, and grazing by yearling cattle began the 5th year. The pastures were then fertilized, grazed, and burned for 15 years. Increasing tree canopies reduced forage production of all grasses. Bahiagrass was the most shade tolerant, while Coastal bermuda was the least. Liveweight gains during the 15 years of grazing totaled 3933, 2302, and 1518kg/ha from pastures with no pines and slash pine spaced 6.1 × 6.1 and 3.7 × 3.7, respectively. Survival of slash pine was low due to heavy attacks by southern pine coneworm and southern fusfform rust. However, the trees grew rapidly and averaged 19.0 and 16.9 m in height, 30.0 and 33.3 cm in diameter, and 181.4 and 90.7 m3/ha of pulpwood after 20 years from the 3.7 × 3.7 and 6.1 X 6.1 spacings, respectively. Slash pine at these spacings planted in undisturbed, native vegetation were 16.0 and 15.7 m tall, 19.6 and 23.4 cm in diameter, and produced 145.5 and 63.6 m3/ha of pulpwood. Combining the production of pines and beef on improved pasture offers an opportunity for multipleproduct yields. Since this approach to agroforestry is not trouble-free, good management is required. Landowners, especially those with small holdings, should consider these alternatives to single-product management when planning their cropping system.

Reduced lignin concentrations found in brown midrib (bmr) mutants of sorghum, Sorghum bicolor (L.) Moench., have great potential for increasing the in vitro dry matter digestibility (IVDMD) of sorghum forage. The objective of this study was to determine the effects of five bmr mutants on IVDMD, lignin concentration and total sugars of young vegetative forage that would be used for grazing or hay. Forage from bmr 12 and bmr 18 harvested 4 weeks after planting was significantly higher in IVDMD than their normal counterparts in each of the 3 years tested. Three other mutants were not consistently higher in IVDMD indicating a possible environmental interaction. Total reducing and non‐reducing sugars were not related to IVDMD and the bmr mutants did not have a significantly different total sugar concentration than normal types. Four weeks after planting, IVDMD of bmr 12 forage was 7.2 and 5.6 percentage units higher than normal forage for leaves and stems, respectively. The differences observed for the bmr gene should lead to significant improvement in animal performance.

Bermudagrass [Cynodon dactylon (L.) Pers.] is a well adapted and widely used forage grass in southern U.S.A. As new cultivars and hybrids are developed there is a need to evaluate and compare their performance to that of the accepted cultivars. This study was initiated to evaluate three established cvs.. Coastal, Coastcross‐1, and Midland, two new cvs., Callie (C. nlemfuënsis Vander.) and Tifton 44 and three experimental hybrids designated Tifton 67, 68, and 84. A split‐split plot design was used to evaluate harvest frequency and fertilizer levels on performance of the grasses on a Plinthic Paleudult soil. The grasses were main plots, N fertilizer rates of 336 and 672 kg/ha were subplots and harvest frequencies of 1, 2, 4, and 8 weeks were sub‐subplots. Data were gathered on forage yield, in vitro dry matter digestibility (IVDMD), crude protein (CP) content, and persistence of the grasses. Dry matter yields were highest in the 1st year for the robust type bermudagrass cvs. Callie, Tifton 67, and Tifton 68. In the 2nd year, Coastal and Tifton 44 were superior due in part to stand losses of the more robust types. Increasing the N rate from 336 to 672 kg/ha significantly (P = 0.05) increased yields, but there were significant interactions with both harvest frequency and genotype. Annual dry matter yields increased with harvest interval except that in the 2nd year there were only small differences among the 1, 2, and 4 week interval. Persistence of the bermudagrasses measured by a single harvest in the spring of the 3rd year ranked Tifton 44, Coastal, and Midland as the top three cultivars under both fertilizer regimes. The other cultivars yielded from 36 to 0.0% of Coastal at the lower N rate and from 57 to 0.0% at the higher rate. These data along with visual observations indicate the superiority of the rhizomatous cvs. (Coastal, Tifton 44, and Midland) in persistence and ability to produce early spring growth.

High quality forage production is needed in late summer and fall until frost. The pearl millet (Pennisetum americanum ✕ napiergrass (P. purpureum Schum.) interspecific hybrids have potential for producing high quality forage during this period but more than 1 year's data on a number of hybrids using different female parents is limited. In 1976, 1977, and 1978, 20 pearl millet ✕ napiergrass interspecific hybrids were seeded in the field in a Fuquay soil (Arenic Plinthic Paleudults : loamy, siliceous thermic) and evaluated for dry‐matter yield percent in vitro dry‐matter digestibility (IVDMD), percent crude protein, agronomic characteristics (seed Production, pest resistance, yield distribution), and breeding behavior (effects of male and female parents on dry matter yield). Most of the interspecific hybrids were equal to the best pearl millet hybrids in yield, IVDMD, and protein. In 1977 and 1978, six and two interspecific hybrids, respectively, were significantly (P = 0.05) higher in dry matter yield. One hybrid, Tift 23A ✕ N23, yielded 34 and 27% more dry matter in 1977 and 1978, respectively, than the best pearl millet hybrid. Hybrids with ‘Tift 23A1’ yielded over 25% more dry matter than hybrids with ‘Tift 23D2A1 when the same male parents were used on both female parents. One of the major advantages of the interspecific hybrids is that they produced almost 50% of their forage from after the middle of August until early December. This study also showed that of the three female parents tested, Tift 23A1 produced the highest yielding hybrids and that much variability for maximizing yield exists among the napiergrass clones used as male parents in the interspecific hybrids.