Eight parental lines, 16 F1 hybrids, 16 2‐component blends of parental lines, and 16 2‐component hybrid blends of grain sorghum (Sorghum bicolor L. Moench) were grown in 9 environments over 2 years in Iowa.Standard analyses of variance and analyses for estimating stability parameters were made for grain yield and yield component data. A stable entry or population was defined as one with a regression coefficient close to 1.0 and deviations from regression near zero. A high mean yield also was deemed an essential attribute for an entry or population.The parameters for grain yield indicated that hybrid blends were the most productive and stable population type, although none of the populations were distinctly superior for all parameters. Hybrid blends had the highest mean yield over all environments and were second among the population types in terms of low deviations from regression and an average regression coefficient near 1.0. Data for the components of yield tended collectively to support the conclusion that hybrid blends were the most stable population type.A hybrid was the highest yielding individual entry in each environment, except one, where a hybrid blend was the most productive. Also, a hybrid had the highest mean yield among individual entries over all environments. Across all environments, 22 of the 32 blended populations yielded more than the pure‐stand mean of then: components. Yields for twelve of the 16 hybrid blends exceeded their mid‐component value. Collectively, the heterogeneous populations yielded 102% of the mean of their homogeneous components. Six of the blends exceeded the mean pure stand yield of their more productive component.

Field research was conducted in Tennessee at Jackson in 1991 and at Milan in 1992 to compare the effect of MSMA and pyrithiobac on cotton development, yield, and quality. In separate treatments to different plots, pyrithiobac at 0.14 kg ai ha–1did not affect development, yield, and quality of cotton. MSMA at 2.24 kg ai ha–1decreased cotton plant internode length 10 to 15% and height by 15% 5 wk after late treatment both years. MSMA applied to 50 cm cotton reduced subsequent plant height in 1992, but other plant characteristics were not affected. In 1991, MSMA increased squares and decreased blooms and bolls for monopodia and sympodia position one and two, which suggested a delay in plant development. In 1991, mechanical harvest lint yields were decreased by MSMA at first harvest while increasing second harvest lint yields. However, in 1991 only MSMA applied late decreased total harvest lint yield 20%. Plant mapping data determined that the yield decrease was a result of decreased yields at sympodia positions one and two. Cotton seed arsenic analysis indicated that MSMA-late increased arsenic levels by ≈ 1 ppmw in 1991 for sympodia at position one and two compared to the untreated check, while position two contained the highest level of 1.8 ppmw.

Knowledge of average yields that can be expected over a period of years for a soil mapping unit helps in the use of soil survey information. Even the most recent soil surveys must rely on estimates from experiments and experience. For yields of principal crops these estimates are adjusted for the effects of soil‐water relationships and often must be extrapolated to similar soils for which no data are available. The objective of this study was to determine the yield on adjacent soils varying primarily in their moisture‐supplying capacity and natural drainage, of adapted perennial and annual warm and cool‐season forages and small grains grown under the same general climatic influence and management. The yields of 12 forage crops that grow mostly from spring to autumn were measured for 5 years on five adjacent soils with similar aspect. Later, eight winter small grain cultivars were grown for hay and grain for 3 and 4 years, respectively, on the same sites. The soils used belong to the Eutrochrepts, Hapludults, Paleudults, Fragiudults, and Ochraquults great groups. The soils were characterized in terms of their yield for each crop, ranging from 1,035 to 5,735 kg/ha for the warm‐season crops and from 2,225 to 6,760 kg/ha dry matter for the cool‐season forages. Since the many forage crops adapted to the landscape studied have different periods of growth and can satisfy different animal nutritional needs in different forage systems, no attempt was made to compare species within each soil studied. However, the data presented will help in soil selection for crops needed within specific forage systems on the landscape.

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Float bed culture, common in the production of tobacco transplants, was investigated for the production of the salad vegetables leaf lettuce and radicchio. Experiments were conducted during Spring and Summer 1999. Seeds were planted on 61 cm × 61 cm, 2.54-cm-thick expanded foam sheets and floated on nutrient solution until plants were ready for harvest. Lettuce plants of the four cultivars evaluated were harvested 53 days after planting. Yields ranged from 99 to 181 g/plant. In the same experiment, aeration of the solution was compared with static solution with plants grown in aerated nutrient solution yielding significantly better than those grown in static solution. There was not a significant cultiva × aeration interaction for yield. Radicchio plants were seeded on expanded foam sheets at 20 plants per sheet. Plants were harvested 69 days after seeding. Those that had been aerated had significantly higher number of heads and leaf, head, and root weight than the nonaerated ones. There were no differences in total leaf weight among the five cultivars evaluated, but `Red Treviso' had significantly fewer and lower weight heads and more root weight than the other four cultivars.