Five group II and five group III soybean [Glycine max (L.) Merr.] cultivars released over a 50‐year period were grown at 12 location‐year combinations in the Midwest to evaluate genetic changes for seed yield, plant height, lodging, seed protein, and oil content and for phenotypic stability for seed yield. Current cultivars yielded 25% more seed than the original plant introductions in both maturity groups. Changes for the other characteristics were not consistent, however. Regression of cultivar means on environmental indices showed a consistent, linear increase in seed yield across the range of test environments, indicating equal stability for yield among the cultivars tested.
Combining ability analyses were computed on a diallel cross of eight inbred sorghum lines in the F1 and F2 generations. Five of the lines were standard combine height grain sorghums and three were widely diverse and relatively recent introductions differing for height and maturity genes. The objective of the study was to determine the usefulness of recent sorghum introductions in a hybrid sorghum breeding program and to determine the yield components responsible for any heterosis obtained. Heterosis was striking, but only if at least one of the parents was an introduction. General combining ability effects were high in the F1 and F2 but specific combining ability effects were high only in the F1. The correlation between the yield of the midparent and the yield of the F1 (r = .07) indicated that the superior parents could not have been selected phenotypically. Number of seeds per head was the most important component of yield in the F1 generation. From the available data it could not be ascertained whether the outstanding performance of the three introductions as parents was due to genetic diversity of many genes or to hybrid vigor associated with a relatively few height and maturity genes.
‘Ioreed,’ ‘Frontier,’ and ‘Common,’ three cultivars of reed canarygrass, Phalaris arundinacea L., each grown at four rates of N, were evaluated for dry‐matter yield, percentage of crude protein, and in vitro dry‐matter disappearance (IVDMD). Nitrogen was applied at 75, 150, 300, and 600 kg/ha/yr. There was a large increase in dry‐matter yield and percentage of crude protein in response to increased N fertilizer, but IVDMD was not affected by N rate. Differences between cultivars were small for all traits. Interactions between N rates and cultivars involving dry‐matter yield existed but did not change the ranking of cultivars.
Perennial ryegrass (Lolium perenne L.) (RG)‐Kentucky bluegrass (Poa pratensis L.) (BG) mixtures, seldom recommended in the past, are becoming more popular since the development of several turf‐type RG cultivars. Older RG cultivars produce poor quality turf because of coarseness and poor mowing quality. The objective of this study was to determine whether a relatively new turf‐type RG cultivar can be grown in a mixture with BG without sacrificing turf quality. A series of mixtures containing one of three RG cultivars (‘Manhattan,’ ‘Pelo,’ and ‘Linn’) and one of three BG cultivars (‘Pennstar,’ ‘Windsor,’ and ‘Kenblue’) was planted on a Typic Fragiudalf soil (Wooster silt loam) in the field in 1972. Three RG seeding rates (0.25, 0.5, and 1.0 kg/100 m2) and two N fertilizer rates (1.7 and 3.4 kg/100 m2) were used. BG was seeded at 1 kg/100 m2 on all plots. Botanical composition of the turf was obtained by counting BG and RG tillers in four samples from each subplot. Quality was determined by rating each subplot on a 1 to 9 scale. The results indicated that Manhattan, a turf‐type RG, produced a high quality turf when mixed with any of three BG cultivars. Mixtures containing Linn, an older RG cultivar, were generally poor in quality but quality differed according to which BG cultivar was in the mixtures. Mixtures containing Manhattan RG or Pelo, an intermediate quality RG, were dominated by the RG, especially in the 2nd year, while those containing Linn RG were dominated by the BG. Mixtures containing Windsor or Pennstar BG averaged higher in quality than those containing Kenblue BG. However, this difference was not apparent in mixtures containing Manhattan RG. Seeding rate had an effect on composition, primarily the 1st year. N rates were not associated with differences in quality or composition. It is concluded that turf‐type RG can be used successfully in mixtures with BG.
Twenty different bird‐resistant grain sorghum hybrids were tested in Ohio in areas where birds consistently reduce corn yields. Very little bird damage was observed and yield data indicate that these hybrids are potential substitutes for corn in areas of Ohio where corn yields are severely reduced by bird depredation.
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