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Sorghum (Sorghum bicolor L. Moench) Seed Internal Morphology Related to Seed Specific Gravity, Weathering, and Immaturity
A. Susana Goggi, James C. Delouche, and Lynn M. Gourley
Germination and vigor problems in sorghum are usually related to weathering during the post-maturation, pre-harvest period and to drought induced seed immaturity. Weathering and immaturity also lowers the specific gravity of the seeds. To examine the effects of weathering and immaturity on the internal morphology of seeds varying in specific gravity, sorghum [Sorghum bicolor (L.) Moench] seeds (Wheatland cv.) from panicles harvested at physiological maturity, exposed to field weathering or to artificially induced immaturity, were separated into high (>1.30) and low (>1.20) specific gravity levels.
Additional index words: sorghum, seed specific gravity, seed weathering, seed immaturity, scanning electron microscopy.
Phomopsis Seed Decay in Soybean with Dense Pubescence1
P.R. Thomison, D.L. Jeffers, W.J. Kenworthy, and P.B. Cregan2
Phomopsis seed decay is a major cause of poor soybean [Glycine max (L.) Merr.] seed quality in regions where the climate is warm and humid during and after seed maturation. Increasing pubescence density on soybean plants may increase retention of moisture in pods and seeds, and thereby influence seed infection by Phomopsis Iongicolla Hobbs, The objective of this study was to evaluate the effect of increased pubescence density on seed infection by P. longicolla and germination.
Additional index words: GIycine max, seed germination, seed-borne diseases, Phomopsis spp., Diaporfhe phaseolorum, Phomopsis longicolla, trichome, isogenic lines, morphology.
Relationship of Uniformity of Soybean Seedling Emergence to Yield1
A field experiment was conducted for two years at Lexington, KY to evaluate the effect of variation in the time of seedling emergence within the plant community on soybean [Glycine max (L.) Merr.] yield. Variation in time of emergence was created by planting alternate seeds in the row either 4 or 7 d after the initial plantings. In the control treatment, all seeds were planted when the initial plantings were made. All seeds were planted by hand in 0.76 m rows at a population of 26 plants m-2 (51 mm between plants in the row).
Additional index words: Glycine max (L.) Merr., plant size, crop growth rate, seed vigor.
Accelerated Aging Techniques for Evaluating Sorghum Seed Vigor1
A.E. Ibrahim, D.M. TeKrony* and D.B. Egli2
Accelerated aging is an established seed vigor test for a number of crop species. This investigation examined the effects of aging temperatures and duration of exposure on the germination of treated and untreated sorghum (Sorghum bicolor L. Moench) seed. Three temperatures (41°C, 43°C and 45°C) and three exposure periods (24, 48 and 72 h) were tested using seed lots of "Topaz" of different ages and two seed treatments (Captan and rnethoxychlor; Captan, methoxychlor and Concept II).
Additional index words: cold test, field emergence, seed safeners, seed treatment.
Occurence and Frequency of Twin and Triplet Peanut (Arachis hypogaea L.) Seedlings1
W.D. Branch and W.R. Guerke2
Cooperative research was conducted between the University of Georgia, Coastal Plain Experiment Station and the Georgia Department of Agriculture, Seed Laboratory in Tifton to study the occurrence and frequency of twin and triplet peanut (Arachis hypogaea L.) seedlings. Twin and triplet peanut seedlings were easily observed fallowing standard germination tests, however the occurrence of each was very low.
Additional index words: Groundnut (Arachis hypogaea L.), haploid breeding, and polyembryonic seed.