Soybean Seed Quality Response to Drought Stress and Pod Position

Abstract

The effects of drought stress on soybean (Glycine max (L.) Merr.] seed quality may be influenced by morphological plant characteristics and the timing of drought stress. Determinate soybean plants were grown near Ames, lA, to ascertain the influences of the timing and frequency of drought stress and pod position on seed quality (as mea· sured by germination, seedling dry weight, and seed leachate current). Plants were well-watered (high reproductive load) or drought-stressed at Dowering (R2) to decrease potential seed number (low reproductive load). Subsequent drought stresses were implemented at the full pod (R4), seed formation (RS), and full seed (R6) stages, in addition to a nonstressed treatment. The harvested pods were grouped into the top main stem, bottom main stem, and branch positions for seed quality testing. An R2 drought-stress (low reproductive load) did not prevent reductions in seed quality from occurring when additional stress was imposed at R4, RS, or R6 plant stages. However, the R2 + R4 stress treatment increased seedling weight by 7% and weight per seed by 12% compared with the R4 drought-stress treatment. Top main stem seeds were of better quality and greater weight than seed harvested from the bottom main stem or branch positions. Branch or bottom main stem seeds were most sensitive to quality reductions when drought occurred during the RS or R6 stages. The results indicate that variable seed quality resulting from drought stress can be attributed to the timing of stress and pod position on the plant.

Phenotypic Responses of Twenty Diverse Proso Millet (Panicum miliaceum L.) Accessions to Irrigation

“…Hommel-adjusted p-values were estimated (p < 0.0001) for the same varieties (Komsomolskoe 996 and Kazanskoe 176) (Table 4). However, our data were not consistent with other reports on soybean [20], pea [21], and corn [22], where water deficit decreased seed-filling duration. Across all three years, the five varieties with the quickest maturity in both irrigated and non-irrigated fields were Bolgar 159, Kamusinszkoe 67, TU-85-087-01, Turghai, and Tuvinskoe with 82, 83, 85, 86, and 86 days, respectively.…”

Effects of drought stress on growth and yield of barley

“…II). Our data were consistent with other reports on soybean [22], pea [17] and corn [26], which showed that drought stress during seed filling had no effect on seed growth rate but decreased seed-filling duration and individual seed weight. Earliness in barley is an advantageous trait in conditions of terminal drought stress in Mediterranean environments [1,7,8,10].…”

Incorporation of crop phenology in Simple Biosphere Model (SiBcrop) to improve land-atmosphere carbon exchanges from croplands

“…The initial biomass values at emergence (Green and Sudia, 1969;Blum et al, 1980;Smiciklas et al, 1992;Richardson and Bacon, 1993;Pinhero and Fletcher, 1994;Hameed et al, 2003) were set considering the average planting density based on the plant and row spacing typical for each crop. Starting from the day of emergence, a daily LAI value was estimated based on leaf carbon (details follow), for deriving fPAR and estimating sub hourly photosynthetic assimilate, respiratory carbon (i.e.…”