Effect of Drought and Defoliation Stress in the Field on Soybean Seed Germination and Vigor

Abstract

Although drought and defoliation stress have been shown to reduce soybean [Glycine max (L.). Merr.] yield, little information has been published regarding their effects on soybean seed quality. Field experiments were conducted in 1986, 1987, and 1989 to evaluate the effect of drought and defoliation (1989 only) stress during soybean seed development on seed germination and vigor. Essex (MG [maturity group] V) and Union (MG III) were grown in 1986 and 1987, and Harper (MG III) and McCall (MG 00) in 1989. Moisture treatments were either well watered or drought stressed during seed development (R5 to R7). In 1989, a total defoliation treatment was also imposed at R6 as an additional stress factor. There were significant reductions in yield and yield components following drought stress in all 3 yr and following defoliation in 1989. Leaf conductance and transpiration also decreased in the drought stress treatments. There was no effect of drought stress on seed germination or seed vigor as measured by accelerated aging germination and the cold test across the four cultivars (determinate and indeterminate) and 3 yr. In 1989 slight changes in 3‐d germination and conductivity occurred for some drought stress treatments. Most of this response, however, was related to increased occurrence of hard seed, which does not represent an indication of a change in vigor. Seed germination and vigor were significantly reduced for small, flat, shriveled, and underdeveloped seeds that only occurred following defoliation. These seeds represented a small portion of the seed lot that would normally be removed during conditioning. The data suggest that drought stress would have no effect on seed germination or vigor, unless the stress was severe enough to produce shriveled, flat, underdeveloped seeds.

Effects of Weed Interference and Starter Fertilizer on Subsequent Seed Germination and Vigour of Soybean (Glycine max [L.] Merr.)

“…In other words, seed germina- Singh et al (1972) reported that large seeds of soybean had greater supply of stored energy to support early seedling growth. Vieira et al (1992) also suggested that when stress was intense enough to cause wrinkled and underdeveloped seed, a decrease in seed vigour was evident.…”

“…High quality seed lots may improve crop yield in two ways: first because seedling emergence from the seedbed is rapid and uniform, leading to the production of vigorous plants, and second the percentage seedling emergence is high were optimum plant population density could be achieved under a wide rang of environmental conditions (GhassemiGolezani and Mazloomi-Oskooyi 2008). Seed quality is affected by various factors experienced during development and maturation (Vieira et al 1992;Westgate et al 1989). Environmental stresses during the growth and development of the mother plant may influence the quality of the produced seeds.…”

“…According to Vieira et al (1992) drought and lack of fertilization decreased the germination of soybean seed but a decrease in seed vigour was evident only when stress was intense enough to cause wrinkled and / or underdeveloped seeds. Other research workers found a decrease in both germination and seed vigour of soybean (Westgate et al 1989;Keigley and Mullen 1976) and corn (Hunter et al 1977;Cloninger et al 1975) seed developing in stress conditions as drought.…”

Effect of partial root-zone irrigation system on seed quality changes of Persian clover (Trifolium resupinatum L.) during seed development and maturation

“…In this case, ZehtabSalmasi et al (2006) showed that limited water supply during seed development and maturation led to significant reduction in seed quality of dill. However, some researches revealed that seed quality was not significantly affected by water limitation during seed filling period (Eskandari et al, 2015;Vieira et al, 1992). These results show that different crops have different reaction to water shortage during seed filling period.…”

Produtividade e qualidade fisiológica de sementes de duas cultivares de arroz de terras altas em dois sistemas de cultivo

“…Avaliando o efeito da adubação mineral e de lâminas de água na qualidade fisiológica de sementes de arroz, Crusciol et al (1999b) observaram menor vigor de sementes, pelo teste de condutividade elétrica em cultivo com menor disponibilidade hídrica. Essa variação de resultados evidencia a necessidade de estudos sobre o assunto (Vieira et al, 1992), principalmente em relação aos cereais.…”