Influence of moisture deficiency and high temperature on protein accumulation in seeds of modern soybean varieties

Abstract

Purpose. The climate forms the areal borders of plant distribution; biochemicals formation and accumulation largely depend on it. The experiments aimed to examine moisture deficiency and elevated temperature effects on protein accumulation in seeds of current soybean varieties were carried out in 2012-2013.

Material and Methods. The material was a series comprising 83 samples of Ukrainian and foreign selection belonging to three ripeness groups with different genetic plasma. Sowing was performed in the Eastern forest-steppeUkraine in accordance with the conventional procedure under field conditions and in a simulated "dry field". The protein content in seeds was determined by Kjeldahl method.

Results. It was found that accumulation of large protein amounts in seeds occurs in the case of stable heat supply in during the bean filling and ripening phases, furthermore, the temperature regimen exerts greater influence than moisture provision. The soybean series was divided into four classes according to protein content in seeds. Class 4 (with a very high protein content) was formed only under "dry field" conditions at elevated temperatures and soil moisture deficit. The information about significant modification variability of protein accumulation was confirmed. All the varieties transferred from one class to another. This suggests a specific reaction of soybean cultivars to stress factor action during bean forming, filling and ripening. In the light of varietal variability under ifluence of environmental conditions, the varieties studied are differentiated into six subclasses in accordance with a level of the trait expression over the study years.

Conclusions. The work is of practical significance, since the sources of high protein content for breeding programs to improve the seed quality have been identified.