RESPONSE OF NON-NODULATING, NODULATING, AND SUPER-NODULATING SOYBEAN GENOTYPES TO POTASSIUM FERTILIZER UNDER WATER STRESS

Abstract

Soil moisture is a principal environmental factor limiting legume productivity in the tropics and sub-tropics. A pot experiment was conducted at the wire house of National Research Centre, Cairo, Egypt to study how potassium (K) fertilizer can mitigate the adverse effect of water stress. Three Japanese soybean (Glycine max L.) genotypes, non-nodulating (NN) (En 1282), nodulating (N) (Eneri) and super-nodulating (SN) (En-b0-1) were grown under two potassium fertilizer levels (25 and 150 mg kg⁻¹ soil as K1 and K2, respectively). The water stress (WS) was conducted for eight days. WS significantly reduced nodules numbers and weights, shoot dry weight, relative water content, seed yield, oil, total carbohydrate contents while protein was significantly increased in the three soybean genotypes compared with well-watered (WW). Water stress and/or K treatments caused significant increase in both free amino acids and proline as well as shoot nitrogen in the three soybean genotypes.

Keywords:

• chemical composition
• growth
• nodulation
• N₂-fixation
• potassium
• soybean
• water stress

ACKNOWLEDGMENT

Dr. Magdi Abdelhamid is grateful to National Institute of Crop Science, Japan for providing soybean seeds to undertake this study.