Soybean genotypic differences in sensitivity of symbiotic nitrogen fixation to soil dehydration

Abstract

Soybean genotypic differences in sensitivity of symbiotic nitrogen fixation were monitored on the following varieties: Impala (South African Republic), Maverick (USA), Rankoshi No.1h (Japan) and their reactions to the water supply at the beginning of the growth stage R1 and R2 – blooming in an interaction with the Nitrazon inoculation of the seeds before a sowing. Seeding of the particular soybean genotypes was made into the containers whilst 50% of seed corn from each genotype was before the sowing inoculated by the usage of Nitrazon inoculant. Water stress was secured by an irrigation interruption for a 7-day period in the mentioned growth stage. This stress had a negative impact on the relative water content (%RWC) plants, proline content (μmol.g^-1Fresh Weight), osmotic potential (MPa), stress index as well as an amount of nodules on the roots by the all monitored varieties. According to an evaluation of the mentioned indicators more significant proline accumulation was confirmed by the genotype Maverick especially by the variant exposed to water deficit (3,25 μmol.g^-1FW according to the calculations on 100% RWC) without the inoculant Nitrazon use and inoculating variant 2,99 μmol.g^-1Fresh Weight according to calculations on 100% RWC. Genotype Maverick had got the best reaction to water stress and even more noticeable resistance to the stress was monitored in the variant with Nitrazon application in the foregoing seed treatment of soybean seeds. The opposite response to the inoculation was monitored by Impala genotype.