Effects of soil temperature and precipitation on nodulation intensity of some soybean (Glycine max. (L.) Merr.) cultivars

Abstract

Root-nodule formation in soybean varieties from maturity groups: '00' and '0' was studied in 1976 - 1978. The highest number and dry weight of root nodules was found in variety 'Evans' while cultivar 'Altona' was the poorest in this respect. The differences found in the tested material were probably caused by the specific interaction between the plant genotype and the particular Rhizobium japonicum strains. The intensity of nodule formation was influenced by climatic conditions, particularly temperature and precipitation. However, temperature and precipitation studied separately showed little effect on nodule formation only the joint effect of both factors was significant as is shown by calculated correlation coefficients. Significant increase of both: nodule number and its dry weight was found during the second period of studies, e.g. durind the end of flowering.