Nitrogen Fixation and Yield of Common Bean Varieties in Response to Shade and Inoculation of Common Bean

Abstract

Light is not only a primary energy source, but it is also one of the environmental factors that affect plant growth and development. Common bean (Phaseolus vulgaris L.) is commonly produced in association with maize as subordinate intercrops in the Sidama region. Under such a production system, the shade effect may limit the photosynthetic and nitrogen-fixing capacity of common beans. The objective of the current study was to assess how inoculation and shade affect the ability to fix nitrogen and yield components of common beans. Three common bean varieties (Hawassa dume, Nassir, and Ibbado), two shade levels (open and 25% shade) as well as two levels of inoculation (uninoculated and inoculated) were used for these purposes. The experiment was set up in factorial randomized complete block design (RCBD) in four replications. In this experiment, Rhizobium inoculation and shade significantly (p < 0.05) affected the number of pods plant-1 and the number of seeds pod-1. The inoculated treatment produced the maximum number of pods plant-1 (14.02) and the lowest number of pods plant-1 (10.95) was obtained from uninoculated treatments. The results also showed that the inoculated Hawassa dume variety from the open treatments derived the maximum percentage of N from N2 fixation, whereas the non-inoculated Ibbado variety from the 25% shade treatments derived the lowest percentage of N. Common bean grown on full light had significantly greater N content than shade.