Search Results
Abstract
Field and greenhouse experiments were conducted to study the relationships among plant growth traits; ratios of dry weights among nodules, roots, and shoots; and traits associated with N2-fixation potential of common bean (Phaseolus vulgaris L.). The dry weights of plant parts and the traits associated with N2-fixation differed among the 10 lines studied. A visual nodulation score used to evaluate N2-fixation potential was correlated positively with nodule dry weight, acetylene reduction (AR) value, root dry weight, and shoot dry weight for plants grown under both greenhouse and field conditions. AR values, nodule dry weight, and visual nodule scores of plants grown in the greenhouse were correlated positively with the respective figures obtained for field-grown plants. These methods of evaluation can be used to discriminate among lines for N2-fixation potential.
Abstract
Mulching ‘Puebla 152’ beans with rice hulls to a depth of 4 cm reduced afternoon soil temperature, soil temperature fluctuation, and slowed the loss of soil moisture. These effects were greatest prior to canopy closure. Fresh weight of nodules, roots, stems, leaves, and total plant increased 50%, 38%, 49%, 24%, and 38%, respectively, with mulching, but pod and final seed weight were unaffected. Mulching had little effect on the concentration of soluble and insoluble carbohydrates. N2 fixation rates (C2H2 reduction) were low (≤ 0.6 µmole/plant per hr) but were as much as 3 times higher in mulched than unmulched plants.