INTERACTIONS OF POD-ZONE PH AND CALCIUM CONCENTRATION ON FRUCTIFICATION OF GROUNDNUT GROWN IN SOLUTION CULTURE

Abstract

Low soil pH and calcium (Ca) deficiency in both the root and pod-zone are important problems for groundnut production world-over on account of the light-textured nature of the soils suitable for its production. An experiment was conducted to examine the interaction of pH and calcium (Ca) supply in the pod-zone on reproductive growth of groundnut. Attached gynophores were cultured singly in solutions at three pH levels (3.5, 5.0, and 6.5) in factorial combination with three solution Ca concentration levels (500, 1000, and 2000 μM). Generally, low pH had an adverse effect on the reproductive growth of groundnut. Approximately 58% of the gynophores cultured in treatment combinations with pH 3.5 produced normal pods, compared to 94% in combinations with pH 5.0 and 6.5. In addition, both pod mass and seed mass were severely depressed in treatment combinations with pH 3.5 compared to combinations with pH 5.0 and pH 6.5. Increasing Ca from 500 to 2000 μM Ca at low pH had limited ameliorative effect on pod-set, pod mass and seed mass, whereas positive responses were higher at the intermediate pH of 5.0. A combination of high Ca and pH appeared to be detrimental to pod and seed growth.

Keywords:

• Arachis hypogaea L.
• embryo development
• gynophore
• pod expansion
• pod-set