Original Articles

Comparison of osmopriming and seed coating with calcium salts for green bean performance under field conditions. I. Cotyledonal cracking

Published in: South African Journal of Plant and Soil
Volume 22, issue 1, 2005 , pages: 9–15
DOI: 10.1080/02571862.2005.10634673
Author(s): T.G. Mazibuko,, A.T. Modi,

Abstract

Cotyledonal cracking is a physiological disorder, which appears as one or a few transverse fissures across legume seed cotyledons early during seed germination or seedling emergence. The fissures hinder translocation of nutrients to the developing seedling and cause stunted seedling growth and low yield. The objective of this study was to examine the effect of calcium, applied as a seed coat or priming osmoticum, on cotyledonal cracking in green beans (Phaseolus vulgaris L.) under field conditions. Seeds of six green bean cultivars (‘Imbali’, ‘Elangeni’, ‘Tongati’, ‘Sodwana’, ‘Tokai’ and Outeniqua') were primed or coated with CaSO4, CaCI2 and Ca(NO3)2 solutions (1,10, 50,100 and 1000 mM). Control seeds were not primed or coated. Dried (~ 10% moisture content on fresh mass basis) seeds were planted in the field at three sites in KwaZulu-Natal, South Africa. A significant reduction in cotyledonal cracking occurred in response to increased calcium molarity, however, no effect of the anions of the calcium salts was observed. Coated seeds performed significantly better than primed seeds with respect to reduction of cotyledonal cracking. Cultivars differed significantly in their sensitivity to cotyledonal cracking. Hence, across all sites, cultivar response to calcium treatments was also correlated to the extent of cotyledonal cracking. There were no significant differences between sites with respect to cotyledonal cracking or calcium effects. This study provided evidence that cotyledonal cracking on green beans can be alleviated by seed calcium treatment.

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