Seed Size, Coat Thickness and Water Uptake Relationships of Chickpea.

To expand marketability of chickpea (Cicer arietinum L.) grain for Western Canada, associations between nutritional content, seed size and seed behaviour are being explored.  While the average seed size is inherent to genotype, the physical seed size and coat characteristics are also affected by growing conditions such as water availability.  The objective was to test varying seed size classes of chickpea cultivars for seed coat thickness and water uptake.  Field plots were seeded in two years at two Saskatchewan locations, Saskatoon and Swift Current; seed yield was collected and plot seed categorized into 50 mg classes, then tested for coat thickness and water imbibition over time by the Peleg and a monomolecular model.  Largest seeded genotypes were CDC Diva, CDC Xena and CDC Yuma in both years.  Small seeded genotypes were CDC Desiray, CDC Anna and Myles.  Seed coat thickness appeared to be associated with market class, the Desi types had colored seed coats and thicker seed coats.  As seed size increased, seed had thinner coats.  In drought, seed had thinner coats but the same pattern of small seed having the thicker coats was still evident.  Larger seed were more effective at water uptake, and imbibed water at higher rates than their small seeded counterparts.  For the initial rate of water uptake, seed with size >300 mg had the greater rates of uptake.  Lower rates of water uptake were seen for small seed sizes.  Large sized seed rapidly takes up water for seedling vigor or for food processing.