Inheritance of Pod Calcium Concentration in Snap Beans (Phaseolus vulgaris L.)

Significant variation for pod Ca concentration among snap bean genotypes was previously observed. To evaluate and better understand the genetics that control calcium concentration of pods in snap bean, two populations of snap beans were evaluated during the summers of 1995 and 1996 at Hancock, Wis. These populations were Ca2 (`Top Crop' × `Evergreen') and Ca3 (`Slimgreen' × `Evergreen'), therefore forming a half-sib structure. The experimental design used in this experiment was an 8 × 8 double lattice repeated each year. No calcium was added to the plants, which were grown in a sandy loam soil with 1% organic matter and 600 ppm Ca. To ensure proper comparison for pod calcium concentration among cultivars, only commercial sieve size number 4 pods (a premium grade, 8.3 to 9.5 mm in diameter) were sampled and used for calcium extractions. After calcium was extracted, readings for calcium concentration of extracts were made using an atomic absorption spectrophotometer. Statistical analyses resulted in distinct differences among genotypes and between years for pod calcium concentration (P = 0.01) in both populations. No significant year × genotype interactions were observed. To assess the power of selection for pod calcium concentration in snap beans, variance components and heritabilities are estimated and discussed.