Genotype by Environment Analysis of the Performance of Two Low Phytate Pea Lines
Approximately 60-80% of total phosphorus is stored in crop seeds as phytate. Phytate is not readily available to humans and non-ruminant livestock because of their lack of phytase enzyme. Surface water pollution may occur as the result of excretion of non-digested phytate phosphorus. In addition, some essential micronutrients are less available to humans and non-ruminant animals as they may be bound to phytate. Two low-phytate pea lines (1-2347-144 and 1-150-81) were recently developed using chemical mutagenesis of the cultivar CDC Bronco by the Crop Development Centre, University of Saskatchewan. The purpose of this research was to study the agronomic attributes of the two low-phytate lines and three normal-phytate lines grown over two years at three locations in Saskatchewan.
The low-phytate lines had similar seedling emergence counts, vine length, lodging score, and mycosphaerella blight score when compared with CDC Bronco. The low-phytate lines had somewhat later days to flowering and days to maturity, and somewhat lower grain yield and seed weight than CDC Bronco. Harvested seeds of the low-phytate lines had substantially higher inorganic phosphorus (1.21-1.28 mg/g) concentration than CDC Bronco (0.24-0.25 mg/g) and the other normal-phytate cultivars. The concentration of phytate phosphorus was reduced in low-phytate lines by about 60% of CDC Bronco. The total phosphorus concentration was similar in all lines and ranged from 3.50-3.80 mg/g. The low-phytate lines had germination rates similar to CDC Bronco under normal conditions; however, their germination rate was reduced after the seeds had been stressed by accelerated aging or cold treatments. Recurrent selection for yield will be used to select low-phytate lines with increased yield, earlier maturity and improved germination under stressed conditions.