Variations in germination and grain quality within a rust resistant common wheat germplasm as affected by parental CO2 conditions

Parental conditions, such as temperature, soil moisture, nutrient availability, light and competition during plant growth and seed maturation, influence seed quality and germinability. Elevated CO2 concentration can be also treated as a parental condition and should be considered when evaluating crop productivity under future climate conditions. Available information on the effect of parental CO2 conditions on seed quality and germinability is limited, particularly for intra-population variations. Therefore, seeds of several entries of a rust resistant common wheat germplasm (Triticum aestivum L., AZ-MSFERS-82RR PI# 552988) grown under three CO2 concentrations (350, 700 and 1000 ppm) were studied to determine the intra-population variation in seed germinability and grain quality, and the relationship between grain quality and germinability. Germination percentage was near 100% for all treatments, but different patterns in germination rate were found among entries: (1) both 700 and 1000 ppm CO2 increased germination rate comparing with 350 ppm CO2, (2) both 700 and 1000 ppm CO2 reduced seed germination rate, and (3) 700 but not 1000 ppm CO2 reduced germination rate. These variations were apparently entry-related, indicating the existence of intra-population variation in the response of germination rate to parental CO2 conditions. Chemical constituents responded to increasing CO2 concentration differently among entries, but the C/N ratio was similar among CO2 treatments. A negative correlation between C content and germination rate was found. The importance of this correlation in seeds of other species should be evaluated because it may serve as an indicator for the effect of CO2 enrichment on seed germinability. Because elevated CO2 parental conditions may affect both seedling establishment and grain quality of crops, intra-population variations in the response of seed germinability and grain quality to CO2 conditions should be considered in future breeding efforts. # 2003 Elsevier Science B.V. All rights reserved.