Grain carbon isotope discrimination and ash content of cv. Nestos bread wheat plants selected for high and low yield in absence of competition

Approximately 1000 plants of bread wheat (Triticum aestivum L., cv. Nestos) were evaluated in Technological Education Farm of Florina, Greece, during the 1998–99 season, in the absence of competition (1 plant/m2). Grain yield of the individual plants ranged from 1 to 90 g (mean: 30.5 g/plant, and SD = 17.1 g). Ten plants with high yield (51-83 g) and ten plants with low yield (10-23 g) were selected to investigate, whether phenotypic variation of individual plants for grain yield was resulted from genetic variation or not. Carbon isotope discrimination (Δ), considered to be an indirect assessment of water use efficiency, and ash content were determined in grain samples of the selected plants. Statistically significant differences were found for both traits with high yielding plants having higher Δ values and lower ash content compared to low yielding plants. Yield of individual plants correlated significantly and positively with Δ values (r=0.65) and negatively with ash content (r=−0.43). Negative correlation was also found between Δ and ash content (r=−0.43). These results confirm the existence of genetic variation within cv. Nestos.