Recurrent selection for mineral content in wheat and barley

Abstract

Three cycles of recurrent selection were completed for 89Sr content of grain in wheat and barley. The purposes were to ascertain the gain that could be achieved in three cycles of selection and to learn about correlated changes in content of other mineral elements. In each species selection was bidirectional resulting in two populations, one high and one low in 89Sr content. In wheat each cycle of selection resulted in genetic gain. The average response per cycle was 7.4±2.6% in the high population and -12.4±1.5% in the low population. In barley gain was achieved in cycles 1 and 2. The average response per cycle was 12.2±3.8% in the high population and -11.2±4.9% in the low population. The heritability of 89Sr content in the F2 generation was 24% and 38% in the high and low populations of wheat and 31% and 34% in the high and low populations of barley, respectively. Selection for Sr content in grain caused correlated changes in Sr content in other plant parts. In wheat there was a negative correlated response in Sr content in mature leaves, while seedling plants in in the two populations did not differ. In barley, leaf Sr content was unaffected, but seedling plants in the high and low populations differed significantly. Correlated changes in Ca content tended to parallel changes in Sr content in all plant parts in both species. Selection for grain Sr also affected P, K, Mg and Mn in wheat, and K, Mg and Na in barley. These correlated responses were not always consistent with the direction of Sr selection among plant parts or between species.