Evaluation of the response to limited water, nitrogen and phosphorus supply in spring barley genotypes selected for vigorous seminal roots

Fourteen F₅- and F₆-pedigrees, previously selected for a more vigorous seminal root system in a cross population of spring barley, were compared with their parents in the response to severe post-sowing drought and limited N- and P-supply. The materials were studied in glass-faced soil boxes, sand-vermiculite cultures and in the field. The F₅'s juvenile rooting superiority was not totally preserved for further growth stages suggesting partly different genetic backgrounds responsible for the seminal root system at various growth stages. Results indicated an absence of close genetic correlations between the seminal and adventitious root systems. The selected spring barley pedigrees exhibiting a more vigorous rooting benefit much more for their ability to avoid drought conditions than for their tolerance to nitrogen and phosphorus limitations. Especially under decreased N availability, the enhanced root extension in F₅ₛ resulted in a depressed shoot dry matter production. Despite a relatively low differentiation in the grain yield, some of the selected F₆-pedigrees were simultaneously found to indicate a high yield potential, an improved stability or tolerance to low-input.