Selection for iron‐efficient old world bluestems

Abstract

Old World bluestems (Bothriochloa ischaemtim (L.) Keng., B. intermedia (R. Br.) A. Camus, B. caucasica (Trin) C. E. Hubb.) native to southwest Asia, have a high torage and beef production potential on the southern Great Plains. However, iron deficiency can be a problem in these warm‐season grasses grown in eroded, calcareous old fields. In this field study 12 Old World bluestem selections were planted into an iron‐deficient, calcareous soil (Quinlan loam, Typic Ustochrepts). Large differences among the selections in degree of chlorosis and dry matter production were found. The selection PI 301535 was the highest dry matter producer and had slight to no chlorosis. In contrast, the cultivars ‘WW Spar’ and ‘Caucasian’ were low to moderate in dry matter production and rated moderate to severe in chlorosis. Dry matter production over all selections during the third growing season was directly correlated (r = 0.90**) with chlorophyll concentration and inversely correlated (r = ‐0.77**) to severity of chlorosis. The diversity in iron efficiency found among Old World bluestems in this study indicates that with additional collections and screening there is a high potential to select other iron‐efficient strains.

Key words:

• Bothriochloa
• Southern Great Plains
• Calcareous soil
• Warm‐season grasses
• Chlorosis
• Chlorophyll