Field Emergence and Plant Density of Sand Bluestem Lines Selected for Increased Seed Germination

Abstract

ABSTRACTUnder field conditions water is often inadequate for satisfactory seedling establishment. This research investigated the field emergence and plant density of two lines (AB‐medium and CD‐tall) of sand bluestem (Andropogon hallii Hack.) and three generations of selection (Syn‐0, Syn‐1, and Syn‐2). Populations AB‐medium Syn‐1 and AB‐medium Syn‐2 were developed from AB‐medium Syn‐0 using two cycles of recurrent selection for increased seed germination at a low water potential. Similarly, CD‐tall Syn‐1 and CD‐tall Syn‐2 were developed from CD‐tall Syn‐0. Our objective was to verify if the increase in seed germination of selected populations would also lead to an increase in field emergence and plant density. Field testing involved planting the six lines in a randomized block design replicated four times at three locations over a 3‐yr period. Field emergence and plant density were determined using a frequency grid method at 30, 60, and 90 d after planting (DAP). Percentage field emergence and plant density varied only with sand bluestem line (P < 0.01), generation of selection (P < 0.01), and number of DAP (P < 0.05). Field emergence averaged 52.5, 57.4, and 61.1% for generation Syn‐0, Syn‐1, and Syn‐2, respectively. Plant density averaged 13.8, 15.2, and 16.1 plants m−2 for generation Syn‐0, Syn‐1, and Syn‐2, respectively. Therefore, selection for increased seed germination in sand bluestem also resulted in greater field emergence and higher plant density.