Seed Characteristics and Field Establishment in Indiangrass, Sorghastrum nutans (L.) Nash1

Abstract

Spikelets harvested in 2 successive years from 11 seed sources of indiangrass, Sorghastrum nutans (L.) Nash, were evaluated for seed set, caryopsis weight, germination at varying times following harvest, and ability to establish plants in the field under different conditions and at varying times following harvest. An appropriate level of seed‐source variation in the seed generation was considered assured by breeding background and management of seed sources. Correlation coefficients showed establishment capability to be closely associated with each of the other traits, although correlation of establishment and spikelet germination appeared to vary according to age and treatment of spikelets, in both germination and establishment tests. Four of five source F values for establishment declined to nonsignificance at .20 when establishment data were adjusted for multiple regression on caryopsis weight and some measure of spikelet germination. Adjustment seemed most effective when spikelets tested for germinability in the laboratory and those used in field establishment had undergone comparable dormancy reduction through either aging or laboratory treatment. Major seed‐source differences in establishment were attributed to laboratory‐evaluated differences in seed traits. Possibility of lesser differences not so attributable was noted. Findings agreed with those of a previous study having different breeding background and management of seed sources. Applications and limitations of laboratory seed analyses, as means of evaluating field establishment capability in breeding programs, were discussed.