Variety and Row Spacing Effects on Recoverability of Soybeans from Simulated Hail Injury 1

Two soybean [ Glycine max (L.) Merr.] cultivars were grown in 100‐ and 50‐cm rows to evaluate the influence of cultivar and row spacing on recoverability from hail injury. ‘Hawkeye’ and ‘Hark’ soybeans were treated at three stages of plant development with 0, 25, and 50% stand reduction and 0, 25, and 50% stem cut‐off at ½ height. The experiment was conducted at Ames, Iowa for 3 consecutive years. The percentage yield loss averaged across years and treatments was the same (7%) for both row spacings of Hark and only 1 percentage point different (3% for 100‐cm and 4% for 50‐cm rows) for Hawkeye. No significant row spacings ✕treatments or row spacings ✕treatments ✕cultivars interactions were observed. Row spacing does not appear to warrant consideration in adjustment of soybeans for recoverability from hail injury. Average yield loss for Hark (7.0%) was more than for Hawkeye (3.5%) when averaged across years, treatments, and row spacings. The cultivars ✕stem cut‐offs interaction was not significant, but the cultivars ✕stand reductions interaction was significant at the 1% probability level. Hark had greater yield loss due to stand reduction than Hawkeye, primarily at the 50% level of stand reduction. Although small differences for recoverability did occur between cultivars, the differences were not great enough to justify the evaluation of all commercial soybean cultivars for their recovery potential. Such an evaluation would be necessary if cultivar is to be considered in the adjustment of hail losses.