Crimson Clover Seed Production and Volunteer Reseeding at Various Grazing Termination Dates

Abstract

Crimson clover (Trifolium incarnatum L.) is a widely used cool‐season annual clover in the southeastern USA, but is not considered a dependable reseeder. Grazing termination dates (GTD) of 2‐wk intervals from 1 April to 15 May for 3 yr were used on small plots of seven crimson cultivars. Seed production characteristics, seed germination after seed harvest, remaining hard seed percentage after 90 d heat treatment, and volunteer reseeding were determined. There was a general decline in flower density, seed weight flower−1 and seed yield as GTD was delayed. There was variability among cultivars for flower density and seed weight flower−1, but in only 1 out of 3 yr for seed production. Percentage germination, soft seed, and hard seed after seed harvest were not influenced by GTD. Cultivars did differ for percentage germination and hard seed in 2 of 3 yr. Cultivar ranking was not consistent among years except for Columbus that always had high germination and low hard seed percentages. ‘Auburn’ and ‘Flame’ maintained the best hard seed percentage after the 90 d heat treatment. Volunteer seedling densities of 100 m−2 or higher occurred if grazing was terminated by mid‐April except for Columbus. The poor reseeding of crimson clover is due to the initial low hard seed production and decline of hard seed percentage during the summer.