Yields of Three Cotton (Gossypium hirsutum) Cultivars as Influenced by Spurred Anoda (Anoda cristata) Competition

The effect of duration of spurred anoda [Anoda cristata (L.) Schlecht.] competition on maturity and yield of three cotton (Gossypium hirsutum L.) cultivars was studied during 1975 through 1977. The seed cotton yields averaged over 3 yr for ‘DES 21326-04′, 'Stoneville 213′, and ‘Deltapine 16’ were 1850, 1570, and 1520 kg/ha, respectively. DES 21326-04 produced 50% of its yield 3 to 8 days earlier than Deltapine 16 or Stoneville 213 with no spurred anoda competition and 6 to 10 days earlier with spurred anoda competition. Spurred anoda competition from planting until July 10, August 10, and September 10 resulted in average yield decreases of 12, 37, and 38%, respectively. Yield reductions varied with cultivar. Deltapine 16 was more competitive than the other two cultivars. Early-season spurred anoda competition reduced the yield of the earliest-maturing cultivar DES 21326-04 more than that of Deltapine 16 or Stoneville 213.