Spurred anoda (Anoda cristata) interference in wide row and ultra narrow row cotton.

摘要

A field experiment was conducted in 2000, 2001, and 2002 at Stoneville, Mississippi, USA, to determine the effects of spurred anoda interference on yield loss in cotton cultivars Delta Pine 5415 (Gossypium hirsutum) and Pima S-6 (G. barbadense) grown under wide (1.0 m; WR) and ultra narrow (0.25 m) row (UNR) spacing. The relationship between spurred anoda density and dry weight per plot was linear. At a spurred anoda density of 8 m-2, spurred anoda dry weight per plot was 507, 322 and 777 g m-2 in 2000, 2001, and 2002, respectively. However, spurred anoda did not interfere with seed cotton yield in 2001, which was probably due to the low branch development in that year. Yield losses exceeded 55% at a spurred anoda density of 8 m-2 compared with the controls in WR and UNR. The effect of spurred anoda density on the number of bolls was nearly identical in 2000 and 2002 regardless of the cotton cultivar and row spacing. Boll weight decreased in response to spurred anoda interference. Spurred anoda interference reduced cotton branch dry weight in WR but not in UNR. The yield decrease as a result of spurred anoda interference in WR was due to the reduction in boll retention or fruiting sites (predicated on a decrease in branch weight). However, in UNR, the yield decrease was due to plant mortality; the plant density of both cotton cultivars decreased by one plant for each additional spurred anoda, but the yield per plant for surviving plants remained constant. Neither WR nor UNR cotton had significant advantage in response to spurred anoda interference. The decreased boll weight observed in UNR, and the failure to increase the number of bolls m-2 to compensate for decreased boll weight in UNR compared with WR may limit its appeal to cotton producers..