Cotton Fruiting Modification with Mepiquat Chloride¹

Abstract

Fruiting of cotton (Gossypium hirsutum L.) was evaluated by main stem node and branch position in 11 experiments over a 4-yr period to determine if mepiquat chloride (MC) (1,1-dimethylpiperidinium chloride) altered fruiting position development or retention. Fruiting events were monitored for main stem nodes 7 to 20 for first fruiting position on sympodial branches (SB1), secondary fruiting positions on sympodial branches (SB> 1), and fruiting positions on monopodia) branches (MD). Ten consecutive plants were plant mapped from each of four replications in each experiment and combined as a 40-plant total for analysis of treatment and node effects using experiments as replications. Mepiquat chloride was applied at 49 g ha-1 when average plant height was 0.57 m and plants averaged 0.9 white blooms m-'. Summed across nodes, plant zones SB1, SB>1, and MD accounted for 60, 26, and 13% of all harvestable bolls, produced 37, 46, and 17% of all fruiting positions, and set 45, 16, and 23% of all fruiting positions as harvestable bolls, respectively. Application of MC did not increase total number of bolls. The interaction of MC treatment and nodes was significant for SB1 and SB> 1, with MC treated plants setting more bolls at lower nodes but fewer at upper nodes. The maximum cumulative benefit occurred at node 12 where MC treated plants had 15% more bolls matured than control plants (58.3 and 50.6 bolls m-', respectively). This advantage from MC treatment was not maintained as upper nodes matured fewer bolls than control plants. Plants treated with MC produced 3.1% fewer (P = 0.07) fruiting positions than control plants (288 and 279m-2 , respectively). Treatment by node interactions were significant for SB1 and SB> 1, with MC increasing fruiting positions up to node 15 at SB1 and up to node 9 for SB> 1, but having fewer at the remaining nodes. Early boll load was stimulated by MC. Late season boll load was decreased, apparently not by limited initiation of fruiting positions, but rather by increased abortion of fruiting forms. Use of MC according to the rate and timing of these tests would be of benefit when length of the season is a primary constraint to yield potential. In full-season, non-rank cotton, however, the early benefit in boll load is lost.

Embebição de sementes e aplicação foliar com cloreto de mepiquat no crescimento e produção do algodoeiro

“…O número de maçãs por planta, número de maçãs na posição um não foram afetadas pelo tratamento de semente através de embebição com CM (Tabelas 3 e 4). A frutificação nesta posição é importante, pois representa 65% da produção (KERBY et al, 1986;ROSOLEN, 2001). Não houve efeito das aplicações foliares para a produção, porém para número de maçãs por planta e para número de maçãs na posição um (Tabelas 3 e 4), houve redução, diferindo do obtido por Laca-Buendia (1989) que apresentou diferença na produção com o uso de Pix na dose de 50 g i.a.ha -1 .…”

Midseason Pest Status of the Cotton Aphid (Homoptera: Aphididae) in California Cotton - Is Nitrogen a Key Factor?

“…1). Part of these changes appears to be linked to the commercial introduction of mepiquat chloride, a cotton plant growth regulator, in 1981 (Kerby et al 1986) and the development of new cotton varieties with a more determinate growth pattern.…”

Chemical Regulators of Gibberellin Status and Their Application in Plant Production

“…The regime typically comprises control of vegetative growth by mepiquat-containing products, defoliation by thidiazuron and boll-opening by ethephon. The growth-retardant mepiquat chloride was commercially introduced for vegetative growth control in cotton in the USA in 1980 and has since become a cornerstone of modern cotton production (Kerby et al, 1996;Edmisten et al, 2010). Instead of or in addition to mepiquat chloride, chlormequat chloride is used for the same purpose in some countries, for instance in Australia.…”

“…Finally, decreases in quantity and quality of the lint due to weathering are reduced in the oldest, first-opened cotton bolls. Valuable contributions on different aspects of using mepiquat chloride in cotton have been presented by Cathey and Meredith (1988), Kerby et al (1986Kerby et al ( , 1996, Cook and Kennedy (2000) and Gwathmey and Clement (2010).…”