Fruiting of Cotton. I. Effects of Moisture Status on Flowering1
- G. Guinn and
- J. R. Mauney2
Yield of cotton (Gossypium hirsutum L.) is proportional to the number of bolls produced, which is influenced by flowering rate and boll retention. Previous reports have presented conflicting information on the effects of water deficit on fruiting some indicated increased flowering while others indicated decreased flowering in response to water deficit. Tests were conducted in 1978, 1979, and 1980 on an Avondale clay loam (a member of the fine-loamy, mixed, hyperthermic family of Typic Torrifluvents) at the Arizona Cotton Research Station in Phoenix to determine the effects of plant water status at daerent times during the season on flowering of cotton. Water deficits decreased flowering in 1978 and 1980. A pronounced lag in response caused flowering to continue unabated during much of each stress period. Once the flowering rate declined, however, it did not start to recover until about 3 weeks after stress was relieved by irrigation. Only in 1979 did we observe more flowers in plots in which the first postemergence irrigation was delayed. The population of lygus bugs (Lygus hesperus Knight) was higher in 1979 than in 1978 or 1980. Furthermore, lygus counts were higher in irrigated than in stressed plots. Because lygus bugs have been shown to cause square shedding, early irrigation may have decreased early flowering indirectly in 1979 by increasing bug populations and resultant square shedding. We found no evidence, however, for a physiological stimulation of flowering of cotton by a water deficit.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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