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Water availability and root-knot nematode management alter seedcotton yield through similar effects on fruit distribution patterns
- Snider, John L., Davis, Richard F., Earl, Hugh J., Timper, Patricia
- Field crops research 2019 v.233 pp. 88-95
- Nematoda, cotton, drought, fruits, fumigants, fumigation, irrigation, nematode infections, plant diseases and disorders, root-knot nematodes, water stress, yield components
- Both root-knot nematode (RKN) infection and water deficit negatively affect yields in many cotton growing regions of the southern United States. The objective of the current study was to determine whether seedcotton yield limitations due to drought and RKN infection were brought about through similar effects on yield components and boll distribution patterns. To this end, yield component and boll distribution assessments were conducted for a seven-year study in Tifton, Georgia that included three irrigation treatments and two fumigant treatments to manage nematodes. Seedcotton yield was strongly affected by year, irrigation treatment and fumigant treatment, but no interactions were observed between the two factors, illustrating that the yield limiting effects of nematode infection could not be mitigated by providing a water-replete condition. Yield declines due to nematode infection and water deficit were primarily driven by a decline in total boll density. Yield distribution patterns revealed that water deficit negatively affected boll numbers for all branch types and at all positions along a fruiting; furthermore, the mainstem node of peak boll distribution was lower under drought. The trend was similar for nematode infected plants (except that boll density at position two was not affected by fumigation and retention at position three increased slightly). One notable difference between drought and nematode effects was that the relative decline in boll density for drought-stressed plants was greater at sympodial positions further from the mainstem, but this was not the case due to nematode infection.