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RECURRENT SELECTION PERFORMANCE FOR FOV RACE 4 RESISTANCE IN SELECTED GERMPLASM AND PROGENY

 

Abstract

Recurrent selection is being used to improve Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) resistance in Upland (Gossypium hirsutum L.) and Pima (G. barbadense L.) cotton using naturally infested fields and artificially inoculum-greenhouse sites. Our primary objective is to introduce a known FOV4 dominant gene that has shown resistance in Pima into the Upland species. In 2013, 2014 and 2015, we evaluated 1155 entries for resistance. These entries were exposed to FOV4 pressure in naturally infested fields and rated. Selected entries were then self- and cross pollinated. Parental lines and F1 populations were then inoculated with FOV4 and grown under greenhouse conditions for rating and reselection. This research will provide additional germplasm to broaden the genetic base for FOV4 resistant cotton.

Introduction

In California, Fusarium wilt of cotton is a serious fungal disease that is caused by Fusarium oxysporum f. sp. vasinfectum (FOV). Practices that have reduced the effects include not planting in sandy or sandy-loam textured soils that have a high infestation of root knot nematode and use crop rotation to help manage soil inoculum levels. This has been useful with FOV races 1 and 3, but Fusarium oxysporum f. sp. vasinfectum (FOV4) has been found to cause substantial damage in the absence of root knot nematode (Meloidogyne incognita) and persists even when crop rotation is practiced. Thus, the only long-term management of FOV4 is developing resistant cultivars. One objective of this study is to evaluate a known resistant FOV4 dominant gene from Pima (PS6) for potential introgression into Upland germplasm. The second objective is to identify and develop Upland germplasm…

 

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Assessment of Fusarium in SJV Cotton: Field Evaluation Support and Variety Screening Evaluations

 

PROJECT SUMMARY
In California, Fusarium wilt of cotton has been considered a potentially serious fungal disease caused by the organism Fusarium oxysporum vas infectum (also called “FOV”). However, in the past, damage associated with Fusarium in SJV cotton has been notable only in production areas with the combination of: (a) moderate to high populations of a specific race of FOV (usually race 1 ); (b) soils witl1 a sandy or sandy loam texture; and (c) root knot nematodes present in high-enough populations to cause significant galling and root damage. Past research generally indicated that FOV damage was worst when both FOV inoculum and nematodes were present in relatively higl1 concentrations. Methods used in the past to limit damage to cotton associated with Fusarium wilt have been to avoid planting cotton in soils in which the combination of sandy or sandy loam texture is combined with the presence of root knot nematode, or grow cotton only infrequently…

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Assessment of Fusarium in the San Joaquin Valley: Field Evaluations and Variety Screening

 

Fusarium w.ilt of cotton in California has been considered a potentially serious fungal disease caused by the organism Fusarium oxysporum vas infectum (also called ”FOV”) for many decades in several areas of the San Joaquin Valley (SJV). In the past, however, damage associated with FOV in SJV cotton has been notable only in areas with the combination of: (a) moderate to high populations of one or more specific races of FOV (usually race 1 ); (b) soils with a sandy or sandy loam texture; and (c) where root lrnot nematodes were present in high-enough populations to cause some significant root damage. Past research generally indicated that FOV damage was worst when both FOV inoculum and nematodes were present in relatively high…

 

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Comparison of Subsurface Drip and Furrow Irrigation of Cotton on Very Sandy Soil Under Fusarium-Nematode Pressure

OBJECTIVES: To compare drip and furrow irrigation by measuring
the emergence, plant growth characteristics, yield, rate of plant die-off, and water use of Acala cotton on very sandy soil with a great deal of pressure from nematodes and Fusarium wilt.

PROCEDURES: This experiment was started in the Spring of 1989 on a 0.4-ha plot of uniform loamy sand soil.

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