2008 Annual Report
1a.Objectives (from AD-416)
The objective of the Western Integrated Cropping Systems Research Unit is to develop new materials and methods for sustainable production of high quality cotton and other crops grown in the irrigated western United States. Specifically, research on integrated management of insects, identification and management of invasive plant pathogens and development of novel germplasm should enable efficient and profitable crop production with limited impact on the environment.
1b.Approach (from AD-416)
An interdisciplinary team consisting of an entomologist, geneticist, ecologist and plant pathologist will work together with Federal, State, and University collaborators to solve the major problems facing sustainable production of irrigated crops in the context of environmental stewardship. Efforts focus on discovering and developing new pest insect controls based on parasites and pathogens that impact only pest insects. Determination of overwintering locations and movement of pest insects will allow for more accurate prediction of future pest infestations and to identify release points of parasites. A process for rapid identification of race 4 Fusarium oxysporum vasinfectum (FOV), a disease new to the US will be developed and used to determine the extent of the infestation and to measure plant responses to remediation attempts. Conventional breeding techniques in combination with modern molecular techniques will lead to cotton germplasm with improved yield and fiber qualities and increased resistance to insects and diseases. “Replacing 5303-21220-002-00D (5/05)."
Soil treatments were examined for their ability to reduce Fusarium oxysporum f. sp. vasinfectum (FOV) race 4 inoculum. Three treatments, methyl bromide+chloropicrin, telone+chloropicrin, and solarization, significantly reduced disease symptoms compared with no treatment. Both high- (60-80 C) and low-temperature (30-40 C) dry heat treatments were evaluated for eliminating FOV in cottonseed. In both tests FOV infection levels decreased with increasing temperature and treatment duration. No temperature treatment eliminated the fungus from cottonseed. Unique isolates of FOV from the southeastern U.S. were identified in collaboration with University of California-Davis and Louisiana State University scientists. The isolates were evaluated for their effects on a panel of cotton varieties varying in susceptibility to Fusarium wilt. Twenty-eight commercial detergents were tested for their ability to kill FOV spores. Four detergents proved effective as disinfectants. The research addresses National Program 304–Crop Protection and Quarantine, Component V. Pest Control Technologies, c) Physical/Mechanical and Cultural Control, and e) Chemical Control. The insect disease, Beauveria bassiana, was tested against adult Lygus bugs at low temperatures. Results indicated mortality caused by the disease varied with both temperature and disease strain. Methods to calibrate the sweep net sampling technique for Lygus adults in cotton were developed and validated. Collection efficiency of the sweep net was about 20% in pre-blooming cotton, but declined to low levels by mid-season. The research addresses National Program 304–Crop Protection and Quarantine, Component V. Pest Control Technologies, a) Traditional Biological Control, and Component VI. Integrated Pest Management Systems and Areawide Suppression Programs, a) Sampling Methods, Detection and Monitoring. Discovery and mapping of molecular markers in cotton continued. A genetic map covering about 60% of the cotton genome and representing 24 of the 26 chromosomes was constructed. DNA sequences of the markers used were previously posted in the Cotton Marker Database (http://www.cottonmarker.org/projects/). Studies to evaluate germplasm for response to the race 4 isolate of FOV continued. A population of 140 breeding lines from a cross between Upland and Pima cottons was tested for resistance to FOV races 1 and 4, and root-knot nematodes, in cooperation with University of California-Riverside and UC-Davis scientists. Results suggested the genes active in the plant disease-response varied with environmental conditions. Ten candidate molecular markers associated with FOV susceptibility or resistance were identified. The markers identified and mapped will be used in additional research to evaluate associations with important cotton traits. The research addresses National Program 301–Plant Genetic Resources, Genomics, and Genetic Improvement, Component II. Crop Informatics, Genomics, and Genetic Analyses, c) Genetic Analyses and Mapping of Important Traits, and National Program 304–Crop Protection and Quarantine, Component V. Pest Control Technologies, b) Breeding for Host Plant Resistance.
Discovery of new isolates of Fusarium oxysporum f. sp. vasinfectum (FOV) in the southeastern U.S. Concern for potential spread of the highly virulent FOV race 4 from California to other cotton production regions has accentuated the need for updated information on distributions of FOV races in the U.S. Recent studies indicated changes in the distributions of FOV races since the previous survey in 1983. In cooperation with University of California-Davis and Louisiana State University scientists, genetic analyses were used, by ARS scientists in the Western Integrated Cropping Systems Research Unit in Shafter, CA, to identify unique isolates of FOV collected from the southeastern cotton production region of the U.S. This discovery indicates a greater diversity of FOV races in the U.S. than was previously recognized, and suggests a need for a more comprehensive survey. Evaluations of selected commercial cotton cultivars for susceptibility to the new FOV isolates indicated some isolates were highly virulent. These findings indicate additional studies are warranted to assess the vulnerability of current varieties and identify those with useful levels of resistance. This accomplishment addresses National Program 304-Component V. Pest Control Technologies, c) Physical/Mechanical and Cultural Control.
Development of methodology for calibration of the sweep net for sampling Lygus adults in cotton. Sampling methods for Lygus in cotton have been intensively studied, but accurate estimates of sampling efficiency are not available. Understanding of the relationship between sample population estimates and actual population levels is essential for development of improved treatment thresholds. ARS scientists in the Western Integrated Cropping Systems Research Unit in Shafter, CA developed a novel method of establishing known population levels of adult Lygus in small cotton plots and determined the collection efficiency of the sweep net in relation to plant development. These methods can be used to unambiguously test the myriad of factors influencing sampling efficiency, and provide a means to improve the reliability of Lygus population estimates. This accomplishment addresses National Program 304-Crop Protection and Quarantine, Component VI. Pest Control Technologies, a) Sampling Methods, Detection and Monitoring.
Commercial detergents for disinfecting Fusarium oxysporum f. sp. vasinfectum (FOV) contaminated equipment. The movement of soiled farm equipment is an important mechanism for spreading FOV race 4 inoculum among fields in the San Joaquin Valley of California. Equipment can be disinfected with household bleach, but this material is corrosive to metal surfaces. Four of the twenty-eight commercially available detergents evaluated by ARS scientists in the Western Integrated Cropping Systems Research Unit in Shafter, CA were effective for killing FOV race 4 spores. These results provide growers with noncorrosive alternatives to bleach for sanitation of contaminated field equipment. This accomplishment addresses National Program 304-Component V. Pest Control Technologies, c) Physical/Mechanical and Cultural Control.
Fusarium wilt-resistant breeding lines of Pima cotton. Fusarium oxysporum f. sp. vasinfectum (FOV) race 4 is a strain of Fusarium wilt recently documented in California. The pathogen is highly virulent against Pima cotton varieties, and only a single commercial variety with useful levels of resistance is available. Four breeding lines (SJ-07P-FR01 to FR04) with good, but not complete, resistance to FOV race 4 were released by ARS scientists in the Western Integrated Cropping Systems Research Unit in Shafter, CA, in cooperation with the University of California. The SJ-07P-FR lines provide needed sources of FOV resistance to cotton breeders and expand the available genetic base of resistant germplasm. This accomplishment addresses National Program 304–Crop Protection and Quarantine, Component V. Pest Control Technologies, b) Breeding for Host Plant Resistance.
5.Significant Activities that Support Special Target Populations
|Number of the New MTAs (providing only)||1|
|Number of New Germplasm Releases||1|
Bennett, R.S., Hutmacher, R.B., Davis, M.R. 2008. Seed Transmission of Fusarium oxysporum f. sp. vasinfectum Race 4 in California. J. Cotton Sci. 12:160-164.
Chen, Z., Scheffler, B.E., Dennis, E., Triplett, B.A., Zhang, T., Chen, X., Stelly, D., Rabinowicz, P., Town, C., Arioli, T., Brubaker, C., Cantrell, R., Lacape, J., Ulloa, M., Chee, P., Gingle, A.R., Haigler, C.H., Percy, R.G., Saha, S., Wilkins, T., Wright, R.I., Van Deynze, A., Zhu, Y., Yu, S., Guo, W., Abdurakhmonov, I., Katageri, I., Ur-Rahman, M., Zafar, Y., Yu, J., Kohel, R.J., Wendel, J., Paterson, A. 2007. Towards Sequencing Cotton (Gossypium) Genomes. Plant Physiology. 145:1303-1310.
Dara, S.K., Mcguire, M.R., Ulloa, M., Kaya, H.K. 2008. Evaluation and Molecular Characterization of Beauveria bassiana for the Control of the Glassy-winged Sharpshooter (Homoptera: Cicadellidae) in California. J. Entomol. Sci. 43(2):241-246.
Detar, W.R., Chesson, J.H., Penner, J.V., and Ojala, J.C. 2008. Detection of soil properties with airborne hyperspectral measurements of bare fields. Transactions of the ASABE 51(2):463-470.
DeTar, W.R. 2008. Yield and growth characteristics for cotton under various irrigation regimes on sandy soil. Agricultural Water Management. Vol 95/1:pp 69-76.
Spurgeon, D.W. 2008. Seasonal patterns in host-free survival of the boll weevil (Coleoptera: Curculionidae) in the subtropics. Journal of Entomological Science. 43(1):13-26.
Spurgeon, D.W., Sappington, T.W., and Rummel, D.R. 2008. Host-free Survival of Boll Weevils (Coleoptera: Curculionidae) from Two Regions of Texas. Southwest Entomol. 33:151-152.
Wang, C., Ulloa, M., Roberts, P.A. 2008. A transgressive segregation factor (RKN2) in Gossypium barbadense for nematode resistance clusters with gene rkn1 in G. hirsutum. Mol. Genet. Genome 279:41-52.
Zhang, J., Yuan, Y., Niu, C., Hinchliffe, D.J., Lu, Y., Yu, S., Percy, R.G., Ulloa, M., Cantrell, R.G. 2007. AFLP-RGA markers in comparison with RGA and AFLP in cultivated tetraploid cotton. Crop Science 47:180-187.