Cost Considerations in Choosing Group Size for Group Testing in the Seed Potato Certification Program

Abstract

Viral diseases that can reduce yield and tuber quality are major concerns for potato growers. To produce healthy potato tubers and prevent yield reduction, a certification scheme for foundation class seed potato propagation has been established at the Seed Improvement and Propagation Station in Taiwan. The certification scheme uses an ELISA technique to index specific virus diseases such as Potato virus Y (PVY), Potato leafroll virus (PLRV), Potato virus X (PVX), Potato virus A (PVA), and Potato virus S (PVS). In order to produce foundation class potato tubers, the Dorfman group testing procedure is adopted. The Dorfman testing procedure utilizes a two-stage sampling scheme. The first stage comprises making measurements on all groups. The second stage involves no retesting for negative testing groups and exhaustive testing of all constituent individual samples of positive testing groups. In the seed potato certification scheme in Taiwan, field investigations have usually used groups of 20 plants. However, because of the limitations of available financial resources, the effect of group size on cost is an important consideration. Thus, selection of group size for design considerations is a critical issue. In order to solve the problem, we present the expected cost model as a nonlinear integer programming problem and determine the optimal group size such that the expected cost is minimized. The result demonstrates that the optimal sample size for group testing is 13 plants per group and that the cost, using this optimal group size, is not greatly different from the cost when using 20 plants per group. Thus, 20 plants per group is reasonable for the group testing procedure with regard to cost considerations. The result of this research could be useful in the execution of the seed potato certification program

Important Physiological Changes Due to Drought Stress on Oat

“…The decrease of Chl concentration in plants may be a nonstomatal limiting factor, and Chl in plants with strong drought resistance is less affected by drought (Kraus et al, 1995). Studies on legumes, chickpeas, and wheat showed that drought stress decreased the content of Chl a and b (Mafakheri et al, 2010;Mathobo et al, 2017). The Chl content of drought-tolerant varieties was higher than that of drought-sensitive varieties (Khayatnezhad and Zaeifizadeh, 2011;Sharifi and Mohammad Khani, 2016).…”

RT-PCR and Real-Time RT-PCR Methods for the Detection of Potato Virus Y in Potato Leaves and Tubers

“…First, for detection in sample sets where the PVY incidence is expected to be low, combining aliquots of tissue sap from fi ve samples into a single RNA extraction (20 μl each × 5 = 100 μl composite for extraction) can greatly reduce the number of samples screened. In this case, PVY-negative reactions indicate all fi ve [ 11 ]. For screening large sets of samples, the RNA extraction protocol can be made more economical by cutting all volumes listed by 50 % without affecting the quality of RNA produced.…”

An approach for joint optimization of probabilistic group test based on cost and time value: taking nucleic acid detection of COVID-19 as an example

“…If the test result in this group is positive, the spare blood samples of each individual in this group need to be tested separately. In the later research process, the group test method has not only been applied to the screening of various infectious diseases, but also can be used to detect battery necrosis, detect regional water pollution and determine potato planting density (e.g., Aprahamian 2018 ; Chiang et al 2010 ). In recent years, regional public health incidents have occurred frequently, directly threatening human life and hindering social and economic development.…”