Development of a Prototype Bayesian Network Model Representing the Relationship between Fresh Market Yield and Some Agroclimatic Variables Known to Influence Storage Root Initiation in Sweetpotato

Abstract

<jats:p>A prototype phenology-driven Bayesian belief network (BBN) model, named BxNET, was developed to represent the relationship between fresh market yield (U.S. #1 grade) and agroclimatic variables known to influence the critical storage root initiation stages in ‘Beauregard’ sweetpotato. This data-driven model was developed from experimental data collected over 3 years of field trials in which management variables were kept as uniform as possible. The BBN was developed assuming that soil moisture measured at the 15-cm depth was not a limiting variable during the first 20 days after transplanting, during which the onset of storage root initiation determined the majority of storage root yield at harvest. The absence of influence from weeds, disease, insect pests, and chemical injury was also assumed. Accuracy of the fully parameterized working prototype was estimated through leave-one-out cross-validation (14% error rate), validation on an independent test data set (20% error rate), and area under the receiving operator characteristic curve (0.59) analysis. As a result of its empirical nature, BxNET is only applicable to the cultivar, location, and the limited set of environmental (air temperature, soil temperature, relative humidity, solar radiation) and management variables as defined in the 3-year study. This beta-level model can serve as a foundation for the development of a final working model through further testing and validation. Additional validation data may require revision of the current model structure and conditional probabilities. These validation studies will also allow the model to be used in other locations. BxNET can be expanded to include other causal variables such as weed incidence, disease presence, insects, and chemical injury. Such an expansion can lead to the development of a model-based decision support system for sweetpotato production. Such a system can help model alternative management scenarios and determine the most reasonable management interventions to achieve optimum yield outcomes under different agroclimatic conditions.</jats:p>

Molecular Regulation of Storage Root Formation and Development in Sweet Potato

“…Storage roots of yellow-orange cultivars contain high amounts of carotenoids, up to 45-100 μg g 1 (Badillo-Feliciano et al 1976;Huett 1976;Junek and Sistrunk 1978;Love et al 1978;Collins and Pope 1979;Ikehashi 1985;Kukimura et al 1988;Bhattacharya et al 1990;Tanahata et al 1993;CTCRI 2006). Growth and/or the yield of the storage roots have been shown to be affected by environmental factors, including soil moisture, temperature, humidity, light, photoperiod, and carbon dioxide (Loretan et al 1994;Hill et al 1996;Mortley et al 1996;Eguchi et al 1998;Pardales et al 1999Pardales et al , 2000Kano and Ming 2000;van Heerden and Laurie 2008;Villordon et al 2010). The high productivity of sweet potato is due to the sink potential of the storage root Hozyo 1977;Hahn 1977).…”

S-metolachlor and rainfall effects on sweetpotato (Ipomoea batatas L. [Lam]) growth and development

“…Some of these roots develop into economically important storage roots through proliferation of cambial cells that form starch-accumulating parenchyma cells (Belehu et al, 2004;Ravi et al, 2009;Villordon et al, 2009). The transformation of adventitious roots into storage roots starts around 2 weeks after transplanting of slips in the field (Togari, 1950;Lowe and Wilson, 1974;Firon et al, 2009;Villordon et al, 2010). Thus, adverse environmental factors such as moisture stress (Gajanayake et al, 2013), unfavorable temperature and management including application of herbicides for the control of weeds during this stage may have detrimental effects on final sweetpotato SR quantity and quality.…”

Using a Scanner-based Minirhizotron System to Characterize Sweetpotato Adventitious Root Development during the Initial Storage Root Bulking Stage

“…During the study, the soil moisture at the 5-cm depth was consistently below 10% volumetric water content in plots with rain shelters, whereas soil temperatures were consistently above 30°C (data not shown). We have previously shown that under these conditions, SRs were generally set at the lower nodes (Villordon et al, 2010). Togari (1950) provided evidence that AR number was related to final SR yield under certain experimental conditions.…”