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Mark E. Uchanski and Adam Blalock

In the desert southwest of the United States, cayenne pepper (Capsicum annuum L.) is an important crop. It is used in the production of hot sauce mash, the precursor to many hot sauces. Because hand harvest is currently required to accommodate staggered crop development, more uniform maturity is desired to facilitate mechanical harvest to decrease labor costs. This study was performed over 3 years (2009–11) and in two locations in southern New Mexico, resulting in five unique year/location scenarios (environments). Four timings of ethephon (0.56 kg a.i./ha) spray applications were evaluated for their potential to increase red cayenne cv. Mesilla yields and percentage of red pods. If yield increases and pigmentation improvements occur, ethephon may facilitate a once-over mechanical harvest. Ethephon was applied once at four key cayenne growth stages based on heat units accumulated after planting (HUAP): 1400 HUAP (late June to early July), 1800 HUAP (mid-July), 2800 HUAP (late August to early September), and 3100 HUAP (mid- to late September). Application timings corresponded to early bloom, peak bloom, late physiological maturity of plants, and preharvest, respectively. A non-sprayed control was also included. Fresh red, green, and non-marketable pod weights were recorded for each treatment in a once-over simulated machine harvest in October and analyzed for statistical differences. Mid- to late-season (2800–3100 HUAP) ethephon treatments significantly decreased undesirable green pod yield and, therefore, increased red pod percentage in four of five environments. Although a red pod yield increase was only observed in one environment (a drip-irrigated plot in 2010), there were no negative impacts on red pod yield in any environment resulting from ethephon application. In addition, pepper quality (yield of unmarketable pods) was not significantly reduced by ethephon. Previous work has focused on increasing red pod yields with mixed results. The results show that ethephon may synchronize cayenne pepper red fruit maturity necessary for mechanical harvest and reduce the labor involved in removing green pods before processing.

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James C. Fulton and Mark E. Uchanski

Stip, a physiological disorder, which affects certain pepper (Capsicum annuum) cultivars and pod types, has received limited formal academic attention. The disorder, frequently noted for its appearance in bell peppers, but also present in pimento and New Mexican pod types, has been attributed in the literature to nutrient imbalances and/or temperature extremes. Symptoms of this disorder present on fully developed fruits as brown, black, and yellow ovoid subcutaneous chlorotic lesions ≈1.3 cm in length and 0.6 cm in width extending from the endocarp to the mesocarp, without apparent expression in the cuticle. Chile pepper has been significantly affected by stip for the past several decades leading to varying degrees of commercial losses. Due to the sporadic and seemingly spontaneous nature of the disorder, prolonged research interest has not been sustained. This review provides the reader a comprehensive synthesis of all available literature regarding this physiological disorder. Especially because research into this disorder is scarce, it is essential that any and all previous research be made available together in one document to interested scientists, breeders, and growers. To achieve this goal, all available stip-related publications were obtained and analyzed; additionally, searches were performed using all names associated with the disorder. The literature suggests that stip manifestation is a consequence of an interaction between a genetic component (open-pollinated cultivars being more susceptible to symptom expression than hybrids) and an environmental component (increased nitrogen application, shading, and soil applications of lime appear to increase both severity and incidence).

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Jay M. Lillywhite, Jennifer E. Simonsen and Mark E. Uchanski

Little data are publicly available about U.S. spicy pepper (Capsicum sp.) consumers and their type-specific preferences. This research adds to the body of knowledge surrounding the demand side of the U.S. spicy pepper market by providing exploratory data to examine U.S. consumer preferences as they relate to seven common spicy pepper types: cayenne (Capsicum annuum), habañero (Capsicum chinense), jalapeño (C. annuum), New Mexico-type long green and red (C. annuum), paprika (C. annuum), poblano/ancho (C. annuum), and serrano (C. annuum) peppers. Data were collected using an online panel survey of 1104 consumers. Results suggest that jalapeño peppers were the most popular fresh spicy pepper purchased by participating food consumers. Paprika powder, a relatively mild spicy pepper product, was the most widely-consumed dried or ground pepper of the seven studied. Women appear more likely to be non-likers of spicy foods than men (P ≤ 0.05). Responses of this survey group suggest that many consumers enjoy spicy peppers and that consumption varies by pepper type. Finally, the most popular pepper types do not necessarily appear to be the “hottest” or “mildest” of those available in the market.

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Mark E. Uchanski, Kulbhushan Grover, Dawn VanLeeuwen and Ryan Goss

Experiential learning can be used as part of the undergraduate curriculum to provide real-world experience in the classroom. A hands-on hoop house construction project was integrated into an undergraduate general education plant science course at New Mexico State University in Las Cruces. The objectives were to provide students with hands-on experience in hoop house construction and data collection and interpretation, evaluate students’ perception about the educational value of the hoop house construction activity and delivery methods, and evaluate individual student’s perceptions about their participation in the group activity and group dynamics. Eighty-four students were enrolled in Spring 2013 semester. Students were surveyed in a follow-up laboratory 10 weeks after the hoop house construction activity for data collection and reflection. The survey tool assessed the impacts of class materials, laboratory materials, and the laboratory teaching assistants (TAs) on the students’ learning experience: perceptions of group work, their role within their groups, and their participation. Ninety percent and 95% of the students agreed or strongly agreed knowledge of basic techniques and practical application of hoop house construction, respectively, were obtained in the exercise. Eighty-five percent of student respondents indicated a gain in their appreciation for scientific data collection and interpretation through this exercise. Also, a majority (65%) of the students agreed this hands-on task improved their appreciation for group activities indicating experiential learning group work during scheduled class time could be a useful tool for team building and other learning experiences. Finally, more than 90% of the students found this activity overall beneficial. We conclude that integrating hoop house construction and data collection into an undergraduate general education plant science course can be an effective way to enhance student learning.

Open access

Brian A. Mitchell, Mark E. Uchanski and Adriane Elliott

This research assessed fruit load management and production techniques for cultivating indeterminate tomatoes in a high tunnel under intensive organic management. The successful production of high-quality, high-yielding crops is important for fruit and vegetable producers, especially growers using high tunnels. High tunnels are well-suited to organic farming and can be used to grow many valuable specialty crops. Fruit load management is practiced in fruit production (e.g., apples, peaches, and grapes), but there is lack of consensus concerning the effectiveness of fruit cluster pruning on tomato (Solanum lycopersicum) and its impact on fruit yield, quality, and marketability. In addition, there is no published research on tomato cluster pruning in certified organic systems or intensively managed high tunnels (e.g., densely planted, trellised, vegetatively pruned plants) for the Front Range of Colorado. In 2016 and 2017, a randomized complete block design was used to test the effects of cluster pruning within a high tunnel on certified organic land at Colorado State University’s (CSU’s) Agricultural Research, Development, and Education Center, South. Two treatments and three tomato cultivars were selected for the study; the treatment–cultivar combinations were replicated six times within a high tunnel. The treatments involved reducing fruit loads to three fruit and six fruit per cluster, whereas plants with unpruned clusters, which naturally developed as many as 10 fruit, served as the control. Tomato cultivars evaluated were ‘Cherokee Purple’, a widely studied heirloom, and two hybrids: ‘Jet Star’ and ‘Lola’. Parameters measured included total yield, individual fresh fruit weight, soluble solids content (SSC), marketable yield, and nonmarketable yield. Individual fresh fruit weight increased for both hybrids in the three-fruit treatment, averaged over two growing seasons. ‘Cherokee Purple’ did not respond to the cluster pruning treatments. There was no decrease in total yield, across all cultivars, between treatments and the unpruned control. However, ‘Jet Star’ yielded more than the other two cultivars. In addition, SSC and marketability measurements were more influenced by cultivar than cluster pruning treatments. ‘Lola’ had a significantly greater SSC than the other two cultivars. ‘Jet Star’ had the greatest marketable yields of all cultivars tested whereas ‘Cherokee Purple’ produced greater nonmarketable (cull) yields. Cluster pruning produced larger organic tomatoes without reducing yield or quality for two of the three cultivars used in the study. Cultivar selection remains one of the greatest factors in determining yield, quality, and marketability of a crop.

Free access

Rachel E. Rudolph, Carl Sams, Robert Steiner, Stephen H. Thomas, Stephanie Walker and Mark E. Uchanski

Biofumigation is a sustainable method of soil management in cash crop rotations that can increase soil organic matter (SOM), moderate soil pH, suppress weeds and soilborne pathogens through glucosinolates (GSL), and increase water infiltration. This 2-year (2011–13) field study evaluated four different Brassica crops for their biofumigant potential in a chile pepper rotation system in southern New Mexico. The four cultivars included: three mustards (Brassica juncea ‘Caliente 61’, ‘Caliente 199’, and ‘Pacific Gold’) and one broccoli (Brassica oleracea var. botrytis ‘Arcadia’). As a result of concerns that these mustards could be hosts for nematodes, a greenhouse study was conducted in the second year to evaluate the biofumigant crops for their southern root-knot nematode (Meloidogyne incognita, RKN) host suitability and their seedling establishment in the presence of RKN. In Year 1 (2011), conditions were ideal, which resulted in high mustard biomass production and, consequently, significantly higher SOM and lower pH than the bare soil control plots. However, there were no chile pepper yield differences among treatments. Conditions were much less favorable in Year 2 and the resultant poor biomass production did not cause an increase in SOM as seen in Year 1. In the RKN greenhouse study, broccoli was the least susceptible biofumigant crop. After one nematode generation (683 cumulative heat units), RKN populations were less than half of the original inoculum level on the broccoli. However, RKN populations increased in the presence of ‘Caliente 61’, ‘Caliente 199’, and ‘Pacific Gold’. Overall, broccoli produced lower biomass and lower GSL concentrations than the mustard treatments but may be a valuable crop for growers with nematode issues because RKN populations decreased in its presence. Based on high biomass production and high GSL concentration, ‘Caliente 199’ showed the most potential as a biofumigant crop for southern New Mexico.

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Emmanuel Alves Dos Santos Hecher, Constance L. Falk, Juliette Enfield, Steven J. Guldan and Mark E. Uchanski

Relatively little season extension research has been conducted in the southwestern United States, particularly with low-cost high tunnels or hoop houses for small-scale farmers. In this study, the economics of winter production of two leafy crops [lettuce (Lactuca sativa) and spinach (Spinacia oleracea)] in high tunnels in two locations in New Mexico were investigated, first using a simulation analysis in which yields were stochastic variables followed by a sensitivity analysis to examine returns from the high tunnel designs more closely. The returns examined in the sensitivity analysis were net of high tunnel materials, crop seed cost, and electricity. Two planting dates were tested and three high tunnel designs were examined: a single layer covering the house (SL), a double layer inflated with air (DL), and a double layer inflated with air and containing black water barrels to store heat (DL+B). The SL and DL designs appear to be the more appropriate technology for both locations for spinach, whereas for lettuce the DL+B model might be a reasonable option in Alcalde, a more-northern location. Overall, the SL and DL models provided adequate protection for growing crops, were less expensive to build, provided more interior growing space, and resulted in higher probabilities of producing positive returns, compared with the DL+B design. The DL design performed similarly to the SL design, but required running electricity to the structure to power the inflation fan, adding to the cost. As a result, expected returns in all cases were higher using the SL design based on the results of the sensitivity analyses. Combining the risk and the sensitivity analyses provides growers with a unique evaluation process to make high tunnel design, planting date, and crop choices.