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Marisa M. Wall, Stephanie Walker, Arthur D. Wall, Ed Hughs and Richard Phillips

In the southwestern U.S. growing region, which includes southern New Mexico, west Texas, and southeastern Arizona, mechanical harvest of chile peppers (Capsicum annuum) is increasing because of the high cost of hand labor. Mechanical harvesters have been developed, but there is limited information on the performance of chile cultivars when machine harvested. Four red chile pepper cultivars (New Mexico 6-4, Sonora, B-18, and B-58) were grown in a farmer's field near Las Cruces, N.M., and harvested in October 2000 using a double-helix-type harvester. Ethephon was applied 3 weeks before harvest at 1.5 pt/acre (1.75 L·ha-1) to promote uniform ripening. Ethephon caused fruit of `B-18' and `B-58' to drop before harvest, thereby affecting yield results. Treatment with ethylene-releasing compounds is not recommended for these cultivars. `Sonora' and `New Mexico 6-4'dropped much less fruit than `B-18' and `B-58' after the ethephon treatment. Dry weight marketable yield ranged from 1419 to 2589 lb/acre (1590.5 to 2901.8 kg·ha-1), and total yield potential (discounting dropped fruit) ranged from about 2500 to 3100 lb/acre (2802.1 to 3474.6 kg·ha-1), depending on cultivar. Harvest efficiencies of 73% to 83% were observed among the cultivars. Trash content of the harvested chile varied from 25% to 42% of dry weight. Trash was predominantly diseased and off-color fruit, leaves, and small stems. Trash content was highest for `Sonora'. `New Mexico 6-4' had the greatest marketable yield and harvest efficiency among the cultivars evaluated in this study.

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Marisa M. Wall, Kate A. Nishijima, Lisa M. Keith and Mike A. Nagao

Longan (Dimocarpus longan) fruit production and global exports are rapidly expanding. Consumer acceptance of this high value crop requires that fruit arrive in excellent condition. Pericarp browning and fungal diseases are the main postharvest problems for longans. Research was conducted to establish optimum storage temperatures and packaging systems to retain fruit quality of ‘Biew Kiew’ longans. Average respiration rates for longans stored at 20 °C (61.6 mg CO2/kg/h) were about twice the rate as those stored at 10 °C (32.7 mg CO2/kg/h) and triple the rate for those stored at 5 °C (21.1 mg CO2/kg/h). Ethylene rates were below 0.4 μg·kg−1·h−1. Fruit quality and shelf life were greatest when stored at 10 °C. Longans held at 20 °C were unmarketable after 10 d, and fruit stored at 5 °C exhibited chilling injury (CI). After storage at 10 °C, longans packaged in microperforated (MP) bags, clamshell (CL) containers, or Peakfresh® film (PF) had the highest visual quality ratings, lowest disease incidences, and longest shelf life when compared with fruit in Lifespan® film (LS) or fiberboard boxes. The most promising packages (MP, CL, PF) were evaluated further under constant 10 °C or simulated shipping (SS) conditions with fluctuating temperatures (22 °C/10 °C/22 °C). Longans in CL containers had the highest visual quality and lowest disease incidence when stored at 10 °C, but there were no differences among package treatments under SS conditions. Also, sensory ratings were greatest for fruit packed in CL or PF when stored at 10 °C but all sensory scores decreased under SS temperatures. When longans were stored under fluctuating temperatures, aril texture and flavor ratings were highest for CL packages. CL, PF, and MP are suitable packages for longans stored under optimal temperatures. However, for longans stored under SS conditions, sensory quality was highest when packaged in CL containers.

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Francisco Molinar Jr., Wayne A. Mackay, Marisa M. Wall and Manuel Cardenas

Experiments were conducted to develop a clonal propagation system for agarita (Berberis trifoliata Moric.). Actively growing agarita shoots were collected from a mature plant at the Texas A&M Univ. Research and Extension Center in El Paso and successfully established on a basal medium consisting of woody plant medium (WPM) salts and Murashige and Skoog vitamins, sucrose at 30 g·L–1, and 0.8% Phytagar supplemented with 11.1 μm BA. Cytokinins (benzyladenine, kinetin, and thidiazuron), subculture period, and age of cultures were tested. The optimal shoot proliferation conditions were WPM basal medium supplemented with 5.5 μm BA and a subculture period of 4 weeks. Culture age did not affect shoot proliferation but did affect rooting. Preliminary experiments with 1.0 μm NAA resulted in nearly 100% rooting of microshoots <6 months old. Shoots from 21-month-old cultures had to be placed on a cytokinin-free medium before successful rooting. On basal medium supplemented with NAA (5.4 μm), 68% of the microshoots rooted with an average of 1.2 secondary roots per microshoot. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1-naphthaleneacetic acid (NAA); N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (thidiazuron or TDZ); 6-furfurlaminopurine (kinetin).

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Susan C. Miyasaka, Marisa Wall, Don LaBonte and Alton Arakaki

Twelve sweetpotato (Ipomoea batatas var. batatas) accessions/cultivars/landraces (entries) were evaluated for yield, resistance to pests, and quality in five field trials planted at Pepe`ekeo, Hawai‘i Island, and replicated over time with blocks planted on May and Oct. 2014, Feb. and July 2015, and Jan. 2016. Plots were harvested at 4.5 to 6 months after planting. In the first two field trials, local entries planted were ‘Okinawan’, ‘Mokuau’, and ‘Kona B’, as well as PI 531094, ‘Beauregard’, PI 573309, PI 573330, ‘Darby’, ‘Pelican Processor’, and ‘Picadito’. Yields of ‘Mokuau’ and ‘Kona B’ were low and were replaced in the latter three field trials with ‘Murasaki-29’ and ‘LA 08-21p’ from Louisiana State University (LSU) AgCenter, Baton Rouge. At harvest, storage roots were graded according to State of Hawai‘i standards and marketable yields included grades AA, A, and B. Then, injuries of storage roots due to infestations of sweetpotato weevil (Cylas formicarius elegantulus) in each category were estimated. Finally, sugar concentrations, anthocyanins, and β-carotene contents were measured in storage roots. Marketable fresh weight yields of entries differed significantly, with ‘LA 08-21p’ having the greatest marketable yield. However, ‘LA 08-21p’ also had the greatest incidence of damage due to sweetpotato weevil, perhaps because of its growth habit as a tight cluster of storage roots located close to the soil surface. Entries also had significantly different sugar concentrations (fructose, glucose, sucrose, maltose, and total sugars). Concentrations of sucrose ranged from 25 to 68 mg·g−1 fresh weight and were greater than those of monosaccharides analyzed. ‘Beauregard’ had the highest sucrose concentration and total sugars. Purple-fleshed cultivars Okinawan and LA 08-21p contained total monomeric anthocyanins that ranged from 34 to 37 mg/100 g dry weight. Orange-fleshed cultivars Beauregard and Darby contained β-carotene that ranged from 5485 to 8302 µg/100 g fresh weight. These results provide yields of storage roots, susceptibility to sweetpotato weevils, and amounts of antioxidants in purple- and orange-fleshed sweetpotato cultivars to growers interested in producing new sweetpotato cultivars.

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Babak Madani, Marisa Wall, Amin Mirshekari, Alagie Bah and Mahmud Tengku Muda Mohamed

Calcium (Ca) is a major plant nutrient that affects cell wall and plasma membrane formation and plays a key role in plant growth, biomass production, and function. Ca can be used to decrease fruit decay and increase firmness and shelf life. Different sources and concentrations of foliar-applied Ca were examined for the effects on nutrient concentration and growth of ‘Eksotika II’ papaya (Carica papaya) plants. Papaya seedlings were established in pots and irrigated with a standard nutrient solution in a net house. Four preharvest sprays were applied as foliar applications with three different sources of Ca {calcium chloride [CaCl2], calcium nitrate [Ca(NO3)2], and calcium propionate [Ca(C2H5COO)2]} at four concentrations (0, 60, 120, and 180 mg·L−1). Plant Ca concentration was unaffected by the different Ca sources. However, increased Ca concentration applied to the leaves enhanced plant accumulation of phosphorous and Ca in the plant, but decreased potassium (K) and magnesium (Mg) concentrations in the tissues. Plants that received Ca at 180 mg·L−1 had greater height and diameter than control plants. In a field trial with mature trees, preharvest applications of Ca (0, 4000, and 5400 mg·L−1) in the form of CaCl2 showed that increasing concentrations improved fruit Ca concentration, texture, and flavor; and decreased weight loss, Mg content, and apparent disease incidence of the fruit.

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Sabine R. Green, Geno A. Picchioni, Leigh W. Murray and Marisa M. Wall

Field-grown cut and dried flowers could provide a high-value crop selection for New Mexico. We conducted a 1-year field study to evaluate flower yield and quality characteristics of common globe amaranth (Gomphrena globosa), ‘Strawberry Fields’ globe amaranth (Gomphrena haageana), cockscomb celosia (Celosia argentea var. cristata ‘Chief Mix’), and wheat celosia (Celosia spicata ‘Pink Candle’). Within-row spacing of 15 or 20 cm combined with two-row or three-row per bed plantings resulted in field planting densities ranging from 66,670 to 120,010 plants/ha of common globe amaranth and ‘Strawberry Fields’ globe amaranth, and 100,005 to 200,010 plants/ha of cockscomb and wheat celosia. All but cockscomb celosia produced four harvests that began 22 May and ended 18 Oct., depending on species. Both globe amaranth species had a 5- to 6-month harvest season, two to three midseason to late-season peak harvests, and over 1000 harvested stems totaling 1.4 to 1.8 kg dry weight per 1.5-m2 plot across the season. Both celosia species had a 4.5-month harvest season, one early summer peak harvest, and fewer than 300 harvested stems totaling 0.6 to 0.7 kg dry weight per plot for the year. Seasonally progressive increases in flowering stem length of both globe amaranth species and wheat celosia, and in flowering stem diameter of both globe amaranth species and cockscomb celosia, were observed. Flowering head size of both globe amaranth species and of wheat celosia varied little with harvest season, whereas the head diameter of cockscomb celosia increased with the season. Postharvest flower retention after mechanical impact was about 2% higher for common globe amaranth than it was for ‘Strawberry Fields’ globe amaranth, decreased by about 6% from early to later harvests for both celosia species, and was inversely related to the head size of both globe amaranth species and cockscomb celosia. Despite the wide range in planting density, the density effect was largely limited to cockscomb celosia. For that species, three-row planting (high density) increased the total number of spray flower (multiple head) stems, provided longer stems later into the season and wider heads midway into the season, and prolonged the production of spray stems (15-cm spacing only). Results demonstrate that these four species are excellent candidates as new specialty crops in semiarid conditions.

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Constance L. Falk, Hildegard van Voorthuizen, Marisa M. Wall, Kathryn M. Kleitz, Steven J. Guldan and Charles A. Martin

Cost and return estimates are presented for selected medicinal herbs grown in a plant-spacing study at two sites in New Mexico. The selected herbs were echinacea [Echinacea purpurea (L.) Moench], valerian (Valeriana officinalis L.), and yerba mansa (Anemopsis californica Nutt.). Significant returns to land and risk were observed in the crops grown at the closest plant spacing, 12 inches (30 cm). Return to land and risk after two growing seasons from echinacea was estimated for a 10-acre (4-ha) farm to be $16,093/acre ($39,750/ha) in Las Cruces and $14,612/acre ($36,092/ha) in Alcalde.

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Kathryn M. Kleitz, Marisa M. Wall, Constance L. Falk, Charles A. Martin, Steven J. Guldan and Marta D. Remmenga

Field studies were conducted to determine the production potential of echinacea (Echinacea purpurea), valerian (Valeriana officinalis), mullein (Verbascum thapsus) and yerba mansa (Anemopsis californica) medicinal herbs at two sites in New Mexico. Las Cruces, N.M., is at an elevation of 3,891 ft (1,186 m) and has an average of 220 frost free days per year, whereas Alcalde, N.M., is at an elevation of 5,719 ft (1,743 m) and averages 152 frost-free days per year. In-row plant spacings of 12, 18 and 24 inches (30.5, 45.7, and 61.0 cm) were compared at both locations. The corresponding plant densities for the 12, 18 and 24 inch spacings were 14,520 plants/acre (35,878 plants/ha), 9,680 plants/acre (23,919 plants/ha), and 7,260 plants/acre (17,939 plants/ha), respectively. Data were collected on growth rates, fresh yield, and dry yield for the herbs grown at each site. All crops at both sites had highest plot yields at the 12-inch spacing, suggesting that optimum in-row plant spacings are at or below the 12-inch spacing. Yields of 1.94 ton/acre (4.349 t·ha-1) of dried yerba mansa root, 0.99 ton/acre (2.219 t·ha-1) of dried echinacea root, and 2.30 ton/acre (5.156 t·ha-1) of dried mullein leaves were realized at the 12-inch spacing at Las Cruces in southern New Mexico. Yields of 1.16 ton/acre (2.600 t·ha-1) of dried valerian root, 0.93 ton/acre (2.085 t·ha-1) of dried echinacea root, and 0.51 ton/acre (1.143 t·ha-1) of dried mullein leaves were harvested at the 12-inch spacing at Alcalde in northern New Mexico. Yields of fresh echinacea flowers were 1.56 ton/acre (3.497 t·ha-1) in Las Cruces. Yields of dried mullein flowers were 0.68 ton/acre (1.524 t·ha-1) in Las Cruces and 0.66 ton/acre (1.479 t·ha-1) in Alcalde.

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Kathryn M. Kleitz, Marisa M. Wall, Constance L. Falk, Charles A. Martin, Marta D. Remmenga and Steven J. Guldan

Field studies were conducted in 1995 and 1996 at Las Cruces, New Mexico, and Alcalde, New Mexico, to compare direct seeding to transplanting for stand establishment and yield estimates of calendula (Calendula officinalis), catnip (Nepeta cataria), lemon balm (Melissa officinalis), stinging nettle (Urtica dioica), and globemallow (Sphaeralcea spp.). Calendula established well from seed or transplants at both sites. Transplanting increased establishment of lemon balm, catnip, stinging nettle, and globemallow. Lemon balm establishment was increased by 230% to 400% at Las Cruces, and catnip establishment was increased by 84% to 100% at Alcalde by transplanting. Direct seeding resulted in little or no stand establishment for stinging nettle and globemallow at Alcalde. In 1996, transplants increased lemon balm and stinging nettle dry weight yields by a factor of three or more at both sites. Dry weight yields of transplanted catnip were 4.86 t·ha−1 in 1995 and 7.90 t·ha−1 in 1996 in Las Cruces. Alcalde yields for transplanted dried catnip were 2.43 t·ha−1 in 1995 and 5.12 t·ha−1 in 1996. Transplanted globemallow dry weight yields were 6.04 t·ha−1 in 1995 and 9.17 t·ha−1 in 1996 for Las Cruces. Transplanted stinging nettle yield in Alcalde was 5.91 t·ha−1 for plants that overwintered and were harvested in the second season. Transplanting versus direct seeding medicinal herbs has the potential to substantially increase stand establishment and yield in New Mexico, particularly in the more northern and cooler part of the state.

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Kate A. Nishijima, Marisa M. Wall, Maureen M. Fitch, Lionel S. Sugiyama, Ronald C. Keith and Wayne T. Nishijima

Papaya (Carica papaya L.) cultivars and breeding lines were evaluated for resistance to Enterobacter cloacae (Jordan) Hormaeche & Edwards, the bacterial causal agent of internal yellowing disease (IY), using a range of concentrations of the bacterium. Linear regression analysis was performed and IY incidence was positively correlated with increasing inoculum concentrations for susceptible cultivars Kapoho Solo and Laie Gold but not for resistant cultivars or lines. It was determined that the inoculum concentration of 9 to 10 Log10 colony-forming units per milliliter (cfu/mL) was able to reliably differentiate resistant and susceptible papaya germplasm. Red-fleshed cultivars SunUp and Sunrise were the most resistant papaya groups evaluated at this dose concentration. Yellow-fleshed cultivars, Kapoho Solo and Laie Gold, were susceptible to E. cloacae. ‘Rainbow’, an F1 hybrid between ‘SunUp’ and ‘Kapoho Solo’ that is yellow-fleshed, was moderately resistant to E. cloacae, exhibiting limited symptoms of the disease. Yellow-fleshed I-Rb F5/F6, an advanced inbred line derived from ‘Rainbow’, is resistant and offers the potential of improving resistance of yellow-fleshed commercial cultivars. A colorimeter was used to objectively measure internal flesh color and distinguish between infected and non-infected tissue in red- and yellow-fleshed papayas using L*C*H* color space analysis. Symptomatic tissue (72.4 and 79.0°) had higher hue angle means than non-symptomatic tissue (62.8 and 75.0°) for all cultivars or lines in red- and yellow-fleshed papayas, respectively. Yellow (“Y”) hue color also distinguished infected tissue from non-infected tissue. Symptomatic tissue that had Y hue color resulted in 79 to 81° hue angle means among red- or yellow-fleshed papayas. Our results demonstrated the usefulness of colorimetry to help detect infected papaya tissue. In surveys of naturally infected papaya, high populations (8.57 × 107 cfu/g) of E. cloacae were recovered in infected fruit of ‘Kapoho Solo’ and represent a food safety concern for fresh and processed papaya. In isolations from inoculated fruits, we observed decreases of ≈1 to 2 Log10 cfu/g in final bacterial populations when high-dose range inoculum concentrations (9 to 12 Log10 cfu/mL) were used. This dose range may represent a saturation range for E. cloacae inoculation.