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  • Author or Editor: Stephanie Walker x
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The inheritance of resistance to Phytophthora capsici Leonian root rot and foliar blight was compared in two different Capsicum annuum L. var. annuum pod types. The seedling was screened for phytophthora root rot, while a genetically identical stem cutting was screened for phytophthora foliar blight to determine if the same gene(s) confer resistance to both disease syndromes. The susceptible parents were `Keystone Resistant Giant #3' (`Keystone'), a bell pepper type, and `Early Jalapeño', while `Criollo de Morelos-334' was the resistant parent. Resistance was observed in both F1 populations screened for phytophthora root and foliar infection indicating dominance for resistance. Reciprocal effects were not detected. To determine if the same gene(s) conferred root rot and foliar resistance, root rot screening results were matched to the corresponding foliar blight stem cutting reaction. The segregation of resistance in the F2 generations was dependent on the susceptible parent. In the F2 generation derived from `Early Jalapeño', root rot resistance and foliar blight resistance segregated in a 9:3:3:1 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. One independent, dominant gene was necessary for root rot resistance, and a different independent, dominant gene was needed for foliar blight resistance. In the F2 generation derived from `Keystone', root rot and foliar blight resistance segregated in a 7:2:2:5 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. This segregation ratio is expected when one dominant gene is required for root resistance, and a different dominant gene is required for foliar resistance. In addition to these two genes, at least one dominant allele of a third gene must be present for expression of root rot and foliar blight resistance.

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New Mexican-type red and green chile (Capsicum annuum) is important to New Mexico’s identity and economy. Producers began experimenting with mechanical harvest in the mid-1960s, but efforts stalled in the 1970s. Adverse impact to production following the implementation of the North American Free Trade Agreement spurred renewed interest in chile mechanization. Through private and public collaboration, the red chile industry in New Mexico has successfully transitioned with more than 80% of domestic acreage currently mechanized. Green chile has proven to be more challenging with fruit damage and lack of efficient mechanical stem removal posing key obstacles. Recent identification and developments in equipment have provided necessary components for mechanization of green chile, but must be scaled-up to production volumes.

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Chile pepper (Capsicum annum) production in the southwest can be impacted by many factors. In particular, factors that alter root growth and development can be critical to pepper productivity. Several factors can cause less-than-optimal taproot formation, including irrigation practices, planting method (seeds vs. transplants), climactic conditions, and competition from weed species for limiting resources. The goals of this research were to quantify the root development of chile peppers established from either seeds or transplants under furrow and drip irrigation. Research was conducted in 2005 at Artesia Plant Science Research Center in Artesia, N.M., using a state-of-the-art drip irrigation system. Differences in root development between both irrigation types and planting methods were measured using of the mini-rhizotron image capturing system. Measurements occurred at a weekly basis to document location, root length density, and pattern of root formation. At the time of harvest, yield and fruit quality were evaluated. Direct-seeded chile plants yielded more fruits than transplanted chile under both irrigation regimes. Patterns of root development differed over time for direct-seeded vs. transplanted and furrow vs. drip-irrigated chile peppers. Planting and irrigation method affected root growth differently at various points in the season. These data can aid in the optimization of management strategies for specific production practices.

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New Mexico green pod-type chile (Capsicum annuum) has significant importance as a vegetable crop. The cultivation and trade of New Mexico pod-type green chile are culturally significant within New Mexico (USA) and contribute to the state’s economy by providing income and employment to farmers and through supporting industries. However, because of the high cost and limited availability of labor, New Mexico pod-type green chile acreage has declined. Traditionally, New Mexico pod-type green chile is hand-harvested when the fruit are full-size but physiologically immature. To preserve and expand the production of New Mexico pod-type green chile, the adoption of mechanical harvest technologies is essential. In 2015 and 2016, experiments were conducted at New Mexico State University’s Los Lunas Agricultural Science Center (Los Lunas, NM, USA) to examine the effects of increased planting density on New Mexico pod-type green chile fruit size, plant architecture, and mechanical harvest efficiency. Two commercial New Mexico pod-type green chile cultivars, NuMex Joe E. Parker and AZ-1904, were direct-seeded on 17 Apr 2015 and 14 Apr 2016. On 11 Jun 2015 and 14 Jun 2016, three plant density treatments were implemented at 39,000 (high), 23,000 (medium), and 15,000 (standard) plants/acre. Before harvest, plant measurements, including height, width, height to first bifurcation, stem diameter, and number of lateral basal branches, were obtained. Plots were mechanically harvested using an inclined double helix harvester, and harvested material was sorted into marketable green fruit, machine-broken fruit, and nonpod plant material. Fruit measurements, including fruit weight, width, length, pericarp thickness, and number of locules, were obtained. Both cultivars exhibited a 9% increase in height to bifurcation accompanied by fewer basal branches grown at high density. Plant density did not significantly affect the fruit length, width, number of locules, and pericarp thickness. Plants grown at high density had an increased percentage of marketable fruit, with ‘NuMex Joe E. Parker’ having a higher percentage of marketable green fruit compared to ‘AZ-1904’. The results demonstrated that an increase in planting density in production fields to 39,000 plants/acre coupled with cultivar selection enhanced efficiency in a mechanical harvest system.

Open Access

The β-carotene and total carotenoid content of different Capsicum fruit types and species were analyzed using HPLC. This information is useful for breeding high carotenoid chiles (New Mexican type) for the food industry, and also provides nutritional data for the range of fruit types within the Capsicum genus. Fresh fruit from 25 accessions and dried fruit from 39 accessions were evaluated in 1996 and 1997. β-carotene levels varied from 0 to 16.6 mg/100 g fresh weight, and carotenoid levels were from 0.1 to 89.6 mg/100 g in red ripe fruit in 1996. The range of values for β-carotene was similar in 1997, but a wider range in total carotenoids (0.4 to 117.3 mg/100 g fresh weight) was observed. Fresh fruit (100 g) of the cultivars `Greenleaf Tabasco', `Pulla', `Guajillo', `NuMex Conquistador', `Ring-O-Fire', and `Thai Dragon' contained greater amounts of β-carotene than the RDA for vitamin A for the average adult. For dried Capsicum entries, New Mexican, aji, pasilla, ancho, and guajillo types had the highest levels of β-carotene. In 1996, β-carotene levels among the dried Capsicum germplasm ranged from 0 to 739.2 μg/g dry weight, and carotenoid levels were from 21.3 to 6,225.9 μg/g. Values were higher in 1997, and ranged from 23.7 to 1,198.1 μg/g dry weight for β-carotene and from 76.9 to 10,120.6 μg/g for total carotenoids. A pasilla type (C. annuum) had the highest total carotenoid content among the dried entries in both years.

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Lettuce (Lactuca sativa) is a high-value crop cultivated worldwide. Harvested lettuce acreage in New Mexico, USA, trails the leading lettuce production states (California, Arizona), but growers in New Mexico are interested in expanding their production. For New Mexico farmers to increase lettuce production to reach new markets, information on heat-tolerant cultivar performance is needed. This study was conducted to evaluate six lettuce cultivars described as heat tolerant by seed suppliers or other sources. In 2020 and 2021, we assessed two butterhead types, ‘Anuenue’ and ‘Mikola RG10’; two green leaf types, ‘Muir’ and ‘Tropicana’; and two romaine types, ‘Parris Island Cos’ and ‘Sparx’, in the Jose Fernandez Garden at the New Mexico State University Heritage Farm in Las Cruces, NM. To determine which cultivars and types of lettuce are better suited for southern New Mexico, we measured these variables: marketable harvest weight, number of days from transplant to first bolt, and number of days from transplant to 50% bolted. In 2020, ‘Sparx’, a romaine-type lettuce, had, on average, 32% higher yield compared with the other lettuce types. In 2021 both romaine-type cultivars, Sparx and Parris Island Cos, produced 19% more marketable yield than the other lettuce cultivars. In 2020, ‘Sparx’ was the last to bolt and to reach the 50% bolted stage, whereas in 2021 ‘Mikola RG10’ and ‘Muir’ were the last cultivars to bolt and reach the 50% bolted stage. These results suggest that ‘Sparx’ would be a good potential candidate for farmers in southern New Mexico. ‘Mikola RG10’ and ‘Muir’, butterhead and green leaf type, respectively, demonstrated slower bolting in 2021, indicating they may be useful cultivars for extending lettuce harvest in New Mexico.

Open Access

Consumer demand for specialty market potatoes has been growing. Cultivated South American diploid potatoes possess great variation for skin and flesh colors, shape, and taste. A long-day adapted population of Solanum tuberosum groups Phureja and Stenotomum (phu-stn) was evaluated for characteristics associated with the type known as papa criolla or papa amarilla in South America. Tubers have intense yellow flesh and may be fried or roasted and eaten whole. A U.S. northern location (Maine), representative of a seed growing region, and two southern locations (Florida and New Mexico), representative of potato growing regions near large Hispanic populations, evaluated yellow-fleshed clones selected within a phu-stn population. Agreement between selectors at two locations was greater than 50%. Tuber skin color and shape were highly correlated between locations; flesh color and tuber dormancy moderately so; eye depth had low correlation between locations; and appearance and skin texture had low or no correlation between locations. Tuber dormancy was generally short, but a few longer dormant clones were identified. There were significant differences among clones for yields, with the highest yields occurring in Maine. More intense evaluations are planned for a subset of these clones before possible release as new varieties. Future breeding efforts will be undertaken to lengthen tuber dormancy in this population.

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New mexico pod–type green chile (Capsicum annuum) is one of New Mexico’s leading horticultural commodities. Cultivated acreage of green chile in New Mexico is threatened because of the high cost and insufficiently available labor for hand harvest. Therefore, mechanization is necessary to sustain the industry. Successful mechanization depends on harvester design coupled with plant architecture that optimizes harvest yield and quality. Harvested green fruit must be whole, unbroken, and unblemished for fresh and processed markets, so harvester design and plant architecture must maximize yield while minimizing fruit damage. In two trials conducted at the New Mexico State University Agricultural Science Center in Los Lunas, six cultivars (AZ-1904, Machete, PHB-205, E9, PDJ.7, and RK3-35) were evaluated for plant architecture and harvest efficiency with a double, open-helix mechanical harvester with two counter-rotating heads. Cultivars were direct seeded on 17 Apr. 2015 and 14 Apr. 2016 and managed according to standard production practices. Plant architecture traits, plant width, plant height, height to first primary branch, distance between first primary branch and first node, basal stem diameter, and number of basal branches were measured before harvest. Mechanical harvest yield components, which included marketable fruit, broken fruit, ground fall losses, unharvested fruit remaining on branches, and nonpod plant material, were assessed after once-over destructive harvests on 2 Sept. 2015 and 31 Aug. 2016. Fruit width, fruit length, and pericarp thickness were measured from a representative sample of 10 marketable fruit. In 2015, ‘AZ-1904’ and ‘PDJ.7’ had significantly (P ≤ 0.05) more marketable yield than ‘Machete’ that had the least marketable yield. No statistically significant differences were found in marketable yield in 2016. When both years were combined, ‘PDJ.7’ had significantly more nonpod plant material harvested and the plants were taller than all other cultivars. We found mechanical harvest performance to be significantly affected by plant height, with shorter plants yielding less marketable fruit. Despite differences in fruit wall thickness, no significant differences were measured in broken fruit. In 2015, ‘AZ-1904’ had significantly less basal branches per plant, reducing obstruction for the picking mechanism. Harvest efficiencies (marketable harvested fruit yield as a percentage of total plot yields) ranged from 64.6% to 39.3% during this 2-year trial, with the highest harvesting cultivars PDJ.7 and AZ-1904. In the future, all new mexico pod–type green chile breeding efforts for mechanical harvest must incorporate desirable plant architecture traits to increase harvest efficiencies.

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