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- Author or Editor: Matthew D. Stevens x
Fusarium crown and root rot (crown rot) develops on tomato from the fungus Fusarium oxysporum f.sp. radicis-lycopersici (FORL). Genetic resistance to crown rot was previously introduced into the cultivated tomato from the wild species Lycopersicon peruvianum and found to be a single dominant gene, Frl, on the long arm near the centromere of chromosome 9 of the tomato genome. In an effort to identify molecular markers tightly linked to the gene, Ohio 89-1 Fla 7226, Fla 7464, `Mocis', and `Mopèrou', lines homozygous for Frl (resistant), were screened with restriction fragment length polymorphism (RFLP) markers in comparison to Fla 7482B and `Monalbo', lines homozygous for Frl + (susceptible). Frl was determined to be between the RFLP markers CT208 and CD8. These two markers are separated by a genetic map distance of 0.9 cM according to Pillen et al. (1996). In addition, we screened a pool of eight resistant plants against a pool of nine susceptibles from a BC1 population segregating for Frl for amplified fragment length polymorphism (AFLP) markers. Fazio et al. (1998) previously determined that crossover events occurred in these 17 plants between Frl and a rapid amplified polymorphic DNA (RAPD) marker, UBC194. Our research has indicated that UBC194 is also between CT208 and CD8 on the centromeric side of Frl. Of the 62 AFLP primer combinations tested, 34 showed more than 63 strong polymorphisms in linkage to resistant phenotypes.
Three cold-climate strawberry production systems, conventional matted row, advanced matted row, and cold-climate annual hill plasticulture, were compared for consumer preference in a pick-your-own (PYO) setting. Replicated 6 × 15 m plots were established in 2002 in Maryland and cropped in 2003 and 2004. To simulate PYO marketing, volunteers were recruited to harvest 3.6-m plots in each of the three production systems and to complete a five-part questionnaire. The questionnaire collected demographic information and allowed volunteers to compare the three systems both prior to and after their harvesting experience. Harvests were carried out twice weekly, with 75 participants in 2003 and 45 participants in 2004. The 2003 season was cool and wet, with frequent rainfall and a high incidence of fruit rot. Spring 2004 was unseasonably hot, resulting in an unusually short harvest season. Consumer preference differed between years and among harvests within a season. The annual hill system was favored early in the 2003 season, with preference shifting to the other systems as the season progressed. The advanced matted row was favored early in the 2004 season. Many of the participants' comments, both positive and negative, were directed at the plastic mulch and raised beds. In several cases, participants indicated that their preferences after picking from each system did not match their initial impressions. Implications of this research to the social components of sustainability will be discussed.
Three cold-climate strawberry (Fragaria ×ananassa) production systems, conventional matted row (CMR), advanced matted row (AMR), and cold-climate plasticulture (CCP), were compared for horticultural and economic aspects of sustainability over a 3-year planting cycle. The systems were tested using a single cultivar, Allstar, to avoid treatment × cultivar interaction. System-specific management operations and materials affected the total production costs of each system. Both CMR and AMR had higher management costs than CCP as a result of labor costs for weed control, but CCP had much higher cost of materials. Overall expenses were lowest for CMR and highest for AMR. Yields in the first fruiting year were highest for CMR at 17.4 Mg·ha−1 followed by AMR and CCP at 13.2 Mg·ha−1 and 11.8 Mg·ha−1, respectively. In the 2004 harvest season, CMR and AMR were the highest yielding at 10.0 Mg·ha−1 and 9.0 Mg·ha−1, respectively, with CCP the lowest yielding at 6.0 Mg·ha−1. Low yield and fruit size in the second year and high material costs for establishment limit the economic viability for CCP when managed as a perennial system.
In consumer-harvested marketing, crop management practices and production systems directly affect the experience of the customer. An experiment was designed to compare overall consumer preference and fruit quality characteristics among three perennial cold-climate strawberry (Fragaria ×ananassa) production systems: conventional matted row (CMR), advanced matted row (AMR), and cold-climate plasticulture (CCP). Replicate plots of each system were maintained for two harvest seasons. Volunteers harvested subplots in each system and completed a survey to evaluate pick-your-own consumer preferences. The CCP system was preferred by a majority of consumers in the first year, whereas the AMR system was rated highest in the second year. Preferences were positively correlated with ease of harvest and fruit appearance and negatively correlated with the percentage of fruit unfit for harvest. Fruit quality measurements made on marketable fruit in the second harvest season indicated that there were no treatment differences in titratable acidity or soluble solids concentration, but significantly lower fruit firmness in the CCP treatment compared with CMR and AMR.
The environmental effects of the three strawberry (Fragaria ×ananassa) cold-climate production systems were compared: the traditional method of conventional matted row (CMR) and the two more recently developed practices of advanced matted row (AMR) and cold-climate plasticulture (CCP). Side-by-side field plots were instrumented with automated flow meters and samplers to measure and collect runoff, which was filtered and analyzed to determine soil, pesticide, and nitrogen losses. Although annual mean runoff volumes were similar for all three production systems, the soil losses from CMR plots were two to three times greater than the CCP plots throughout the study and two to three times greater than the AMR plots only in the first year of the 3-year study. In general, decreases in erosion and runoff volumes were observed in plots that were disturbed less by machine operations and had less foot traffic as a result of decreased need for hand weeding and in the plots that used straw mulch in the furrows between the beds. Timing and intensity of precipitation events also influenced the amount of soil erosion. Pesticide residues and nitrogen losses were also greatest in the runoff from the CMR plots. The two systems that used drip fertigation, AMR and CCP, also had higher nitrogen uptake efficiencies. Overall, the CCP and AMR systems performed similarly for most criteria; however, considering the nonrenewable nature of the plastic mulch and the need to dispose of the plastic mulch in a landfill, the AMR system was more environmentally sustainable than the CCP system.
Tomato spotted wilt virus (TSWV) and Phytophthora infestans (late blight) in tomato (Solanum lycopersicum) have a worldwide distribution and are known to cause substantial disease damage. Sw-5 (derived from S. peruvianum) and Ph-3 (derived from S. pimpinellifolium) are, respectively, TSWV and late blight resistance genes. These two genes are linked (within 5 cM on several maps) in repulsion phase near the telomere of the long arm on chromosome 9. The tomato lines NC592 (Ph-3) and NC946 (Sw-5) were crossed to develop an F2 population and subsequent inbred generations. Marker-assisted selection (MAS) using three polymerase chain reaction-based codominant markers (TG328, TG591, and SCAR421) was used in F2 progeny with the goal of selecting for homozygous coupling-phase recombinant lines. From 1152 F2 plants, 11 were identified with potential recombination events between Ph-3 and Sw-5; of those, three were male sterile (ms-10). F3 progeny were generated from the remaining eight F2 recombinants, and resistance to both pathogens, or Ph-3 and Sw-5 in coupling phase, was confirmed in three of those. Recombination was suppressed fivefold in our F2 population to 1.11 cM between genes when compared with published maps of the same region. However, MAS was an efficient tool for selecting the desirable recombination events for these two pathogen resistance genes.
With increased mobile device usage, mobile applications (apps) are emerging as an extension medium, well suited to “place-less” knowledge transfer. Conceptualizing, designing, and developing an app can be a daunting process. This article summarizes the considerations and steps that must be taken to successfully develop an app and is based on the authors’ experience developing two horticulture apps, IPMPro and IPMLite. These apps provide information for major pests and plant care tasks and prompt users to take action on time-sensitive tasks with push notifications scheduled specifically for their location. Topics such as selecting between a web app and a native app, choosing the platform(s) for native apps, and designing the user interface are covered. Whether to charge to download the app or have free access, and navigating the intra- and interinstitutional agreements and programming contract are also discussed. Lastly, the nonprogramming costs such as creating, editing, and uploading content, as well as ongoing app management and updates are discussed.
Mobile device applications (apps) have the potential to become a mainstream delivery method, providing services, information, and tools to extension clientele. Testing, promoting, and launching an app are key components supporting the successful development of this new technology. This article summarizes the considerations and steps that must be taken to successfully test, promote, and launch an app and is based on the authors’ experience developing two horticulture apps, IPMPro and IPMLite. These apps provide information for major pests and plant care tasks and prompt users to take action on time-sensitive tasks with push notifications scheduled specifically for their location. App testing and evaluation is a continual process. Effective tactics for app testing and evaluation include garnering focus group input throughout app development and postlaunch, in-house testing with simulators, beta testing and the advantages of services that enhance information gained during beta testing, and postlaunch evaluations. Differences in promotional and bulk purchasing options available among the two main device platforms, Android and iOS, are explored as are general preparations for marketing the launch of a new app. Finally, navigating the app submission process is discussed. Creating an app is an involved process, but one that can be rewarding and lead to a unique portal for extension clientele to access information, assistance, and tools.