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Open access

Seth D. Wannemuehler, Chengyan Yue, Wendy K. Hoashi-Erhardt, R. Karina Gallardo and Vicki McCracken

DNA-informed breeding techniques allow breeders to examine individual plants before costly field trials. Previous studies with tree fruits such as apple (Malus ×domestica) and peach (Prunus persica) have identified cost-effective implementation of DNA-informed techniques. However, it is unclear whether breeding programs for herbaceous perennials with 1- to 2-year juvenile phases benefit economically from these techniques. In this study, a cost-benefit analysis examining marker-assisted selection (MAS) in a Pacific northwest U.S. strawberry (Fragaria ×ananassa) breeding program was conducted to elucidate the effectiveness of DNA-informed breeding in perennial crops and explore the capabilities of a decision support tool. Procedures and associated costs were identified to create simulations of the breeding program. Simulations compared a conventional breeding program to a breeding program using MAS with low (12.5%), medium (25%), and high (50%) removal rates, and examined different scenarios where MAS had diminishing power to remove individuals as selections reenter the breeding cycle as parent material. We found that MAS application under current costs was not cost-effective in the modeled strawberry program when applied at the greenhouse stage, but cost-effectiveness was observed when MAS was applied at the end of the seedling trials before clonal trials with a removal rate of 12.5%.

Open access

Ronald S. Revord, Sarah T. Lovell, John M. Capik, Shawn A. Mehlenbacher and Thomas J. Molnar

Eastern filbert blight (EFB), caused by the fungus Anisogramma anomala, is a primary limitation to european hazelnut (Corylus avellana) cultivation in eastern North America. American hazelnut (Corylus americana) is the endemic host of A. anomala and, despite its tiny, thick-shelled nuts, is a potentially valuable source of EFB resistance and climatic adaptation. Interspecific hybrids (Corylus americana × C. avellana) have been explored for nearly a century as a means to combine EFB resistance with wider adaptability and larger nuts. Although significant progress was made in the past, the genetic diversity of the starting material was limited and additional improvements are needed for expansion of hazelnut (Corylus sp.) production outside of Oregon, where 99% of the U.S. crop is currently produced. Our objective was to determine if C. americana can be a donor of EFB resistance. We crossed 29 diverse EFB-resistant C. americana accessions to EFB-susceptible C. avellana selections (31 total progenies) to produce 2031 F1 plants. In addition, new C. americana germplasm was procured from across the native range of the species. The new collection of 1335 plants from 122 seed lots represents 72 counties and 22 states. The interspecific hybrid progenies and a subset of the American collection (616 trees from 62 seed lots) were field planted and evaluated for EFB response following field inoculations and natural disease spread over seven growing seasons. EFB was rated on a scale of 0 (no EFB) to 5 (all stems containing cankers). Results showed that progeny means of the interspecific hybrids ranged from 0.96 to 4.72. Fourteen of the 31 progenies were composed of at least one-third EFB-free or highly tolerant offspring (i.e., ratings 0–2), transmitting a significant level of resistance/tolerance. Several corresponding C. americana accessions that imparted a greater degree of resistance to their hybrid offspring were also identified. In addition, results showed that 587 (95.3%) of the 616 C. americana plants evaluated remained completely free of EFB. These findings confirm reports that the species rarely expresses signs or symptoms of the disease and should be robustly studied and exploited in breeding.

Open access

Hui He, Yanwei Yu, Jiamin Li, Luyun Hu and Fan Zhou

We quantitatively assessed the effects of a six-session edible horticultural therapy (EHT) program on long-term-hospitalized (LTH) female patients with schizophrenia. A total of 60 patients were enrolled in the project and randomly divided into an experimental group (30 patients, received EHT) and a control group (30 patients, did not receive EHT). The two groups were evaluated before and after EHT using the Brief Psychiatric Rating Scale (BPRS), the Chinese version Scale of Social Functioning for Psychotic Inpatients (SSFPI), and the Life Satisfaction Index A (LSIA). The clinical symptoms of patients with schizophrenia improved significantly and they recovered social function, but there was no significant change in life satisfaction. In the control group, clinical symptoms recovered but there was no improvement in social function and life satisfaction significantly decreased. In addition, patients in the EHT group expressed satisfaction with the program. In conclusion, EHT can improve the clinical symptoms of schizophrenia and promote recovery of social function; however, its impact on life satisfaction remains unclear.

Open access

Rui Wang, Masatake Eguchi, Yuqing Gui and Yasunaga Iwasaki

Uniform flower development is crucial for the uniform production of mature fruit, and it is essential in the management and production of commercial strawberry (Fragaria ×ananassa) in greenhouses. Environmental factors such as temperature, light intensity, and photoperiod have been extensively evaluated to determine their roles in strawberry flower induction and growth; however, data on the role that lighting conditions play in the uniformity of flower development are still lacking. The aim of this study was to clarify the influence of light intensity on the uniformity of strawberry flower development in forcing culture. Two experiments were conducted to evaluate plants’ response to both shading and light-emitting diode (LED) treatments. Plant growth parameters (i.e., leaf area, dry matter, and number of leaves between inflorescences) and flower development data [i.e., time from flower beginning to full bloom (FB), time from transplanting to flowering (TB), and bud number (BN)] were recorded. As expected, flower development was enhanced when exposed to LED light and was delayed when shaded. Within each cultivar, a strong relationship between lighting environment and uniformity of flower development was also detected. In both experiments, TB and BN showed less variation when exposed to high light intensity compared with low intensity. This trend was true for other parameters as well, including dry matter, leaf area, and number of leaves between inflorescences. However, there were no significant differences in FB between the shading and LED treatments. The results show that strawberry growth and flower development were highly variable in a low light environment. In addition to light being an important factor in inflorescence initiation and high yield production, the results of this study also show that the amount of light supplied is an important factor in maintaining uniform flowering in forcing culture.

Open access

Tao Dong, Fang-cheng Bi, Yong-hong Huang, Wei-di He, Gui-ming Deng, Hui-jun Gao, Ou Sheng, Chun-yu Li, Qiao-song Yang, Gan-jun Yi and Chun-hua Hu

An efficient biolistic transformation system of banana combined with a liquid medium selection system was developed during this study. An embryogenic cell suspension (ECS) of Musa acuminata cv. Baxi (AAA) was bombarded with a particle delivery system. After 7 days of restoring culture in liquid M2 medium, embryogenic cells were transferred to a liquid selection M2 medium supplemented with 10 μg/mL hygromycin for resistance screening. The untransformed cell clusters were inhibited or killed, and a small number of transformants proliferated in the liquid selection medium. After the 0th, first, second, and third generation of antibiotic screening, there were 0, 65, 212, and 320, respectively, vitality-resistant buds obtained from a 0.5-mL packed cell volume (PCV) of embryogenic cell suspension. The β-glucuronidase (GUS) staining, polymerase chain reaction (PCR) analysis, and Southern blot hybridization results all demonstrated a 100% positive rate of regenerated resistant seedlings. Interestingly, the number of buds obtained through third-generation screening was almost equal to that obtained from the original ECS in M2 medium without antibiotics. These results suggested that the liquid medium selection system facilitated the proliferation of a positive transgenic ECS, which significantly improved the regeneration rate of transformants. This protocol is suitable for the genetic transformation of all banana genotypes and is highly advantageous to varieties with low callusing potential.

Open access

Lie Li, Yu-xin Tong, Jun-ling Lu, Yang-mei Li and Qi-chang Yang

Light, as the energy and signal sources for plant growth and development, is one of the most important environment factors in recently developed plant factories with artificial light (PFALs). To find the optimal combination of light wavelengths for lettuce (Lactuca sativa cv. ‘Tiberius’) plant growth in a PFAL, four treatments, each using red (R; 662 nm) and blue light (B; 447 nm) with a ratio of 4:1 and photon flux density (PFD) of 150 μmol·m−2·s−1, and mixing, respectively, with 50 μmol·m−2·s−1 of green light (G; 525 nm; RBG), yellow light (Y; 592 nm; RBY), orange light (O; 605 nm; RBO) and far-red light (FR; 742 nm; RBFR), were set up during this experiment. A combination of R and B with a ratio of 4:1 and PFD of 200 μmol·m−2·s−1 was set as the control (RB). The responses of lettuce growth, morphology, anatomical structure of the lettuce leaf, photosynthetic performance, lettuce nutritional quality, and energy use efficiency were investigated. The results showed that RBG, RBO, and RBFR increased the shoot fresh weight of lettuce by 20.5%, 19.6%, and 40.4%, and they increased the shoot dry weight of lettuce by 24.2%, 13.4%, and 45.2%, respectively, compared with those under RB. The Pn under RBY was significantly lower than that under RB, although no significant differences in chlorophyll or carotenoid content were found between RBY and RB. RBG increased the lettuce leaf area, the thickness of the leaf palisade tissue, Pn, and light use efficiency compared with those under RB. Plants grown under RBO showed better photosynthetic capacity, such as higher Pn, ΦPSII, and other photosynthetic parameters. RBFR caused an increase in lettuce leaf area and energy use efficiency, but a decrease in leaf thickness and Pn of the single leaf. Moreover, tipburn injury was observed under RBFR. Therefore, these results demonstrate that RBG and RBO can be considered optimal combinations of light wavelengths for lettuce growth in a PFAL in this experiment, although plant growth can also be improved by using RBFR.

Open access

Samuel F. Hutton, John W. Scott and Joshua H. Freeman

Open access

Rebecca Grube Sideman

High tunnels can facilitate production of ripe colored bell peppers (Capsicum annuum) in locations with short growing seasons by extending the length of the growing season and protecting fruit from biotic and abiotic stressors. We grew 10 cultivars of bell pepper over 3 years in a high tunnel in Durham, NH. Yields of marketable colored fruit ranged from 1576 to 2285 g/plant in 2015, from 1194 to 1839 g/plant in 2016, and 1471 to 2358 g/plant in 2017. Significant differences in marketable yield among cultivars existed only in 2015 and 2017. Of the 10 cultivars evaluated, those developed for controlled environments produced greater marketable yields than those developed for production in the field or unheated tunnels (P < 0.0001). The seasonal production patterns were similar among cultivars in all 3 years: a single peak in production occurred between 159 and 175 days after seeding, followed by much lower but steady production until frost ended each growing season. Our results demonstrate that reasonable yields of colored bell peppers can be produced in high tunnels in locations with short growing seasons. We suggest that further work may be needed to identify optimal pruning and canopy management strategies to maximize yields and fruit quality.

Open access

Archana Khadgi and Courtney A. Weber

Caneberry crops (raspberry and blackberry) are globally commercialized specialty crops with a high fresh market value. Field management of canes and harvesting of fruits can be complicated by the presence of prickles (the botanically accurate term rather than spines or thorns) on the stems, petioles, and underside of the leaves. Both field management and fruit harvesting could be simplified by the development of cultivars with prickle-free canes. Scanning electron microscopy (SEM) was used to analyze and compare prickle development in different Rubus species. Comparisons were made between prickled vs. prickle-free red raspberry (Rubus idaeus L.), black raspberry (Rubus occidentalis L.), blackberry (Rubus hybrid), complex hybrid with purple fruit (R. occidentalis × R. idaeus), and the hairy and prickled wineberry (Rubus phoenicolasius Maxim). Samples from stems and leaves with petioles attached were used for imaging. There were distinct differences between prickled vs. prickle-free phenotypes in each species. The images of prickle development suggest that prickles either develop directly from glandular trichomes (in red raspberry and wineberry) or that the signal originates from glandular trichomes (in blackberry). Black raspberry prickle development was similar to that of blackberry, suggesting that prickles developed after a developmental signal from glandular trichomes rather than as a direct development from glandular trichomes. The prickle development in the purple hybrid was unique in the presence of one-sided lumps in the trichomes, which has not been seen in any other Rubus species to date; however, both prickled and prickle-free plants exhibited simple nonglandular trichomes. Unlike previous studies, an increase in the number of simple trichomes was not specific to prickle-free plants, but rather variability among the different genotypes was observed. This study adds to the basic understanding of prickle development in the genus Rubus as a first step in the development of prickle-free versions of important cultivars through gene-editing procedures for improving the ease of field management and harvesting.