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- Author or Editor: Luisa Santamaria x
Solanum quitoense, also known as naranjilla or lulo, is a native species of Ecuador and Colombia. Its value is based on the uncommon sweet-sour flavor of its fruits, which is appreciated in the national and international markets. The worst problem for this crop is the root-knot nematode Meloidogyne incognita. The main objective of our research is to develop root-knot nematode–resistant naranjilla via somaclonal variation. Seeds of Solanum quitoense `Baeza' germinated quicker than those of `Dulce'. Seeds given a 2-week dark treatment had 100% germination compared to 75% germination for seeds placed under lights (16-h photoperiod, 60 mmol·m–2s–1). Single-node explants proliferated an average of nine nodes after 1 month of culture. Microcuttings (two nodes, 3.5 cm) stuck in sand and placed under a humidity dome under mist had an average of five roots averaging 25 cm in length after 3 weeks. Stems regenerated shoots better than petioles or leaves and explant orientation/polarity had no effect on regeneration. Root cultures of Solanum quitoense inoculated in vitro with Meloidogyne incognita showed susceptibility to root-knot nematodes.
Growing demand for appropriate training opportunities for Oregon’s increasingly scarce agricultural workers continues to outpace extension’s available time and resources. New, more efficient, and innovative ways of reaching this audience must be explored to better fill the need and demand. Hybrid teaching, which refers to course delivery through a blend of traditional, face-to-face teaching, along with online instruction outside of the classroom, is being implemented in some English-language extension programs. A hybrid pesticide training course was designed and delivered in Spanish over the course of 4 weeks to nursery and landscape workers in Oregon to assess their reception of hybrid teaching. The delivery method was very well received and the students showed interest in taking more courses offered in a hybrid format. Initial and final practice exams included in the course were used to assess student performance and showed significant improvement from the students who completed the course. One student became certified and licensed to apply pesticides in the Oregon.
Solanum quitoense is a perennial herbaceous plant native to the tropical regions of Colombia and Ecuador. It has attracted the attention of the international market because of the special taste of its fruits and its being a non traditional crop. The main problem in its culture is its susceptibility to root-knot nematodes, Meloido-gyne incognita (Kofoid & White) Chitwood. Two cultivars of S. quitoense were examined, `Baeza' and `Dulce'. The main objective of this research was to develop protocols for proliferation, rooting and establishment, and regeneration and screening for root-knot nematode resistance. S. quitoense was easy to proliferate, root and reestablish without using growth regulators. Regenerants were initiated from petioles and internodal stem sections cultured on MS medium supplemented with BA 1 to 10 mg·L–1. From 420 explants cultured for each cultivar, there were 226 regenerants for `Baeza' and 279 for `Dulce'. Screening of regenerants for root-knot nematode resistance was carried out in the greenhouse with the regenerants of `Dulce'. Twenty-one regenerants, inoculated with 1000 eggs per plant (determined based on a previous experiment), had five or fewer galls after 5 weeks. Follow-up greenhouse and in vitro screening experiments are presently ongoing.
The oomycete Phytophthora phaseoli is one of the most threatening pathogens of lima bean (Phaseolus lunatus) in the humid Mid-Atlantic United States. In the last 60 years, P. phaseoli has evolved to overcome genetic resistance in the host and several physiological races have been identified during the last 6 decades. Six physiological races A, B, C, D, E, and F have been identified over the years. Only race F has been detected in the field over the past decade. Identifying and characterizing sources of resistance to this pathogen and determining the nature of resistance were the main objectives. Eight commercial cultivars and 35 germplasm accessions of P. lunatus were evaluated for their reaction to races E and F. Four commercial cultivars and four accessions with resistance to race E, and two cultivars and four accessions with resistance to race F were identified. None of the germplasm evaluated were resistant to both races. Five populations of F2 plants and a recombinant inbred line (RIL) population were produced and inoculated to investigate the inheritance of resistance to races E and F. Resistance to races E and F was determined to be conferred by single, independent, dominant genes.