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  • Author or Editor: John Larsen x
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Influences of rootstocks on ‘Goldspur Golden Delicious’ apple (Malus domestica Borkh.) respiration rate, ethylene evolution, skin color, firmness, internal color, soluble solids content (SSC), acidity, carbohydrate, and mineral content were evaluated over an extended harvest and after cold storage. At first harvest, fruit from trees on seedling rootstock entered the climacteric (as determined by ethylene evolution) first (after 10 days) followed by fruit from M.26 trees, while apples from trees on MM.111 required 16 days. After 60 days in storage, CO2 and ethylene production were greatest for apples from trees on MM.111 rootstock. Fruit from trees on M.26 developed more external color, contained more acids, had a higher SSC, and appeared to mature between apples grown on the other two rootstocks. Fruit from trees on M.26 were firmer than those on MM.111. Apples from trees on seedling rootstock contained less fructose, glucose, and sucrose than apples from M.26 or MM.111. Calcium content was highest in fruit from trees on M.26.

Open Access

Phytophthora blight of vegetables caused by Phytophthora capsici causes significant economic losses in production of Solanaceae and Cucurbitaceae crops in Mexico. The development of universal resistant chili pepper cultivars is challenging due to the diverse virulence phenotypes produced by P. capsici. The objective of the study was to characterize the diversity of phenotypic interactions for P. capsici isolates recovered from production fields in Michoacán, Mexico, to facilitate the development of resistant cultivars. Virulence phenotypes were characterized for 12 isolates of P. capsici using 26 Capsicum annuum New Mexico Recombinant Inbred Lines (NMRILs) in greenhouse conditions. Criollo de Morelos CM-334 and California Wonder were used as resistant and susceptible controls, respectively. Seedlings at the four to eight true leaf stage were inoculated with 10,000 zoospores per seedling and disease severity was evaluated at 20 days post-inoculation. Two of the P. capsici isolates did not infect any pepper host even though the isolate was less than a year old. The 10 virulent isolates were designated in 10 virulence phenotypes. The information generated by this study is of utmost importance for efforts of producing resistant cultivars specific for Michoacán producers.

Free access