The stramenopile plant pathogen Phytophthora capsici Leon. causes root, crown, and fruit rot on a large number of high-value vegetable crops ( Granke et al., 2012 ; Hausbeck and Lamour, 2004 ). Initially described by Leonian as a pathogen of
, and have frequently produced nonrepeatable results ( Huang et al., 1990 ; Williams et al., 1966 , 1967 ). Detached leaf assays have been used to maintain cultures of the crown rust fungus ( P. coronata ) from oats ( Avena sativa L.); however, it
Abstract
Dormant rhubarb crowns do not force well until their rest period or physiodormancy (7) has been broken by sufficient chilling in the field during late fall. There are many reports that during exposure of dormant plants to cold, the free amino acids contents change. Asen and Stuart (1) found that dormant leaves and buds of Hydrangea macrophylla showed an increase of some free amino acids after 6 weeks of storage at 4 to 5°C. Another worker (8) reported that in one alfalfa variety there was a 20% increase of acids from August to December. Schneider (4) found that the levels of some free amino acids in leaves of Ilex crenata nigra rooted cuttings changed during storage at cool temperatures. In this study buds and roots of dormant rhubarb crowns were analyzed to determine the free amino acids present and also possible changes in acids levels that might indicate the end of the rest period.
Anthracnose crown rot and fruit rot caused by species of the fungal genus Colletotrichum produce significant losses in strawberry ( Fragaria × ananassa ) production with crown rot, resulting in plant death and fruit rot, which in turn results
nonfreezing cold acclimation conditions, and sucrose content in crown tissues was associated with freezing tolerance ( Dionne et al. 2001 ). Perennial ryegrass ( Lolium perenne ) crown tissue water-soluble carbohydrates (WSC) increased during cold acclimation
characteristics. Two important aspects of plant management for fruit production for growers, yet not well understood for the day-neutral varieties grown on the Central Coast of California, are the role of initial bare-root crown diameter at transplanting time and
Abstract
Ethylene (C2H4) was higher in the internal atmosphere of crown gall infected rose bushes than in healthy plants. C2H4 was higher in the crown and root tissues than in the top of normal as well as crown gall infected plants.
-layer branch from the top to the bottom of the crown), the middle terminal bud (the terminal bud of the middle-layer branch of the crown), and lower terminal bud (the terminal bud of the bottom-layer branch of the crown). Samples were taken from four directions
Thermotolerance of pineapple crowns (`Champaka 153') to 50C and above was increased with a 30-min first treatment at 30, 35, or 40C. Pineapple crowns receiving a 30-min heat treatment, before a second heat treatment at 50 or 55C, exhibited significantly less leaf damage than controls receiving no first treatments (P ≤ 0.05). The degree of thermotolerance was dependent upon the season in which crowns were harvested; greater thermotolerance occurred in crowns harvested in April than those harvested in October. Maximum thermotolerance occurred after an interval of at least 8 h between the first treatment and the higher temperature heat treatment. Thermotolerance was stable for at least 24 h.
Abstract
Seed of asparagus (Asparagus officinalis L.) germinated normally after 2 months of constant freezing (-10°C) or chilling (4°) under water-saturated conditions in laboratory germination studies. However, temperatures cycling weekly from chilling to freezing for 2 months reduced germination to less than 50%, and temperatures cycling weekly from warm (21°/16°, day/night) to chilling to freezing for 2 months reduced germination to 0. The stands of asparagus, field-seeded in November and December, were reduced 85% by winterkill in comparison to spring seeding in March and April. Seeding densities from 10 to 40 seed/m did not compensate for stand loss. The greatest contributor to winterkill apparently was seed rot. March seeding increased plant height, but not crown quality or the number of shoots initiated in comparison to conventional April seeding. High seeding densities did not reduce plant growth or crown yields in the spring plantings. Stand establishment was not different between the spring planting dates. Early March seeding at high densities is recommended.