Showing papers on "Biotic stress published in 1994"

Expanding the production and use of cool season food legumes

Abstract: Processing and animal feeds. Climate change and biotic and abiotic stresses. Host plant resistance to manage biotic stress. Policy Incentives. Breeding methods and selection indices. Infrastructural support. Cool season food legume breeding. Management to control biotic and abiotic stress. Biotechnology and gene mapping. Crop physiology and productivity. Farmers' constraints and on-farm research. Reports of seven concurrent discussion groups based on geography. Continuation of the IFLRC concept. Conference summary.

Trypsin inhibitor activity in mature tobacco and tomato plants is mainly induced locally in response to insect attack, wounding and virus infection

Abstract: Wounding of plants by insects is often mimicked in the laboratory by mechanical means such as cutting or crushing, and has not been compared directly with other forms of biotic stress such as virus infection. To compare the response of plants to these types of biotic and abiotic stress, trypsin inhibitor (TI) activity induced locally and systemically in mature tobacco (Nicotiana tabacum L.) and tomato (Lycopersicon esculentum L.) plants was followed for 12 days. In tobacco, cutting, crushing and insect feeding all induced comparable levels of TI activity of approx. 5 nmol·(mg leaf protein)−1 in wounded leaves, while tobacco mosaic virus (TMV) infection of tobacco induced 10-fold lower amounts in the infected leaves. In tomato, feeding by insects also led to the induction of a level of TI activity of 5 nmol·(mg leaf protein)−1. In contrast, both cutting and crushing of tomato leaves induced 10-fold higher amounts. These data show that biotic stress, in the form of insect feeding and TMV infection, and abiotic stress, in the form of wounding, have different effects on local levels of induced TI activity in mature tobacco and tomato plants. Irrespective of the type of wounding, in neither tobacco nor tomato could systemic induction of TI activity be observed in nearby unwounded leaves, which suggests that systemic induction of TI activity in mature tobacco and tomato plants is different from systemic TI induction in seedlings. Wounding of tobacco leaves, however, did increase the responsiveness to wounding elsewhere in the plant, as measured by an increased induction of TI activity.

Biotic and abiotic stresses of cool season food legumes in the western hemisphere

Abstract: Pea, lentil, faba bean, and chickpea suffer from many of the same biotic and abiotic stresses throughout the world. The recent large increase in production of pea and lentil in western Canada has been relatively free of biotic stresses. However, as production increases further and as these crops are grown with increasing frequency in the same fields, increased problems with biotic stresses will occur. The most severe biotic stresses will be the soilborne diseases and the Ascochyta complex of foliage diseases. Fortunately, genetic differences occur in response to most of these biotic stresses and are being incorporated into new cultivars.

Biotic and abiotic stresses of pulse crops in Europe

Abstract: Biotic and abiotic stresses seriously reduce seed yields of pulses in Europe and are major causes of yield instability.

Breeding for Abiotic Stress Tolerance

Abstract: The combined effect of all abiotic stress factors is worldwide seen enormous and the deterioration of many soils due to poor farm management is aggravating this. Especially stress factors that reduce and retard growth and development (drought, salinity, acidity, frost, heat, water logging, iron shortage etc.) are very important. These stresses tend to occur highly heterogeneously in time and space making selection in the field very inefficient. If the tolerance to the stress factor is simply inherited (tolerance to acid soil and Altoxicity) it is possible to develop an efficient greenhouse or laboratory screening test. Is the tolerance a complex trait no efficient screening test is yet available and breeding for it is a tedious one (drought tolerance) or may not even be advisable at all (salt tolerance).

A Novel Method to Monitor Root Decomposition Demonstrates that Salt Stress Can Enhance the Rate of Tomato Root Decomposition

Abstract: This study quantified the effects of an abiotic stress, salinity, and a biotic stress, phytophthora root rot, on root mortality and decomposition in tomato (Lycopersiron esculentum Mill.). Rhizotron windows were used to measure root mortality rates in mature, container-grown plants. A novel assay was developed to monitor root decomposition by quantifying root-length disappearance over time using petri dishes in incubation chambers. Phytophthora root rot infection was induced by salt stress in the presence of Phytophthora parasitica Dastur inoculum; however, the moderate levels of disease induced had no effect on rates of root mortality or on root decomposition. Genotypic differences in root decomposition under salt stress were shown by the decomposition assay, the first report of intraspecific variation in root decomposition rates