Tolerance of spring barley cultivars to leaf rust, Puccinia hordei

Yield and Yield Components Response to Defoliation of Spring Wheat Genotypes with Different Level of Resistance to Helminthosporium Leaf Blight

“…There could also be compensatory increase in photosynthesis of spikes, leaf sheaths, and peduncles contributing to increased yield in tolerant genotypes. Also, storage and their mobilization to sink under disease stress conditions, or compensation in photosynthetic capacity, relative to non-diseased tissue were suggested as a possible mechanisms associated with tolerance (Kramer et al, 1980). Based on these it was hypothesized that genotypic differences for compensation and contribution from sources other than upper two leaves exists for grain yield and TKW.…”

Crop Tolerance of Foliar Pathogens: Possible Mechanisms and Potential for Exploitation

“…Tolerance is given by the slope of the relationship, thereby obviating the need for absolute parity of infection Inglese & Paul, 2006). The most common measurement of infection severity is the area under disease progress curve (AUDPC) which provides a measure of lesion area integrated over time (Kramer et al, 1980;Inglese & Paul, 2006). Newton et al (1998) used a variation of this approach to determine the relative tolerance of powdery mildew amongst spring barley genotypes.…”

“…Thus, the relative tolerance of spring barley cultivars to leaf rust measured in a two-year study differed between years (Kramer et al, 1980). Similarly, spring barley genotypes designated as tolerant of powdery mildew infection varied between years and fertilizer N treatments (Newton et al, 1998(Newton et al, , 2000.…”

“…The extinction coeffi cient for transmission of PAR through the canopy is infl uenced by several factors including leaf inclination, leaf shape, leaf size distribution through the canopy, elevation of the sun and the relative proportions of direct and diffuse radiation (Kramer et al, 1980;Campbell, 1986). Crop species and varieties with planophile leaf habits tend to have a larger extinction coeffi cient than those with erect leaves and a higher proportion of the incident radiation is intercepted with a small canopy size (Figure 7.2) (Angus et al, 1972).…”

“…It has been hypothesised that crops with a large potential assimilate supply relative to the storage capacity of grains will be relatively tolerant of post-fl owering loss of green leaf area to disease (Kramer et al, 1980;Gaunt, 1995). This could arise from the possession of a large canopy size and/or water soluble carbohydrate (WSC) storage reserve relative to the number of grains.…”