Barley yield losses due to defoliation of upper three leaves either healthy or infected at boot stage by Pyrenophora teres f. teres

Abstract

This paper evaluates, in the greenhouse and under natural conditions, barley yield losses due to defoliation treatments of the upper three leaves either healthy or infected at the boot stage by Pyrenophora teres f. teres. Defoliation was assumed as a loss of a similar leaf area caused by net blotch disease severity of 100%. Contribution to grain yield was defined herein as a difference between defoliation treatments and a treatment where plants lost all their upper three leaves. In contrast, yield losses referred to differences in yield between defoliations and the control. In the greenhouse, removal of the antepenultimate leaf did not affect any yield component. For main stems, defoliating upper three leaves reduced grain yield by 30% and this was mainly due to flag leaf removal. These losses were similar to those induced by net blotch disease under natural conditions, but were of 42% for all tillers. Grain yield losses due to disease severity were not equivalent to the defoliation effect of a similar healthy leaf area. On the other hand and for a significant contribution to grain yield, flag leaf was dependent on the presence of the other two leaves. Inoculation and defoliation of 21 cultivars induced similar grain yield losses of 32%. However, biotic stress reduced by 40% the contribution of their upper three leaves. Under field conditions, yield losses were not significant until barley plants lost more than one upper leaf and flag leaf contribution was equivalent to that of the remaining leaves. Characteristic roots, defined as leaf coefficients for plant performance, were 0.13, 0.06 and 0.01 for the flag, penultimate and antepenultimate leaves, respectively. Because antepenultimate leaves become trivial at the boot stage, we propose that coefficients of the remaining leaves should be used when modelling yield losses due to barley foliar diseases.

Reduction of OsFLW7 expression enhanced leaf area and grain production in rice

“…Exploring yield potential and identifying genes beneficial to yield are important goals in the modern rice breeding. Generally, controlling leaf morphology, increasing photosynthesis efficiency and modulating the ''sink-source" relationship can promote the breeding of high-yield rice as well as other cereal crops [2][3][4]. The morphology of the leaf includes length, width and degree of curl after its emergence from the meristem and is determined by the establishment of polarity along the adaxial-abaxial, ventral-dorsal and medial-lateral axes and regulated at genetic, hormonal and environmental levels [5,6].…”

The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality

“…The most important leaves in the barley canopy for yield and grain filling are typically the top three leaves for barley (Jenkyn and Anil Kumar 1990;Poole 2005Poole , 2009Jebbouj and El Yousfi 2009). Given the importance of the upper leaves in relation to grain yield and quality, recommended fungicide application timing is at flag leaf emergence in barley, Zadoks 39 (Zadoks et al 1974;Alberta Agriculture and Rural Development 2014b).…”

DEFOLIATION ENHANCES GREEN FORAGE PERFORMANCE BUT INHIBITS GRAIN YIELD IN BARLEY (HORDEUM VULGARE L.)

“…Reduction in GY by forage removal might be related to late cutting stage (between jointing and booting stages), which resulted in the greater loss of GY in barley (Royo, 1999;Royo et al, 1997). Consistent grain losses due to defoliation were reported in both barley (Jebbouj and Yousfi, 2009;Jenkyn and Anilkumar, 1990) and wheat (Zhu et al, 2004). Single cutting may be the optimal choice to achieve both forage supply in winter and early spring and grain harvest in summer for the majority of winter barley region in China.…”