Sowing Density and Cultivar Effects on Pith Expression in Solid‐Stemmed Durum Wheat

Autor: Brian L. Beres, Kirby T. Nilsen, J. M. Clarke, Curtis J. Pozniak
Rok vydání: 2016
Předmět:
Zdroj: Agronomy Journal. 108:219-228
ISSN: 1435-0645
0002-1962
DOI: 10.2134/agronj2015.0298
Popis: 219 The WSS has been one of the most damaging insect pests of common and durum wheat across the northern Great Plains of North America for more than a century (Beres et al., 2011c). Severe yield losses occur when WSS larval feeding activity damages the inner stem tissue, which reduces fl ag leaf photosynthetic ability (Delaney et al., 2010), and damages vascular bundles impairing the fl ow of water and nutrients to the developing grain (Morrill et al., 1992). Th e greatest sawfl y damage occurs in the southern parts of Alberta and Saskatchewan, southeastern Manitoba, and throughout Montana, North Dakota, South Dakota, and western Minnesota (Beres et al., 2011c). Th e life cycle of the WSS has been reviewed in depth by Beres et al. (2011c). Briefl y, the insect spends up to 10 mo of the year in its larval stage nested inside the wheat stem. In early spring, larvae will undergo pupation to reach the adult stage. Peak sawfl y emergence generally occurs from 10 June to 10 July in western Canada (Beres et al., 2011b). Adult sawfl ies live for approximately 1 wk and usually mate shortly aft er emergence followed by oviposition within a few days. Th e female sawfl y has a specialized saw-like ovipositor (hence “sawfl y”) used to cut the wheat stem. During this process, the female will search for a suitable host plant in which to lay an egg, usually beginning at the upper internode of the developing wheat plant (Beres et al., 2011c). Females prefer succulent plants that are at early boot to anthesis stage with a large enough stem diameter suitable for oviposition (Holmes and Peterson, 1960). Eggs hatch approximately 1 wk aft er deposition, and larvae immediately begin feeding on the inner stem wall (Holmes, 1954). As the growing season progresses, larvae tunnel down through the stem, damaging vascular tissue disrupting the fl ow of nutrients and water to the developing wheat kernel (Morrill et al., 1992). At the end of the growing season, larvae will chew a notch around the inner perimeter of the stem at the base of the plant causing it to lodge. (Holmes, 1977). Due to the reduction in grain mass coupled with the fact that lodged stems are oft en Agronomic Application of Genetic Resources
Databáze: OpenAIRE
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