Three-component barley mixtures: Ratio effects in replacement series

Abstract

. 2001. Three-component barley mixtures: Ratio effects in replacement series. Can. J. Plant. Sci. 81: 651-656. Within a species, cultivar mixtures may offer yield and quality advantages if the cultivars have complementary abiotic and biotic stress tolerances. This study was conducted at Botha, Lacombe and Olds, Alberta, from 1992 to 1994 to determine the effect of relative seeding ratios on yield and other traits of 16 three-component barley (Hordeum vulgare L.) mixtures of Virden:Abee:Tukwa all grown at a standard seeding rate of 250 seeds m -2 . Grain yields of these mixtures fell between the yields of the monocrops, with yields of the 20:40:40 and 50:30:20 mixtures being higher than expected based on the weighted mean yields of the monocrops. When stability of yield was measured using ranking or regression analyses, several mixtures had desirable combinations of high yields and good stability with the 20:40:40 and the 40:20:40 mixtures being identified using either method. Test weights, kernel weights, percent thins, protein contents, and disease levels of the mixtures were intermediate to the monocrops; while lodging levels were as low as the best monocrop. As the proportion of any one cultivar in the mixture increased, the traits it brought to the mixture also increased. These mixtures had no yield advantage over growing a high yielding monocrop. Le poids spécifique, le poids d'amande, le pourcentage de graines minces, la concentration de protéines et le taux de maladie des mélanges se situent à mi-chemin de la valeur correspondante pour la culture pure, mais le taux de verse était égal au plus faible enregistré pour la monoculture. Quand la proportion de graines d'un cultivar augmente dans le mélange, les caractères de ce dernier se démarquent aussi davantage. Les mélanges ne présentent aucun avantage sur la production d'une seule espèce à rendement élevé.

Effects of inter-varietal diversity, biotic stresses and environmental productivity on grain yield of spring barley variety mixtures

“…4). We found that b i values were sometimes higher than that of all their components (Mix3 and Mix4), whereas Juskiw et al (2001) by a comparable approach found b i values of mixtures to be intermediate relative to component values. In the review of 36 studies, Smithson and Lenné (1996) found the environmental regression coefficients of both mixtures and component varieties to be very variable between studies.…”

“…These stability concepts are frequently used to compare crop properties (for a review, see Piepho 1998), including comparisons of variety mixtures and their components (e.g. Smithson and Lenné 1996;Juskiw et al 2001;Cowger and Weisz 2008). Here, the overall yield variation, of mixtures was slightly higher than that of pure stand varieties, and since this measure encompasses both the response to environmental productivity and sensitivity to weeds and diseases, it seems more informative to consider these sources of variation separately.…”

“…In order to promote genotype comparisons across different studies, values of b i should always be interpreted in conjunction with the overall yield level of the genotype (Piepho 1998). In essence, genotypes with b i [ 1 are responsive to high environmental productivity when having a high yield level (Clay and Allard 1969;Juskiw et al 2001), such as Landora and Mix1. Oppositely, in conjunction with a low yield level it is indicative of high vulnerability to low environmental productivity, of which none were found in this study (Fig.…”

Influence of genotypic mixtures on field pea yield and competitive ability

“…One of the solutions that may have potential for improving field pea competitive ability is genotypic mixtures. Genotypic mixtures have been proposed as a sustainable alternative to improve crop productivity (Wolfe 1985;Sarandon and Sarandon 1995;Jedel et al 1998) because they tend to allow the crop to adjust to varied biotic and abiotic stresses during the growing season (Wolfe 1985;Juskiw et al 2001). Several studies have investigated the potential use of genotypic mixtures, with some studies finding a small increase in grain yield when mixtures were compared with pure stands.…”

The agronomic value of annual plant diversity in crop-weed systems

“…The weaker cultivar diversity-productivity relationship may reflect the much narrower range of genotypic and phenotypic diversity found in a single plant group (cereals) compared with three crop groups (cereals, oilseeds and legumes). Juskiw et al (2001) also reported that barley cultivar mixtures had no yield advantage over growing a highly productive mono-cultivar crop. Nevertheless, Essah and Stoskopf (2002) found that mixtures of phenotypically different barley cultivars can produce yield advantages over mono-cultivar crops.…”