Performance of Timothy Strains

This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Performance of Kentucky Bluegrass Strains

This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Progress from selection in la posta maize population evaluated under three nitrogen fertilizer levels

Nitrogen (N) is an important nutrient whose application directly influences the yield of maize (Zea mays L.) and other non-leguminous crop plants. In 1986, cycles 0, 2, 4, and 6 of CIMMYT Population 43, improved using full-sib family selection for grain yield and other traits, were evaluated at 0, 80, and 160 kg N ha-1 at six locations in Ghana, West Africa. Grain yields across environments and cycles averaged 3.0, 4.7 and 5.2 Mg ha-1 at 0, 80 and 160 kg N ha-1, respectively. Cycle responses showed that grain yield, plant height, lodging, and ear rating (based on size and uniformity of ears) increased, days to mid-silk decreased, and grain moisture and number of ears per plant did not change as fertilizer N was increased. The greatest response to applied N was observed at 80 kg N ha-1 for all traits. Similar N response patterns were observed in all cycles. Least square estimates of progress per cycle of selection for grain yield, days to mid-silk, plant height, and lodging were 1.6, -0.6, -1.5, -1.1% at zero fertilizer N; 2.1, -0.8, -1.5, -3.5% at 80 kg N ha-1 and 1.8, -0.7, -1.4, -2.8% at 160 kg N ha-1, respectively. These results indicate that (i) selection was effective for improving grain yield, days to mid-silk, plant height, and lodging in the population at 80 and 160 kg N ha-1, and (ii) recurrent selection for improved agronomic performance had little effect on the N fertilizer response of the population.L'azote (N) est un \ue9l\ue9ment nutritif important dont l'application influence directement le rendement du ma\uefs (Zea mays L.) et d'autres cultures non l\ue9gumineuses. En 1986, les cycles am\ue9lior\ue9s de 0, 2, 4, et 6 de Population 43 de CIMMYT utilisant \ue8la s\ue9lection familiale des vrais parents' pour le rendement en grains \ue9taient \ue9valu\ue9s \ue0 0, 80 et 160 kg/ha d'azote dans six localit\ue9s du Ghana, Afrique de l'Ouest. Les rendements en graines \ue0 travers les environnements et les cycles \ue9taient en moyenne de 3.0, 4.7 et 5.22 Mg/ha respectivement \ue0 0, 80 et 160 kg/ha d'azote. Les cycles de r\ue9ponse ont montr\ue9 que le rendement en grains, la taille de plant, la verse, et le taux d'\ue9pi (bas\ue9 sur la grandeur et l'uniformit\ue9 des \ue9pis) ont augment\ue9, les jours \ue0 la mi-soie ont diminu\ue9, l'humidit\ue9 des grains et le nombre d'\ue9pis par plant n'ont pas chang\ue9 quand la quantit\ue9 d'azote a \ue9t\ue9 augment\ue9e. La r\ue9ponse la plus significative \ue0 l'application de l'azote a \ue9t\ue9 observ\ue9e \ue0 80 kg/ha d'azote pour tous les traits. Les tendances similaires des mod\ue8les de r\ue9ponse \ue0 l'azote ont \ue9t\ue9 observ\ue9es dans tous les cycles. Les estimations des progr\ue8s de moins carr\ue9s par cycle de s\ue9lection pour le rendement en grains, le nombre de jours \ue0 la mi-soie, la hauteur de plant et la verse \ue9taient 1.6, -0.6, -1.5, -1.1 % \ue0 0 kg/ha d'azote, 2.1, -0.8, -.1.5, -3.5 % \ue0 80 kg/ha de N et 1.8, -0.7, -1.4, -2.8 % \ue0 160 kg/ha d'azote, respectivement. Ces r\ue9sultats montrent que (i) la s\ue9lection \ue9tait efficace pour am\ue9liorer le rendement en grain, le nombre de jours \ue0 la moiti\ue9 de soie, la hauteur de plant, et la verse dans la population \ue0 80 et 160 kg/ha d'azote et (ii) la s\ue9lection r\ue9currente pour la performance agronomique am\ue9lior\ue9e a eu peu d'effet sur la r\ue9ponse de l'engrais azot\ue9 de la population

Seed Dormancy in Hairy Vetch (Vicia villosa Roth) Is Influenced by Genotype and Environment

Seed dormancy complicates the agricultural use of many legume species. Understanding the genetic and environmental drivers of seed dormancy is necessary for advancing crop improvement for legumes, such as Vicia villosa. In this study, we quantify the magnitude of genetic and environmental effects on physical dormancy among 1488 maternal V. villosa plants from 18 diverse environments. Furthermore, we explore the relationship between physical dormancy and environmental conditions during seed development. Additive genetic variance (h2) accounted for 40% of the variance, while the growing environment explained 28% of the variance in physical dormancy. Maternal lines showed complete variance in physical dormancy, as one line was 100% dormant, and 56 lines were 0% dormant. Distributions of physical dormancy varied widely among seed production environments, with some site-years strongly skewed toward physically dormant seed, while other site-years exhibited little dormant seed. Twenty-three weather variables were associated with environmental and error effects of physical dormancy. High mean and minimum relative humidity, low mean and maximum temperature, and high precipitation weakly grouped with low physical dormancy. Weather variables calculated from fixed time windows approximating seed maturity to seed harvest at each site-year tended to be less predictive than biological seed drying windows calculated based on seed maturity of each maternal line. Overall, individual and cumulative effects of weather variables were poor predictors of physical dormancy. Moderate heritability indicates that breeding programs can select against physical dormancy and improve V. villosa for agricultural use. Marker-based approaches would maximize selection for physical dormancy by reducing the influence of unpredictable environmental effects