Jan Rozbicki

Ontogenetic-based sequential path analysis of grain yield and its related traits in several winter wheat cultivars

Studies that provide representative insights for determining yield through its related traits during the ontogeny of modern cultivars subjected to sources of environmental variation are limited for different crops, including wheat. Most of the empirical evidence on the relationships between the yield of small grain cereal crops and its contributing traits has been obtained under dry or semidry conditions. The aims of this paper were to (1) illustrate how an path analysis can be used to clarify and interpret the relationships between grain yield (GY), yield components, and other yield-related traits of 25 winter wheat cultivars subjected to sources of environmental variation and (2) determine how the yield-related traits contribute to the yield variation. The data used in this analysis were generated from multi-environment trials across wheat-growing areas in Poland. Using Ward’s clustering procedure was capable of identifying the most critical predictor traits of the yield components and their contributions to cultivar-focused GY variation. Our findings document, confirm, and improve the basic biological understanding of how to grow modern wheat cultivars for high GY through effectively stimulating the improvement of yield-related traits through the optimization of developmental stage-based agronomic strategies. Our results confirmed empirically that modern European wheat cultivars grown in a temperate climate require favorable conditions, the use of appropriate N fertilizer and growth regulators, and the application of fungicide to protect against leaf diseases and to provide conditions that effectively increase the time to anthesis, the Leaf Area Index per spike at anthesis, and the grain filling duration, and reduce plant height and flag leaf disease severity, thus leading to a high GY. A high yield level is obtained by the performance of preferred yield-related traits that can maintain the three yield components at relatively high levels.

Assessing grain yield and quality traits stability of spring wheat cultivars at different crop management levels

Eleven spring wheat cultivars were compared in terms of the stability of their grain yield and grain quality. The cultivars’ stability was evaluated separately at two different crop management levels – moderate-input management and high-input management. Three stability models were used for the two crop management levels based on a linear mixed model framework with restricted maximum likelihood. The Shukla model was the most appropriate for the evaluation of stability of tested spring wheat cultivars. The thousand-grain weight, starch content, Zeleny sedimentation value and test weight were characterized, and the stability ranking cultivars at moderate-input management level was mostly consistent with the rank of cultivars 24 for high-input management level. For grain yield, grain protein content and wet gluten content, the stability rankings were not consistent. Cultivars ‘Monsun’ and ‘Parabola’ are the most stable cultivars for grain yield in moderate-input management and high-input management, respecti...

Within-Field Variability of Winter Wheat Yield and Grain Quality versus Soil Properties

ABSTRACT Within-field variability in wheat grain yield and its quality always exists in production fields and depends, among other factors, mainly on various soil properties related to nutrients and water availability. The aim of the research was to examine the relationships between selected soil properties such as texture; pH; content of the available phosphorus (P), potassium (K), magnesium (Mg), and organic carbon; and winter wheat grain yield and quality under rainfed conditions. Six crop fields with winter wheat (Triticum aestivum, L.) in three sites located in different regions of Poland were examined during two seasons. The grain yield was mainly determined by the soil texture, and the majority of the chemical soil properties did not have a significant effect on grain yield. The grain quality traits were determined by the examined soil properties to a smaller degree than grain yield. The relationships were not consistent across sites and years.