ABSTRACT. Humid rain-fed agriculture is a special environment for wheat (Triticum aestivum) culture that tends to negatively affect wheat yield and quality. To identify quality characters of wheat in a humid environment, we conducted quality analysis and quantitative trait loci (QTL) detection in a recombinant inbred line whose parent had a high level of quality for several years. We found that high-quality wheat had less gluten content and lower protein content. Apparently, wheat quality and associated quantity traits were in a dynamic state of equilibrium. We detected 83 QTL for 10 wheat quality traits in this recombinant inbred line population. Nine QTL were detected in both evaluation years; Q.DT.scau-2A, linked to Xwmc522-2A, was detected at the same genetic location in both years. Other QTL for different traits were detected simultaneously in more than one location. Consequently, there appeared to be pleiotropic genes that control wheat quality. Based on previous studies and our research on QTL analysis of grain protein content, we conclude that there must be one or more genes for grain protein content on chromosome 6B, whose expression was little affected by environment. We constructed a consensus map and QTL detection in humid rain-fed agriculture projected the QTL on it. It was useful for choosing optimal markers for marker-assisted breeding and map-based cloning.

Abstract. Exploring an effective fertilization practice is crucial for achieving a sustainable dryland winter wheat cropping system. Following a split-plot design, this study was conducted to investigate the combined effect of manure (-M or +M; main plot) and various rates of nitrogen (N) fertilizer (0, 75, 150, 225, and 300 kg N ha-1; sub plot) on grain yield, water and N use efficiencies of winter wheat, and soil nutrients. The results showed that the treatments with manure improved the grain yield by 8%, and WUE by 10% relative to that without manure throughout the study years. The highest winter wheat yield and WUE were both recorded in the M+N225 treatment, which were not significantly different from those for M+N75 and M+N150 treatment. In contrast, high levels of N fertilizer (> 150 kg N ha-1) combined with manure not only caused a reduction in the N use efficiency (NUE), but it also caused an increase in the soil residual nitrate-N (from 43.7 to 188.9 kg ha-1) relative to without manure. After three years of continuous cropping, the treatment combining manure with 150 kg N ha-1 fertilizer had the highest SOM, available P and available K, which was 24%, 379% and 102% higher than that for unfertilized treatment (CK), and 10%, 267%, and 55% higher than that for without manure, respectively. Thus, the combination of manure (17.5 t ha-1 poultry or 30 t ha-1 pig manure) with 75-150 kg N ha-1 N fertilizer is recommended for improving winter wheat yield, water and N use efficiencies, and reducing soil nitrate-N residue as well.