Nitrogen fertilization and precipitation affected Wheat (Triticum aestivum L.) in dryland the Loess Plateau of South Shanxi, China

Wheat (Triticum aestivum L.) is a staple crop worldwide, and its yield has improved since the green revolution, which was attributed to chemical nitrogen (N) fertilizer application. An experiment was conducted to set seven nitrogen application levels of N0, N90, N120, N150, N180, N210 and N240 kg ha^-1 before sowing. The results showed that grain yield under the nitrogen rate of N210 kg ha^-1 was significantly increase the water intake during jointing to anthesis, Soil water storage of dryland wheat in fallow period was higher than water consumption in jointing stage and the leaf area index at anthesis, the tiller percentage rate, the jointing-anthesis, and nitrogen accumulation were closely related to yield and its components. Nitrogen fertiliser rate N150 kg ha^-1 significantly increased dry matter buildup from jointing to flowering in dryland wheat compared to N fertiliser rate N210 kg ha^-1. The rise of nitrogen application rate, there were no significant variance in nitrogen accumulation of Stem + leaf sheath and cob + glume at maturity, respectively. N fertiliser rate N210 kg ha^-1 compared to N180 kg ha^-1 significantly reduced grain gliadin content in dryland wheat, respectively. Wheat crops under N210 kg ha^-1 could achieve both high NUE and grain yield simultaneously with only moderate N fertilizer in South Shanxi, China.

Wide space sowing achieved high productivity and effective nitrogen use of irrigated wheat in South Shanxi, China

Wheat (Triticum aestivum L.) is a staple crop worldwide, and its yield has improved since the green revolution, which was attributed to chemical nitrogen (N) fertilizer application. However, regular N application decreases N use efficiency (NUE, the ratio of grain dry matter yield to N supply from soil and fertilizer). Various practices have been implemented to maintain high crop yield and improve NUE. Nowadays, the enhanced sowing method, i.e., wide space sowing (WS), has improved the productivity of wheat crops. However, how the sowing method and N application rate affect N use and yield productivity has not been fully elucidated. Field experiments with treatments using two sowing methods (WS, and drill sowing, DS) and four N application rates (0, 180, 240, and 300 kg ha^-1, represented as N0, N180, N240, and N300, respectively) were conducted from 2017 to 2019. The results showed that grain yield under WS was 13.57-16.38% higher than that under DS. The yield advantage under WS was attributed to an increased ear number. Both the higher stem and productive stem percentage accounted for the increased ear number under WS. Higher total N quantity and larger leaf area index at anthesis under WS contributed to higher dry matter production, resulting in higher grain yield. Higher dry matter production was due to pre-anthesis dry weight and post-anthesis dry weight. The wheat crop under WS had a 12.44-15.00% higher NUE than that under DS. The increased NUE under WS was attributed to higher N uptake efficiency (the ratio of total N quantity at maturity to N supply from soil and fertilizer), which was the result of greater total N quantity. The higher total N quantity under WS was due to both higher pre-anthesis N uptake and post-anthesis N uptake. Remarkably, compared to DS with 240 kg N ha^-1, WS with 180 kg N ha^-1 had almost equal grain yield, dry matter, and total N quantity. Therefore, wheat crops under WS could achieve both high NUE and grain yield simultaneously with only moderate N fertilizer in South Shanxi, China.

Effects of Planting Distance on Yield and Agro-morphological Characteristics of Local Rice (Bara Variety) in Northeast Afghanistan

To evaluate the effect of planting distance on yield and agro-morphological characteristics of Bara variety (local variety of rice), a field experiment was carried out at the experimental station of the Agricultural Faculty of Kunduz University in 2016. Randomized Completely Block Design (RCBD) with four replications was used in the experiment. Transplanting distances with four levels viz. 10x10 cm, 15x15 cm, 20x20 cm, and 25 x 25 cm were used as treatment. Results showed that planting distance had significant effects on tillers number, leaf color, non-filled grain, total grain, and 1000 grains weight. In contrary, no significant effects on plant height, panicle length, number of filled grain per panicle and grain yield were observed between spacing. The spacing of 25 x 25 cm had produced the highest performance for most of the agro-morphological traits evaluated. Grain yield was found similar in all spacing but other yield components like total number of tillers (16.63) and total grain per panicle (119.43) were found statistically superior in 25 x 25 cm planting distance. Overall, the results of this study revealed that the planting distance of 25 x 25 cm seemed to be the best as requires lower seed and fertilizer (lower cost) and can, therefore, be suggested to the farmers for a better valorization of Bara variety in northeastern Afghanistan. Similar investigations are strongly recommended in other agro-ecological zones of the country where Bara variety is largely grown to confirm these findings.

A major locus for chloride accumulation on chromosome 5A in bread wheat

Chloride (Cl⁻) is an essential micronutrient for plant growth, but can be toxic at high concentrations resulting in reduced growth and yield. Although saline soils are generally dominated by both sodium (Na⁺) and Cl⁻ ions, compared to Na⁺ toxicity, very little is known about physiological and genetic control mechanisms of tolerance to Cl⁻ toxicity. In hydroponics and field studies, a bread wheat mapping population was tested to examine the relationships between physiological traits [Na⁺, potassium (K⁺) and Cl⁻ concentration] involved in salinity tolerance (ST) and seedling growth or grain yield, and to elucidate the genetic control mechanism of plant Cl⁻ accumulation using a quantitative trait loci (QTL) analysis approach. Plant Na⁺ or Cl⁻ concentration were moderately correlated (genetically) with seedling biomass in hydroponics, but showed no correlations with grain yield in the field, indicating little value in selecting for ion concentration to improve ST. In accordance with phenotypic responses, QTL controlling Cl⁻ accumulation differed entirely between hydroponics and field locations, and few were detected in two or more environments, demonstrating substantial QTL-by-environment interactions. The presence of several QTL for Cl⁻ concentration indicated that uptake and accumulation was a polygenic trait. A major Cl⁻ concentration QTL (5A; barc56/gwm186) was identified in three field environments, and accounted for 27–32% of the total genetic variance. Alignment between the 5A QTL interval and its corresponding physical genome regions in wheat and other grasses has enabled the search for candidate genes involved in Cl⁻ transport, which is discussed.