Effects of Weak- and Semi-Winter Cultivars of Wheat on Grain Yield and Agronomic Traits by Breaking through Traditional Area Planting

Global warming has changed the suitability of areas traditionally planted with crops, raising concerns about cereal security. To investigate the possibilities and constraints of increasing yields by breaking through traditional area plantings of wheat cultivars, a two-year field experiment was conducted in southern and northern locations in the Yangtze River basin (YRB), China (separated by approximately 180 km), with seven weak-winter types and six semi-winter types, respectively, bred for the two regions. The movement of weak-winter-type cultivars to the north increased or did not change grain yield and their grain yields were not significantly higher than those of local semi-winter-type cultivars. The movement of semi-winter-type cultivars to the south significantly decreased their yields. Thus, breaking through traditional area plantings did not significantly increase grain yields compared with those of local wheat cultivars. Grain yield of wheat planted in the northern YRB was higher by 5 to 20% than that in the southern YRB because of an increase in spikes that resulted from a longer spike formation phase. In addition, the post-anthesis leaf area declined more slowly in the northern YRB because of higher main stem and tiller survival. High-yielding cultivars always had more spikes and larger photosynthetic areas after anthesis than those of low-yielding cultivars regardless of the planting locations, which led to increases in post-anthesis biomass. However, the grain yield of different cultivars was highly variable under different environmental conditions. The coefficient of variation (CV) of grain yield in different cultivars was significantly positively correlated with the CV of spike number and post-anthesis biomass, implying that flexibility spike number and post-anthesis biomass in response to environmental changes can maximize release of yield potential. Therefore, improving main stem and tiller survival can increase spike number and maintain post-anthesis photosynthetic areas and help to establish a large, highly stable, and productive population with a high level of suitability and production through effectively utilizing the resources during the late growth phase. Valuable suggestions for breeding high-yield and -stability cultivars and confirming their planting range in the future are given.

Changes of Extreme Agro-Climatic Droughts and Their Impacts on Grain Yields in Rain-Fed Agricultural Regions in China over the Past 50 Years

Climate change and climate extremes and their impacts on agriculture, water resources, and ecosystems have become important issues globally. Agricultural sustainability and food security are facing unprecedented challenges due to the increasing occurrence of extreme climatic events, including, notably, extreme droughts in recent years in China. In this study, a threshold determination model of extreme agro-climatic droughts (EADs) was built based on the cumulative probability distribution functions (CDF) of an agricultural drought index—the consecutive days without available precipitation (CDWAP). The CDWAP was established by combining meteorological data with the characteristics of cropping patterns and the water requirement in different growing periods of crops. The CDF of CDWAP was obtained based on the relationship of CDWAP and its occurrence frequency. Based on the model, the spatial pattern of the thresholds of EADs and the threshold exceedance time series of EADs in 500 meteorological stations were obtained, and then changes in the frequencies and intensities of EADs in China and their impacts on grain yields in rain-fed regions during the past 50 years were analyzed. The results follow: (1) The threshold value of EADs in China gradually increased from southeast to northwest. The stations of the highest value were located in the Northwest China, with the CDWAP more than 60 days, while the lowest value was in the middle reaches of the Yangzi River, with the CDWAP less than 16 days. (2) The frequencies and intensities of the EADs increased mostly in the east areas of the Hu Huanyong line, which was also the main agricultural production region in China. The North China (NC) and Southwest China (SW) regions showed the highest increasing rates of the EADs; their frequencies and intensities were 11.3% and 2.2%, respectively, for the NC region, and 9.3% and 2.7%, respectively, for the SW region. (3) Case studies in the NC, SW, and SE regions indicated that there was a negative correlation between grain yields and EAD frequency and intensity; i.e., the low grain yields often occurred in the year with relatively higher frequency or/and stronger intensity of EADs. The correlation coefficients of grain yield and EAD were generally greater than that of merely extreme climatic droughts; therefore, the study of EAD is necessary when researching the impacts of extreme drought events on grain yield.

Photosynthetic enhancement, lifespan extension, and leaf area enlargement in flag leaves increased the yield of transgenic rice plants overproducing Rubisco under sufficient N fertilization

Background: Improvement in photosynthesis is one of the most promising approaches to increase grain yields in crop plants. In our previous research using an isolated experimental paddy field, transgenic rice plants overproducing Rubisco by 30% (RBCS-sense rice plants) showed up to 28% increase in grain yields under sufficient nitrogen (N) fertilization. Furthermore, the plant N contents above-ground sections and Rubisco contents of the flag leaves were higher in the RBCS-sense rice plants than the wild-type rice plants during the ripening period, which may be reasons for the increased yields.Result: In this research, the photosynthetic capacity and canopy architecture were analyzed to explore factors for the increased yields of RBCS-sense rice plants. It was found that N had already been preferentially distributed into the flag leaves at the early ripening stage, contributing to maintaining higher Rubisco content levels in the enlarged flag leaves and extending the lifespan of the flag leaves of RBCS-sense rice plants throughout ripening periods under sufficient N fertilization. The higher amounts of Rubisco also improved the photosynthetic activity in the flag leaves throughout the ripening period. Although the enlarged flag leaves of the RBCS-sense rice plants occupied large spatial areas of the uppermost layer in the canopy, no significant prevention of light penetration to leaves below the flag leaves was observed. Additionally, since the CO2 assimilation rates of lower leaves between wild-type and RBCS-sense rice plants were the same at the early ripening stage, the lower leaves did not contribute to an increase in yields between the two genotypes.Conclusion: It was concluded that improvements in the photosynthetic capacity by higher leaf N and Rubisco contents, enlarged the leaf area, and extended the lifespan of flag leaves, causing an increase in grain yields of RBCS-sense rice plants grown under sufficient N fertilization.

Repeated Manure Application for Eleven Years Stimulates Enzymatic Activities and Improves Soil Attributes in a Typic Hapludalf

Animal manure may be a valuable resource for the development of agricultural sustainability. We proposed to verify the feasibility of applications of three types of animal manures to improve soil attributes and to sustain crop yields under intensive cropping and no-tillage systems. The field experiment was established in 2004 on Typic Hapludalf soil with pig slurry (PS), cattle slurry (CS), pig deep-litter (PL), mineral fertilizer (MF) and a non-fertilized treatment. From 2004 to 2015, were grown black oat, maize, forage turnip, black beans, and wheat. Soil samples were taken after winter 2014 and summer 2015, and submitted to chemical, physical, microbiological and biochemical analyses. Animal manures increased soil pH, but MF caused acidification of soil. The PL and CS applications reduced soil density, and increased total pore volume and hydraulic conductivity. Animal manures increased soil P fractions, total organic carbon, total nitrogen, stimulated soil respiration, and had higher activities of glucosidase and acid phosphatase. Wheat had its biggest dry matter and grain yields with MF, but maize grain yields with CS were higher than MF. All indicators pointed that application of animal manure converges to an interesting strategy to recycle nutrients at farmyard level and to contribute to global sustainability.

Irrigation with Activated Water Promotes Root Growth and Improves Water Use of Winter Wheat

Magnetic or oxidation treatment of irrigation water can promote the transport of water and nutrients by the root system, improve the efficiency of water and fertilizer use and potentially increase yields. Hydroponic and field experiments were conducted to explore how irrigation with magnetized and/or oxidized water affects grain yield and water-use efficiency (WUE) in winter wheat with an emphasis on physiological changes in the root system. Hydroponic cultivation of winter wheat with pure groundwater and brackish water included the following treatments: control group (CK−G, CK−B); magnetization (GM, BM); oxidation (GO, BO); and the combination of magnetization and oxidation (G(M+O), B(M+O), G(O+M), B(O+M)). Field experiments only tested irrigation with various types of groundwater, including the control group (IG), magnetization treatment (IGM), oxidation treatment (IGO), and the combination of the two treatment methods (IG(M+O), IG(O+M)). Hydroponic cultivation revealed that the magnetic treatment and oxidation of both groundwater and brackish water can significantly improve the root vigor of winter wheat, i.e., improvements of 100.5–253.7% and 100.4–213.9% were seen in the groundwater and brackish treatment groups, respectively, relative to the control group. The root length density (RLD) of wheat increased by 67.6% (GM), 79.4% (GO), 7.5% (BM), and 40.0% (BO) relative to the respective control groups (CK−G and CK−B). Moreover, the root weight density (RWD) for BO and B(O+M) treatments improved significantly (66.7% and 55.4%, respectively) relative to CK−B. The maximal increases in root surface area density (RSD) were observed in treatments GO and B(O+M), which showed values 125% and 100%, respectively, higher than what was measured for the control groups. The root/shoot ratios of the GO and G(O+M) treatments improved significantly (by 75.3% and 62.0%, respectively) relative to CK−G. The results of field experiments showed that wheat in the IGO and IG(O+M) plots absorbed more water from the soil than wheat in the of IG plots (increases of 13.9% and 16.9%, respectively). Furthermore, the IGO and IG(O+M) treatments produced significantly higher grain yields and WUE than the IG plots, with IGO producing the maximum yield (11.7 × 103 kg ha−1) and IG(O+M) the highest observed WUE (30.3 kg ha−1 mm−1). Hence, the research provides clear evidence that the irrigation of winter wheat with magnetized and/or oxidized water can increase grain yields and WUE.

SOWING TIMES IN ADAPTATION, STABILITY, PRODUCTIVITY, AND OIL AND PROTEIN CONTENTS OF SOYBEAN GENOTYPES1

ABSTRACT No isolated factor influences soybean development and production more than the sowing date, but the responses of cultivars sown on different sowing dates depends on their sensitivity to environmental conditions. Thus, this study evaluated the adaptability and stability of 17 soybean genotypes in relation to yield, as well as to the grain oil and protein contents as a function of different sowing times. The experiment was designed in randomized blocks with three replications and a 17 × 5 factorial scheme. The genotypes were: Conquista, CD 223 AP, Elite, Garantia, Bioagro lineage, M-Soy 8400, M-soy 8001, Nambu, Sambaíba, Esplendor, UFVS 2006, UFVS 2005, UFVTN 102, UVF 18, UFV 16, Valiosa, Vencedora, and the five sowing dates were: SD1 = 11/3, SD2 = 11/20, SD3 = 12/07, SD4 = 12/23, and SD5 = 01/09. The M-Soy 8001, UFV 18 and Garantia genotypes showed high oil contents, with adaptation to all sowing dates and stability when sown on the most favorable dates. The Bioagro lineage, CD 223 AP, and Garantia genotypes were adapted and stable when sown on all sowing dates and had higher protein contents than the other genotypes, regardless of the sowing date. The Elite, Nambu, and Garantia genotypes were adapted and stable when sown on the most favorable sowing dates and presented high grain yields when sown in early December. The findings indicate that the Garantia genotype is the most suitable for the growing conditions of the central-north region of the state of São Paulo.

Introducing cover crops as fallow replacement in the Northern Great Plains: II. Impact on following wheat crops

The introduction of cover crops as fallow replacement in the traditional cereal-based cropping system of the Northern Great Plains has the potential to decrease soil erosion, increase water infiltration, reduce weed pressure and improve soil health. However, there are concerns this might come at the cost of reduced production in the subsequent wheat crop due to soil water use by the cover crops. To determine this risk, a phased 2-year rotation of 15 different cover crop mixtures and winter wheat/spring wheat was established at the Northern Agricultural Research Center near Havre, MT from 2012 to 2020, or four rotation cycles. Controls included fallow–wheat and barley–wheat sequences. Cover crops and barley were terminated early July by haying, grazing or herbicide application. Yields were significantly decreased in wheat following cover crops in 3 out of 8 years, up to maximum of 1.4 t ha−1 (or 60%) for winter wheat following cool-season cover crop mixtures. However, cover crops also unexpectedly increased following wheat yields in 2018, possibly due in part to residual fertilizer. Within cool-, mid- and warm-season cover crop groups, individual mixtures did not show significant differences impact on following grain yields. Similarly, cover crop termination methods had no impact on spring or winter wheat grain yields in any of the 8 years considered. Wheat grain protein concentration was not affected by cover crop mixtures or termination treatments but was decreased in winter wheat following barley. Differences in soil water content across cover crop groups were only evident at the beginning of the third cycle in one field, but important reductions were observed below 15 cm in the last rotation cycle. In-season rainfall explained 43 and 13% of the variability in winter and spring wheat yields, respectively, compared to 2 and 1% for the previous year cover crop biomass. Further economic analyses are required to determine if the integration of livestock is necessary to mitigate the risks associated with the introduction of cover crops in replacement of fallow in the Northern Great Plains.

RESULTS OF THE STUDY OF COLLECTIBLE VARIETIES OF PEAS IN THE CONDITIONS OF THE KIROV REGION

The article presents the results of studying the genotypes of peas by a complex of breeding valua-ble traits. The research was carried out in 2014-2021 in accordance with the methodological guidelines of the VIR and the State Commission for Variety Testing of Agricultural Crops. The objects of study are 59 collectible varieties of peas of various morphotypes, the standard is the Krasnoufimsky 93 variety (Sverdlovsk region). The aim of the work was to isolate the genetic sources of peas by a set of traits for further use in the breeding process. The weather conditions during the study period were contrasting, which allowed the most objective assessment of the studied samples. Grain yields ranged from 126 g/m2 (2021 g) to 468 g/m2 (2014 g). As a result of the study, varietal samples were determined that significantly exceeded the standard for grain yield. The highest yield on average for 2014-2021 was obtained from samples Tigra (Germany) – 437 g/m2, Stabil (Austria) – 376 g/m2, Grana (USA) – 353 g/m2, G-21594 (Kirov region) – 340 g/m2, G-24596 – 331 g/m2, etc. Genotypes with high indicators of productivity elements were identified. The maximum value of the number of productive nodes was noted in the Serio variety (USA) – 4.6 pcs., the number of beans – in G-21594 (7.5 pcs.), the number of grains – in the Verkholuzskaya variety (Komi Republic, 32.2 pcs.), productivity – in the Stabil variety (6.6 g). Most of the studied genotypes (78%) had a mass of 1000 seeds 150-250 g. The largest seeds were characterized by sample No. 40 (Bulgaria, weight of 1000 seeds 340 g). It was found that the grain yield, the number of productive nodes, beans and grains per plant differed the most in the studied cultivars, the mass of 1000 seeds varied slightly.