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Our study aimed to determine morphometric data for wild boar (Sus scrofa) in various areas of the Czech Republic and the potential influence of environment on its body measurements. Three localities with varying agricultural systems and overall landscape structure were selected. Hunted boars were measured for height at the withers, body length, ear length, metatarsal length and weight (depending on the circumstances, either dressed with head, without head, or undressed). We also determined the age of the hunted boars according to teeth development. During 2003-2007, a total 654 boars were examined in various age categories. Body development was similar in all areas and without statistically significant differences until the age of 6-7 months. From 8 months, statistically significant differences in body proportions occur across all localities. It is just at that time that carrying capacities change in the selected localities. The results show that morphometric differences among boars of the same age are influenced by external environmental conditions in which the boars live.

The study compares the role of agricultural green subsidies in rural development of the Czech Republic before and after joining the European Union (EU) in 2004. We use the perspective of multifunctional agriculture and contribute to the research on the contemporary trends in Czech agriculture by using the data collected through surveys in 2000 and 2006, as well as 2008 comparative statistical support, to ask if there have been significant changes and improvements in farmers' evaluations of these programs. The empirical case study results show some positive changes connected with the participation in the Common Agriculture Policy (CAP). In spite of improvements, farmers continue to cite two primary weaknesses and constraints - administrative procedures and shifting program guidelines - that were evident prior to joining the EU. It can be assumed that the environmental subsidies in the Horizontal Rural Development Plan 2004-2006 have had an effect on the stabilization of the livelihoods of rural inhabitants. In general, there is a positive shift of valuation of the CAP among farmers in the Czech Republic.

Influence of growth regulators chlormequat chloride, ethephon, trinexapac-ethyl, and a combination of chlormequat chloride and ethephon on decreasing sunflower height was examined in the years 2006-2009. Height was reduced by as much as 63 cm by double application of chlormequat chloride (915 g/ha) + ethephon (465 g/ha) at early and later growth stage (BBCH 32 and 50). Trinexapac-ethyl (375 g/ha) did not affect the height. One-time application of chlormequat chloride (1440-2160 g/ha), chlormequat chloride (458 g/ha) + ethephon (233 g/ha) (BBCH 30 or 50), or ethephon (480 g/ha) (BBCH 30) was sufficient for a ca 30 cm reduction during flowering, but this effect did not last until harvest. With double application (BBCH 30 and 50), reduction lasted until harvest. For ethephon (480 g/ha), application at BBCH 50 reduced height by as much as 35 cm and lasted until harvest. Combining a lower rate of ethephon with ammonium sulfate was effectively equivalent to using a full rate. Flower head diameter at maturity showed no significant negative influence compared to the control. In 2008 and 2009, a delay in flowering onset was observed after applying growth regulators.

The circadian rhythm of body core and surface temperature in 10 Comisana sheep kept under a natural photoperiod (06:30/19:00) was evaluated. Every 3 h for 24 consecutive hours rectal temperature (RT) and foot temperature were recorded. Particularly, foot temperature was recorded by infrared thermography, an ideal technique for evaluating the temperature not only at one point but also at the eight points as follows: in the right front of the interdigital area (FA1), in the left front of the interdigital area (FA2), in the right rear of the interdigital area (RA1), in the left rear of the interdigital area (RA2), in the right front of the interdigital line (FL1), in the left front of the interdigital line (FL2), in the right rear of the interdigital line (RL1) and in the left rear of the interdigital line (RL2). Two-way repeated measures ANOVA using SPSS, followed by Scheffé's test, showed a significant effect of the time of day and side of temperature collection (P < 0.05) on temperature values. The single cosinor procedure showed a daily rhythmicity of RT and foot temperature in all tested sides. The circadian oscillations of RT reflected the familiar circadian patterns of endogenous sources and the results of foot temperatures supported the idea that the daily rhythm was, at least in part, influenced by variation in the blood flow to the extremities. The infrared thermography providing more information on the development of disturbances in the peripheral circulation may be used with an advantage in occupational health examinations and in special clinical work.

This case study describes the pregnancy of a German Shepherd bitch with a singleton (one puppy) litter as a result of early embryo resorption. Resorption was confirmed by ultrasonography and the pregnancy was regularly monitored by USG and measurements of progesterone levels until parturition. These levels stayed within the physiological range. One healthy puppy was delivered within the timeframe of a physiological pregnancy although the inner chorionic cavity diameter (ICCD) protocol used for predicting the time of parturition showed divergence from the real time of whelping.

This paper describes the course and variation in the brain base arteries in fallow deer. The metrical features of the brain base arteries were determined with an image analysis system. The main sources of blood supply to the brain in fallow deer are internal carotid arteries; vertebral arteries rarely participate in blood supply. The brain base arteries in fallow deer show variation both in their course and in the way of descent of particular vessels. The highest variation was observed in the way of the opening of caudal cerebral arteries. The volume of the arterial circle of brain in fallow deer is similar to the volume of the basilar artery. Considering the correlation between specific parameters, it can be concluded that the volume of the basilar artery is highly correlated with the volume of the posterior part of the arterial circle of the brain, i.e., the volume of the caudal communicating arteries.

This research deals with productivity and cost of rock disintegration and side casting of materials with the use of a hydraulic hammer mounted on a PC 220 Komatsu crawler excavator, which is used on rocky slopes of Hyrcanian forests of Iran. A continuing time study was applied during the road construction. To estimate the volume of rock disintegration, the average end area equation was used. The increasing cut-slope height decreased productivity. The productivity of hydraulic hammer averaged at 5.5 m³.h^-1 for the mean work volume of 5.07 m³.m^-1. The unit cost of the system was 7.7 €.m^-3. From the economic point of view a new machine with multipurpose system could be recommended for forest road construction operations in rocky areas.

Every year, an analysis of economic results of a sample of agricultural enterprises farming in various production and climatic conditions in the territory of the Czech Republic is carried out by applying economic statistical methods. Based on these results, long-term trends of economic results and their influencing factors are defined. This article is based on the analysis of development of economic indicators of a sample of agricultural enterprises in the Czech Republic in the period 2003-2009, divided according to the proportion of the LFA. The year 2009 brought, in comparison with the previous years, a strong deterioration in economic results. In 2009, the economic result was the worst during the whole monitored period. The decrease in the average number of workers together with the increase in labour productivity manifests a long-term tendency. Agricultural subsidies tend also to grow in the long-term even though their growth has been slowing down.

Grazing-induced variations in vegetation may either accelerate or reduce soil carbon storage through changes in litter quantity and quality. Here, a three-year field study (2005-2007) was conducted in Tibetan alpine meadow to address the responses of surface soil (0-15 cm) organic carbon (SOC) storage in the plant growing season (from May to September) to varying grazing intensity (represented by the residual aboveground biomass, with G₀, G₁, G₂, and G₃ standing for 100%, 66%, 55%, and 30% biomass residual, respectively), and to explore whether grazing-induced vegetation changes depress or facilitate SOC storage. Our results showed that: (i) Higher grazing intensity resulted in lower biomass of grasses and sedges, lower root biomass, and in a change in plant community composition from palatable grasses and sedges to less palatable forbs. (ii) Increased grazing reduced the SOC content and storage with only G₃ showing an SOC loss during the plant growing season. (iii) Soil organic carbon storage exhibited a highly positive correlation with the residual aboveground biomass and root biomass. Our results imply that a grazing-induced reduction in plant biomass productivity and changes in species composition would depress soil carbon storage, and that an increase in grazing pressure can lead to a gradual change of alpine meadow soils from being 'carbon sinks' to become 'carbon sources'.

Bread-making quality of wheat flour is influenced by wheat storage proteins. The percentage of sodium dodecyl sulphate (SDS)-unextracted polymeric proteins in total polymeric proteins (% UPP), as one important factors determining bread-making quality, is largely influenced by the individual and interactive effect of genetical background and environmental conditions. Four spring wheat cultivars were grown in green house. Two of the cultivars have high molecular weight glutenin subunits 5+10 while the other two have 2+12. Four different nitrogen regimes and two different temperature levels (distinguished as low and high temperature) were used. The results highlighted the importance of interactive influence of cultivars, nitrogen regimes and temperature levels for creating differences in the amount of % UPP during grain maturation period (GMP) and at maturity. The shift to end up with either high or low % UPP at maturity happened early during GMP (around 12 days after anthesis). Influences of cultivars on % UPP was found early during the GMP while influences of temperature and nitrogen regimes were seen much later during the GMP. The results will help in understanding the relationship between quality parameters of wheat flour and how these are influenced by different environmental and genetic factors.

The present paper is aimed at the use of satellite navigation of field machinery during seeding, this operation belonging to the most important field practises. Our attention was focused on the determination of the accuracy of the satellite navigation system based on using the correction signal real-time kinematic and its correct application for planting a wide-row crop (sunflower) and seeding a narrow-row crop (spring barley). The aim of the field experiment was also to specify the level of the necessary accuracy of satellite navigation systems during planting and seeding. The length of seeding/planting equipment was confronted with the accuracy of navigation of individual passes, especially when turning on the headlands. In the conclusion, the importance is highlighted of the automated tractor headland control during satellite navigation of combined field machines in the crop production.

In an Island of the Netherlands, Pine (Pinus nigra) was planted to stabilize the dunes and to protect the arable lands from the blowing sand. This research was conducted to understand the most important environmental factors responsible for a vegetation change in the Pine plantation and effect of this change on the rare orchid population: Goodyera repens and Listera cordata. Vegetation sampling was carried out according to the Braun-Blanquet phytosociologic method within the three sites of this Island. Twinspan analysis confirmed the definition of three site types and redundancy analysis showed a significant difference between the pure Pine stands and the plots with regeneration. The results revealed that the most significant explanatory variables were litter cover, broadleaved tree cover, and shrub cover indicating the vegetation change under the Pine plantation. The abundance of Goodyera repens is strongly associated with the Pine forest and negatively related to broadleaved cover. Listera cordata could apparently cope with vegetation change. Controlling the herbaceous layer in the Pine plantation can promote the orchid population but on the contrary, promoting the natural regeneration of broadleaved species might endanger them.

The paper deals with the analysis of the proposals of the European Union Common Agricultural Policy reform (the EU CAP) after 2013 and modelling forecast of its impacts on Slovak agriculture. The behaviour of business entities in agriculture is significantly influenced by the current support scheme and the level of support within the EU CAP but also by market conditions. The impacts of the particular scenarios on the changes of production indicate that Slovak agriculture will approach just slowly the 2008 production level. This will be decisively influenced by the price development. Despite of this, it is evident that the most favourable result can be achieved under the Flat Rate Scenario while the absolute abolition of direct payments (Liberal Scenario) will bring very unfavourable economic consequences with impacts on agricultural production in Slovakia.

The Fusarium species associated with maize are widely distributed in Malaysia. Eight Fusarium species were obtained in this country. A series of field samplings was conducted from 2006 to 2008, when 167 Fusarium isolates were obtained from maize plants in seven locations throughout Malaysia. The determination was based on micro- and macromorphological features (growth rates, colony features, mode of production of microconidia, macroconidia, conidiophores, and chlamydospores). F. proliferatum (29.9% isolates), F. semitectum (22.2% isolates), F. verticillioides (13.7% isolates), and F. subglutinans (12.6% isolates) were found out most frequently. F. equiseti, F. pseudograminearum, F. oxysporum, and F. solani were also isolated. This is the first report on the occurrence of F. equiseti, F. pseudograminearum, and F. subglutinans associated with maize plants in Malaysia.

A scientific shelf-life study for Listeria monocytogenes in the typical Slovak cheese "bryndza" was performed in accordance with the requirements of the Commission Regulation (EC) 2073/2005. Based on the previous positive findings of L. monocytogenes in the final products, the producer decided to perform laboratory tests, the results of which would allow him a different evaluation of these positive results. Both the physico-chemical (pH, a_w) and microbiological examinations of "bryndza" cheese stored at 5.8-6.2°C were performed every two days till the end of the product shelf-life (7 days). Microbiological analyses were performed after artificial contamination of the final product with a mixture of three L. monocytogenes strains. The growth potential of L. monocytogenes was calculated as the difference in the counts of this bacterium between the last day and the first day of the test. The Slovak traditional "bryndza" cheese has been found not to support the growth of L. monocytogenes. Thus, the counts of L. monocytogenes must not exceed 50 CFU/g at the beginning and 20 CFU/g at the end of the product shelf-life in order to ensure its safety for the consumer.

In this experiment we proved an effect of dolomite limestone on chemical immobilization in soil contaminated by trace metals, namely Cd, Pb, and Zn. Primary, we set up lysimeter pot experiment to measure soil leaching without vegetation. Willow clone (S. × smithiana Willd) was cultivated in the second lysimeter pot as a new approach to monitor Pb, Cd and Zn leaching, which was affected by soil liming (used in 1% rate). At the time of both harvests, aboveground biomass increased significantly at the amended variant. After the second harvest aboveground biomass production increased by 80% in comparison with the first one, Cd and Zn concentration in biomass decreased 2-fold and 3-fold, respectively. Dolomite limestone as a process of liming: (i) restricted metals leaching from the soil substrate; (ii) reduced metal uptake by willow; and (iii) increased biomass production of willow. Liming also alleviated the plant stress imposed by risk elements resulting in better plant growth and lower levels of stress markers (total nitrogen content and the main amino acid metabolism parameters in the willow leaves) yet through different mechanisms.

The leaf spotting disease complex is a major biotic constrain in enhancing grain production in the major wheat growing regions. Two leaf spotting diseases, tan spot, caused by an ascomycete fungus Pyrenophora tritici-repentis, and Stagonospora nodorum blotch besides causing average yield losses of 5-10%, cause significant losses in grain quality by red smudge, black point and grain shriveling. Conservation agriculture in combination with wheat monoculture involving cultivation of susceptible cultivars has resulted in frequent onset of leaf spots epidemics worldwide. Development of resistant wheat cultivars, in conjunction with crop rotation, will provide an effective, economical, and environmentally safe means of controlling leaf spot. International Maize and Wheat Improvement Center (CIMMYT), Mexico has initiated major efforts to mitigate the threat of tan spot. Efforts include screening of wheat germplasm, identification of new sources of resistance, characterization of new tan spot resistance genes through classical and molecular genetic analysis, incorporation of resistance into adapted cultivars, and assessing the variability in the tan spot fungus. Screening studies reveal that elite CIMMYT germplasm has high level of resistance to tan spot caused by P. tritici-repentis race 1. These germplasm have diverse genetic make-up and the resistance is likely broad based. Association mapping studies done with CIMMYT germplasm reconfirmed the presence of previously identified genomic regions for tan spot resistance; however, novel genomic regions on long arm of chromosomes 6A and 7B have also been identified. Studies done to date indicate that CIMMYT germplasm possess high level diverse genetic based resistance to tan spot of wheat. Efforts are in place to develop desired wheat cultivars with tan spot resistance. Virulence studies indicate presence of P. tritici-repentis race 1 only with some variability in level of toxin Ptr ToxA produced in each of the 76 isolates studied.

In this study, the effects were investigated of salinity, foliar and soil applications of humic substances on the growth and mineral nutrients uptake of Corn (Hagein, Fardy10), and the comparison was carried out of the soil and foliar applications of humic acid treatments at different NaCl levels. Soil organic contents are one of the most important parts that they directly affect the soil fertility and textures with their complex and heterogenous structures although they occupy a minor percentage of the soil weight. Humic acids are an important soil component that can improve nutrient availability and impact on other important chemical, biological, and physical properties of soils. The effects of foliar and soil applications of humic substances on the plant growth and some nutrient elements uptake of Corn (Hagein, Fardy10) grown at various salt concentrations were examined. Sodium chloride was added to the soil to obtain 20 and 60mM saline conditions. Solid humus was applied to the soil one month before planting and liquid humic acids were sprayed on the leaves twice on 20^th and 40^th day after seedling emergence. The application doses of solid humus were 0, 2 and 4 g/kg and those of liquid humic acids were 0, 0.1 and 0.2%. Salinity negatively affected the growth of corn; it also decreased the dry weight and the uptake of nutrient elements except for Na and Mn. Soil application of humus increased the N uptake of corn while foliar application of humic acids increased the uptake of P, K, Mg,Na,Cu and Zn. Although the effect of interaction between salt and soil humus application was found statistically significant, the interaction effect between salt and foliar humic acids treatment was not found significant. Under salt stress, the first doses of both soil and foliar application of humic substances increased the uptake of nutrients.

A British cat was presented with generalized fatty infiltration of the heart compromising both ventricles and atria, resembling arrhythmogenic right ventricular cardiomyopathy. Due to the nature and progression of the disease, the final diagnosis was achieved at necropsy. According to our knowledge only a few cases of fatty infiltration of the heart have been reported in cats, this being the first in which the pathological findings were seen in both atria.

The Lusatian lignite-mining district (Eastern Germany) is characterized by a high share of marginal post-mining areas. At these sites, crop yield is generally low, and hence, conventional land use systems often fail in terms of reliable and efficient crop production. In this paper the attempt is made to evaluate the production of woody biomass for bioenergy in short rotation coppices (SRC) and alley cropping systems (ACS) with black locust (Robinia pseudoacacia L.) and lucerne (Medicago sativa L.) from the aspect of possible ecological and economic benefits compared to the conventional agricultural recultivation practice. The results show that, due to both high establishment and harvesting costs and comparatively low prices of energy wood, land use systems such as SRC or ACS are currently hardly profitable compared to conventional agriculture. However, the cultivation of black locust resulted in a higher humus accumulation and in a lower harvest-related nutrient export than the cultivation of lucerne as a typical recultivation crop in this region. Therefore, it can be concluded that for an improvement of soil fertility woody biomass production is more beneficial than the conventional agricultural recultivation practice.

The paper examines the role of social capital in Czech agricultural sector. It is argued that social capital, just like economic capital, can be employed as a resource for the improvement of economic performance of agricultural enterprises. This hypothesis is tested on a sample of primary data and an analysis of the selected indicators of social capital is presented. These include personal social networks, membership in agricultural associations and access to sources of information. Following the results, it is argued that the presence of informal personal ties displays a stronger relationship to the entrepreneurial success than formal membership in agricultural associations. This outcome suggests a comparatively strong role of social capital in the dynamics of the sector.

The biological efficacy of some biorational and conventional insecticides against different stages of Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) was evaluated under laboratory and semi-field conditions. Seven different commercial products were tested, including the biorational insecticides: Spinosad, Mectin, Fitoverm, Match, Neemix in addition to two conventional insecticides: Actara and Actellic. Data indicated that all tested insecticides showed low toxic effects to L. decemlineata eggs, but most hatching neonates died shortly after hatching. All tested insecticides at their field rates showed high toxicity to larvae of L. decemlineata. The highest mortality was obtained in earlier instars, as compared to older ones, and mortality increased with the time of exposure. Moreover, the lower concentrations (up to 25% of the field rate) of Actara, Mectin, Spinosad, and Fitoverm showed high efficacy against L. decemlineata third instar larvae. Also, Actara caused the highest mortality in L. decemlineata adults, followed by Spinosad, Mectin, and Fitoverm as compared to Actellic, Match, and Neemix. In pupal bioassay, Fitoverm caused the greatest reduction in L. decemlineata adult emergence followed by Mectin, Actara, Actellic and Spinosad. In translocation bioassays, Actara caused the highest mortality in L. decemlineata 3^rd instar larvae or adults followed by Spinosad and Mectin. The residual activity of tested insecticides against third instar larvae was also evaluated. Actara, Spinosad, and Mectin were more persistent under field conditions, consequently the mortality rates after 30 days of application were 46.67%, 44.44%, and 35.56%, respectively.

In five consecutive growth seasons from 2003 to 2007 a response of maize variety Eurostar (var. FAO 240) to supply of NPK fertilizer supplemented with magnesium or zinc was investigated. The aim of the study was to evaluate the role of zinc (NPK + Zn) or magnesium (NPK + Mg) in controlling nitrogen management by maize crop fertilized with 80 and 140 kg N/ha. In the course of the study, total grain nitrogen content did not show any response to both experimental factors and weather variability, as well. However, the obtained results indicate, that magnesium and zinc have significantly increased SPAD (chlorophyll index) indices of maize cob leaf at anthesis. A significant effect of both factors interaction on nitrogen accumulation in grain and cob covering leaves was noted, but limited to the 80 kg N/ha treatment. The physiological role of Mg and Zn in nitrogen management was most manifested throughout its greater recovery from nitrogen fertilizer applied at the rate 80 kg N/ha, amounting to 92 and 94% respectively; for the NPK, it was only 78%.

This study aims to reveal and to compare effects of two different systems of nitrogen (N) nutrition (sidedress application or injection application) on toxicity of NH₄⁺ and mixed nutrition. We investigated whether NH₄⁺ or mixed (NH₄NO₃) application causes significant changes in the endogenous levels of cytokinins (CK), whole plant N and their effects on yield of selected plants. Ammonium sulphate or ammonium nitrate were used as N source in the pot experiment. The yield of Festulolium and Trifolium pratense L. above-ground biomass and roots was more substantially enhanced after sidedress application of both ammonium sources in comparison with injection application. Our results confirmed that the accumulation of CKs in plants is in correlation with their N content (R² = 0.66-0.98). Proportions between individual CK forms remained relatively steady and their dynamics exhibited similar trends after N application. Our results indicate that the negative effect of the application of NH₄⁺ on the growth of Festulolium and clover plants could be effectively modulated by the presence of NO₃^-.

In this study, the aim was to investigate the anatomy of the aortic arch in ground squirrels (Spermophilus citellus). Five ground squirrels were investigated. The materials were carefully dissected and the arterial patterns of arteries originating from the aortic arch were examined. The brachiocephalic trunk and the left subclavian artery were separated from the aortic arch. The brachiocephalic trunk first gave the left common carotid artery, and then the right subclavian and common carotid artery detached from it. In all the animals examined, at the cranial thoracic entrance and after leaving from this entrance, similar branches arising from the left and right subclavian arteries were the common branch of the internal thoracic artery and the intercostal suprema artery, separate branches as the vertebral and descending scapular arteries and a common branch of the cervical superficial, the cervical profund, the suprascapular arteries and the spinal ramus. After separation of these branches, the continuation of the artery gave the external thoracic artery on the external face of the thoracic cavity and then formed the axillar artery. The axillary artery separated into the subscapular and the brachial arteries. In conclusion, the pattern of arteries originating from the aortic arch and the branches of these arteries were partially similar to what has been observed in red squirrels, and thus differ from other rodents and domestic mammals.

Climate change is expected to influence the distribution and population dynamics of many insect pests, with potential severe impacts on forests. Spruce bark beetle Ips typographus (L.) (Col.: Curculionidae, Scolytinae) is the most important forest insect pest in Europe whose development is strictly regulated by air temperature. Therefore, climate change is anticipated to induce changes in the pest's distribution and development. We used the PHENIPS model to evaluate climate change impacts on the distribution and voltinism of spruce bark beetle in the Czech Republic. Two future time periods - 2025-2050 (near future) and 2075-2100 (distant future) - are addressed. The period 1961-1990 is used as the reference. We found that while a two-generation regime dominated in the Czech Republic in the reference period, significant three-generation regime regions are projected to appear in the near future. In the distant future, the three-generation regime can be expected to occur over all existing coniferous stands in the Czech Republic. The analysis of altitudinal shift of n-generation regime regions indicates noticeable expansion of Ips typographus development to higher elevations, leading for example to disappearance of one-generation regime regions in the distant future. Uncertainties and limitations of the presented findings are discussed as well.

Sorghum anthracnose is a disease of worldwide importance and host-plant resistance is the most practical method of disease management. In this study, 154 sorghum accessions from the Botswana collection maintained by the United States National Plant Germplasm System were inoculated with Colletotrichum sublineolum and evaluated for disease resistance at the Tropical Agriculture Research Station in Isabela, Puerto Rico during 2007 and 2008. A resistant response was observed for 69 accessions in 2007 and for 48 accessions in 2008 with no acervuli development observed on inoculated leaves. The low frequency of resistant germplasm is expected from a region of low annual rainfall. However, disease severity was low for the susceptible accessions with a mean severity of 11% for the 85 susceptible accessions observed in 2007 and 17% for the 106 susceptible accessions identified in 2008. The highest frequency of resistant accessions was observed for the Ngamiland district with 58% of the accessions rated as resistant, whereas the frequency of resistant accessions ranged from 22% to 36% for the other districts. The lowest mean disease severity was also observed for the susceptible accessions from the Ngamiland district with the highest mean disease severity observed for susceptible accessions from the Kgatleng district. The resistant accessions identified in this study would be useful for the development of disease resistant varieties and the results indicated an ecogeographic association with disease resistance.

In arid and semiarid regions of northern China, there is an increasing interest in using water-saving superabsorbent polymer (SAP) for field crop production. Experiments were conducted during 2009 and 2010 to study the growth and yield characteristics of summer corn (Zea mays L.) under different (control, 0; low, 10; medium, 20; high, 30 and very high, 40 kg/ha) rates of SAP in a drought-affected field of northern China. Corn yield increased slightly following SAP application at low and medium rate, but significantly at high and very high rates by 22.4 and 27.8%. At the same time, plant height, stem diameter, leaf area, biomass accumulation, harvest index and relative water content as well as protein, sugar and starch contents in the grain increased significantly following SAP treatments. The optimum application of superabsorbent polymer for corn cultivation in the study area would be 30 kg/ha as it best increased the grain yield and quality and maintained higher levels of soil nutrients. Lower rates (10 and20 kg/ha) or higher (≥ 40 kg/ha) rates would neither be sufficient nor economical. We suggest that the application of SAP at 30 kg/ha could be an efficient and economic soil management practice for summer corn production in the drought affected regions of northern China or other areas with similar ecologies.

Approximately 20 years ago, we began our efforts to understand grain yield in winter wheat using chromosome substitution lines between Cheyenne (CNN) and Wichita (WI). We found that two chromosome substitutions, 3A and 6A, greatly affected grain yield. CNN(WI3A) and CNN(WI6A) had 15 to 20% higher grain yield than CNN, whereas WI(CNN3A) and WI(CNN6A) had 15 to 20% lower grain yield than WI. The differences in grain yield are mainly expressed in higher yielding environments (e.g. eastern Nebraska) indicating genotype by environment interactions (G × E). In studies using hybrid wheat, the gene action for grain yield on these chromosomes was found to be mainly controlled by additive gene action. In subsequent studies, we developed recombinant inbred chromosome lines (RICLs) using monosomics or doubled haploids. In extensive studies we found that two regions on 3A affect grain yield in the CNN(RICLs-3A) with the positive QTLs coming from WI. In WI(RICLs-3A), we found a main region on 3A that affected grain yield with the negative QTL coming from CNN. The 3A region identified using WI(RICLs-3A) coincided with one of the regions previously identified in CNN(RICLs-3A). As expected the QTLs have their greatest effect in higher-yielding environments and also exhibit QTL × E. Using molecular markers on chromosomes 3A and 6A, the favorable alleles on 3A in Wichita may be from Turkey Red, the original hard red winter wheat in the Great Plains and presumably the original source of the favorable alleles. Cheyenne, a selection from Crimea, did not have the favorable alleles. In studying modern cultivars, many high yielding cultivars adapted to eastern Nebraska have the WI-allele indicating that it was selected for in breeding higher yielding cultivars. However, some modern cultivars adapted to western Nebraska where the QTL has less effect retain the CNN-allele, presumably because the allele has less effect (is less important in improving grain yield). In addition many modern cultivars have neither the WI-allele, nor the CNN-allele indicating we have diversified our germplasm and new alleles have been brought into the breeding program in this region.