eChapters

1.1 Write True/False

Q.1    The process of knowing all the relevant information from the known sample to the unknown population, is known as “Statistical Inference.”
Q.2    An enquier may be completely unknown to some feature of the population but he may want to guess completely about that feature based on a random sample drawn from the population. This type of problem is known as the “Problem of Estimation.”

2.1  Write True/False

Q.1    From theoretical point of view, the most general method of estimation is the “Maximum Likelihood Estimation Method.”
Q.2    The method of “maximum Likelihood Estimation” was initially formulated by the statistician named as “C.F. Gauss.”

3.1  Write True/False

Q.1    The estimates obtained though various methods of point estimation, in general, do not concide with the true values of the parameters.
Q.2    The statistician is interested in finding an ‘interval’ within which the true value of the parameter θ is expected to lie with certain ‘confidence coefficient’, say (1 – α).

4.1 Write True/False

4.1.1 Preliminaries

Q.1    In selection of a test, one should try to keep the probabilities of both types of error small.
Q.2    Under a non-sequential sampling scheme (i.e. fixed sample size n), it is not possible to minimise both the errors at the same time.

5.1  Write True/False

Q.1    The null hypothesis H₀ is said to be composite if it does not specify the joint probability of x₁, x₂, ......, x_n completely.
Q.2    We may write null hypothesis as :
    H₀ : θΣ Ωθ_0-

6.1  Write True/False

Q.1    A procedure to make an inference about the unknown values of parameters of one or more than one distribution in which the sample size say n is a ramdom variable, is known as “Sequential procedure.”
Q.2    The principal feature of sequential procedure is a ‘Sampling Scheme’ which provides a rule under which one decides at each stage of sampling whether to stop or continue the sampling work.

7.1  Write True/False

Q.1    All the problem of statistical inference may be considered as the problem of “Decision making in the face of uncertainty.”
Q.2    The problem of point estimation is the problem if deciding which value in the “parameter space” Wq is the true value of the parameter.

8.1 Write True/False

Q.1    Any linear function of sample observations which is used to estimate the population parameter or parametric function,is called the “Linear estimator.”

9.1  Write True/False

Q.1    In the subject matter of order statistic, the useful beta distribution is written as :

There is no cereal in the world which has no immense patentability as in maize and that’s why it is called the “Queen of cereals”. It is the world’s leading cereals crop after rice and wheat. It is one of most important cereals of Nepal. At national level, it stands second position after rice in term of area and fourth in term of production after rice, potato and sugarcane. Maize is the most important cereals crop of hill and mid hills of Nepal. It is grown single as well as mixed cropping with millets or legumes or potato. Maize crop in hill is grown as rainfed farming. Generally, farmer of such region does not apply chemical fertilizer but they fertilize the land with organic manures in three seasons viz., rainy, winter and spring season. In rainy season it grown in upland while in spring season in low land. The winter maize is grown in Terai and inner Terai in low land as well as upland.

1.    Kernel type: Dent, Flint, Floury, Waxy, Sweet and Pop corn 
        •    Dent corn (Zea mays indentata Staurt.)
        •    Flint corn (Zea mays indurate Staurt.)
        •    Pop corn (Zea mays everta Staurt.)
        •    Sweet corn (Zea mays saccharata Staurt.)
        •    Flour/soft corn (Zea mays amylacea Staurt.)
        •    Waxy corn (Zea mays ceatina Kulesh)

Maize is a tall, determinate annual C₄ plant varying in height from (1-4) meters producing large, narrow, opposing leaves (about a tenth as wide as they are long), borne alternately along the length of a solid stem. The botanical features of various plant parts are as follows: 

Root

Root system of maize consists of seminal roots, crown or coronal or adventitious or fibrous roots and brace, pop or aerial roots. Seminal roots - which develop from radical and persist for long period. Crown roots developing from the lower nodes of stem below ground level which are the effective and active roots of plant and.  Brace or prop roots, produced by lower two nodes. The roots grow very rapidly and almost equally outwards and downwards. Favorable soils may allow corn root growth up to 60 cm laterally and in depth.

•    A corn plant requires a certain number of growing degree units (GDUs) to reach maturity, regardless of the number of calendar days it takes to accumulate.
•    The relationship of GDU accumulation and corn development, along with utilizing the estimated number of days to reach a certain growth stage, can help predict when important growth stages will occur.
•    Growth stages can be used to help growers make timely applications of herbicides and fungicides. The following information is on corn growth and development from emergence to R6 growth stage.
•    Corn growth stage development can vary according to corn maturity. An early maturing product may produce fewer leaves or develop through growth stages faster than a slower paced late maturing product. This is important to remember when staging corn in relation to accumulated GDUs.

Basic principles of breeding hybrid maize
1. Inbreeding
•    Produce a plant which breeds true
•    Produce uniform plants
•    Increase the homozygosity at all or specific loci in the plant genome
•    We know what inbreeding does and I do not propose to spend people’s money to learn how to reduce corn yield-Hopkins

Germplasm
 
Germplasm of crop may be defined as sum total of hereditary materials, i.e. all alleles of various genes present in a crop species and its wild relatives. The germplasm can be utilized in a breeding programme in following ways:
•    Direct release as a variety
•    It may be subjected to selection for developing a variety
•    It may be used as one of parents in hybridization programmes

Terminology of experiments
    
Evaluation trials are important in plant breeding where the selected lines are compared with standard varieties. In most cases, it will be necessary to make comparable yield trials under field conditions. In such case, the field becomes the experimental unit. In these cases, the field becomes the experimental unit. It requires the use of small plots and adequately replicated.

Progeny test

Progeny trials involve large numbers of progenies of a family type, such as full-sib, half-sib, or S1 lines. The progenies are evaluated to identify those that may be used to generate synthetic or experimental varieties, or recombined to form an improved population in a recurrent selection program. Progenies in the trials are normally a random sample from the particular population under study. Therefore, data obtained from progeny trials may be used to estimate genetic variances and covariances from which heritability estimates, predicted responses to selection, genetic correlation coefficients, and correlated responses to selection may be obtained. Progeny trials are normally researcher-managed. Progeny trials involve complex field designs, such as balanced incomplete block, lattice, and alpha-lattice. Some examples of lattice are 11 × 11 for 121 progenies, 14 ×14, 16 × 16, etc. Because of the large number of entries, single-row plots with only 2–3 replications in a few environments are used in progeny trials.

Formation of a Rectangle

Experiments are usually laid out in square or rectangular plots for data and yield estimation, even though the field may be irregular. The plot is usually placed on the contour, parallel with a road, or in a north-and-south alignment. To mark a plot, construct a right angle and then form a rectangle or square.

Characteristics of a well-planned experiment
 
•    The treatments, design, management, and data collected should be consistent with the objectives.
•    The experiment should be planned and conducted so that there will be a high probability of measuring differences between treatments with an acceptable degree of precision. 
•    The experiment must be planned and executed to ensure that treatment effects are estimated in an unbiased way.

Introduction
Project title:
Objective (S):

Plant diseases are of paramount importance to humans because they damage plants and plant products on which humans depends for food, clothing, furniture, the environment and in many cases the housing. The kinds and amounts of losses caused by plant diseases vary with the plant or plant products, the pathogen, the locality, the environment, the control measures practiced and combination of these factors (Agrios, 2005). Disease is one of the major biotic constraints to reduce crop yield and also deteriorate the quality of product that ultimately reduce the market price.

Biometric observations

The phenological stages i.e. germination, tasseling, silking, and physiological maturity were recorded from fixed mid three rows of each plot. A particular stage was supposed to be completed while 90% of the observed plant showed the characteristics of that phase and number of days was counted from date of sowing.

Days to emergence (DOE)
 
When the plant shoot pokes through the soil surface. Count the 75% seedlings emerged from at least 50% of the total rows starting from the centre. If 75% of the total expected seedlings emerged, then can be considered as 75% emergence. How the growth stages of maize are distinguished can be observed from the chart below.

Hypothesis: A statement about the value of a population parameter developed for the purpose of testing.

Type I and Type II Errors

•    Type I Error: Rejecting the null hypothesis when it should not be rejected.
    •    Therefore accepting the alternative hypothesis (your theory) when you should not.
    •    Probability of a Type I error is called a.
•    Type II Error: Failing to reject the null hypothesis when it should be rejected.
    •    Therefore not accepting the alternative hypothesis (your theory). Opportunity loss.
    •    Probability of a Type I error is called b.
•    Minimizing Type I errors is the main concern of hypothesis testing

The first step in applying the correct rate of fertilizer is calculating crop nutrient requirements. A soil test is the only way to measure how much P₂ O₅ and K₂ O are available in soils, and soil tests are available through several private and public laboratories.

Fertilizer Calculation

To compute the equivalent amount of fertilizer necessary to supply the corresponding amounts of nutrients, the following formula is used:

Definition of terminologies and concept

Variables: Variables are the characteristic, number or quantity which increases or decreases over time and takes different values in different situations. Variables are those, whose value varies according to the situations. For example, maize yield, Stover, fertilizer, labor, land, pesticides, etc.
 
Dependent variable: Variables whose value is dependent on independent variables. These variables take different values only in response to independent variables. Yield of maize is dependent on amount fertilizer, fertilizer application methods, labor, pesticides etc. So in this case maize yield is dependent variables while amount fertilizer, fertilizer application methods, labor, pesticides are independent variables. However in other situation, maize yield can be used as independent variables also.

Crop growth rate (g m^_-2 day^_-1)

Crop Growth Rate is referred to a whole crop, so you need to consider the area of the ground where crop is present. It is measured as mass increase in crop biomass per unit ground area per unit time.
Equation for that is, CGR= W₂-W₁ / t₁-t₂

Peer-reviewed academic journals publish a variety of article types, such as “research articles” that report original research, “reviews” of the literature, and “case reports” of a small number of interesting cases. Each article type has its own specific format, and it is important that you use the appropriate one.

Hypothesis become theories and theories attain rank of laws after withstanding rigorous experimental tests. Feasibility of a process is confirmed in the laboratory. Qualitative and quantitative analyses give complete chemical picture of the substance. It is with these considerations in mind we proceed to learn what is there in a laboratory.

Carbohydrates are synthesized from CO₂ and H₂O in chlorophyll containing plants during photosynthesis. The term carbohydrate was originally coined for this class of compounds as most of them were hydrates of carbon or could be represented by the general formula C_n(H₂O)n. Not all the carbohydrates however, have this empirical formula, for example deoxyribose (C₅H₁₀O₄) and glucosamine (C₆H₁₃O₅N). Further lactic acid (C₃H₆O₃) formaldehyde (HCHO or CH₂O) and acetic acid (CH₃­.COOH or C₂H₄O₂) with this general formula is not a carbohydrate. Carbohydrates are defined as the compounds having either an aldehyde or a ketone group or a modified aldehyde or ketone group and other carbon atoms with alcoholic (-OH) group. Hence the continued usage of the term carbohydrate is for convenience rather than exactness.

Amino acids are essential components of all living cells as building blocks of proteins. They are also metabolically active and supply substrates for many other biochemical reactions. In a bacterial cell, about 0.4% of the dry weight is amino acids. The amino units in other living systems varies according to species, age and part of the body.

Lipids are a hetrogenous group of substances, widely distributed throughout the plant and animal kingdom. In plants they are present in the seeds nuts and fruits, while in the animals they are stored in adipose tissues, bone marrow and nervous tissues. Lipids are relatively insoluble in water and readily soluble in organic solvents such as ether, chloroform, carbon disulfide, benzene, hot alcohol etc. The term lipid was used by the German biochemist Bloor in 1943 for a major class of tissue components and foodstuffs.

Nucleic acids like proteins occur in all living cells. They device their name because of their primary occurrence in the nucleus and acidic nature. Deoxyribose nucleic acid (DNA), one of the two nucleic acids is a major component of chromosomes. Small amounts of DNA are also found associated with chloroplasts and mitochondria.

The term enzyme was coined in 1878 by Friedrich Wilhelm Kuhne to designate these biological catalysts that had previou-sly been called ferments. As they quicken most of the chemical reactions occurr-ing in the body, the enzymes have been designated as the “manifestations of nature’s impatience”.

Franz Holfmeister’s (LT, 1850-1922) definition, “vitamins are substances which are indispensable for the growth and maintenance of the animal organism, which occur both in animal and plants and are present in only small amounts in food”, still holds good, although it has been interpreted in various ways.

The pigments are energy-rich organic compounds. The potential chemical energy of these compounds comes from the light energy. The light enrgy to be effective in photosynthesis must be absorbed by a suitable pigment. This vital role is performed by a suitable pigment. This vital role is performed by the green pigment. Chlorophyll, carotenoid (carotenes and xanthophylls), anthocynin and phycibilins.

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. Polyphenols are a structural class of mainly natural, but also synthetic, and semisynthetic, organic chemicals characterized by the presence of large multiples of phenol structural units. The number and characteristics of these phenol structural underlie the unique physical, chemical, and biological (metabolic, toxic, therapeutic, etc.) properties of particular members of the class. The term polyphenol derives from poly-, from the ancient Greek word (polus, meaning “many, much”) and the word phenol which refers to a chemical structure/substructure formed by attaching to an aromatic phenyl or benzenoid ring an alcohol-type hydroxyl (-OH) group (giving rise to the “-ol” suffix). The term “polyphenol” has been in use since 1894.

An anti-nutritional factor is a substance which, when present in human or animal foods, reduces growth. Examples are phytate, protease inhibitors (notably soybean trypsin inhibitor) and excessive dietary fiber.

Anti-Nutritional Factors

    ·    Protease inhibitors inhibit the activity of trypsin, chemotropism and other proteases. They are found in legumes such as beans and peas, but also in cereals, potatoes, and other products. Their presence results in impaired growth and poor food utilization.

Thiamann (1948) designated the plant hormones by the term ‘phytohormones’ in order to distinguish them from animal hormones. He defined a phytohormone as “an organic compound produced naturally in higher plants, controlling growth or other phy-siological functions at a site remote from its place of production and active in minute amounts.”

According to Johannes van Over-beek (1950), the plant hormones are defined as “organic compounds which regulate plant physiological process – regardless of whether these compounds are naturally occurring and/or synthetic; simulating and/or inhibitory; local activators or substances which act at a distance from the place where they are formed.”

Abstract

The functioning and stability of terrestrial ecosystem are determined by plant biodiversity and species composition. So far, little attention has been paid to the effects of microbe-plant interactions, particularly the mycorrhizal symbiosis, on ecosystem variability, productivity and plant biodiversity. The most common type of mycorrhizal association is the arbuscular mycorrhizal (AM) type. The role of AM fungi in the uptake of diffusion limited nutrients like P and in conferring resistance to soil-borne-diseases is well documented.

Abstract

Study was undertaken to investigate the toxicity of heavy metals on the structure and function of ectomycorrhizal fungi and their ability to colonize the pine seedlings. Ectomycorrhizal fungi were isolated, cultured and multiplied on MMN medium. Six heavy metals (Cd, Ni, Zn, Pb, Cu and Al) were selected and different concentrations viz; 0 ppm (control), 10 ppm, 50 ppm, 100 ppm, 200 ppm and 500 ppm were used for treating the seedlings. The study was continued for one year. Different growth parameters were measured. Factors such as soil moisture, pH and soil organic carbon on ectomycorrhizal colonization were also analyzed. The mycorrhizal colonization was more in those seedlings having lower concentration of heavy metal treatment. Statistical data analysis has shown that the heavy metals had negative correlation with mycorrhizal colonization. High concentration of metals were toxic to external mycelium, which ultimately resulted in reduction of ectomycorrhizal development. The accumulation of metals in the fungal mycelium and protecting root against metal toxicity was an important factor.

Abstract

Contamination of environment with heavy metals has become a serious global problem due to its threat to animal and human health. Removal of this non-biodegradable, hazardous heavy metals through bio-materials has received paramount interest and intense attention in the last few decades as bio-materials play crucial role in remediating heavy metal polluted environment through a process called “biosorption”. The term biosorption, therefore, has become a popular theme in recent years due to its relatively simple, inexpensive, eco-friendly with rapid mechanism of removing heavy metals from polluted environment. There have been burgeoning studies around the globe for alleviating the problem of heavy metal pollution by selecting and developing an effective bio-sorbent with minimum treatment process for field application. This review aims to provide vast information on types of biosorbent available, their exploitation for better efficiency and their economic attractiveness for the restoration of heavy metal polluted environment.

Abstract

Contamination groundwater and soil due to heavy metals (HMs) has aggravated into a threat not only for people inhabiting the polluted areas but also for the vegetation of the region. Relying on the use of obligate symbionts, arbuscular mycorrhizal fungi (AMF) in remediation of contaminated sites can be a productive approach. These fungi due to high cation exchange capacity have the ability to adsorb heavy metals (HMs) on fungal tissues; they also possess enzymes responsible for reduction of metals to less toxic forms. In areas with high toxicity of various HMs such as lead, AMF extends its extraradical mycelium (ERM) beyond the depletion zone of plant roots increasing the availability of nutrients such as potassium, phosphorus, magnesium, and sulphur resulting in increased plant growth and yield. Production of phenol and organic acids by the fungus have been reported to increase iron diffusion, that is a co-factor for antioxidant enzyme superoxide dismutase. AMF sequester HMs in fungal structures and bind them in their chitin cell walls preventing their translocation to aerial plant parts.

Abstract

Excessive use and treatment of soil with pesticides under the adage, “if little is good, a lot more will be better” has played havoc with human and other life forms and can also cause populations of beneficial soil microorganisms to decline, which indirectly affect soil fertility. Soil constitutes a major environmental sink for many pesticides. These pesticides are either taken up from soil by plants and then pass into the bodies of invertebrates, water or air, directly or indirectly and affect public health and beneficial biota of the ecosystem. Bioremediation provides very attractive, eco-friendly and economic solution to many of our hazardous pollution problems. For both economic and ecological reasons, biological degradation has become an increasingly popular alternative for treatment of hazardous wastes.

Abstract
 
Within the time scale for soil formation, humans appeared to the planet within the last 1 million years. They shifted their lifestyle from hunter-gatherer to nomadic animal husbandry and finally to cultivation of domesticated crops only within the last 10,000 yrs. Earlier, these crops were cultured in a semi-nomadic style as land was plentiful, so when soil lost its productivity, people abandoned it in favor of new-land. Gradually, as land became scarcer and population exploded, agriculture evolved to continuous cropping of the same parcel of land. This discovered the major concern for soil health. As organic matter is key to soil health, humus is the last stage of organic matter decomposition. Humus is a complex aggregate of dark brown colored amorphous substances, which have originated during the decomposition of plant and animal residues by microorganisms, under aerobic and anaerobic conditions. Humus and living microorganisms are connected by numerous ways which must be appreciated in order to understand the origin and nature of humus. Our attempt is to narrate the role of organic matter and vital role of microbes in humification process.

Abstract

Electronic waste or e-waste is one of the emerging problems in developed and developing countries worldwide. The constantly changing today’s world of technology has led to the serious problem of e-waste. The previous studies show that India has generated 0.6 million tons of e-waste in 2014 which may increase to 0.7 to 0.9 million tons by 2015–2016. E-waste constitutes multiple components some of which are toxic that can cause serious health and environmental issues if not handled properly. The challenge is to develop innovative and cost-effective solutions to decontaminate polluted environments, to make them safe for human habitation and consumption, and to protect the functioning of the ecosystems which support life. Biological approach is currently applied to recovery of metals from contaminated soil, groundwater, surface water, and sediments including air.

Abstract

Now a days, the public has become more sensitive towards the protection of the environment and general awareness has increased about the adverse effects of industrial effluents contaminate with various pollutants, including dyes on the environment. Dyes are an important class of synthetic organic compounds used in many industries, especially textiles. Consequently, they have become common industrial environmental pollutants during their synthesis and later during fiber dyeing. Textile industries are facing a challenge in the field of quality and productivity due to the globalization of the world market. The dyes, which are widely used in textile industries when left in water bodies without any treatment cause environmental pollution and in turn are toxic, carcinogenic and mutagenic. The efficient treatment of the sludge from the industries is not economical and a challenging task. Currently, a number of different technologies and methods such as biological, physical and chemical are widely used for the removal of dyes. The treatment technologies for the removal of textile dyes from the textile wastewater found that over the past two decades interestingly focused on biodegradation methods such as microbial decolourization, enzymatic decolourization, adsorption by microbial biomass (living or dead) and bioremediation systems as a better alternative as the available physico-chemical methods.

Abstract

With recent advances in molecular biology and rapid developments in new analytical techniques, engineering of microbes for the bioremediation processes has been extensively studied as recombinant microbes can degrade various toxic pollutants effectively. The prospect of microbial engineering has greater potentialities for agriculture and environmental applications and this may provide us deeper insight in understanding the microbial interactions and biotransformation processes. Though much work has been carried out on bioremediation using genetically engineered microorganisms, its application is restricted to environment due to the concerns of health and environment over ecosystem. Nevertheless, evaluation of risk assessment has also been carried out in order to ascertain the potential benefits of transgenic microbes.

Abstract

Traditional practices of restoring and vegetating mine spoils, which include mechanical tillage, the addition of tons of organic and mineral inputs, seeding of herbaceous plants, and regular fertilization, are often expensive and not sustainable on the long term in the Canadian boreal forest biome. Phytobial restoration and remediation may be an excellent alternative to these traditional practices while accelerating ecosystem reconstruction and sustainable reforestation of mined sites. In this review, the role and importance of root symbionts – ectomycorrhizal fungi, PGPR, and Frankia – on boreal tree fitness are discussed. Furthermore, highlights of recent research studies done by our team in Canada on ecological restoration and bioremediation of boreal mined sites are presented.

Abstract
 
Opencast mining destroys the original land ecosystem and microbial community due to mining and stockpiling of mine rejects on adjoining land, which is a matter of great environmental concern. Mining creates formation of wastelands, formation of gullies, ravines, overburdens, reduced water infiltration and increased runoff. Reclamation of mined out areas is often difficult due to its chemical, physical and biological traits. Absence of topsoil is the most common feature of the mine spoils dumps. Arbuscular mycorrhizal fungi (AMF), the synonym of VAM fungi, are important microbes of soil that form symbiotic association with most of the terrestrial plants on the earth. Observations led to use of legume microsymbionts as biological substitutes for fertilizers. AMF diversity increases with species diversity of plants as the potential number of association increases. Dominant arbuscular mycorrhizal fungi can prevent the invasion of non-mycorrhizal plants on land where they have established symbiosis and promote their mycorrhizal host.

Abstract

Mine spoils pose adverse conditions for soil microbes and plant growth, due to its low organic content and other essential nutrients, unfavourable soil chemistry and poor soil texture. Poor microbial population inhibits nutrient transformation, consequently the establishment of the plants and ultimately affects the process of ecological succession. A synergy among different groups of beneficial microbes accompanied by plantation of suitable tree species on mined over area has proved to be effective for speedy and efficient revitalization of the mined affected lands. Inoculation of plantation with efficient strains of native microbes accelerates the soil redevelopment and helps to establish nutrients cycle readily which attracts native flora thereby the pace of natural regeneration is increased. It is therefore imperative to consider the application of effective microflora in restoration of mined lands along with the plantation.