An insight on science

In the whole scientific community, science is considered as the most honest follower of the truth. Although, it is also said that nobody knows what the truth exactly is. My own experiences of the world till my age made me know that, the truth is all about strengthening the number. Only those facts are accepted, which are followed by masses, while the fact that is not succeeded to fetch followers is not given comparatively better treatment, like the truth should be considered for. Even sometimes such fact is rejected without any consideration too. Today, it is universally known that the planet Earth moves around the Sun which is static. But, when Galileo introduced the fact for the very first time, fatefully he was rewarded with a death sentence.

We have been experienced that such number game has been proved as the most appropriate method in elections, in politics, in the system, in society and in democracy. But a scientific approach does not set only through number game. Every thought, object, or result is important for science, which exists and can be concerned by any of our senses beyond the known boundary of knowledge. For example, if anyone is working with micropropagation technique to regenerate cells or callus or plant organ through hundreds of plant explants and all cultures are going well besides few, which are being infected or contaminated by a particular fungus, then What should a true observer do? Shouldn’t he throw out the infected one? Anyone might question on my example but there is an answer in the history.  Alexander fleming observed the fungal mycelium beyond the scope of his investigation which helped him to discover the drug Penicillin. In science, such sudden incidents are termed as ‘Serendipity’, but it happens because of the way of observation which could give importance to the existence of a small one over mass. Such observations should be counted.

Science origins inside the cognitive axis of mind and observation is the mainstay of science which depends on the ability of a mind to integrate the observations with the experiences and memories stored inside it. Science does not persist in books, literature or in the library. In fact, these all tells us about the history of science. Science does not continue because of practising instrumentation and chemistry in a laboratory. The most applicable definition of science that I could know from my teacher is –‘Science is a tool to develop methodologies’ hence the practice of science is an art.  Science never lies in profession or position or hierarchy or a system.   Dr C V Raman was working as a finance Officer in an organisation when he hypothesised ‘Raman effect’ in 1928. Two years later, he was awarded Nobel Prize for his contribution. The world knows him as a scientist but he was an accountant by profession. What I want to say is that the science lies in mind. A mind that imagines beyond the perception of mass is the most fruitful for science.

An insight on science

Wishing all a happy new year with more forestry stuffs

Hello Beautiful people!

My surroundings are busy in preparation of MP Forest Service exams and meanwhile many are busy in IFS-0 2016 preparation. I am happy to share with you all the notes covering syllabus of both the exams:

The precise class notes of Forest Mensuration can be downloaded from

and for rest of the topics please find


For anyother assistance ,do not hesitate to leave me a comment.


All the best!

Wishing all a happy new year with more forestry stuffs

Allelopathy in agroforestry


Planting forest trees along with crops to get maximum of the potential of site is principle of agroforestry. Understanding Crop to Crop, tree to tree and tree to crop becomes essential for such approach. Reports say that trees have positive and negative effect on crop yield. it is species specific. Some weeds adversely influence the physiology of trees as well. It is found that every plant releases chemicals from its organ which helps on its survival and the same chemical affect the growth of other plants  by support or sometimes by inhibition. Such characteristics are known as allelopathy. some times it results symbiotic relationship or some time affect negatively.

After going through the literature related to allelopathy habits of plants, I conclude that the tree plantations also must be free from weeds for high productivity.

Much research in agroforestry systems is concerned with increasing the biological input of nutrients to trees and to the crops grown concurrently or consecutively or consecutively with them and with determining how and in what quantities these nutrients become available. The exchange of nutrients among the plants of the agroforestry system results largely from the activity of appropriate soil microorganisms. Associative or symbiotic microorganisms are responsible for nitrogen input and for the availability of other minerals, especially phosphorous, in the ecosystem. Other bacteria make available the nutrients of dead and decaying plants for uptake by the root systems of crop species. Symbiotic microorganisms like Rhizobium and Frankia have potential roles of nitrogen fixation, plant growth regulation, phosphate solubilization and concerned with nutrient transformations of decaying plant material.

The important nitrogen-fixing symbioses are:-

1) those between many legume trees species and Rhizobium or Bradyrhizobium and

2) those between Frankia and woody species within the eight non leguminous plant families (so called acinorhizal plants that are nodulated by the nitrogen-fixing actinomycete.

For temperature and warm temperate conditions, the most important of the Frankia associations are with Alnus (Betulaceae) or Elaeagnus and Hippophae (Elaeagnaceae), and in the tropics and subtropics, with members of the Casuarinaceae. The most promising candidates for agroforestry are the Casuarina and Allocasuarina genera.

Allelopatic Relationship:

Interference occurs when one plant species fails to germinate, growth more slowly, shows symptoms of damage, or does not survive in the presence of another plant species. Interference can result from competition, allelopathy, or other indirect influences. Competition is the phenomenon by which one plant removes limited resources (such as light, water, or nutrients) from the environment, thereby reducing the survival or growth of a neighboring plant. Allelopathy is the phenomenon in which a plant or microorganisms releases a natural product into the environment that subsequently reduces or enhances the survival or growth of neighboring plants.

Agroforestry intentionally combines woody perennials with agricultural crops or pasture plants in variety of spatial or temporal arrangements, thus the choice of species combinations may dramatically influencing the productivity and ultimate success of some agroforestry systems. The challenge in plant interference work is identifying which of trees various factors because the associated plant response. Allelochemicals originating in foliage teachings, root products, or mulches of crops or woody plants may result in reduced productivity or death of companion plants.
The concept of allopathy is at least 2,000 years old, though the team was not coined until 1973(Wills, 1985). During the past 30 years there has been a significant effort to understand the role of allelopathy in ecological processes.
Because agroforestry is a relatively new field, little work has been conducted on species compatibility (Wood, 1988). Some species currently used in agroforestry systems reportedly have allelopathic interference from Eucalyptus foliage leaching and volatiles and plant residues has been described. Also, residual mulches of Luceaena lecucocephala reportedly have allelopathic properties.

Alleopathy and intercropping: Allelopathy interference can result form natural products in intercrop foliage leaching, root products, and volatiles. There are four ways in which these chemicals are released into the environment.
1) Leaching: – Leaching is the removal of substance from plants by aqueous solutions such as rain, dew, and fog. Radioisotope labeling of plant tissue before leaching has shown that large quantities of both inorganic elements and may classes of organic natural products are leached from plant tissue.

2) Root Exudation: – Root exudation is the release of substances into the surrounding medium by healthy, intact plant roots. A variety of natural with leaves, the amounts of organic materials are much smaller (Rovira, 1969). Boulterand colleagues (1986) found that greater amounts of amounts of amino acids were exuded into sand by pea roots than into solutionculture. Similarly, exudation in soils can be expected to bary with soil physical and chemical properties. Root exudation usually is increased greatly by wilting conditions and root damage.

3. Volatization: – Volatization is the release of natural products into the atmosphere. A variety of plants either secretes or excretes metabolic products into special structures such as incomes and glands into intercellular spaces and canals or onto leaf surfaces. In hot dry weather, natural products with high vapor pressure released into the atmosphere where they may be associated directly by plants or adsorbed onto soil surface.

Allelopathy and Mulching:

Allelopathic interference can result from natural products released from mulches of plant residue. To improve nitrogen of crop plants plant residue mulches particularly of nitrogen-fixing species are commonly used in agroforestry systems. These plant residues may in fact result in allelopathic interference and decreases crop production.
Examples of Allelochemicals: Phenols, Benzoic acid, Aldehydes, Acetophenon, Cinnamic acid, Quinonenes, Flavonoids, tannins, Gentistic acid, etc.


Open for Discussion


Allelopathy in agroforestry

get Indian Forester’s article free


Today I received a 23000 Rs package of all volumes of Indian Forester from 1875 (Volume 1) to 2011 (Volume 137). Forestry professionals are acquaintance with the journal Indian Forester. It is a peer-reviewed scientific journal covering research in forestry. It is one of the oldest forestry journals still in existence in the world. It was established in 1875 and is published by the Indian Council of Forestry Research and Education (ICFRE).  It publishes valuable research articles related o forestry research free of cost, therefore it charges the readers with very nominal prize and subscription rate. I went through few of the articles published before year 1900 and I noticed that a mass of researchers are still working/(copying) on the same way. No updated!!!! 😦

The journal is available online in paid form (one needs to pay 50Rs/article to read).

But good news is that…

those who are in urgent need of any specific article can approach me with detail of its Year, Volume and title information. I can mail happily!

Open for the discussion



get Indian Forester’s article free

Global and local initiations for conservation (Laws and Policies)


The current topic briefs the International and National initiatives (acts, policies, and conventions) to conserve the bio-diversity  .


  1. CBD : Convention on biological diversity, 1992
  2. CITES : Convention on International Trade in Endangered Species of flora and fauna
  3. ICPNVP : International Convention for the Protection of New Varieties of Plants
  4. ESA : Endangered Species Act
  5. IPRS : Intellectual Property Rights (Patent, Copyrights)
  6. TRIPS : Trade Related to IPR
  7. PBRs : Plant Breeders Rights
  8. GI : Geographical Indication of Goods Act


  1. 1972 : UNEP – United Nations Environment Program
  2. 1980 : IUCN – International Union for Conservation of Nature
  3.           : WWF -World Wild Fund
  4. 1983 : WCED – World Commission on Environment & Development

National (India)

  1. IFA : The Indian Forest Act 1927 & Amendments
  2. WPA : Wildlife Protection Act 1972 & Amendments
  3. FCA : Forest Conservation Act 1980 & Rules
  4. NFP : National Forest Policy 1988
  5. GI : Geographical Indication of Goods Act 1999
  6. PVPFRA : Plant Varieties Protection and Farmers Right Act 2001
  7. BDA : Biodiversity Act 2002 & Amendments

Open for discussion!


Global and local initiations for conservation (Laws and Policies)


Wish you all a very happy Diwali! I continue my earlier post describing the nature of variation in natural population:-

Deviations from Hardy Weinberg (HW) = evolution!

The strength of the Hardy Weinberg (HW) law is that one can deviate from the assumptions quite a bit and the data will still approximate Hardy Weinberg proportions (HWP).
The weakness of the HW test is that the deviation from the assumptions has to be very strong in
order to detect the effect of this evolutionary force, e.g., selection.

Deviations from HW assumptions involve:
(1) Non-random mating, e.g., inbreeding, mate-choice.
(2) Mutation. The effects of mutation in populations are usually negligible as mutation rates are low—but mutation is an important force in creating new variation.
(3) Migration is important if the migration rate is high and the two population are very distinct genetically.
(4) Genetic drift due to small population size (chance effects)—genetic drift effects are important in both small and large (but finite) populations in terms of short and long term effects of changes in allele frequencies over generations due solely to drift effects (note that the finite size of a sample taken from a population is taken into account in the statistical tests for HWP and finite population size itself does not cause significantly detectable deviations from HWP).
(5) Selection has to be strong to cause deviations from HWP,

More details about the first four of these:

1. Non-random mating: individuals with certain genotypes sometimes mate with one another more commonly than would be expected on a random basis.
When like mates more often with like we term this positive assortative mating, e.g., height, IQ.
Positive assortative mating increases the proportion of homozygous individuals but does not alter the allele frequencies. Negative assortative (or “disassortative”) mating is preference for different genotypes. For example, there is evidence that a person is attracted to potential mates by phermones indicating that the other person has different alleles in the immune system than he/she has.
With self-fertilizing plants the level of heterozygosity is reduced by 1/2 each generation (with the
remaining 1/2 divided equally between the two homozygous classes. Self-fertilizing plants have  more homozygotes than expected under Hardy-Weinberg and often show significant deviations
from HWP.
Inbreeding (mating with close relatives) is another form of non-random mating. Relatives are
more likely to carry the same recessive allele for a rare recessive trait—inbreeding increases the number of affected individuals with homozygous rare recessive traits. Marriages between first cousins have about twice the rate of birth defects as random matings.

2. Mutation: in and of itself does not change allele frequencies to a noticeable extent as mutation
rates are low. However, mutations are the raw material of evolution, the ultimate source of
genetic variation. Although the frequencies of mutants are initially rare, and most are lost from the population, nevertheless some increase in frequency due to genetic drift effects and also selection.

Mutation is any change in the DNA sequence that is transmitted to offspring. A mutation can be a change in a single nucleotide, the insertion or deletion of one or more nucleotides, the
rearrangements of chromosomes or parts of chromosomes, as in the chromosomal fusion example, the duplication of one or more chromosomes, and even the doubling of the whole
genome because of an error in meiosis.

Mutation does not change allele frequencies but it creates new alleles which are then affected by selection and drift.
Mutation rates of single nucleotides are very small, roughly 2×10–9 per base per generation, yet
these are important mutations for evolutionary changes. Larger scale mutations may be much
more frequent. Trisomy 21 is a whole-chromosome duplication in humans that causes Downs
Syndrome. A woman aged 39 has a 1/137 chance of having a trisomy-21 child. Mutations of this
type play no evolutionary role because the extra chromosome creates sterility because of problems during meiosis.
Duplications of whole genes plays an important role in evolution. One copy can retain its function
while the other can diverge to perform a similar or quite different function. Alpha and beta and
other globin genes are the result of an ancient duplication.

3. Migration: is the movement of individuals from one population into another, which can alter allele frequencies, and if there are large genetic differences cause a statistically significant deficiency of heterozygotes from Hardy-Weinberg expectations.
Gene flow results from the movement of gametes or individuals. A high level of gene flow
prevents the divergence of different populations of a species. In the absence of gene flow,
isolated populations will tend to become more different because of the combined effects of
genetic drift, mutation and natural selection. A low level of gene flow moves alleles to other
populations. The effect is similar to that of mutation, in creating more variability on which
natural selection can act.
4. Genetic drift: (chance effects) random change in the frequency of alleles at a locus. short term genetic drift effects: cause changes in allele frequencies, both in small and large
populations. The change in allele frequency due to genetic drift in a small population appears larger, statistical testing can determine whether changes are larger than expected by chance.

Open for discussion!


Nature and extent of genetic variations in natural population

Today, I am dealing the above subject. It is a part of Unit-9, ASRB, ARS-NET, Agroforestry syllabus. Concept of genetic variation can scramble the mind of those non-genetic fellows. but it is not too difficult to understand.

Every trait or character is expressed due to action of a gene (In case of qualitative character, like eye colour) or cumulative action of many genes (in case of quantitative character like weight). Genes are located in a particular location on chromosomes which are termed as ‘locus’. Every locus has alternative form of gene known as alleles. If their is a locus consisting genes of height (Tt) then ‘T’ is allele responsible for height and ‘t’ is for dwarfness.

The frequency of these alleles in the population follow a hypothetical rule of HWE even it is transferred generation by generation.

Hardy Weinberg (HW) ruled the state of idol allelic frquency level of an idol population. A natural population is supposed to follow the HW equilibrium  (HWE) state. I hope, it will be a good start to understand the extent of genetic variation of population.

How much genetic variation is there in natural populations?

Before 1966 there were two disparate views on the extent of overall genetic variation in natural populations: classical and balance. The classical view assumes that at nearly every locus every individual is homozygous for a wildtype allele. In addition, each individual is heterozygous for rare deleterious alleles, and occasionally heterozygous for a selected allele maintained in the population by balancing selection. The balance view in its extreme form on the other hand assumed that there was a lot of genetic variation in populations so that most individuals will be heterozygous for alternative alleles at very many of their loci. This genetic variation was believed to be maintained by some form of balancing selection.

The year 1966 is important in population genetics, as it marks the use of an objective test to measure the extent of genetic variation in populations—gel electrophoresis. The initial, and later, studies showed that more than approximately 30% of loci (and this is an underestimate) exhibit variation in natural populations.

So, we now know, and more recent DNA based technologies have confirmed this, that a great deal of variation does exist in natural populations. In humans approximately 1/1,000 DNA base pairs is polymorphic (referred to as a SNP—single nucleotide polymorphism). In contrast, humans differ from chimpanzees approximately every 1/100 base pairs.

From these observations, it would seem that the balance school wins out. However, the classical theory has been retained in terms of the so-called neutral (or neo-classical) theory. Also to consider is that some, or much, of the variation in natural populations may represent a transient polymorphism—the evolutionary lag school.

The argument is that there will ultimately be changes in a species ecosystem (via environmental changes or evolutionary advances by other species) and consequently if a species is to survive it must evolve continually and rapidly to catch up to the latest changes in its ecosystem. neutral school: much of the genetic variation in populations is evolutionary noise, and the allelic variants are selectively equivalent. balance school: most variation has adaptive significance and is maintained by some form of balancing selection. evolutionary lag school: much of the variation in a population is transient variation, as advantageous alleles replace other alleles. Even if an allele is selected it will take a long time to become established in the population unless the selection is extremely strong (for example, with selection of 1% it takes 2,000 generations to fix an allele in a population, which equates to about 45,000 years for humans).

(To be continued in next post)

Nature and extent of genetic variations in natural population

Genetic load, inbreeding depression and hybrid vigor covary with population size

A nice example is providing empirical evaluation of established theory. I, like many students, am guilty of lapping up most textbook theory as if it was handed to me by God on a stone tablet. That’s why I’m thankful for investigators like Jennifer Lohr and Christoph Haag, who recently provide a comprehensive experiment published in Evolution that explains how a fundamental aspect of molecular ecology (population size) relates to three big evolutionary co-factors (genetic load, inbreeding depression, hybrid vigor).

If you’ve taken any population genetics course, a good evolution class, or read some primary literature on genetic drift and population size, here are the predictions you’d likely make:

Population size goes down, genetic drift increases, so:

  1. genetic load increases
  2. hybrid vigor increases
  3. inbreeding depression decreases

These factors have some pretty clear implications for the evolution of things like dispersal and the investment in local adaptation, and the associated theoretical literature that these predictions stem from is dense. But empirical evaluations are rare and have been limited by different effects between traits, which may relate to local adaption. Lohr and Haag use groups of Daphnia that have varying levels of genetic diversity to conduct outbreeding/inbreeding trials, establish clones, and measure life history traits.

The result? Well, yeah, it is what you’d expect.

As genetic diversity decreases, hybrid vigor increases, genetic load increases, and inbreeding depression decreases. While not surprising, these authors went to great lengths providing evidence for theory central to the way we think about how population size influences evolutionary trajectory.

Even if you already have a good feel for these ideas, the introduction of this paper is worth reading for clarity alone. Maybe you could pass it along to your own students or maybe even suggest they find another theory to test themselves. Something “simple” might be sitting right under their nose.


Lohr, J. N., & Haag, C. R. (2015). Genetic load, inbreeding depression and hybrid vigor covary with population size: an empirical evaluation of theoretical predictions.Evolution. DOI: 10.1111/evo.12802

Genetic load, inbreeding depression and hybrid vigor covary with population size

What is phylogenetics and how it is helpful to characterize a species?

I have been studying for molecular characterization of tree species (specifically Tectona grandis L. f.). Phylograph is a visual result of such finding which is acquaint to all taxonomist,  ecologist and geneticist . An insight on the above subject is as following:

Phylogenetic diversity


Phylo genetic diversity (PD) is a measure of the genetic diversity contained within different branches of a phylogenetic tree and is useful when deciding which species or populations to conserve in order to retain maximum levels of genetic diversity and hence evolutionary potential.PD can also inform about how much unique genetic diversity a taxonomic unit (or subset of taxonomic units) contains and therefore how evolutionarily distinct that unit is. To calculate PD you construct a phylogenetic tree that depicts the evolutionary relationships among taxonomic units. PD for a given sub-set of taxonomic units is then the “minimum length of all phylogenetic branches required to span a given set of taxa on the phylogenetic tree” (Faith 1992). The larger the value of PD the greater the level of diversity captured. PD can be applied to different taxonomic groupings (populations, species, orders, etc.) and can be used in conjunction with measures of extinction risk or threat level to set conservation priorities for both taxonomic units and geographic areas. PD aims to identify for conservation those taxa with maximum underlying genetic diversity and taxonomic distinctness. Because PD can be applied at different taxonomic levels it avoids the issue of what defines a unit as a species or population.


Phylogenetic Diversity

Central to calculating PD is the construction of a phylogenetic tree  which depicts the evolutionary relationships between taxonomic units based on the number of genetic differences between them. Within the tree the branches are the segments connecting different nodes. The nodes represent either real taxonomic units in the tree or hypothesised ancestors of extant taxonomic units. For the purpose of PD calculation the tree is rooted with a species known to be a common ancestor of all other taxonomic units in the tree.

To calculate PD for a subset of the taxonomic units ‘s’ within the tree (this can range from one taxonomic group through to the whole tree), first calculate the minimum spanning path (MSP). The MSP is ‘the smallest assemblage of branches within the whole phylogeny such that for any two members of ‘s’, a path along the phylogeny connecting the two can be found that only uses branches within the assemblage’.

Once the MSP has been determined then PD for the taxonomic subset can be calculated by summing the lengths of all the branches within the MSP.  This calculation can be done manually in simple trees, but for trees of greater complexity a matrix can be constructed containing pair-wise branch distances between taxonomic groups, implemented in the software Phylogenetic Diversity Analyzer (PDA; Minh et al. 2006).

Using PD to set priorities

PD is intended to facilitate the assessment of biodiversity, in combination with other metrics and considerations when deciding which species out of a subset to focus conservation efforts on or when planning the location and scale of reserves (see Moritz et al. 2000)

For example, for a network of protected areas that contains a particular subset of taxonomic units, the increase in PD that is obtained when adding an additional taxonomic unit (‘x’) to the network can be calculated. This is termed calculating the gain in PD (G; Faith 1992).

G = 0.5 (Dx,i + Dx,j – Di,j)

Where Dij is the pairwise distance between taxa ‘i’ and ‘j’, and ‘x’ represents the new taxonomic unit.  The taxonomic units that would contribute the most to increasing diversity within the protected area are the ones which maximise G.

EDGE: Incorporating Extinction Risk

PD provides a useful relative metric of diversity among taxonomic lineages , but other factors are also important, such as extinction risk. Threats from anthropogenic causes can be taken into account qualitatively, for example by comparing the geographic distribution of taxonomic units with anthropogenic threats in those areas. However a recent quantitative approach has been developed that combines Evolutionary Distinctiveness (ED – a derivative of PD) with the IUCNs red list classification (Referred to as EDGE; Isaac et al. 2007).

ED divides total PD amongst all members within the taxonomic subset by applying a value to each branch that is equal to its length divided by the number of nodes which the branch gives rise to. Thus ED takes into account the uniqueness of lineage s, giving priority to those with the highest levels of uniqueness. For example, a species with few close relatives that has been evolving independently for millions of years will have a high ED (such as the aardvark or various taxa in Madagascar) whereas a species that has radiated recently and has many close relatives will have a low ED.

To incorporate extinction risk and calculate EDGE:

EDGE = ln(1 + ED) + GE * ln(2)

Where GE = Rank based on IUCN red list classification.

EDGE can be calculated in the software package ‘Tuatara’ (Maddison & Mooers 2007).


PD values are comparable within a given study, based on the methods used to produce the full phylogeny.  However, comparisons between studies may not be possible if the methodology differs. Further, the strength of inference depends on the accuracy of the phylogeny, which is only an approximation of an evolutionary history, and dependent on the data included and the methods applied.

It is appropriate to compute PD based on the use of more than one marker type. This is because the stochastic nature of evolution means that a single locus is not necessarily representative of the evolutionary history (and therefore the genetic diversity) of a whole population or species.

The central aim of PD is to conserve as much evolutionary uniqueness as possible, however it is calculated using neutral markers (DNA not involved in selection /adaptation) and therefore may not reflect the full extent of evolutionary potential within a species/population (for more information please see the pages on Genetic Diversity and adaptive potential ).

Practical Applications

PD (and its derivatives) is a useful measure that can be applied to conserving genetic diversity within taxonomic units when conservation resources are finite and must be prioritised. Because PD takes into account extinct ancestors of the units in question and the relationships amongst extant units, it allows us to select sets of units which maximise the evolutionary potential contained within an ecosystem. PD should be combined with external factors such as geographic distribution, anthropogenic threats and extinction risk to consider the broader threat level for setting conservation priorities.

Relevant management topics:

  1. Assessing extinction risk
  2. Genetic tools for ecosystem management
  3. Measuring biodiversity using genetic tools
  4. Monitoring the genetic consequences of threats to populations


Faith D (1992) Conservation evaluation and phylogenetic diversity. Biological Conservation. 61, 1-10.

Isaac NJB, Turvey ST, Collen B, Waterman C, Baillie JEM (2007) Mammals on the EDGE: conservation priorities based on threat and phylogeny. PLoS ONE. 2(3):e296

Maddison WP, Mooers AO (2007). Tuatara: Conservation priority in a phylogenetic context. Version 1.0.

Minh BQ, Klaere S, von Haeseler A (2006) Phylogenetic diversity within seconds. Systematics Biology. 55, 769-773.

Moritz C, Patton JL, Schneider CJ, Smith TB (2000) Diversification of rainforest faunas: an integrative molecular approach. Annual Review of Ecology & Systematics. 31, 533-563.

The topic is open for discussion!

What is phylogenetics and how it is helpful to characterize a species?

Criteria for selection of phenotypically superior trees of Aegle marmelos (Bael)

There are guidelines for selection of plus trees with wood related characteristics for timber species improvement program but it is rather difficult to get Data recording information and characteristics that should be followed to select genetically superior high fruit yielding trees.

Therefore, following criteria is being posted to help field workers to obtain and record data of tree and population surveyed for selection of superior trees of Aegle marmelos or Bael/ bel:

Physical Information

  1. Accession/Code/ Number
  2. GPS address
  3. Forest Range/compartment/ Village
  4. Date
  5. Natural/Plantation
  6. Seed raised/ cloned
  7. Age
  8. Disease (Fungal) symptoms
  9. Pest attack symptoms
  10. Natural regeneration (root suckers etc.)
  11. Population composition
  12. Intra-species spacing

Tree morphology characters:

  1. Total Height
  2. Bole height
  3. of main branches
  4. Crown diameter
  5. GBH

Fruits physical characters

  1. No of fruits in tree
  2. Shape
  3. Size
  4. Transverse diameter
  5. Polar diameter
  6. Weight
  7. Pulp Weight
  8. No of seeds/ fruit
  9. Seed weight (per 100)

Collection and establishment of germplasm

  1. Root Suckers
  2. Branch Cuttings
  3. Seeds

Patch Budding

Six months to one-year old seedlings are used as rootstock for budding. The scion shoots should be selected from the mother plants, which are prolific bearers and free from disease and pest incidence. Patch/ modified ring budding during mid of May to September gives 60 to 90 per cent success under north Indian conditions. However, in south India, bael propagation is being done almost 8-10 months in a year with the aid of greenhouse and nethouse facilities. Besides budding, veneer and soft wood grafting are also successfully attempted with about 70 per cent success. However, considering the efficiency, budding appears to be an ideal method for bael propagation. Bael scion shoots can safely be stored/ transported in sphagnum moss / moist newspaper for 5-7 days with ample success.

Soft wood/Wedge grafting

When the seedling attains pencil thickness, it is ready for grafting. The top of the rootstock is cut off at the height of 15-18 cm from the surface of poly bag or ground. Splitting the beheaded rootstock vertically down the center, to a point 4 to 5 cm below the cut surface. Scion stick is collected from desired variety. The shoot with 6 to 8 healthy buds, 12 to 18 cm long pencil thick is cut from the selected mother plant. Scion stick should be cut from both sides into a tapering wedge approximately 4 to 5 cm long. The tapered end is inserted into the split stem of the rootstock. The rootstock and scion are wrapped tightly with 2 cm wide and 25 to 30 cm in length polyethylene strip. Immediately after grafting, the scion is covered with poly cap. Within 12 to 15 days of grafting scion shoots sprout, which is visible from outside. The polycaps are carefully removed after 21 days and these are kept for hardening. Early removal of poly caps results in high mortality. Winter months suitable for wedge grafting in the field conditions, while round the year can be grafted in greenhouse. Field transferable grafts become ready within 6-8 months of seed sowing. This method ensures 100 per cent establishment and survival of transplants in the field on account of undisturbed root system. Budding and wedge method of propagation is the appropriate technique for mass multiplication of bael plants.

Criteria for selection of phenotypically superior trees of Aegle marmelos (Bael)