Agricultural situation of Pyuthan

this pic indicates the real agricultural situation of nepal. Who are living in the village far from the valley.
Here a women is starting to uproot the seedling of Finger millet to  plant in her field. they depent on it.

Introduction to Gibberlins

                                                                                   GIBBERLINS

Introduction

Gibberellic Acid (GA) is a natural hormone in plant that promotes and regulates growth and development in plants. It belongs to the family of hormone known as Gibberellins. Scientists are exploring the benefits it can offer in enhancing and maximizing fruit and vegetable yield. There is also evidence that it helps in the seed germination process in some plants. Gibberellins (GAs) are a large family of tetracyclic, diterpenoid compounds, some of which function as endogenous plant growth regulators. Through phenotypic analyses of mutants with reduced GA production, it has been revealed that bioactive GAs play an essential role in many aspects of plant growth and development, such as stem elongation, flower and fruit development, and seed germination. Despite considerable effort, it has not yet been determined precisely where the bioactive GAs are synthesized in plants, or which cells/tissues are targeted by the bioactive GAs to initiate GA-mediated biologic actions. GAs is primarily synthesized at the site of their action. There is some evidence for the presence of GAs in xylem and phloem exudates, indicating a long-distance transport of GAs through these tissues.

                                                            

                                                                         Gibberllins

The nature of gibberlins

Unlike the classification of auxins which are classified on the basis of function, gibberellins are classified on the basis of structure as well as function. All gibberellins are derived from the ent-gibberellane skeleton. The structures of this skeleton derivative along with the structure of a few of the active gibberellins are shown above. The gibberellins are named GA₁....GA_n in order of discovery. Gibberellic acid, which was the first gibberellins to be structurally characterized, is GA₃. There are currently 136 GAs identified from plants, fungi and bacteria.  The most widely available compound is GA3, or gibberellic acid, which is a fungal product. The most important GA in plants is GA1, which is the GA primarily responsible for stem elongation.

Gibberellin Biosynthesis and Metabolism

 GAs are synthesized from mevalonic acid in young tissues of the shoot (exact location uncertain) and developing seed. GAs are probably transported in the phloem and xylem. Gibberellins are diterpenes synthesized from acetyl CoA via the mevalonic acid pathway. They all have either 19 or 20 carbon units grouped into either four or five ring systems. The fifth ring is a lactone ring as shown in the structures above attached to ring A. Gibberellins are believed to be synthesized in young tissues of the shoot and also the developing seed. It is uncertain whether young root tissues also produce gibberellins. There is also some evidence that leaves may be the source of some biosynthesis .3 acetyl CoA molecules are oxidized by 2 NADPH molecules to produce 3 CoA molecules as a side product and mevalonic acid. Mevalonic acid is then Phosphorylated by ATP and decarboxylated to form isopentyl pyrophosphate. 4 of these molecules form geranylgeranyl pyrophosphate which serves as the donor for all GA carbon atoms. This compound is then converted to copalylpyrophosphate which has 2 ring systems Copalylpyrophosphate is then converted to kaurene which has 4 ring systems Subsequent oxidations reveal kaurenol (alcohol form), kaurenal (aldehyde form), and kaurenoic acid respectively. Kaurenoic acid is converted to the aldehyde form of GA12 by decarboxylation. GA12 is the 1st true gibberellane ring system with 20 carbons.  From the aldehyde form of GA12 arise both 20 and 19 carbon gibberellins but there are many mechanisms by which these other compounds arise. Certain commercial chemicals which are used to stunt growth do so in part because they block the synthesis of gibberellins. Some of these chemicals are Phosphon D, Amo-1618, Cycocel (CCC), ancymidol, and paclobutrazol. During active growth, the plant will metabolize most gibberellins by hydroxylation to inactive conjugates quickly with the exception of GA3. GA3 is degraded much slower which helps to explain why the symptoms initially associated with the hormone in the disease bakanae are present. Inactive conjugates might be stored or translocated via the phloem and xylem before their release (activation) at the proper time and in the proper tissue.

Functions of Gibberellins

Active gibberellins show many physiological effects, each depending on the type of gibberellins present as well as the species of plant. Some of the physiological processes stimulated by gibberellins are outlined below Stimulate stem elongation by stimulating cell division and elongation. 

• Stimulates bolting/flowering in response to long days. 
• Breaks seed dormancy in some plants which require stratification or light to induce germination. 
• Stimulates enzyme production (a-amylase) in germinating cereal grains for mobilization of seed reserves. 
• Induces maleness in dioecious flowers (sex expression). 
• Can cause parthenocarpic (seedless) fruit development. 
• Can delay senescence in leaves and citrus fruits. 

Physiological effect of gibberellins:

Germination:

This hormone also plays the central role in breaking seed dormancy in plant species that require their seeds to be exposed to light or their seed coats to be cracked before germination. During the germination process, seeds initially take water, which triggers the germ of the plant to begin growing. The seed begins to produce hormones and enzymes that stimulate the plant to grow. Among these hormones are the gibberellins, which regulate the synthesis of proteins and the growth of stem tissues. Introducing additional gibberellins in the form of gibberellic acid can greatly accelerate seed germination. A standard solution is typically used for most seeds and is effective for both breaking the dormancy of seeds and accelerating their sprouting and initial growth. Gibberellins are responsible for promoting growth in the embryo of a seed. Gibberellin released by the embryo travels towards the aleurone layer, its target tissue situated in the endosperm region of the seed (alongside the embryo). Gibberellin acts as the inducer, as its presence allows the enzyme induction of amylase, which can break down starch INTO a sugar to be used in the embryo. Sugar is used in the plant to synthesize proteins and break out of dormancy.

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Increased Growth:

Gibberellins are a group of plant hormones that influence growth and development. Gibberellic acid occurs naturally in the plant and is used commercially to manipulate plant growth. Stem growth - GA1 causes hyperelongation of stems by stimulating both cell division and cell elongation. The hormone gibberellic acid is used by plants to induce growth .Growth is regarded as the elongation of plant cells, which is most profound at the tips of stem shoots. As days lengthen, gibberellic acid acts to induce flowering, as in the case of plants in the mustard family like radish, cauliflower and broccoli. Thus, the new seedling begins growth and breaks out of the seed. Gibberellins initiate this process in Summer, when the external environment exhibits favorable conditions for plant growth. This produces tall, as opposed to dwarf, plants. Bolting in long day plants - GAs cause stem elongation in response to long days.

Flowering:

If Gibberellic acid is applied to young plants, the result is often premature flowering of the plant. According to the California Rare Fruit Growers, “formation of male flowers is generally promoted by concentrations of 10 to 200 ppm.; female flowers by concentrations of 200 to 300 ppm.” These dosage amounts should be taken into consideration when using Gibberellic acid for premature flowering.

Increased Yield from Fruit Plants:

In fruit plants that have not been properly pollinated, Gibberellic acid is used to increase the fruit yield from these plants. Often, the resulting fruit is seedless.  Gibberellic acid is applied to plants to increase overall plant growth, and it is often used on grapes. Gibberellic acid not only increases the number of grapes per bunch but also the average size of each grape.

Frost Protection:

Gibberellic acid, if sprayed on plants in full-bloom, can counteract the deadly effects of frost when the weather gets cold.

Commercial Use of gibberlin:

Commercially, gibberellins are produced by fungal cultures, and it is the purified natural products that are applied to plants. Generally, gibberellic acid (GA3) is used, because this is the only gibberellin obtainable in commercial quantities, although an expensive mixture of GA4 and GA7 is now commercially available for specific purposes. Dwarf  landscape plants and potted flowering plants are treated with a hormone that inhibits the synthesis of gibberellic acids. The absence of gibberellic acid results in smaller, more compact plants.The most popularly used gibberlins are written as follows:

Seed Treatment:

Seeds are protected by a thick seed coat that must be permeated before germination can take place. Seeds that are difficult to germinate are often treated with giberellic acid to increase germination rates. Gibberellic acid is frequently used as a substance to stimulate germination in seeds that have become dormant. This is one of the most common and widespread uses of Gibberellic acid on plants.

Sex Expression

Presence of gibberellic acid is needed for male flower parts, the anther with its stamen, pollen and filament, to be formed in the developing flower bud. This is the case for plants with perfect flowers, those that have both male and female parts in the same blossom, as well as for plants that form single-sexed male flowers.

Secondary Effects

The presence of gibberellic acid, depending on specific plant species, can have secondary effects. One is the prevention of seeds in fruits, or the fleshy swelling of the ovary without forming seeds, such as in modern bananas. An abundance of this hormone can retard the dropping of dying leaves or the ripe fruits of citrus, a process called senescence.

Enhanced production of seedless grapes

 Bigger, more uniform bunches with larger fruit are produced. Among other effects, the gibberellin causes lengthening of the peduncle (stalk) attaching each grape to the cluster, thus permitting larger grapes to form. Virtually all the grapes that go to market are now treated with gibberellin.

The production of hybrid cucumber seed:

 Most high-producing cucumbers are F1 hybrids. GA sprays induce the production of male flowers on cucumber plants that normally produce only female flowers. The seed from neighboring all-female plants of a different strain is then exclusively hybrid.

Increased malt production:

 The addition of GA to germinating barley during beer production enhances a-amylase production so that more malt is produced more quickly. As the malt is the raw material for fermentation, a greater production of beer is made possible by this technique.

Increased sugarcane yield:

 GA promotes the elongation of sugarcane stalks with no change in the sugar concentration, so that the net yield of sugar is increased.

                                                                                 Mukesh RamjaliNepali

                                                                              MSc.Ag first sem

                                                                          Article unpublished

Impact of climate change in neplease farming

                                   Nepalese farming and Climate Change

 Always we are recognized by Nepal is agricultural based country out of we are still deficient on agriculture produce like rice, oilseed, pulse, vegetable, milk and milk produce, meat etc. Million tones annually we exported from other country. Directly or indirectly more than 80% people is engaged on Agriculture. The data shows that people staying the region of Karnali region dying annually cause of starvation. We are unable to provide food to our total population. Our country is agricultural based but programmed lunch by our government is not agricultural based. Minimum 40% of total budget should be allocated for this sector which is not implemented by our government. Without legal formalities and budged allocation increase in agricultural produce has not been possible. Besides this agriculture is highly dependent upon following component like seed, soil, fertilizer, irrigation, harvesting technique, marketing channel etc. And all of this is dependent upon climate. Climate change is burning issues now a day. It is due to emission of green house gas especially carbon monoxide, methane, chlorofloro carbon etc. The increase in the amount of these in our environment cause global warming. These gases are emission by most developed country like USA, China, and European Union, India. Our country has very little contribution towards it but we are most affected by it because it’s have impact in all areas nothing is beyond of climate change. Recent research work suggests that human-induced climate changes, particularly increases in temperature, are taking place. Even a slight increase in global average temperature can be accompanied by much greater changes in local and regional climates. Farming are unique areas in terms of detecting climate change and for assessing climate-related impacts because in the existing system changes occur rapidly with height over relatively short horizontal distances; as do the vegetation and hydrology Notwithstanding the uncertainties in the timing and exact magnitude of changes predicted in the Farming system, it is thought that many natural systems will be affected and their vulnerability to damage will increase. It is also thought that high mountain areas will be subject to greater increases in temperature than elsewhere; glaciers and snowfields will recede; and water supplies will decrease with severe impacts on irrigation to agricultural land and drinking water supplies as well as on supplies of hydroelectricity. Shifts in monsoon precipitation patterns are expected, leading to the possibility of increased frequency and intensity of droughts and episodes of intense precipitation. These in turn may lead to increases in floods, landslides, and erosion. Increased glacial melt may also lead to increases in the formation of glacial lakes and subsequent glacial lake outbursts. Recent outburst was occurred in Pokhara which cause loss of human beings, Agricultural produce and its diversity. This was too costly to our people who are living in such areas. Changes in monsoon precipitation will also have significant impacts on current agricultural practices in our country. Many farmers are waiting for the rain to start farming but their hope is decreasing. Nepalese agriculture is highly dependent on monsoon because more than 70% of agriculture land is rainfed areas without rain fall no one will able to cultivate their crops. Our farmer is facing much problem like unavailability of fertilizer in time, irrigation water, quality seed, and incidence of disease outbreak causes significant loss of agricultural produce. Now a day’s people are facing the problem of disease in many crops, such as leaf blight in maize, neck blast in rice, rust in wheat, blight in potato and tomato which has cause significantly loss. This disease is controlled by excessive uses of chemical which has detrimental effect to natural environments causes destroy of funa and flora of soil. Which causes serve loss in recent year. Soil is becoming acidic, by the excessive use of fertilizer like ammonium sulphate and chemicals also contribute in the global warming of earth so excessive uses of these chemicals should be minimized. Now a days new concept has developed sustainable farming which includes organic farming, Integrated insect pest management (IPM), Integrated soil nutrient management (ISNM). Such practices have given significantly good result in the perception of farmer and consumer. The use of these practices does not give large amount of produce but it give sustainable yield without hampering the natural environment. The use of organic manure, vermini compost, biopesticide has given goods result. So increase in such things should encourage from government sector and private sector also. Land is limited and population is increasing in geometric ratio but agricultural product is increasing by arthemetric progression. Recent challenge to the agriculturist is to develop the resistant varieties which can adapt to the new environment and give maximum amount of agricultural production for the demand of increasing population. Nepal Agricultural Research Council (NARC) is working for the development of the new varieties which can adopt to the changing environment but it is still not sufficient for the demand of our country. There is lack of awareness among the farmer about the use of improved varieties this is due to their socioeconomic condition. So our government effort should be made to focused on the farmer based program to increase their livelihood and to adapt in this changing environment .Many small and cottage industry should encourage to promote agriculture produce and give them respect. In our country there is a promising problem that is young generation is hesitating to do farm work or establish the agriculture based enterprise so this concept should be avoided. Young should encourage establishing these farm. If we want to develop our nation first up all we should respect our work what we do .For the development of agriculture sector it is highly based on climate so to adapt in this changing environment new technology should be adopted to cope these difficulties, resistant varieties, water stress tolerance, high yielding varieties should be selected. In this way we can adapt in this climate changing environment.   

                                                                                                                    Mukesh Ramjali(Nepali) 

                                                                                                                     MSc.Ag 1^st year

                                                                                                               IAAS,Rampur ,Chitwan