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13/04/2017

किसान धनी बनाउने कृषिविद् मदन राईका
१० सूत्र!! हरेक किसानले पढ्नै पर्ने!!
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‘बीस वर्षमा नेपाललाई अर्गानिक देश
बनाउँछु,’ ललितपुरको जाउलाखेलमा रहेको
डीएनएन गेष्टरुममा कृषिविद् मदन राईले
उत्साहित हुँदै सुनाए, ‘म त्यसको जिम्मेवारी
लिन्छु । दस वर्षमै अर्गानिक देश बन्छ । तर, २०
वर्षमा नेपाल विश्वकै पहिलो अर्गानिक देश
बन्नेछ ।’ पहिलो अर्गानिक देश हुनेबित्तिकै
सालिन्दा पाँच करोड पर्यटक नेपाल आउँछ ।
सर्वोच्च शिखर सगरमाथा नेपालमै छ । नेपाल
धर्मको त्रिवेणी पनि हो । पाँच करोड
पर्यटक भित्रिनेबित्तिकै १० करोड मानिसले
रोजगारी पाउँछन् । नेपालमा तीन करोड
जनसंख्या छ । कामदार नपुगेपछि विदेशबाट
झिकाउनुपर्छ । रासायिक मल र कीटनाशक
औषधि बिक्री गर्ने नेपालकै पहिलो अधिकृत
तथा कृषिविद् मदन राईसँग ‘किसानलाई धनी
कसरी बनाउन सकिन्छ’ भनेर रातोपाटीका
लागि दीपेन्द्र राईले गरेको कुराकानीको
सम्पादित अंश :
‘प्रतिशतका आधारमा संसारमा सबैभन्दा बढी
किसान भएको देश नेपाल होला,’ कृषिविद्
राईले दाबी गरे, ‘नेपाल अनपढ किसानप्रधान देश
पनि हो । पढ्यो भने हलो जोत्न पर्दैन भन्ने
मान्यता छ । पढ् है पढ्, पढिनस् भने हलो जोत्ने
होलास् भन्नेको बाहुल्य छ । अनि कसरी
शिक्षित व्यक्ति खेतीकिसानमा आकर्षित
होलान् ?’
हलो जोत्नु भनेको उब्जाउने संकेत हो । वनस्पति
तथा धातुको उत्खनन/सम्भार गरेर त्यहाँबाट
उत्पादित उब्जनीबाट मानिसले ज्यान बचाएका
छन् । पढेलेखेकाले हलो जोत्न नहुने भएपछि ५०
काटेका, त्यो पनि अनपढले मात्रै खेतीकिसानी
गर्ने भए । अनपढ किसानको संख्या दिनदिनै घट्दै
छ । यसैले सालिन्दा खेतबारी बाँझिदै गएका छन्
। पछिल्लो समय वैदेशिक रोजगारीमा गएकाहरू
स्वदेश फर्केपछि कृषितिर आकर्षित छन् ।
उब्जाएर देशलाई धनी बनाउन कृषिभन्दा अर्को
आधार नभएको राईको जिकिर छ ।

25/12/2016

Fungicides and How to Use Them Effectively
This article was published originally on
6/1/2011
Viruses, nematodes, and bacteria can cause
plant disease, but fungi are the number one
disease-causing organism. As a result,
fungicides are frequently used by homeowners
when managing plant disease problems.
Fungicides are pesticides that can kill or
inhibit growth of fungi on plants, but they are
not effective against bacteria, nematodes, or
viral diseases. Fungicides can be classified
based on if they are absorbed by the plant and
if they can move around in plant tissues, their
'curative' properties, how they kill the fungi
(mode of action), and type of chemical. Some
of the major categories are described below:
1. Contact vs systemic: Contact fungicides
(protectants) are not absorbed by the
plant and stick to plant surfaces. They
provide a protective barrier that prevents
the fungus from entering and damaging
plant tissues. Systemic products (also
known as penetrants), are absorbed by
the plant and are able to move from the
site of application to other parts of the
plant.
2. Preventive vs curative: Preventive
fungicides work by preventing the
fungus from getting into the plant. The
preventive fungicide must come into
direct contact with the fungus and they
have to be re-applied to new plant
tissues (as leaves or needles expand in
the spring) or if the product washes off.
Curative fungicides affect the fungus
after infection. This means they have the
ability to stop the disease after the
infection has started or after first
symptoms are observed.
3. Mode of action: This refers to how the
fungicide affects the fungus. Fungicides
may work by damaging the cell
membrane of the fungus, or by inhibiting
an important process that the fungi. It's
important to incorporate different modes
of action by mixture or by alternating
products to maintain effectiveness and
prevent fungicide resistance.
4. Chemical group: this classification may
vary depending on chemical
composition, structure, and mode of
action.

10/02/2016

काउली क्रूसिफेरी परिवारमा पर्ने एउटा तरकारी बाली हो । यसको
प्रमूख वानस्पतीक जात ब्रासीका ओलेरेसीया बोट्राईटीजलाई खेती
योग्य मानिएकोछ । हावापानीः काउलीको बनस्पतिक बृद्धि हनु ७.२
डि.से. देखि २३.८ डि.से. सम्म हुन्छ तर पनि उचित तापक्रम
१५.५देखि १८.३ डि.से. मानिएको छ ।
काउलीको जात हेरी कसैलाई फुल फुल्नू भन्दा अगाडी ७—८
डि.से.को तापक्रमको आवश्यकता पर्दछ भने हरूजातको लागि चिसो
तापक्रमको आवश्यकता पर्देन । काउलीको अगौटे जातहरूलाई ज्यादा
चिसो भयो भने काउलीको फुल ज्यादै सानो फुल हुन्छ भने कुनै
जातलाई ज्यादा गर्मी भएमा काउलीको फुल खुकूलो हुनूको साथै पातै
पात भएको हनु सक्दछ ।
पोषण र तापक्रम मिलेमा काउलीको खेती बेमौसममा पनि गर्न
सकिन्छ । अगौटे जातलाई वनस्पतिक विकासहनु बढि तापक्रम
चाहिन्छ ९२० २६ डि.से..) र विकास भैसकेपछि त्यसमा फल लाग्न
सुरु हुन्छ । यस्तो किसीमको काउलीलाई जाडो समयमा रोप्दा
वनस्पतिक विकास हनु नपाई पहिले नै न्युन तापक्रमले गर्दा गुच्चा
जत्रो मात्र फुल लाग्ने गर्दछ । छाटो समयमै काउली तयार हुने हुदाँ
अगौटे काउलीलाई ३ महिने काउली पनि भनिन्छ । त्यस्तै मध्य
मौसमी जातलाई ९१५२० डि.से.) र स्नोवल जस्तो जातलाई ९
१०१५ डि.से..) तापक्रमको आवस्यकता पर्दछ ।
कम तापक्रम चाहिने मध्य मौसमी जातहरूलाई गर्र्मी मौसममा
लगाइयो भने पातै पात मात्र लाग्ने र तापक्रम घटेपछि फुल आउँछ ।
पछौटे जात भने जाडो मौसममा विकास भै केहि तापक्रम वढेपछि फुल
लाग्ने भएकोले यो ढिलो लगाए पनि गर्मी याममा तयारी गर्न
सकिन्छ ।
माटोः मल भएको मलिलो दोमट किसिमको माटो राम्रो मानिन्छ ।
पानीको निकास राम्रो सँग हुने र पानी राम्रो सँग अड्याउन सक्ने
किसिमको माटो काउली खेतीका लागि राम्रो हुन्छ । माटोको
अम्लीयपना भने ५.५ सम्म हुनु पर्दछ । बर्षाको मौसममा काउलीमा
मूख्यत ओइलाउने, जराफेद तथा गाठो कुहीने, फूल कुहीने आदिले निकै
सताउँदछ । अतः बेर्ना सार्नु अगाडी माटोलाई राम्रोसँग खनजोत
गर्नु पर्दछ । यदि हलुका बलौटे किसिमको माटोमा यसको खेती गर्ने
हो भने प्रशस्त मात्रामा कम्पोष्ट वा गोबर मलको प्रयोग गर्नु
पर्दछ ।
माटोको तयारीः काउली खेती गर्ने जग्गामा पानी निकासाको
व्यवस्था धेरै राम्रो बनाउनु पर्दछ । धेरै चिसो र हिलो जग्गामा
यसको खेती राम्रो हुदैनँ । माटोलाई ३ ४ पटक राम्रो संग खनी माटो
बुरबुराउदो बनाउनु पर्दछ । पानीको निकासको लागि जमीन समथर
छैन भने जमीन समथर बनाउनु पर्दछ ।
खेती गर्ने समयः बेमौसमी खेती भन्नाले मौसम भन्दा अधि वा पछी
भन्ने बुझिन्छ । काउलीको जात अनुसार बेर्ना सार्ने समय फरक
हुन्छ । उदाहरणको लागि काठमाण्डौ र पाचँखाल एउटै हावापानी
पाईने क्षेत्र भएता पनि पाचँखालमा उत्पादन हुने समयमा
काठमाण्डौमा भने । E-Book shrawan
बीउदरः प्रति रोपनी बीउ कति लाग्दछ भन्ने कुरा बीउको आकार
प्रकार उमार शक्ति लगाउने समय, बीउको जात, आदीमा भर पर्दछ
तापनि साधारणतया काउलीको हाईव्रिड जातहरू ८ देखि १० ग्राम
प्रति रोपनी सम्म प्रयोग गरिन्छ । जति जती बर्षा भयो त्यति बीउ
बढि प्रयोग गरेको पाईन्छ ।
नर्सरी ब्याड: व्याड राख्ने जग्गालाई कम्तीमा ३÷४ पटक सम्म
खनजोत गरी राम्रो जग्गा, खुकुलो, मल भएको, पानी नजम्ने, घाम
लाग्ने, दोमट खालको माटो छानी माटोको उपचार फर्मालीन,
मालाथियन, बेभिष्टिन जस्ता औषधिले गरी व्याडको तयारी गर्नु
पर्दछ । व्याडको चौडाई १ मीटर र व्याडको उचाई १५ से.मी. उठेको
बनाउनु पर्दछ । लम्बाई भने आफ्नो आवश्यकता अनुसार बनाउन
सकिन्छ । दुइटा व्याडको बीचमा ३० –४० सेमी चौडा कुलेसो बनाउनु
पर्दछ ।
उपचार भएको बीउलाई तयार पारिएको नर्सरी व्याडमा सानो
छेस्काले वा चुच्चो कुट्टोले १० से.मी.को. फरकमा २–३ से.मी
गहिरा धर्साहरू कोरी हरेक धर्सामा एकनाससंग बीउ पर्ने गरी
खसाल्नु पर्दछ । बीउलाई पातलो गरी खसाल्न ४–५ भाग सुख्खा
माटो, बालुवा वा धुलो कम्पोष्ट मल मिसाएर छर्न सकिन्छ । बीउ
छरी सके पछि फुको माटोले छोपी हल्का सिंचाई दिनु पर्दछ । मौसम
अनुसार तुषारो, चर्को घाम र बर्षाबाट कलिला विरुवाहरूलाई बचाउन
प्लाष्टिकको टनेल अथवा परालको छानो बनाउन राम्रो हुन्छ ।
प्लाष्टिकको टनेल प्रयोग गर्दा दिउसो हटाउने र राती छोप्ने काम
गर्नु पर्दछ । समय समयमा झारपात हटाउनु पर्दछ । रोग कीरा
लागेको छ छैन हेरी रहनु पर्दछ । बेर्नाहरूलाई दोस्रो व्याडमा सारेर
बेर्ना जर्खराउने कार्य गर्नु राम्रो हुन्छ । एक रोपनी जग्गाका लागि
बेर्ना तयार गर्न २.५ बर्ग मीटर ड्याभ आवश्यकता पर्दछ भने
यसरी तयार गरेको बेर्ना २०–२५ दिनमा खेतबारीमा सार्न सकिन्छ
। हाल बेर्ना उर्मानको लागि प्लाष्टिक टे« र कोकोपिट पनि बजारमा
उपलब्ध छन् यसको प्रयोगले काम सजिलो हुनका साथै छिटो पनि
हुने गर्दछ र राम्रो बेर्ना सजिलै तयार गर्न सकिन्छ ।
बेर्ना सार्ने तरिका: काउलीको जात अनुसार समय फरक हून्छ ।
अगौटे जातका काउलीका बेर्ना ३÷४ पाते भए पछि सार्न उपर्युक्त
हुन्छ भने पछौटे जातका काउलीका बेर्नाहरू ५–६ पाते भए पछि
सार्न लायक हुन्छन् । जग्गा खनजोत गरेपछि अन्तिममा ड्या
बनाउनु पर्दछ । अगौटे जातका लागि ४५ से.मी.– ४५ से.मी. फरक
पर्ने (२४६४ बेर्ना ) र मध्य मौसमी जातका लागि ४५से.मी.– ६०
से.मी.को फरक पर्ने (१८५१ बेर्ना ) र पछौटे जातका लागि ६०
से.मी.– ६० से.मी.को फरक पर्ने (१३७७ बेर्ना ) गरेर ड्याभ दुरी
बनाउनु पर्दछ । साधारणतया १ रोपनी जमीनमा १८५१ बोट काउली
अटाउँदछ । प्राय बैसाख देखि भदौ सम्म रोपिने बेमौसमी काउलीको
जात अगौटे र मध्यखालको हुने भएकोले एक मीटरको चौडाईको
ड्याबमा ५० से.मी. फरकमा २ लहरमा रोपिन्छ । यसरी लगाउँदा
अगौटे जात २००० बेर्र्ना लाग्ने गर्दछ ।
सिंचाइः काउलीलाई सिंचाई गर्दा धेरै कुरामा विचार पु¥याउनु पर्दछ
। रोप्ने वित्तीकै सुख्खा छ भने हल्का पानी दिनु पर्दछ । गर्मी
समयमा ७ दिन देखि १० दिनको फरकमा पानी दिनु पर्दछ । बर्षाको
समयमा भने सिंचाईको सट्टामा पानीको ड्याभ कुलेसोमा पानी नजम्ने
गरी केहि भिरालो बनाई दिनु पर्दछ । गोबरमल र हाईव्रिड काउली
खेतीलाई साधारणतया अन्य जातहरूलाई भन्दा मलखाद बढिनै दिनु
पर्दछ । कति मलखाद दिने भन्ने कुरा माटोको मलिलोपना, जात र
याममा भर पर्दछ । २००० केजी गोबरमल र प्राभ पर्दछ । विरुवा
रोप्ने खाल्टो खाल्टोमा मल दिन सके बेस हुन्छ । रासायनीक
मलखाद साधारणतया प्रति रोपनी रासायनीक मलखाद कहीले कहिले
कति कति दिने भन्ने कुरा तलको तालिकामा उल्लेख गरिएको छ ।
गोडमेलः बेर्ना सारेको १५२० दिन पछि पहिलो र ४० दिन पछि राम्रो
संग दोस्रो पटक गोडमेल गरी उकेरा दिनु पर्दछ । प्रत्येक विरुवामा
यसै समयमा ४ – ५ ग्रामका दरले युरीयाले टप ड्रेसिभ्̈ गर्नु पर्दछ
।
बाली लिनेः जात अनुसार काउलीको बाली लिने समय पनि फरक फरक
हुन्छ । बेलाबेलामा मलखाद, भिटामिन, रोगनासक औषधि तथा
प्राविधिकले भने अनुसार लगाईएको बेमौसमी काउली विरुवा रोपेको
४५ दिन देखि १५० दिनमा काट्न तयार हुन्छन (ट्रपिकल–४५ दिने,
सिल्भर कप–४० दिने, सिल्भरकप–६० दिने, काठमाण्डाँै लोकल १५०
दिने आदी ) । जात अनुसार फुलको आकार पनि सानो ठुलो हुने
भएकाले उपर्युक्त अवस्था हेरी टिप्नु पर्दछ । काउलीको सेतो भाग
अर्थात वरिपरी कलिलो पातले कोपीलाई बेर्नु छाडेपछि गुणस्तर
नविग्रीदै काट्नपु र्दछ र नजिकको संकलन केन्द्र वा सोझै होलसेलमा
लागि बेच्नु पर्दछ ।
उत्पादनः उत्पादन के कति हुन्छ भन्ने कुरा माटोको उर्वरा शक्ति ,
उत्पादनशिल जातको छनोट, प्रविधिको प्रयोग , रोग किराको
समस्या , बजारको समस्या, त्यस ठाउको हावापानी आदीमा भर
पर्दछ तापनी साधारणतया हाईव्रिड जातहरूको उत्पादन ६०० देखि
९०० के.जी. प्रति रोपनी सम्म हुन्छ । स्नोक्राउन÷रेमी ८०० देखि
१२०० केजि सम्म र लोकल जातहरूमा ज्यापु १५०० देखि १८०० केजि
काठमाण्डाँै लोकल १५०० देखि २००० केजि सम्म प्रति रोपनि
उत्पादन भएको पाइन्छ ।

04/02/2016

Role of Biofertilizers in soil fertility and Agriculture

Biofertilizers are known to play a number of vital roles in soil fertility, crop productivity and production in agriculture as they are eco friendly and can not at any cost replace chemical fertilizers that are indispensable for getting maximum crop yields. Some of the important functions or roles of Biofertilizers in agriculture are:

They supplement chemical fertilizers for meeting the integrated nutrient demand of the crops.

They can add 20-200 kg N/ha year (eg. Rhizobium sp 50-100 kg N/ha year ; Azospirillum , Azotobacter : 20-40 kg N/ha /yr; Azolla : 40-80 kg N/ha; BGA :20-30 kg N/ha) under optimum soil conditions and thereby increases 15-25 percent of total crop yield.

They can at best minimize the use of chemical fertilizers not exceeding 40-50 kg N/ha under ideal agronomic and pest-free conditions.

Application of Biofertilizers results in increased mineral and water uptake, root development, vegetative growth and nitrogen fixation.

Some Biofertilizers (eg, Rhizobium BGA, Azotobacter sp) stimulate production of growth promoting substance like vitamin-B complex, Indole acetic acid (IAA) and Gibberellic acids etc.

Phosphate mobilizing or phosphorus solubilizing Biofertilizers / microorganisms (bacteria, fungi, mycorrhiza etc.) converts insoluble soil phosphate into soluble forms by secreting several organic acids and under optimum conditions they can solubilize / mobilize about 30-50 kg P2O5/ha due to which crop yield may increase by 10 to 20%.

Mycorrhiza or VA-mycorrhiza (VAM fungi) when used as Biofertilizers enhance uptake of P, Zn, S and water, leading to uniform crop growth and increased yield and also enhance resistance to root diseases and improve hardiness of transplant stock.

They liberate growth promoting substances and vitamins and help to maintain soil fertility.

They act as antagonists and suppress the incidence of soil borne plant pathogens and thus, help in the bio-control of diseases.

Nitrogen fixing, phosphate mobilizing and cellulolytic microorganisms in bio-fertilizer enhance the availability of plant nutrients in the soil and thus, sustain the agricultural production and farming system.

They are cheaper, pollution free and renewable energy sources

They improve physical properties of soil, soil tilth and soil health in general.

They improve soil fertility and soil productivity.

Blue green algae like Nostoc, Anabaena, and Scytonema are often employed in the reclamation of alkaline soils.

Bio-inoculants containing cellulolytic and lignolytic microorganisms enhance the degradation/ decomposition of organic matter in soil, as well as enhance the rate of decomposition in compost pit.

BGA plays a vital role in the nitrogen economy of rice fields in tropical regions.

Azotobacter inoculants when applied to many non-leguminous crop plants, promote seed germination and initial vigor of plants by producing growth promoting substances.

Azolla-Anabaena grows profusely as a floating plant in the flooded rice fields and can fix 100-150 kg N/ha /year in approximately 40-60 tones of biomass produced,

Plays important role in the recycling of plant nutrients.



C

04/02/2016

Composition of Organic Matter

Soil organic matter plays important role in the maintenance and improvement of soil properties. It is a dynamic material and is one of the major sources of nutrient elements for plants. Soil organic matter is derived to a large extent from residues and remains of the plants together with the small quantities of animal remains, excreta, and microbial tissues. Soil organic matter is composed of three major components i.e. plants residues, animal remain and dead remains of microorganisms. Various organic compounds are made up of complex carbohydrates, ( Cellulose, hemicellulose, starch) simple sugars, lignins, pectins, gums, mucilages, proteins, fats, oils, waxes, resins, alcohols, organic acids, phenols etc. and other products. All these compounds constituting the soil organic matter can be categorized in the following way.

Organic Matter (Undecomposed)

Organic:

Nitrogenous:

Water Soluble eg. Nitrates, ammonical compounds, amides, amino acids etc.

Insoluble eg. Proteins nucleoproteins, peptides, alkaloids purines, pyridines chitin etc.

Non Nitrogenous:

Carbohydrates eg. Sugars, starch, hemicellulose, gums, mucilage, pectins, etc.

Micellaneous: eg. Lignin, tannins, organic acid, etc.

Ether Solube: eg. Fats, oils, wax etc.

Inorganic

The organic complex / matter in the soil is, therefore made up of a large number of substances of widely different chemical composition and the amount of each substance varies with the type, nature and age of plants. For example cellulose in a young plant is only half of the mature plants; water-soluble organic substances in young plants are nearly double to that of older plants. Among the plant residues, leguminous plants are rich in proteins than the non-leguminous plants. Grasses and cereal straws contain greater amount of cellulose, lignin, hemicelluloses than the legumes and as the plant gets older the proportion of cellulose, hemicelluloses and lignin gets increased. Plant residues contain 15-60% cellulose, 10-30 % hemicelluslose, 5-30% lignin, 2-15 % protein and 10% sugars, amino acids and organic acids. These differences in composition of various plant and animal residues have great significance on the rate of organic matter decomposition in general and of nitrification and humification (humus formation) in particular. The end products of decomposition are CO2, H2O, NO3, SO4, CH4, NH4, and H2S depending on the availability of air.

Curren

04/02/2016

Flowering Plant Parasites (Phanerogams)

Most of the diseases are caused by fungi bacteria and viruses. There are few seeds plants called flowering parasites (Phanerogams) which are parasitic on living plants. Some of these attack roots of the host, while some parasites on stem. Some are devoid of chlorophyll and entirely dependent on their host for food supply, while other have chlorophyll and obtain only mineral constituents of food from host by drawing nutrition and water they are called as Holoparasites or complete or total parasite. They have haustoria as absorbing organs, which are sent deep into the vascular bundle of the host to draw nutrients, water and minerals.

Flowering Plant Parasites: There are two types of parasites.

1) Root Parasites:

i) Striga (Partial root parasite)

ii) Orobanche (Complete root parasite)

2) Stem Parasites:

i) Dodder (Cuscuta) (Complete stem parasite)

ii) Loranthus (Partial Stem parasite)

1. Root Parasites:

1. Total or Complete or Holoparasite:

Orobanche (Broom r**e or Tokra)

It is annual flashy flowering plant growing to height of about 15-50 cm long, yellow or brownish colour and covered by small thin scaly leaves. Flowers appears in the axil of leaves are white or tubular. Fruits appears in the axil of leaves are white or tubular. Fruits are capsule containing and seeds are very small, black in colour remain viable for several years. The hausteria of parasite penetrates into the roots of hosts and draw its nourishment. The growth of the plant is re****ed, may die some times. It attacks to***co, tomato, brinjal, cabbage, cauliflower.

2. Hemi Partial or Semi Root Parasite:

Striga (Witch W**d or Turfula or Talop)
Family Scrophulariaceae

It is a small plant with bright green leaves grows upto height 20-60 cm leaves beers chlorophylls and developed in clusters of 10-20 % host plant. They are obligate parasites therefore, do not obtain all their nutrient from their host root. Flowers are pink in colour, seed are very minute and produce in grate number 5000 to 100000 seeds plant per years. One flower contain 1200-1500 seeds and remains viable upto 12-40 years. Dissemination takes place with rain water, flood, wind and irrigation water. It cause yellowing and wilting of host leaves. It attacks sugarcane jowar, Maize, cereals and millets.

b. Stem Parasites:

1. Total or Complete or Holoparasite:

Cuscuta or dodder (Amarvel, Lovevine) Family cuscutaceae.
Genus – Cuscuta
It is non chlorophyllous, leaf less parasitic seed plant.

It is yellow pink or orange in colour and attached to the host. They do not bear leaves but bear minute function less scale leaves is produces flower and fruits. Flower are white, pink or yellowish in colour and found in clusters. Seed are form in capsules. A single plant may be produce 3000 seeds.

The first appearances of parasites is noticed as thread like leaf less stem which devoid of green pigment and twine around the stem or leaves of the host. When stem of parasitic plant comes in contact with host, the minute root like organs. i.e. hausteria penetrates into the host and absorbs. When the relation ship of the host is firmly established, the dodder plant looses the contact from soil.

These affect plant get weakened and yield poorly the seeds spread by animals, water and implements and remain viable when condition are unfavorable.

It attacks berseem alfalfa, clover, flax, onion, potato, ornamental and hedge plants.

2. Partial, Semi or Hemi Stem Parasites:

Loranthus
Family- Loranthaceae.
It is a partial parasite of tree trunks and branches with brown stem, dark green leaves but no roots.

1. Stem is thick and flattened of the node, appear in clusters at the point of attack which can be easily spotted on the trees.

2. At the point of attachment with the tree, it shows swellings or tumourous growth where the haustoria are produced. It produces flowers which are long, tabular, greenish, white or red colour and found in clusters. It produces fleshy berries with single seed.

3. The affected host plant beco

04/02/2016

Classification of Plant Tissue Culture Technique

I) Embryo Culture:

For embryo culture, embryos are excised from immature seeds, usually under a ‘hood’, which provides a clean aseptic and sterile area. Sometimes, the immature seeds are surface sterilized and soaked in water for few hours, before the embryos are excised. The excised embryos are directly transferred to a culture dish or culture tube containing synthetic nutrient medium.

Entire operation is carried out in the ‘laminar flow cabinet’ and the culture plates or culture tubes with excised embryos are transferred to a culture room maintained at a suitable temperature, photoperiod and humidity. The frequency of excised embryos that gives rise to seedlings generally varies greatly and medium may even have to be modified made for making Interspecific and Intergeneric crosses within the tribe Triticeae of the grass family. The hybrids raised through culture have been utilized for i) Phylogenetic studies and genome analysis. ii) Transfer of useful agronomic traits from wild genera to the cultivated crops and iii) to raise synthetic crops like triticale by producing amphiploids from the hybrids.

Embryo culture has also been used for haploid production through distant hybridization followed by elimination of chromosomes of one of the parent in the hybrid embryos cultured as above. A popular example includes hybridization of barley and wheat with Hordeum bulbosum leading to the production of haploid barley and haploid wheat respectively. Haploid wheat plants have also been successfully obtained through culture of hybrid embryos from wheat X maize crosses.

Application of Embryo Culture:

i) Recovery of distant hybrids.
ii) Recovery of haploid plants from Interspecific crosses.
iii) Propagation of orchids.
iv) Shortening the breeding cycle
v) Overcoming dormancy.

In addition ovule and o***y can also be cultured.

II) Meristem Culture:

In attempts to recovery pathogen free plants through tissue culture techniques, horticulturists and pathologists have designated the explants used for initiating cultures as ‘shoot –tip’, tip, meristem and meristem tip. The portion of the shoot lying distal to the youngest leaf primerdium and measuring up about 100 µm in diameter and 250 µm length is called the apical meristem. The apical meristem together with one to three young leaf primordia measuring 100-500 µm constitute the shoot apex. In most published works explants of larger size (100-1000 µm long) have been cultured to raise virus- free –plant. The explants of such a size should be infact referred to as shoot-tips. However, for purpose of virus or disease elimination the chances are better if cultures are initiated with shoot tip of smaller size comprising mostly meristematic cells. Therefore, the term ‘meristem’ or meristem-tip’ culture is preferred for in vitro culture of small shoot tips.

The in vitro techniques used for culturing meristem tips are essentially the same as those used for aseptic culture of plant tissues. Meristem tips can be isolated from apices of the stems, tuber sprouts , leaf axils , sprouted bunds o cuttings or germinated seeds.

Application of Meristem Culture:

i) Vegetative propagation
ii) Recovery of virus free stock.
iii) Germplasm exchange
iv) Germplasm conservation

III) Anther or Pollen Culture:

Angiosperms are diploid the only haploid stage in their life cycle being represented by pollen grains. From immature pollen grains we can sometimes raise cultures that are haploid. These haploid plants have single completes set of chromosomes. Their phenotype remains unmasked by gene dominance effects. In china, several improved varieties of plants have been grown from pollen cultures.

When pollen grains of angiosperm are cultured, they undergo repeated divisions. In Datura innoxia the pollen grains from cultured anther can form callus when grown on a media supplemented with yeast extract or casein hydrolysate. Similarly, when isolated anthers are grown on media containing coconut milk or kinetin, they form torpedo- shaped embryoids which in due co

21/01/2016

SEED PROCESSING

Seed lots received from the field are often at high moisture content and contain trash and other inert material, w**d seeds, deteriorated and damaged seeds, off-size seeds, etc. Seed processing is necessary in order to dry the seeds to safe moisture level; remove or reduce to the extent possible the various undesirable material, w**d seeds, other crop seeds, deteriorated or damaged seeds.

Other than this the seed lot heterogeneity in its physical characters like size, colour, shape etc. The seed lot is heterogeneous due to the following reasons

The soil is heterogeneous and there is a lot of variability in the fertility status of the soil due to the availability of nutrients, physical, chemical and biological properties.
Variability is introduced due to the position of seed set on the plant/fruit , time of pollination and fertilization over a period of time
Variability is created by biotic factors like pest and variability infestation.
Variability is also due to the management practices like water, land preparation, leveling, staggered sowing, and uneven distribution of fertilizer and irrigation water, uneven plant protection sprays and uneven maturity at harvest.
The inherent qualities such as germinability and vigour are exemplified by certain physical characteristics of the seed i.e., large size, a denser seed, optimum length etc., So, if grading is done to obtain a particular range of size, shape, length and density of the seeds, the quality of the lot is upgraded.
In its common usage in India, seed processing refers to all the steps necessary for preparation of harvested seed for marketing, namely, handling, drying, shelling, preconditioning cleaning, size grading, treating and packaging, etc.
Seed Processing Plant Layout Planning
Layout plan for construction of a seed processing plant should be carefully planned to ensure that the thorough seed cleaning, upgrading, seed treatment and other seed processing operations are carried out efficiently, without mixing and damaging seed lots, with a minimum of equipment, personnel, time and at minimum cost. The following factors should be considered in planning and designing a seed processing plant:

Kinds of crop seeds to be handled and kinds of contaminating crop and w**d seeds usually present in the seed lots
Size of operation
Whether drying facilities should be required
Selection of suitable equipment
Location of the plant
Source of power for running machinery
System of seed delivery to processing plant and
Availability of labour
The key to efficient plant layout is a thorough knowledge of what needs to be done, and sound planning. First, the general sequence of processes involved between the time seeds enter the processing plant and the time they are cleaned, packaged and ready for shipment, must be charted. The sequence of operations depends upon the kind of crop and the initial quality of seed lot, type of contaminants, moisture content of the seed lot, etc. The layout planner must have an intimate knowledge of the seed to be processed, its physical characteristics, the contaminants in it, and also of the selection of machines used to bring the seed to acceptable marketing standards.
Seed Processing Plant Building Layout
Seed processing plant building will comprise of following components:

Receiving-cum-drying platform
Processing area
Auxiliary building
Receiving-cum-drying platform
This area will be utilized to receive the raw seed and to sun dry small lots of crop seeds. This area can also be utilized for storage of seeds on wooden palettes. The platform will be connected to processing shed through a rolling shutter.
Processing area
The processing area should be situated between the shed and ventilated storage building. The hall should be connected to ventilated flat stores through a covered gallery for easy movement of processed and packaged seed to seed stores. The hall should have a big rolling shutter in the processing plant to permit entry of seed processing equipment into the hall for installation.
Height will be kept t

21/01/2016

SEED DRYING

The process of elimination of moisture from the seed is called drying. Seed drying should reduce the seed moisture content to safe moisture limits to maintain its viability and vigour during storage, which may otherwise deteriorate quickly owing to mold growth, heating and enhanced microbial activity. Seed drying also permits early harvesting, long term storage of seeds, more efficient use of land and manpower, the use of plant stalks as green fodder and production of high quality seed.
Depending upon the climate and method of harvesting adopted the threshed seed may or may not be dry enough for safe storage. Under less favorable conditions, threshed seed needs further drying.
Stage of moisture elimination
The moisture from the seed is eliminated in 2 stages

Surface moisture of the seed that initially removed by the drying air.
The removal of the moisture in the surface cause an imbalance in the moisture potential in the surface of the seed and the inner portion of the seed which leads to the migration of moisture from the inner organ to the surface.
The migration of moisture to the surface is slower than the evaporation and a moisture gradient is developed in the kernal.
Elimination of moisture from the seed depends upon the relative humidity and temperature of the environment surrounding the seed. When RH of the atmosphere is less than the seed, moisture is eliminated from the seed. While drying, care should be taken to minimize /prevent oxidation and decomposition and volatilization. In this process there will be loss of dry weight of seed which is widened when the processes take place at high temperature. Hence, high moisture seeds should be dried at low temperature.



Equilibrium moisture content
A seed is in equilibrium with the environment when the rate of moisture loss from the seed to the surrounding atmosphere is equal to the rate of moisture gained by the seed from the atmosphere.
Drying temperature
Greater the seed moisture content lesser should be the drying temperature and vice versa.
10% MC and below 110 o F (43.3o C)
10-18 % MC 100 o F (42.2 o C)
18-30 % MC 90 o F (32.2 o F)
The rate of drying depends on

Initial seed moisture content
Size of the bin and capacity
Depth of spread of seed
The rate of air blow
Atmosphere air temperature and relative humidity
Static pressure
Drying temperature
Methods of drying
I. Physical drying (or) natural drying (or) traditional sun drying
II. Mechanical (or) artificial drying

Drying with forced natural air
Drying with forced artificially heated air
Drying with desiccants
Drying with infrared rays
I. Physical drying / Natural drying / Traditional Sun drying
This is the common conventional method in which drying of the harvested crop is carried out in the field or threshing floor by the radiant energy of the sun. This does not involve any expenditure. To achieve uniform drying, the seed should be spread in thin layer. High moisture content seed with a moisture content of more than 17% should be dried first under shade / light to reduce the moisture content less than 17% and then dried under heavy sun i.e. noon drying. Sun dried seeds should not be allowed to remain open in the floor during night, since seed will absorb moisture from air. 2-4 days are needed to reduce the moisture content to 10-12%. Direct sunlight also can adversely affect seed germinability owing to high temperature and ultraviolet radiation, especially if the moisture content of the seed is high.
Advantages
1. Easy and cheap
2. Does not require any expenditure or fuel.
Disadvantages
1. The rate of drying is slow
2. Loss due to attack by insects, birds and animals
3. Large floor area is required
4. Involves extra labour for collecting and exposing during the day
5. Sun drying cause sun checks or hot spots due to variation in temperature from time to time. This checks or spots induce high amount of breakage while processing
6. mechanical admixtures a

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