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Wednesday, July 1, 2015

POMEGRANATE - HEALTH FRUITS

  

Pomegranate (Punica granatum) or BUAH DELIMA in Malay are exotic fruits and nutritious. Pomegranate fruit is one of the most popular, nutritionally rich fruit with unique flavor, taste, and heath promoting characteristics. The tree was categorised as deciduous tree belonging within the Lythraceae family from genus Punica and the fruit is thought to originate in the Sub-Himalayan range of North India. There are no report from DOA about the planting of this fruit in Malaysia but I estimated less than 20 hectare CHE respectively. Most pomegranate fruits are planted as a hobby by those who rally know the technology and able to buy the planting materials. One pomegranate fruits weighed about 200 - 300 gram priced at RM10.-00 - RM12.00  per fruit at IOI Shopping Mall, Putrajaya. Many health drinks for beautification of skin are formulated from this fruit extracts. The product claims that this health drinks able to promote health and whiter skin colour. This plant are rare to many local farmers. Along with sub-arctic pigmented berries and some tropical exotics such as mango, it too has novel qualities of functional foods, often called as “super fruits.” Botanically the matured tree are able to produce a small size
fruit-bearing. 


Pomegranate tree grows to about five
and eight meters tall (See next picture). It is cultivated at a commercial scale in vast regions across Indian sub-continent, Iran, Caucuses, and Mediterranean regions for its fruits. Completely grown-up tree bears numerous spherical, bright red, purple, or orange-yellow coloured fruits depending on the cultivar types. Each fruit measures about 6-10 cm in diameter and weighs about 200 gm. Its tough outer skin (rind) features leathery texture. Interior of the fruit is separated by white, thin, spongy, membranous, bitter tissue into discreet compartments. Such sections, packed as sacs, filled with tiny edible sweet, juicy, pink pulp encasing around a single, angular, soft or hard (in case of over mature fruits) seed. The red ripe fruits are easily harvested manually or mechanised.

 

Health benefits of Pomegranate are nutririous fruit known from decade ago. The fruit is moderate in calories; 100 g provides 83 calories, slightly more than that in the apples. It contains no cholesterol or saturated fats. It is a good source of soluble and insoluble dietary fibers, providing about 4 g per 100 g (about 12% of RDA), which aid in smooth digestion and bowel movements. The fruit is suggested by nutritionists in the diet for weight reduction and cholesterol controlling programs. Regular inclusion of fruits in the diets boosts immunity, improves circulation, and offers protection from cancers. Certain ellagitannin compounds such as Granatin B, and Punicalagin are found abundantly in the pomegranate juice. Studies suggest that punicalagin and tannins are effective in reducing heart-disease risk factors by scavenging harmful free radicals from the human body. Total antioxidant strength of pomegranate fruit measured in terms of its oxygen radical absorbance capacity (ORAC) is 2341 ┬Ámol TE/100 g. The fruit is an also good source of antioxidant vitamin-C, provides about 17% per 100 g of daily requirement. Consumption of fruits rich in vitamin C helps the body develop resistance against infectious agents by boosting immunity. Regular consumption of pomegranate has also been found to be effective against prostate cancer, benign prostatic hyperplasia (BPH), diabetes, and lymphoma. Further, it is an also good source of many vital B-complex groups of vitamins such as pantothenic acid (vitamin B-5), folates, pyridoxine and vitamin K, and minerals like calcium, copper, potassium and manganese.
 

According to many reports, world’s best pomegranates are grown in the southern states of Afghanistan in Kandahar, Balkh, Helmand and Nimruz provinces (See picture). The pomegranate fruit is judged ripe when it develops distinctive color and impart metallic sound when tapped by the finger. Fruits must be picked up before they turn overmature, otherwise, their seeds get harder, inedible, and the whole fruit tend to crack open and damage. In the store, choose pomegranates that have smooth skin, free from any bruises, cuts or mold. At home, store the fruits in cool dark place at room temperature for 5-8 days or more. In general, they possess a long shelf life. You can also place them inside the refrigerator for a couple of weeks. or preparation and serving method normally wash pomegranate fruit in cold water or rinse in tepid water to bring to normal temperature if kept in the cold storage. Pomegranate is one of the most extensively cultivated fruits for food, juice, flavor, and color, making it a common ingredient in new functional foods often called “super fruits." To experience its rich flavor, eat fresh fruit as it is without adding anything. The fruit is eaten out of hand by making superficial vertical incisions over its tough skin and then breaking it apart.


Clusters of juice sacs are lifted out, and the white membrane, pith, and rinds are separated from the arils. Alternatively, hold the section of fruit upside down and beat gently with wooden stick, so that its seeds drop down detached. Separating its juicy, delicate arils is simplified by performing this task in a bowl of cold water, whereby its seeds settle down at the bottom and pulp and pith float. Remove water and gently pat dry seeds using soft cloth. Arils also make an attractive garnish when sprinkled on salads and dishes.  Fresh fruits make fantastic refreshing juice. Pomegranate juice can be used in soups, jellies, sorbets, sauces as well as to flavor cakes, baked apples. It is used in the preparation of traditional Persian recipes such as fesenjan, made from pomegranate juice and ground walnuts; rice pilaf, and delicious ash-e-anar soup. Pomegranate concentrate is a popular item used in the Middle Eastern and Mediterranean recipes. The juice is concentrated to about 250% stronger, and when added in cooking, gives unique flavor and intense sweet taste. That's all folks.


By,
M Anem,
Senior Agronomist,
Precint 11, Putrajaya
Malaysia.
(6 Rejab 1436H)

Wednesday, June 24, 2015

PINEAPPLES - THE BEST OF IT


PINEAPPLE (Ananas comosus) as I know belongs to the Bromeliaceae family, from which one of its most important health-promoting compounds, the enzyme bromelain, was named. The Spanish name for pineapple, pina, and the root of its English name, reflects the fruit's visual similarity to the pinecone. Pineapples are actually not just one fruit but a composite of many flowers whose individual fruitlets fuse together around a central core. Each fruitlet can be identified by an "eye," the rough spiny marking on the pineapple's surface. Pineapples have a wide cylindrical shape, a scaly green, brown or yellow skin and a regal crown of spiny, blue-green leaves. The fibrous flesh of pineapple is yellow in color and has a vibrant tropical flavor that balances the tastes of sweet and tart. The area closer to the base of the fruit has more sugar content and therefore a sweeter taste and more tender texture. Although thought to have originated in South America, pineapples were first discovered by Europeans in 1493 on the Caribbean island that came to be known as Guadalupe. When Columbus and other discovers brought pineapples back to Europe, attempts were made to cultivate the sweet, prized fruit until it was realized that the fruit's need for a tropical climate inhibited its ability to flourish in this region. By the end of the 16th century, Portuguese and Spanish explorers introduced pineapples into many of their Asian, African and South Pacific colonies, countries in which the pineapple is still being grown today. In Malaysia pineapple are grown commercially in Johore and few other states for about 14,000 hectare annually.

 

Since pineapples are very perishable, and modes of transportation to bring them stateside from the Caribbean Islands were relatively slow centuries ago, fresh pineapples were a rarity that became coveted by the early American colonists. While glazed, sugar-coated pineapples were a luxurious treat, it was the fresh pineapple itself that became the sought after true symbol of prestige and social class. In fact, the pineapple, because of its rarity and expense, was such a status item in those times that all a party hostess had to do was to display the fruit as part of a decorative centerpiece, and she would be awarded more than just a modicum of social awe and recognition. In the 18th century, pineapples began to be cultivated in Hawaii, the only state in the U.S. in which they are still grown. In addition to Hawaii, other countries that commercially grow pineapples include Malaysia, Thailand, the Philippines, China, Brazil and Mexico and few other tropical countries. 

Pineapples have exceptional juiciness and a vibrant tropical flavor that balances the tastes of sweet and tart. They are second only to bananas as America's favorite tropical fruit. Although the season for pineapple runs from March through June, they are available year-round in local markets. Pineapples are a composite of many flowers whose individual fruitlets fuse together around a central core. Each fruitlet can be identified by an "eye," the rough spiny marking on the pineapple's surface. Pineapples have a wide cylindrical shape, a scaly green, brown or yellow skin and a regal crown of spiny, blue-green leaves and fibrous yellow flesh. The area closer to the base of the fruit has more sugar content and therefore a sweeter taste and more tender texture. Pineapple is an excellent source the trace mineral manganese, which is an essential cofactor in a number of enzymes important in energy production and antioxidant defenses. For example, the key oxidative enzyme superoxide dismutase, which disarms free radicals produced within the mitochondria (the energy production factories within our cells), requires manganese. In addition to manganese, pineapple is a good source of thiamin, a B vitamin that acts as a cofactor in enzymatic reactions central to energy production.

Fresh pineapple.

By,
M Anem,
Senior Agronomist,
Precint 11, Putrajaya
WP, Malaysia.
(10 Rejab 1436H)

Friday, June 19, 2015

BANANA GENOMIC STUDY

  

FOR DECADES, the generation of informative banana and plantain DNA markers has been focused to catalyse progress in Musa breeding and germplasm characterisation. Important knowledge has been gained about the development of varieties resistant to various biotic and abiotic stresses, the identification of the A and B genomes, and the diagnosis of varieties and cultivars and their levels of heterozygosity. In addition, useful genes and promoters have been identified for the effective transformation of target cultivars. Despite all these achievements, intensive research has not been done on the most important fungal banana pathogens, Mycosphaerellafijiensis and M. musicola, which are still major causes of loss in banana-growing regions worldwide. The direct comparison of their population structure is expected to lead to a better understanding of the extent of their genetic diversity. Our initial efforts focused on the development of polymorphic locus-specific SSR markers for M. fijiensis and M. musicola. This technique, along with other PCR-based DNA fingerprinting techniques such as DNA Amplification Fingerprinting (DAF) and Selective Amplification of Microsatellite Polymorphic Loci (SAMPL), allowed us to carry out a comparative survey. Here we discuss the differences in genetic diversity and structure of both pathogen populations as detected by the different techniques, and the distribution of genetic diversity at regional and local levels in Central America and northern South America.


The last decade has witnessed a series of advances in banana and plantain research that are expected to catalyse progress in a major field of banana breeding: the development of Musa varieties resistant to various biotic and abiotic stresses. The contributions of molecular biologists to this advancement included the generation of informative DNA markers for the identification of the A and B genomes, the detection of genetic diversity in germplasm, the diagnosis of varieties and cultivars and levels of heterozygosity, the origin of the B genome in hybrids, the establishment of genetic maps and the construction of a bacterial artificial chromosome (BAC) library with approximately fivefold genome coverage. Useful genes and promoters have also become available for the effective transformation of target cultivars using, for example, specific Agrobacterium tumefaciens strains and optimised protocols for regeneration of embryogenic cell suspension cultures. Transgenic plants have been tested for the presence and expression of foreign genes.


Transgenic bananas expressing vaccines against human intestinal pathogens show potential [4]. Also, expression levels of a series of genes involved in the fruit-ripening process were determined. Finally, the nucleome of Musa has now been characterised in more detail, using flow cytometry and fluorescence in situ hybridisation (FISH; [6]). Telomeres of the Arabidopsis type, several gene clusters and retrotransposons have been localized, and the ploidy of any banana material can be estimated unequivocally. Notwithstanding all these (and other) achievements, a bias towards the host plant becomes obvious: a similarly intensive research activity with comparable results is lacking for the most important banana pathogens, especially the fungal pathogens. Although several laboratories are devoting their work to unravelling, for example, the infective power and potential of both pathogenic Mycosphaerellas, and though the results of this work over two decades are impressive, we lack a cooperative, dedicated, constant and engaged research effort on Mycosphaerella, especially since both ascomycetes, M. fijiensis and M. musicola,still are the major troublemakers in most banana-growing regions of the world (though Fusarium oxysporum f.sp. cubense, FOC, can also be included). Whereas the collection of isolates and their culture is routine, their genetic and pathological characterization is less common worldwide. The physiology of both fungi is more or less reduced to toxins, and the genetic make-up of Mycosphaerella is virtually unknown. For these reasons we have switched exclusively to Mycosphaerella fijiensis and M. musicola, after having isolated a series of Resistance Gene Analogues (RGAs) from banana, developed a series of informative microsatellite markers for Musa and employing them for the characterization of genetic diversity in wild and cultivated Musa.

Our initial research has focused on the development of polymorphic, locus-specific microsatellite markers for M. fijiensis and M. musicola. We have used these highly informative markers to study population structure and its dynamics in both pathogens. The comparison of the two pathogen populations is expected to lead to a better understanding of the extent of genetic diversity and genetic differentiation at local and regional levels, as well as the influence of environmental pressures on their spread to potentially new colonisation sites. Moreover, it could also predict the behaviour of new epidemic forms, thus helping breeders and farmers with basic information on genetic diversity, population structure, and fungal dynamics. To our knowledge, only one study has assessed the genetic diversity of both pathogens in parallel, but attempts to transfer molecular markers from M. fijiensis to M. musicola and vice versa were not successful. However, the polymorphic SSR markers developed for M. fijiensis and M. musicola in the course of this project, along with other PCR-based DNA fingerprinting techniques such as DNA Amplification Fingerprinting (DAF) and Selective Amplification of Microsatellite Polymorphic Loci (SAMPL), have allowed us to carry out a truly comparative survey of the genetic diversity of both pathogens. Here we report the results of such a study with populations from different Latin American countries. We discuss (a) differences in genetic diversity and structure of the two populations as detected with different techniques, (b) the distribution of genetic diversity at regional and local levels in Central America and northern South America, and (c) evidence for isolation by geographical barriers and distances. Thanks.
Source of info:  http://www.fao.org/docrep


By,
M Anem,
Senior Agronomist,
Banana Kulim Estates, Kota Tinggi,
Johor, Malaysia.
(9 Rejab 1436H)

Monday, June 15, 2015

USE OF PROTOPLAST IN BANANA

 

BANANA (Musa spp) is now easily amenable to in vitro culture, and plants are regenerated from various explants through organogenesis, embryogenesis, anther culture and even from cultured protoplasts. This has created great opportunities for other biotechnological applications. Cell suspensions, for example, opened the way for gene transfer and improved the production, the quality, and therefore the manipulation of cell suspension-derived protoplasts. Through genetic engineering it has become possible to confer new traits on banana plants, using either particle bombardment  or Agrobacterium-mediated transfer. Protoplasts facilitate the direct transformation of plant cells by DNA microinjection and electroporation. However, many characters of agricultural interest are multigenic or ill-defined, and current transformation methodologies allow the integration of only a few foreign genes. Protoplast fusion, however, allows the transfer of several useful characters, even if detailed genetic or molecular knowledge of genes encoding for these desired characters is lacking. Protoplast fusion is therefore a complementary tool to increase nuclear and cytoplasmic variability and to confer desirable agronomic traits.



 
Important banana cultivars are susceptible to many pests and diseases, particularly Mycosphaerella fijiensis and Fusarium oxysporum f.sp. cubense, nematodes and insects. Very interesting traits of resistance have been identified in this genus for most serious diseases. However cross-breeding is very difficult in the genus since most edible cultivars are sterile even after profuse pollination by wild pollen-fertile genotypes. Protoplast fusion is therefore an option, as it can overcome such sexual barriers which occur frequently in banana, and which cannot be bypassed even through embryo rescue. Therefore somatic hybridisation between wild and cultivated banana is expected to produce hybrids combining agronomic traits with genetic resistance to pests and pathogens.

Protoplast fusion has the added benefit that it creates the possibility of generating asymmetric fusions, whereby selected cytoplasmic organelles, chromosomes or chromosome fragments from an irradiated protoplast donor could be combined with the genome of an acceptor protoplast. This strategy is of especial interest in banana, where the subspecies balbisiana is considered to be a source of multiple resistance and therefore could be partially utilised to improve banana cultivars, of which the most important component is the subspecies acuminata. Protoplast fusion also makes the creation of synthetic triploid banana genotypes possible by, for example, combining haploid protoplasts derived from anther culture with protoplasts from a diploid improved cultivar.

Chimerism and somaclonal variation are factors that seriously limit rapid clonal propagation of banana. By their nature, protoplasts avoid chimerism because they originate from a single cell, and protoplasts may be use to dissociate chimeric plants. On the other hand the cellular heterogeneity of protoplast populations can be useful for isolating somaclonal variants with improved characters such as increased yield or pathogenic resistance, so that somaclonal variation may also be exploited to provide new sources of genetic variability. Banana protoplast isolation and culturing is nowadays routine, although protoplast research on banana started 15 years later than on model plants. Now it is regrettably underused because of the strong emphasis on molecular and genomic studies in banana. Nevertheless, protoplasts have much to offer for non-conventional banana breeding, since they overcome sexual incompatibilities at interspecific and even at the intergeneric level, and allow the incorporation of multigenic traits such as yield, resistance to stress, pests and diseases. Finally protoplast techniques may improve banana when other classical methods have failed. Thanks. Adapted from:http://www.fao.org/docrep/007
By,
M Anem,
Senior Agronomist
Banana Gropu Farming Project,
Kg Air Kuning, Gemenceh,
Negeri Sembilan,
Malaysia.
(6 Rejab 1436H)


Wednesday, June 10, 2015

BANANA IN VITRO MUTATION BREEDING

BANANA IN VITRO MUTATION BREEDING is a new technology in planting material mass production for banana. Edible bananas are mostly sterile polyploids and must be propagated vegetatively, hence genetic improvement through cross-breeding is not possible. Mutation breeding has been suggested as an excellent alternative approach for banana improvement. In addition, the heterozygosity of asexual banana clones makes them suitable for mutation induction. The heterozygotic status is expected to be Aa in loci of diploid cultivars while the triploids of A genomic types can exist in either Aaa or Aaa forms. For interspecific hybrids, the heterozygotic constitution could be AaB, Aab, AAb, ABb, aBb or aBB. Mutation induction may uncover a recessive phenotype by mutating, inhibiting or deleting the corresponding dominant allele.

The use of cultured shoot tips for mutagenesis has facilitated mutation induction and the regeneration of potential mutants. An early flowering mutant of Grand Naine, GN-60Gy A, which also showed differences in the zymograms of soluble proteins and esterase isozymes, was induced by Novak after exposing shoot tips to gamma radiation. Further selection of GN-60Gy A in Malaysia has resulted in the release of an early fruiting Cavendish banana called Novaria. Matsumoto and Yamaguchi selected an aluminium-tolerant mutant from irradiated protocorm of a Cavendish banana.

Pisang Berangan (AAA) is a popular dessert banana, having good fruit quality, flavour, colour, pulp texture, size and shelf life. However, it is relatively tall and very susceptible to Fusarium wilt (Fusarium oxysporium f.sp cubense) and freckle disease caused by Cladosporium musae. Consequently, a mutation breeding program was initiated using gamma irradiation to induce genetic variation so that plants could be selected with one or more of the following characteristics: (a) tolerance to Panama disease; (b) short plant stature; and (c) early fruiting and high bunch weight. The present review aims to present the current status of the research, problems encountered, and research strategies. This short report adapted from a study by FAO. Further information linked to :
http://www.fao.org/docrep/007/ae216e/ae216e08.htm


By
M Anem,
Senior Agronomist
Dole Cavendisf Commercial Farm
Hulu Bernam
Selangor,
Malaysia.

Saturday, June 6, 2015

PAPAYA EXOTICA - FROM MALAYSIA

 PAPAYAS (Carica papaya) in Malaysia, before the advent of Eksotika, were very inconsistent in yield and generally had very poor eating qualities. Popular varieties then were Sitiawan, Batu Arang and Subang and their fruit size were large and inconvenient to handle and serve. Papayas were grown mainly for domestic consumption and export was insignificant. Breeding for Eksotika In 1972, MARDI started a backcross breeding programme for improving papayas. The Sunrise Solo which has excellent eating qualities but with poor yield and small fruit, was introduced from Hawaii. It was crossed with the locally adapted, large-fruited Subang 6. Subsequent progenies underwent a series of ‘self-pollination’ and backcrossing to Sunrise Solo to reconstitute its excellent eating qualities while selecting for larger fruit size of the Subang 6. After 15 years of breeding and selection, a line called ‘Backcross Solo’ with the features of Sunrise Solo but with increased fruit size and local adaptability of Subang 6 was selected. In1987, it was released as the ‘Eksotika’. The Eksotika had shortcomings in fruit freckles, soft texture and sensitivity to environmental stress. Eksotika was crossed with its sister line (Line 19) which was resistant to freckles and had better keeping qualities. The resultant F1 hybrid was more robust, higher yielding and had much improved fruit cosmetics and keeping quality. This hybrid named ‘Eksotika II’ was released  in 1991. This article in "Anim Agriculture Technology" I write about the potential for export of exotica papaya.

Technology package for Technology package for Eksotika One of the major reasons for successful adoption of Eksotika was the development of component technologies like agronomic requirements, P&D (Pest and Desease Management) and post harvest needs to give a complete technology package to the industry. The nutritional requirement for optimal growth and fruit production was determined through comprehensive field trials analysis and critical nutrient deficiency symptoms, in particular boron, were resolved. There were initial problems with pest, disease and weed management and all these were adequately controlled with appropriate use of agrochemicals and integrated pest management programme. Knowing and giving what the crop wants had helped tremendously in building up confidence in investing in cultivation of Eksotika papaya.

Commercialization of Eksotika Getting Eksotika to the market requires efficient post-harvest management and this includes knowledge of the optimum time to harvest (maturity indices) and ripening behaviour of the fruit during storage. Packaging using corrugated fibre board boxes holding a net weight of 6 kg was developed. This is the best packaging in terms of economy, efficiency and cosmetic appeal for the export of Eksotika. Early export of Eksotika was entirely by air which was very expensive and also has limitation in cargo space. Research on the use of refrigerated reefers for cheaper export by sea was successful and today more than 50% of the export of Eksotika to Hong Kong is done this way. The road to commercialization of Eksotika was not entirely smooth in the beginning. Up scaling projects with more receptive, innovative and enterprising companies scored significant success. The Eksotika fruits started to make inroads into previously untapped markets like Hong Kong, China, Middle East countries and Europe.

Many growers started to emulate the success of these companies and the acreage and export of Eksotika climbed at a very rapid rate to become the most important export fruit in the country today. Getting Eksotika successfully to the market was in some ways helped by the quality standards set by SIRIM and monitoring compliance of standards of exported fruits by FAMA. In supply of planting materials, MARDI produces high quality, affordably- priced Eksotika seeds under an ISO 9001 certification. Eksotika papaya for the world The advent of Eksotika had given the fruit industry a dramatic boost, particularly in generation of export earnings. In 1986, the year before Eksotika was released, the export revenue of papaya was a mere RM3 million. The export revenue climbed steadily every year since then and today it has passed the RM100 million mark. The Eksotika is the flagship variety exported both by refrigerated sea reefers and air freight to its major market in Hong Kong and China. The export trade to Singapore, the Middle East countries and Europe is also increasing. Malaysia currently is the second most important exporter of papaya in the world, thanks to the research in developing a complete technology package for Eksotika. Thanks.

By,
M Anem,
Senior Agronomist,
Bukit Mambai Fruits Farm
Labis, Segamat,
Johor, Malaysia.
(5 Rejab 1436H).

Sunday, May 24, 2015

PROTOPLASTS IN PLANT TISSUE

Banana protoplasts

Protoplasts are naked cells that lack cell walls (Figure above). They are spherical with a plasmolysed cell content and are contained within a plasmalemma. In principle, each individual protoplast can reform a cell wall, and later initiate either a callus through sustained divisions, or an embryo, defined as a somatic embryo. In banana they are obtained from in vivo tissues or in vitro cultures. As early as 1902, a scientist known as Haberlandt has stated that individual nucleated plant cells could convert into entire plants, either directly or through a callus stage. This phenomenon is termed 'totipotency' and denotes the recovery of a whole organism from a single cell, and is also applicable to protoplasts. In theory all cells are totipotent, but in practice it depends on the past cellular environment. Usually the morphogenetic competence is retained at the unicellular stage that corresponds to a protoplast. However since protoplasts are not exposed to the stabilizing and inductive influence from neighbouring cells, they may have lost their plant regeneration capacity. In fact, factors such as the genotype or species of the manipulated plant, and the ontogenetic state of the explant source, exert a powerful effect on the regeneration potential of protoplasts. Consequently the development of appropriate in vitro conditions for protoplast regeneration is complicated. Notwithstanding this, successful efforts have been made in isolation, cultivation and regeneration of protoplasts, since Nickell and Torrey pointed out their merit for crop improvement.
 
 

Various tissues and an increasing number of plant species and genotypes have been successfully used in protoplast culture, but so far sufficient quantities of protoplasts for practical applications are not routinely met. While the value for agriculture of protoplasts still needs to be demonstrated, they are an invaluable tool for studies on permeability of ions and solutes, photosynthesis, phytohormones, phytochrome, and maintenance of totipotency. Moreover, protoplasts are useful for the uptake of foreign genetic material and to produce somatic hybrids through protoplast fusion. In addition, protoplasts are an excellent system for studies on cell genetics and even for plant virology. These studies rely on isolated, clean and healthy protoplasts, which requires the appropriate choice of osmoticum, hydrolysing enzymatic solution, and pretreatment of the donor explant either in vivo or in vitro. This involves the right choice of explant age, cold treatment, phytohormone pretreatment, light intensity or photoperiod, and subculture rhythm, which affects both the internal metabolic status of the cells and cell-wall composition. Prior to cultivation isolated protoplasts need to be freed from enzymatic remains and debris, which are considered to be toxic. Culture in or on solid medium is considered to be more advantageous than in liquid medium because the development of a single protoplast into a colony can be followed up much better. For development, different factors such as medium composition are crucial, especially the nature and quantity of growth hormones. Other important factors are the physical environment, plating density, and embedding conditions or the use of feeder layers, which all contribute in one way or another to cell-wall regeneration and cell division. Once cell divisions start, the level of auxin(s), as well as the colony density, usually need to be reduced to avoid overcrowding. This is done by subculturing, which gives the additional benefit that an adequate nutrient supply is maintained. Finally, for rooting, plants are usually transferred to cytokinin-free medium, possibly containing some auxin, and exposed to high light intensities, usually in illuminated plant growth chambers. During recent decades, plant biology workers have recognised the potential of protoplasts in many experimental systems, since an efficient enzymatic method for protoplast isolation was first established. Thanks.
 
By,
M Anem,
Senior Agronomist,
Private J-Plant Tec, Air Hitam,
Johor, Malaysia.
(8 Rejab 1436H)