Yield loss associated with downy mildew is most likely related to soft rots that occur after plant canopies collapse and sunburn occurs on fruit. Cucurbit downy mildew only affects leaves of cucurbit plants.
|
|
In the United States, cucurbit production accounts for approximately 229,000 hectares with a value of $1.43 billion.Cantliffe, D.J., et al. "Current trends in cucurbit production in the U.S.", University of Florida Horticultural Society, United States, 2007. Retrieved 4 December 2013.
|
|
The complete distilling apparatus consists of three parts: the "cucurbit" (Arabic: ; Greek: , ), the still pot containing the liquid to be distilled, which is heated by a flame; the "head" or "cap" (, ; Greek , ) which fits over the mouth of the cucurbit to receive the vapors, with an attached downward-sloping "tube" (, ), leading to the "receiver" (, ; , or , ) container. In the case of another distilling vessel, the retort, the "cap" and the "cucurbit" have been combined to form a single vessel. The anbik is also called the raʾs (head) of the cucurbit. The liquid in the cucurbit is heated or boiled; the vapour rises into the anbik, where it cools by contact with the walls and condenses, running down the spout into the receiver.
|
|
Diabrotica speciosa, also known as the cucurbit beetle and in Spanish as vaquita de San Antonio is an insect pest native to South America. Its larvae feed on the roots of crops. The cucurbit beetle (Diabrotica speciosa) is also known to transmit several viruses such as comoviruses and different mosaic viruses. Diabrotica speciosa (D.
|
|
Downy Mildew. In: Zitter TA, Hopkins DL, and Thomas CE, eds. Compendium of Cucurbit Diseases. APS Press, St. Paul, Minnesota, 25-27.
|
|
O. Bahar and Burdman, S. Bacterial fruit blotch: A threat to the cucurbit Industry (2010). Israel Journal of Plant Sciences. 58:19-31.
|
|
R. foveicollis has a wide distribution across southern Europe, Asia, Australia and Africa. It is a serious pest of cucurbit crops in northwestern India.
|
|
The cucumber beetle (Acalymma albidovittata) is a beetle of the family Chrysomelidae and a serious pest of cucurbit crops in subtropical and tropical South America; Argentina, Bolivia and Brazil.
|
|
Larvae complete three instars while feeding on the roots of the host plant and pupate in the soil. Multiple generations are possible. In tropical areas, the cucurbit beetle reproduces continuously.
|
|
He was unemployed until 2006, when he joined a circus in Jilin province. Though recruited for his height, he now also does magic tricks and plays the saxophone and cucurbit flute.
|
|
The USDA originally thought the disease was exclusively in seedlings, however the first BFB outbreak in 1987 proved that entire fields could be lost to fruit decay. Today, many outbreaks in the United States result in 90-100% fruit loss per diseased field, prompting lawsuits by farmers over contaminated seed. In the 1990s, A. citrulli was found to infect most other cucurbit species. During this time, Bacterial Fruit Blotch spread through cucurbit fields around the globe very quickly.
|
|
Acidovorax is a genus of Proteobacteria. All species are facultative. A. avenae causes bacterial fruit blotch on cucurbit crops.Garrity, George M.; Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.) (2005).
|
|
Besides the direct damage their feeding causes to the plant, these insects can act as vectors for cucurbit yellow vine disease caused by the bacterium Serratia marcescens. This disease can kill the plants.
|
|
Henosepilachna sumbana, known commonly as the cucurbit ladybird, and sometimes listed as Henosepilachna cucurbitae is a pest ladybird species. H. sumbana feeds on cucurbits; vine-growing fruits such as melons, pumpkins, gourds, and cucumbers.
|
|
Some well- known pests include the western corn rootworm (D. virgifera virgifera), the spotted cucumber beetle and its larva, the southern corn rootworm (D. undecimpunctata), the cucurbit beetle (D. speciosa), the banded cucumber beetle (D.
|
|
Often, an exaggerated upward leaf-curling will occur. Regardless of which cucurbit is involved, only the leaves are infected, not fruit, flowers, stems or roots. Disease of the leaves results in three major effects: 1. reduced yields, 2.
|
|
Anastrepha grandis is a fruit fly, also known as the South American cucurbit fruit fly. It is a pest of various cultivated species of Cucurbitaceae, especially the pumpkin, squash and melon. Anastrepha grandis is found in almost all South American countries.
|
|
Scientists are also conducting research on Phytoremediation, which focuses on the ability of certain cucurbit species to remove persistent organic pollutants (POPs) such as PCBs and DDT from soil. The department also tests soil samples sent in by Connecticut businesses and residents.
|
|
Mathewson, J. A. (1968). Nest construction and life history of the eastern cucurbit bee, Peponapis pruinosa (Hymenoptera: Apoidea). Journal of the Kansas Entomological Society 41(2) 255-61. This species is an important pollinator of cultivated crops of squash, pumpkins, and related plants.
|
|
As described in the 1728 edition of Cyclopaedia, the following method was used to distill brandy: > A cucurbit was filled half full of the liquor from which brandy was to be > drawn and then raised with a little fire until about one-sixth part was > distilled, or until that which falls into the receiver was entirely > flammable. This liquor, distilled only once, was called spirit of wine or > brandy. Purified by another distillation (or several more), this was then > called spirit of wine rectified. The second distillation was made in balneo > mariae and in a glass cucurbit, and the liquor was distilled to about one > half the quantity.
|
|
S. marcescens and S. Proteamaculans are considered to be opportunistic plant pathogens. S. marcescens causes cucurbit yellow vine disease (CYVD). CYVD was first detected in pumpkin and squash. CYVD infects the phloem tissue in plants and causes wilting, yellowing, phloem discoloration, plant decline, and eventually death.
|
|
Putucusi (possibly from Quechua phutu bud, -q a suffix, k'usi a cucurbit species, a small zucchini or Cucurbita pepo,Diccionario Quechua - Español - Quechua, Academía Mayor de la Lengua Quechua, Gobierno Regional Cusco, Cusco 2005: phutu - s. Ramillete de flores. k'usi - s. Bot. (Cucúrbita sp.) Calabacín pequeño.
|
|
The red color of the diaper can be mistaken for hematuria (blood in the urine), which may cause unnecessary investigations by the physicians.The Red Diaper Syndrome. Rev Chil Paediatr. 1960 Jul;31:335-9 S. marcescens causes cucurbit yellow vine disease, leading to sometimes serious losses in melon fields.
|
|
The dimensions of cucurbiturils are generally on the ~ 10 Å size scale. For instance, the cavity of cucurbit[6]uril has a height ~ 9.1 Å, an outer diameter ~ 5.8 Å, and an inner diameter ~ 3.9 Å. Review: The Cucurbit[n]uril Family Jason Lagona, Pritam Mukhopadhyay, Sriparna Chakrabarti, Lyle Isaacs Angewandte Chemie International Edition Volume 44, Issue 31, Pages 4844 - 4870 2005 Abstract Cucurbiturils were first synthesized in 1905 by Robert Behrend, by condensing glycoluril with formaldehyde,Ueber Condensationsproducte aus Glycoluril und Formaldehyd, Robert Behrend, Eberhard Meyer, Franz Rusche, Justus Liebig's Annalen der Chemie 1905, 339, 1-37\. but their structure was not elucidated until 1981. Cucurbituril W. A. Freeman, W. L. Mock, and N.-Y.
|
|
They feed on flowers of the plants, if these are available, rather than feeding on leaves. This causes reductions in fruit yield. If flowers are not available, adult beetles prefer the foliage of the cucurbit crops.EPPO/CABI (1997a) Diabrotica barberi and Diabrotica virgifera. In Quarantine Pests for Europe (2nd ed), pp. 233-237.
|
|
Cucurbiturils have also been explored as supramolecular catalysts. Larger cucurbiturils, such as cucurbit[8]uril can bind multiple guest molecules. CB[8] forms a complex 2:1 (guest:host) with (E)-diaminostilbene dihydrochloride which is accommodated by CB[8]'s larger internal diameter of 8.8 angstrom and height 9.1 angstrom.A facile, stereoselective [2 + 2] photoreaction mediated by cucurbit[8]uril Sang Yong Jon, Young Ho Ko, Sang Hyun Park, Hee-Joon Kim and Kimoon Kim Chemical Communications, 2001, (19), 1938 - 1939 DOI Abstract The close proximity and optimal orientation of the guest molecules within the cavity enhances the rate of the photochemical cyclization to give cyclobutane dimer with a 19:1 stereoselectivity for the syn configuration when bound to CB[8].
|
|
Bacterial wilt is a complex of diseases that occur in plants, such as cucurbit, solanaceae (tomato, common bean[1,2], etc) and are caused by pathogens Erwinia tracheiphila, a gram-negative bacterium; Curtobacterium flaccumfaciens pv. flaccumfaciens, a gram positive bacterium. Cucumber and muskmelon plants are most susceptible, but squash, pumpkins, and gourds may also become infected.
|
|
The muskmelon is an annual, trailing herb. It grows well in subtropical or warm, temperate climates. Muskmelons prefer warm, well-fertilized soil with good drainage that is rich in nutrients, but are vulnerable to downy mildew and anthracnose. Disease risk is reduced by crop rotation with non-cucurbit crops, avoiding crops susceptible to similar diseases as muskmelons.
|
|
Datasets in SAMPL4 consisted of binding affinities for host–guest systems and HIV integrase inhibitors, as well as hydration free energies of small molecules. Host molecules included cucurbit[7]uril (CB7) and octa-acid. The SAMPL4 hydration challenge involved 49 submissions from 19 groups. The participation of the host–guest challenge also grew significantly compared to SAMPL3.
|
|
Branched hairs or scopae on the hind legs help to carry the large, coarse pollen of cucurbits. Males lack scopae, as they do not collect pollen. This bee relies on wild and cultivated squashes, pumpkins, gourds, and related plants. It may occasionally obtain nectar from other types of plants, but the female will only use Cucurbit pollen to provision her young.
|
|
2) Adult wasps emerge from the larvae after about 15 days, mate, and search for more beetle larvae to parasitize. Pediobius foveolatus wasps will also parasitize the larvae of squash beetle, Epilachna borealis, a closely related species that feeds on cucurbit crops. Pediobius foveolatus wasps are extremely small, about 1-2mm long (Fig. 1 and 3), and will not harm humans, beneficial insects, or any organisms outside the beetle genus Epilachna.
|
|
Cucurbiturils are commonly written as cucurbit[n]uril, where n is the number of glycoluril units. Two common abbreviations are CB[n], or simply CBn. These compounds are particularly interesting to chemists because they are suitable hosts for an array of neutral and cationic species. The binding mode is thought to occur through hydrophobic interactions, and, in the case of cationic guests, through cation-dipole interactions as well.
|
|
The larger sizes are a particularly active area of research since they can bind larger and more interesting guest molecules, thus expanding their potential applications. Crystal structure of the CB[10]•CB[5]complex including a chlorine anion. Cucurbit[10]uril is particularly difficult to isolate. It was first discovered by Day and coworkers in 2002 as an inclusion complex containing CB[5] by fractional crystallization of the cucurbituril reaction mixture.
|
|
Fungicides applied specifically for downy mildew control may be unnecessary. Broad spectrum protectant fungicides such as chlorothalonil, mancozeb, and fixed copper are at least somewhat effective in protecting against downy mildew infection. Systemic fungicides are labeled for use against cucurbit downy mildew, but are recommended only after diagnosis of this disease has been confirmed. In the United States, the Environmental Protection Agency has approved oxathiapiprolin for use against downy mildew.
|
|
On adult leaves, the symptoms appear the same as the ones left by other abiotic or biotic stressors so diagnosis is not as straight forward. They include large irregular leaf lesions which are brown to black in watermelon and reddish brown in melon. Bacterial fruit blotch lesions spread along main midrib in adult leaves.S. Burdman and Walcott, R. Acidovorax citrulli: generating basic and applied knowledge to tackle a global threat to the cucurbit industry (2012).
|
|
Within the cucurbit family, P. cubensis isolates will exhibit a specific host range, that is, it will infect certain cucurbits and not others. For example, if cucumber and squash are grown side-by-side sometimes only the cucumber is diseased. When a pathogen exhibits this type of host specificity within a plant family, it is referred to as a pathotype. At least five pathotypes of P. cubensis have been described in the U.S.Thomas, CE, 1996.
|
|
Cucurbita-5-ene with standard carbon numbering. Cucurbitacin is any of a class of biochemical compounds that some plants — notably members of the pumpkin and gourd family, Cucurbitaceae — produce and which function as a defence against herbivores. Cucurbitacins are chemically classified as triterpenes, formally derived from cucurbitane, a triterpene hydrocarbon – specifically, from the unsaturated variant cucurbit-5-ene, or 19(10→9β)-abeo-10α-lanost-5-ene. They often occur as glycosides.
|
|
A severe isolate of PRSV has also been shown to cause tissue necrosis. Cucurbit symptoms tend to be similar to papaya symptoms including blisters, mosaic, yellowing, and leaf distortions. This virus produces two types of inclusion bodies visible under a light microscope with proper staining of epidermal strips. One inclusion is the typical cylindrical inclusion (CI) which is considered diagnostic for the potyvirus group, and the other is called the amorphous inclusion (AI).
|
|
Peponapis pruinosa is a species of solitary bee in the tribe Eucerini, the long-horned bees. Its common name is eastern cucurbit bee. It may be called the squash bee, but this name can also apply to other species in its genus, as well as the other squash bee genus, Xenoglossa. This bee occurs in North America from the East Coast of the United States to the West Coast and into Mexico.
|
|
Eggs on underside of squash plant's leaf Squash bug eggs on the underside of yellow crookneck squash leaves Nymphs of several instars, on squash Anasa tristis of the family Coreidae is a major pest of squash and pumpkins, found throughout North America, and is a vector of the cucurbit yellow vine disease bacterium.Arnold, 2001 These bugs can emit an unpleasant odor when disturbed. It is commonly known as the squash bug but shares this name with certain other species.
|
|
In mainland China, planting of eggplant (as an open field vegetable) is done by plastic mulching and inter cropping with trellised cucurbit crops. Vine shades protect the crop during summer; however inter cropping is now less popular due to labor shortage. Small quantities of eggplant are cubed and stewed in tomato sauce and then canned, but the majority of the crop is sold in the open market. Eggplant appetizers are also made with onions and other vegetables.
|
|
Praecitrullus fistulosus, commonly known as Tinda, also called Indian squash, round melon, Indian round gourd or apple gourd or Indian baby pumpkin, is a squash-like cucurbit grown for its immature fruit, a vegetable especially popular in South Asia. It is the only member of the genus Praecitrullus. The plant is as with all cucurbits, a prolific vine, and is grown as an annual. The plant also is prickly with small thorns similar to the zucchini.
|
|
Coridius janus sometimes known as the red pumpkin bug is a species of bug in the family Dinidoridae. It feeds by sucking on the sap on soft parts of plants especially in the cucurbit family and causes damage to crops. The species was originally described in the genus Cimex by Fabricius and later placed in the genus Aspongopus. The antenna is five segmented with the third segment longer than the first which is shorter than all other segments, the body outline is oval.
|
|
Bacterial fruit blotch (BFB) affects cucurbit plants around the world and can be a serious threat to farmers because it spreads through contaminated seed. BFB is the result of an infection by Gram-negative Acidovorax citrulli bacteria, which has only been recently studied in detail.Bin Li, Yu Shi, Changlin Shan, Qing Zhou, Muhammad Ibrahim, Yanli Wang, Guoxing Wu, Hongye Li, Guanlin Xiea and Guochang Sunb. Effect of chitosan solution on the inhibition of Acidovorax citrulli causing bacterial fruit blotch of watermelon.
|
|
An old enemy re- emerges: downy mildew rears its ugly head on cucumber, impacting growers up and down the Eastern U.S. American Vegetable Grower, Feb. pp. 14-15. Considered a highly destructive foliar disease of cucurbits, successful breeding in the mid-twentieth century provided adequate control of downy mildew in cucumber without the use of fungicides. The resurgence in virulence has caused growers great concern and substantial economic losses, while downy mildew in other cucurbit crops continues to be a yearly hindrance.
|
|
Cucurbits are susceptible to diseases such as bacterial wilt (Erwinia tracheiphila), anthracnose (Colletotrichum spp.), fusarium wilt (Fusarium spp.), phytophthora blight (Phytophthora spp. water molds), and powdery mildew (Erysiphe spp.). Defensive responses to viral, fungal, and bacterial leaf pathogens do not involve cucurbitacin. Species in the genus Cucurbita are susceptible to some types of mosaic virus including: cucumber mosaic virus (CMV), papaya ringspot virus-cucurbit strain (PRSV), squash mosaic virus (SqMV), tobacco ringspot virus (TRSV), watermelon mosaic virus (WMV), and zucchini yellow mosaic virus (ZYMV).
|
|
The eggs, which are yellow, are laid in batches of up to five in the soil at the base of cucurbit plants. They hatch after eight to fifteen days and the larvae feed on the roots or tunnel into them, feeding for eighteen to thirty-five days and passing through four instar stages. They are creamy white at first but have turned yellowish-orange by the time they pupate in chambers in the ground. The adult beetles emerge after from four to fourteen days.
|
|
Cucurbituril's host–guest properties have been explored for drug delivery vehicles. The potential of this application has been explored with cucurbit[7]uril that forms an inclusion compound with the important cancer fighting drug oxaliplatin. CB[7] was employed despite the fact that it is more difficult to isolate since it has much greater solubility in water and its larger cavity size can accommodate the drug molecule. The resulting complex was found to have increased stability and greater selectivity that may lead to fewer side effects.
|
|
During eggs stage (Ovoid, about 0.74 × 0.36 mm, clear white to pale yellow), D. speciosa becomes active in mid-spring and quickly starts locating host plants for feeding and egg deposition. Females oviposit throughout the field and eggs typically hatch within 6–9 days and can take up to 30 days with under low temperature conditions. Eggs are yellow, oval shaped laid in clusters of 25-50 below leaf surface, and measure about 0.7 mm long and 0.5 mm wide. Adult females deposit eggs in soil crevices at or near the base of cucurbit plants.
|
|
The species is legally listed as a noxious weed in the American state of Colorado (Class C) and Hawaii, and the Australian state of Victoria (regionally prohibited in the West Gippsland region, and regionally controlled in several others). Despite not being an agricultural weed in itself, it hosts a number of insects and diseases, including both pests and beneficial insects. It is also a potential reservoir of the cucumber mosaic virus, Erysiphum cichoraceum (the cucurbit powdery mildew) and Texas root rot. A study found V. thapsus hosts insects from 29 different families.
|
|
Once a plant is infected, there is no way of stopping the spread of the disease. Some cucurbit cultivars are less susceptible than others, so it is beneficial to plant these cultivars. However, since wilt-resistant plants have not yet been developed, the most effective way to prevent the disease is to keep beetle populations at a minimum. While various methods of beetle control have been tested, the most effective preventative measure is to keep beetle populations as low as possible through careful field monitoring and insecticide sprays.
|
|
Marrow cutaway According to the Oxford English Dictionary, the first mention of vegetable marrows dates to 1822, zucchini to 1929, and courgettes to 1931. Before the introduction of Cucurbita species from the New World, marrow signified the immature, edible fruits of Lagenaria, a cucurbit gourd of African origin widely grown since Antiquity for eating when immature and for drying as watertight receptacles when grown to maturity. Vegetable marrows (distinct from courgettes) on sale in a British supermarket. Marrows are commonly cultivated in the British Isles, and the term "marrow" for the plant and for the fruit is current there, especially for the striped, thicker-skinned cultivar.
|
|
Cucurbit[10]uril Simin Liu, Peter Y. Zavalij, and Lyle Isaacs J. Am. Chem. Soc.; 2005; 127(48) pp 16798 - 16799; (Communication) Abstract The melamine diamine guest was then separated from the CB[10] by reaction with acetic anhydride that converted the positively charged amine groups to neutrally charged amides. Cucurbiturils strongly bind cationic guests, but by removing the positive charge from the melamine diamine guest reduces the association constant to the point it can be removed by washing with methanol, DMSO, and water. The CB[10] has an unusually large cavity (870 Å3) that's free and capable of binding extraordinarily large guests including a cationic calix[4]arene.
|
|
Charlock and Shepherd's purse may carry clubroot, eelworm can be harboured by chickweed, fat hen and shepherd's purse, while the cucumber mosaic virus, which can devastate the cucurbit family, is carried by a range of different weeds including chickweed and groundsel. Pests such as cutworms may first attack weeds but then move on to cultivated crops. Some plants are considered weeds by some farmers and crops by others. Charlock, a common weed in the southeastern US, are weeds according to row crop growers, but are valued by beekeepers, who seek out places where it blooms all winter, thus providing pollen for honeybees and other pollinators.
|
|
Until recently, the earliest known depictions of this genus in Europe was of Cucurbita pepo in De Historia Stirpium Commentarii Insignes in 1542 by the German botanist Leonhart Fuchs, but in 1992, two paintings, one of C. pepo and one of C. maxima, painted between 1515 and 1518, were identified in festoons at Villa Farnesina in Rome. Also, in 2001 depictions of this genus were identified in Grandes Heures of Anne of Brittany (Les Grandes Heures d'Anne de Bretagne), a French devotional book, an illuminated manuscript created between 1503 and 1508. This book contains an illustration known as Quegourdes de turquie, which was identified by cucurbit specialists as C. pepo subsp. texana in 2006.
|
|
Cucurbituril Synthesis Cucurbiturils are amidals (less precisely aminals) and synthesized from urea 1 and a dialdehyde (e.g., glyoxal 2) via a nucleophilic addition to give the intermediate glycoluril 3. This intermediate is condensed with formaldehyde to give hexamer cucurbit[6]uril above 110 °C. Ordinarily, multifunctional monomers such as 3 would undergo a step-growth polymerization that would give a distribution of products, but due to favorable strain and an abundance of hydrogen bonding, the hexamer is the only reaction product isolated after precipitation. Decreasing the temperature of the reaction to between 75 and 90 °C can be used to access other sizes of cucurbiturils including CB[5], CB[7], CB[8], and CB[10].
|
|
Powdery mildew of cucurbits Multiple species of fungus can cause powdery mildew of cucurbits: cucumbers, squashes (including pumpkins), luffas, melons, and watermelons. Spores of powdery mildew on cucumber leaf seen through Foldscope Section of leaf of cucumber showing powdery mildew infection, photo taken with Foldscope Since 1925, commercial Cucumis melo (cantaloup and muskmelon) production has been engaged in a biological "arms race" against cucurbit powdery mildew (CPM) caused by the fungus Podosphaera xanthii, with new cultivars of melons being developed for resistance to successively arising races of the fungus, identified simply as race 1, race 2, etc. (seven in total by 2004), for races found around the world, and race N1 through N4 for some divergent races native to Japan. Various subraces have been identified, and given names such as race 2U.
|
|
Fredric Hasselquist, in his travels in Asia Minor, Egypt, Cyprus and Syria in the 18th century, came across the "Egyptian or hairy cucumber, Cucumis chate", which is today included in the Armenian variety. It is said by Hasselquist to be the “queen of cucumbers, refreshing, sweet, solid, and wholesome.” He also states “they still form a great part of the food of the lower-class people in Egypt serving them for meat, drink and physic.” George E. Post, in Hastings' Dictionary of the Bible, states, “It is longer and more slender than the common cucumber, being often more than a foot long, and sometimes less than an inch thick, and pointed at both ends.” The Cucumis melo subspecies Chate was the most frequently encountered cucurbit in ancient Mediterranean images and texts, and was most likely the type of cucumber grown year-round for Emperor Tiberius of 1st century Rome.
|
|
In Paraguay it is usually prepared with medicinal herbs, with the exception of the citrus juice preparation which is often prepared in the South of that country. Mixing fruit juices with tereré is commonly called "tereré de jugo" (tereré prepared with juice)-in northeastern Argentina- or "tereré ruso" (Russian tereré) -more used in Paraguay- because this practice is more common with Slavic immigrants in the northeast of Argentina and southern paraguay. Guampas/Mates/Cuias are a kind of glass that can be made from animal horns, usually made from cattle horns, but some people made guampas from stainless steel, wood, mate/porongo (a kind of cucurbit native from South America), or silver. The new guampa/mate/cuia or the one not used for some time needs to be watered before use, because the lower part of the cuia is usually capped with a round piece of wood.
|
|
Cucurbit berries or pepos, particularly from Cucurbita and Lagenaria, are the earliest plants known to be domesticated – before 9,000–10,000 BP in the Americas, and probably by 12,000–13,000 BP in Asia. Peppers were domesticated in Mesoamerica by 8,000 BP. Many other early cultivated plants were also berries by the strict botanical definition, including grapes, domesticated by 8,000 BP and known to have been used in wine production by 6,000 BP. Bananas were first domesticated in Papua New Guinea and Southeast Asia. Archaeological and palaeoenvironmental evidence at Kuk Swamp in the Western Highlands Province of Papua New Guinea suggests that banana cultivation there goes back to at least 7,000 BP, and possibly to 10,000 BP. The history of cultivated citrus fruit remains unclear, although some recent research suggests a possible origin in Papuasia rather than continental southeast Asia. Chinese documents show that mandarins and pomelos were established in cultivation there by around 4,200 BP.
|
|
Such modern selective breeding of plants for phytopathological resistance to particular fungal races involves a great deal of genetic research; this PI 313970 versus race S case involved multi-stage hybridization to propagate a recessive gene, pm-S in successive generations, and how this may affect other recessive and codominant genes for resistance to other races of P. xanthii "remains to be determined". A 2004 literature review regarding powdery mildew races that parasitize various cucurbit plants concluded that "race identification is important for basic research and is especially important for the commercial seed industry, which requires accuracy in declaring the type and level of resistance ... in its products". However, identifying specific races was seen as having little utility in horticulture for choosing specific cultivars, because of the rapidity with which the local pathogen population can change geographically, seasonally, and by host plant. At least three other Erysiphaceae fungi can cause powdery mildew in cucurbits: The most frequent, after P. xanthii, is Erysiphe cichoracearum, the former primary causal organism throughout most of the world.
|
|