Progress 10/01/96 to 09/30/02
Outputs
Transgenic tomato plants, with the coat protein (CP) of cucumber mosaic virus (CMV) were systematically infected by an unusual strain of the virus from California. In summer squash and melon the high level of resistance to squash mosaic virus (SqMV), conferred by the CP gene of the virus, was inherited recessively. A Chinese melon was resistant to CMV and tolerant to SqMV. Leaves and fruits of SqMV infected plants remained free of symptoms, and the tolerance was inherited recessively. American commercial cultivars of summer squash, highly tolerant to zucchini yellow mosaic virus, were susceptible to certain Australian, Egyptian, and Taiwanese strains, but resistant to Chinese strains. In beans, the resistance to the NL8 strain of bean common mosaic necrosis virus was conferred by a single dominant factor. In beans possessing only the I gene for BCMV resistance, the NL-8 infection caused necrosis and premature death. In beans, resistance to passionfruit woodiness virus
was conferred by a single dominant gene. A strain of watermelon mosaic virus caused severe infection in beans grown in Massachusetts. The Nigerian Curcurbita moschata was resistant to this unusual strain, but it infected C. equadorensis and C. maxima PA 419801, known to be resistant to other strains of the virus. In several foreign lines of pepper, newly recognized sources of resistance controlled certain strains of CMV. Tomato plants with the replicase gene of CMV (Serotype 2), were mildly infected by the virus. Only a few plants produced fruits of normal shape, size and color.
Impacts
Genes for resistance to viral infection of vegetables have improved substantially the yield and quality of many crops and have enabled fewer applications of insecticides to control vectors.
Publications
- Provvidenti, R. 2001. Inheritance of resistance to the NL-8 strain of bean common mosaic necrosis virus in bean. HortScience 36: 958-960.
- Provvidenti, R. 2002. Inheritance of resistance to squash mosaic virus in a transgenic summer squash transformed with the coat protein gene of pathotype 1. HortScience 37: 575-577.
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Progress 01/01/01 to 09/30/01
Outputs
An experimental squash line (Curcurbita pepo L.) containing the coat protein gene (CP) of a strain of squash mosaic virus was found to be resistant to strains of pathotypes 1 and 2 from Arizona, California, New Jersey and New York. An analysis of genetic populations derived from crosses and reciprocal backcrosses of a homozygous CP squash line with a susceptible cultivar of the same species revealed that the high level of resistance mimics the response of a single recessive gene. Annual viral surveys of vegetables in western New York revealed the presence of tobacco ringspot mosaic and tomato ringspot mosaic viruses. They were frequently found in cucumber (Cucumis sativus L.). During our screening of several hundred domestic cultivars and foreign introductions, no resistance or tolerance to either virus was found. The virus epidemic affecting the bean crop in western New York during the 2001 growing season was identified to be caused by a strain of CMV, BCMV, and a
strain of BYMV, in descending order. The infectivity and identity of these viruses were established on sets of differential hosts in the greenhouse. A strain of BCMV was able to overcome the resistance of commercial bean varieties.
Impacts
The proper diagnosis of vegetable viruses and the characterization of resistance genes are critical in the development of adapted and resistance varieties of vegetables for sustainable management of these important pathogens.
Publications
- Provvidenti, R., 2001. Inheritance of Resistance to the NL-8 Strain of Bean Common Mosaic Virus in Bean. HortScience 36 (5):958-960.
- Provvidenti, R., and Tricoli, D.M., 2002. Inheritance of Resistance to Squash Mosaic Virus in a Transgenic Summer Squash (Curcurbita pepo L.) Transformed with the Coat Protein Gene of a Strain of Pathotype 1. HortScience 37: (Accepted for publication).
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Progress 01/01/00 to 12/31/00
Outputs
In the summer months of the year 2000, a virus was found to be widespread in summer squashes (Cucurbita pepo L.) in some areas of Massachusetts. In greenhouse and laboratory tests, using differential hosts and serology, the causal agent was identified as a strain of watermelon mosaic virus (WMV). This unusual strain, WMV-MA, caused prominent systemic symptoms in several Cucurbita species and it was able to systematically infect Cucurbita equadorensis and C. Maxima PI-419081-1 (China), which are resistant to other strains of this virus. However, plants of C. moschata 'Nigeria Local' were systematically resistant and can be used to develop new resistant cultivar of C. pepo. In common bean (Phaseolus vulgaris L.) the resistance to the NL-8 strain of the bean common mosaic necrosis virus (BCMNV) was determined to be conferred by a single dominant factor. This factor is present in several American bean cultivars and Plant Introductions. A search for sources of resistance
to tobacco and tomato ringspot viruses in cucumber (Cucumis sativus L.) is continuing.
Impacts
(N/A)
Publications
- Provvidenti, R. 2000. Inheritance of resistance to passionfruit woodiness virus in common bean (Phaseolus vulgaris L.) HortScience 35: 880-881.
- Provvidenti, R. 2000. A strain of watermelon mosaic virus from Massachusetts causes prominent symptoms on squashes and systematically infects Cucurbita equadorensis and C. maxima PI 419081-1. Cucurbita Genet. Coop. 23:68.
- Provvidenti, R. 2000. Inheritance of resistance to the NL-8 strain of bean common mosaic necrosis virus in bean (Phaseolus vulgaris L.) HortScience 35: (Accepted for publication).
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Progress 01/01/99 to 12/31/99
Outputs
The symbol smv has been assigned to the coat protein (CP) gene of squash mosaic virus (SqMV) in summer squashes (Cucurbita pepo). This CP gene is presently used to develop experimental squash lines resistant to SqMV and to other common cucurbit viruses. Studies are in progress to determine the inheritance of resistance of this CP gene in melon (Cucumis melo). Inheritance studies on the high level of tolerance to SqMV found in a melon (Cucumis melo) from the Fujian Province of China ('China 51') have revealed that the tolerance is conditioned by a single recessive gene. Previous surveys had indicated that tobacco ringspot virus (TRSV) is of common occurrence in local cucurbits grown in several areas of mainland China. An extensive screening to locate sources of resistance to this virus, using a collection of 67 lines of Chinese cucumber (Cucumis sativus), was unsuccessful. None of the lines were resistant or tolerant to this virus.
Impacts
(N/A)
Publications
- Provvidenti, R. 2000. Inheritance of resistance to passionfruit woodiness virus in common bean (Phaseolus vulgaris L.). HortSciences 35: (Accepted for publication)
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Progress 01/01/98 to 12/31/98
Outputs
The coat protein (CP) gene of a strain of squash mosaic virus (SqMV) previously incorporated in plants of summer squash (Cucurbita pepo) was successfully introduced in several melon lines (Cucurbita melo). In melon this gene confers resistance also to several domestic and foreign strains of SqMV belonging to pathotypes I and II. However, in some lines the virus was able to infect inoculated leaves, but failed to move systematically. In other lines, plants appeared to be locally and systematically resistant. Studies are in progress to determine the inheritance of these two types of resistance. A melon collected in the Fujian Province of China in 1951 ('China 51') previously was found to be highly tolerant to SqMV and resistant to cucumber mosaic. Plants of this Chinese melon were systematically infected by strains of both pathotypes of SqMV, but leaves and fruits remained symptomless. Extensive testing involving hundreds of melon seeds from SqMV infected plants of
'China 51'revealed that none of the strains belonged to both serotypes of the virus and was seed transmitted in this line. Genetic studies involving crosses and backcrosses with the America cultivar 'Honeydew' are indicating that the high level of tolerance is inherited recessively.
Impacts
(N/A)
Publications
- Provvidenti, R. 1998. A source of high level of tolerance to squash mosaic virus in a melon from China. Cucurbit Gen. Coop. 21:29-30.
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Progress 01/01/97 to 12/31/97
Outputs
A coat protein (C)) gene of a strain of squash mosaic virus (SqMV) was incorporated in plants of summer squashes (Cucurbita pepo). This gene confers resistance to domestic and foreign strains of the virus belonging to pathotypes I and II. Genetic studies have demonstrated that the high level of resistance is conferred by a single recessive factor. Using regular breeding, this CP gene is presently incorporated in several summer cultivars and breeding lines. The resistance to zucchini yellow mosaic virus, found in 'Nigerian Local' (Cucurbita moschata) by this researcher, has been used by American seen companies to develop commercial zucchini-type squashes. The new cultivars, Dividend, Jaguar, Puma, Revenue, and Tigress were found to be highly tolerant or tolerant to American strains, susceptible to Egyptian, Australian and Taiwanese strains, and highly resistant to a strain from mainland China. All the previous efforts to locate in melons resistance to pathotypes of
SqMV have been unsuccessful, however, screening of foreign cultivars and land races has continued. Recently a melon, collected by a California gardener in the Fujian Province of China in 1951, was found to be highly tolerant to this virus. Plants were systemically infected by strains of the two pathotypes of SqMV, but leaves and fruits remained symptomless. This 'China 51' melon is resistant to cucumber mosaic virus, but susceptible to other cucurbit viruses. Genetic work is in progress to determine the inheritance of the tolerance to SqMV and the resistance to CMV.
Impacts
(N/A)
Publications
- Provvidenti, R. 1997 Resistance to Viral Diseases of Cucurbits Conferred by Biotechnological and Natural Resistance Genes (In Chinese). China Vegetables 4: 55-57.
- Provvidenti, R. 1997 New American summer squash cultivars possessing a high level of resistance to a strain of zucchini yellow mosaic virus from China. Cucurbit Gen. Coop. 20: 57-58.
- Robinson, R. W. and R. Provvidenti. 1997 Differential response of Cucurbita pepo cultivars to strains of zucchini yellow mosaic virus. Cucurbit Gen. Coop. 20: 58-59.
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Progress 01/01/96 to 12/30/96
Outputs
In tomato (Lycopersicon esculentum) the dominant gene Wmv, which derived from the coat protein of a strain of cucumber mosaic virus (CMV-WL) confers a high level of resistance. However, additional research has revealed that: 1) in grafts between CMV-resistant and-infected plants, the resistant plants developed systemic infection, indicating that they were not immune; 2) the markers GUS (b-glucuronidase) and NPT-II (neomycin phospho- transferase) in transgenic plants were not completely reliable for predicting resistance; and 4) Cmv gene conferred resistance to a number of CMV strains containing satellites, but one of these strains interfered with its function . A CP gene of a strain of squash mosaic virus (SqMV) was introduced in summer squash (Cucurbita pepo) plants, where it conferred a high level of resistance to strains of the virus belonging to serogroups I and II. These strains were from the USA, Australia, China, Egypt, and Israel. SqMV-resistant plants were
crossed with those of susceptible cultivars, and inheritance studies are in progress. A papaya strain of papaya ringspot virus (PRSV-P) caused very prominent symptoms on cucurbits. This valuable strain is controlled, in cucurbits, by the same genes conferring resistance to strains of PRSV-W. Thus, it can be used routinely in screening germplasm for resistance to this virus, which can be held in papayas for months.
Impacts
(N/A)
Publications
- Fuchs, M., R. Provvidenti, J. L. Slightom, and D. Gonsalves. 1996. Evaluation of transgenic tomatoes expressing the coat protein gene of cucumber mosaic virus strain WL under field conditions. Plant Disease 80:270-275.
- Gonsalves, C., B. Xue, S. Z. Pang, R. Provvidenti, J. L. Slightom, and D. Gonsalves. 1996. Breeding transgenic tomatoes resistant to tomato spotted wilt and cucumber mosaic viruses. Acta Horticulturae 431:442-448.
- Provvidenti, R. 1996. A Taiwan strain of papaya ringspot virus fron Carica papaya causing prominent symptoms on cultivated cucurbits. Cucurbit Gen. Coop. 19:83-84.
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Progress 01/01/95 to 12/30/95
Outputs
In tomato (Lycopersicon esculentum) the coat protein (CP) gene of the white leafstrain of cucumber virus (CMV-WL) was able to confer a high level of resistance against American, Asian, European, and Oceanian strains belonging to serogroups I and II of the virus. The resistance is governed by a single dominant gene to which the symbol Wmv was assigned. Eight Phaseolus vulgaris lines were released in 1995. They possess genes conditioning high levels of resistance to strains of the following viruses: bean common mosaic, bean yellow mosaic, broad bean wilt, blackeye cowpea, clover yellow vein, cowpea aphid-borne, pea mosaic, soybean mosaic, and watermelon mosaic. These dry-bean lines are very productive and can be easily grown in several areas of the world. A single dominant factor (Hss) conditioning a lethal necrosis response to soybean mosaic virus infection was located in some lines of P. vulgaris. The Smv gene for resistance to the virus and Hss segregate
independently. Genotypes possessing both genes are resistant to the virus, demonstrating that Smv can neutralize Hss. In pea (Pisum sativum) two random amplified polymorphic DNA (RAPD) markers were identified, which are linked to the single dominant gene (En) conferring resistance to pea enation mosaic virus. One marker, P256/990, mapped very near the Adh-I gene (alcohol dehydrogenase isozyme), about 6 cm from En. The other marker, B500/400, was located about 8 cm from En on the same side as P256/990.
Impacts
(N/A)
Publications
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Progress 01/01/94 to 12/30/94
Outputs
Resistance to Australian strains of passionfruit woodiness virus (PWV) was foundin a number of American cultivars and plant introductions of Phaseolus vulgaris. This resistance occurs mainly in bean lines known to be resistant to the prevalent strain of bean common mosaic virus. Using the cultivars Black Turtle 1, Clippers, and Redkote and four strains of PWV (K, Mild, Tip Blight, and #51), inheritance studies revealed that resistance is not strain specific and conferred by a single dominant gene, to which the symbol Pwv has been assigned. The coat protein (CP) gene of the most severe strain of zucchini yellow mosaic virus, the Connecticut strain ( ZYMV-CT) has been introduced into a commercial melon cultivar (Cucumis melo). Transgenic plants possessing 4n chromosomes have displayed a very high level of resistance to any concentration of the virus. Conversely, transgenic plants with 2n chromosomes displayed only tolerance, which is not effective at high viral titers.
The same results were obtained with other strains of ZYMV from USA, Europe, the Middle East, and Asia. The cultivar Cow Leg of bottle gourd or calabash gourd (Lagenaria siceraria) from Taiwan was found to be resistant to six viruses: cucumber mosaic, papaya ringspot, squash mosaic, tobacco ringspot, watermelon mosaic, and zucchini yellow mosaic. This is an unique multi-viral- resistant cultivar, which is also highly productive and of excellent quality.
Impacts
(N/A)
Publications
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Progress 01/01/93 to 12/30/93
Outputs
Transgenic summer squash (Curcurbita pepo) and melon (Cucumis melo) plants possessing the coat protein genes of two American strains of zucchini yellow mosaic virus (ZYMV-CT and ZYMV-FL) were evaluated with strains from America, the Middle East, and Asia. The results clearly indicated that the resistance conferred by these CP genes can be strain specific. Transgenic squash plants with the ZYMV-CT CP gene were fully resistant. Conversely, melons with ZYMV-CT CP gene were susceptible to a California strain, but summer squashes with ZYMV-FL CP gene were fully resistant. This strain specificity is not confined to ZYMV, since squash lines also possessing CP genes of cucumber mosaic virus or watermelon mosaic virus-2 were infected by some strains of each virus. Thus, in specificity, these man-assembled genes are not different from natural genes. In field trials, authorized by USDA APHIS, transgenic summer squash plants with ZYMV-FL CP gene were resistant to widespread
natural infection caused by the homologous virus. However, in autumn, due to low night temperatures (10-15 C) and possibly low light intensity, plants which were originally free of symptoms, developed numerous chlorotic spots on the foliage, but fruits (old and young) remained symptomless. The same symptoms were present in plants grown in a highly protected screenhouse. ELISA and recovery tests confirmed the presence of ZYMV-FL in foliage, but fruits were found to be free of it.
Impacts
(N/A)
Publications
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Progress 01/01/92 to 12/30/92
Outputs
A very high level of resistance in Pisum sativum to an Australian strain of passionfruit woodiness virus was found in several domestic and foreign cultivars. Inheritance studies have revealed that this resistance is conferred by a single recessive gene, to which the symbol pwv will be assigned. Linkage tests have indicated that this gene is located on chromosome 2, linked to a group or cluster of genes conferring resistance to other potyviruses. Resistance to strains of passionfruit woodiness virus from Australia and Puerto Rico was found in some cultivars of Phaseolus vulgaris. Inheritance studies conducted in two cultivars have indicated that the resistance is conditioned by single dominant genes. Studies are in progress to determine whether these genes are similar or closely linked to other dominant factors previously found in the same cultivars. Resistance to clover yellow vein virus, pea enation mosaic virus, and two strains of pea seed-borne mosaic virus was
located in some cultivars and plant introductions of lentils (Lens culinaris) from Turkey. Transgenic tomato plants possessing the coat protein (cp) of two serologically diverse strains of cucumber mosaic virus were evaluated under the same conditions. One of these cp genes, deriving from a mild strain of the virus and belonging to serogroup II, offers a very high level of resistance to a number of strains belonging to serogroups I and II. The cp gene deriving from a very severe strain of CMV confers resistance only to strains of serogroup I.
Impacts
(N/A)
Publications
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Progress 01/01/91 to 12/30/91
Outputs
Resistance in Pisum sativum to white lupin mosaic virus was found to be governedby a single recessive gene, to which the symbol wlv was assigned. This gene appears to be located on linkage group 6, which also includes three resistance genes for pea seed-borne mosaic virus (sbm-1, and sbm-3, sbm-4) and one of clover yellow vein virus (cyv-2). The resistance conferred by wlv is not temperature-dependent and the virus apparently is not seedborne in susceptible genotypes. The biological properties of three strains of passionfruit woodiness virus (PWV) from Puerto Rico (PWV-PR), Australia (PWV-K), and Thailand (PWV-TH) were compared using cultivars of Phaseolus vulgaris and Pisum sativum. In susceptible bean genotypes these three strains of PWV cause essentially similar symptoms, but they can be easily differentiated by resistant genotypes. All the pea cultivars tested were infected by PWV-TH, and none by PWV-PR. A number of the same pea cultivars were readily infected
by PWV-K, but others were highly resistant. Preliminary data indicate that resistance in beans to PWV is dominant, whereas in pea, it is recessive. Plant introductions of Citrullus lanatus from Zimbabwe previously found to be resistant to the Florida strain of zucchini yellow mosaic virus (ZYMV-FL) were determined to be resistant to low temperatures. In cross and backcross populations of cold-resistant and cold-sensitive lines, the resistance was inherited monogenically dominant.
Impacts
(N/A)
Publications
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Progress 01/01/90 to 12/30/90
Outputs
CU-R89, a red kidney bean breeding line, was released for commercial use. This is the first red kidney variety in the nation with resistance to BYMV and several strains of BCMV. Field trials have established that CU-R89 is comparable in productivity and quality to the leading commercial varieties of its type. Inheritance studies have demonstrated that resistance to the NL8 strain of bean common mosaic virus in Pisum sativum is governed by a single recessive gene to which the symbol bcm has been assigned. This gene is located on chromosome 2 and is closely linked to mo, cvy-1, pmv, sbm-2, conferring resistance to bean yellow mosaic virus, clover yellow vein virus, pea mosaic virus, and the lentil strain of pea seedborne virus, respectively. In recent years, a newly recognized potyvirus, tentatively named white lupin mosaic virus, has occurred in white lupin and pea crops, causing severe symptoms. Resistance was found in some landraces of P. sativum from Ethiopia and
preliminary studies have indicated the presence of a single recessive gene. Allozyme diversity at the Gpi-2 (phosphoglucoisomerase) locus was shown in 56 landraces of Citrullus lanatus from Zimbabwe. Gpi-2a or Gpi-2b was present in lines found to be resistant to the Florida strain of zucchini yellow mosaic virus (ZYMV-FL), but no linkage was detected with the zym locus. No seed transmission of zucchini yellow mosaic virus occurred in 6800 pumpkins (Cucurbita pepo) that had derived from seeds of ZYMV-infected fruits.
Impacts
(N/A)
Publications
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Progress 01/01/89 to 12/30/89
Outputs
The high level of resistance to pea mosaic virus (PMV) in Pisum sativum was found to be conferred by a single recessive gene (pmv). It was also found that this gene is situated on chromosome 2 because it is closely linked to mo for resistance to bean yellow mosaic virus, cyv for clover yellow vein virus, and sbm-2 for the lentil strain of pea seedborne mosaic virus. The isozyme Pgm-p was shown to be a very useful marker for pmv and closely associated genes. Resistance to zucchini yellow mosaic virus in an Africa accession of watermelon (Citrullus lanatus) was determined to be governed by a single recessive factor (zym), which confers a very high level of resistance. However, this resistance is confined to the Florida strain of the virus (ZYMV-FL), which is known to be the most prevalent strain occurring in cucurbits grown in the USA. The locus for the isozyme Gpi-2, which was found in the original virus resistant plants, was demonstrated to be inherited
independently of the zym locus. Resistance to cucumber mosaic virus, tobacco mosaic virus, broadbean wilt virus, and pepper mottle virus was located in a collection of wild accessions of Capsicum frutescens and C. chinese from Latin America. Preliminary studies have clearly indicated that resistance to CMV is strain specific and that resistance genes for two strains of CMV are inherited independently. B-21, a dry black bean breeding line with multiple virus resistance was recently released for commercial use.
Impacts
(N/A)
Publications
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Progress 01/01/88 to 12/30/88
Outputs
Linkage tests have revealed that on chromosome 6 of Pisum sativum there is a tight cluster of four genes (sbm-1, sbm-3, sbm-4 and cyv-2), which are responsible for resistance to: the Standard, Lentil, and P4 strains of pea seedborne mosaic virus (PSbMV), and to clover yellow vein virus, respectively. The genes sbm-3 and cyv-2 may be repetitive entities of other genes previously located on chromosome 2. It was also determined that this cluster of genes for viral resistance is closely linked to a factor known as wlo, which is responsible for the waxless condition of leaves and stipules. Using this morphological character as a marker gene, it has been possible to transfer resistance to these four viruses for six generations without viral tests. In Phaseolus vulgaris, resistance to watermelon mosaic virus 2 (WMV-2) is conferred by two distinct dominant alleles at independent loci. The gene Wmv prevents systemic spread of the virus, conversely, the gene Hsw confers both
local and systemic resistance below 30 C. At higher temperatures, inoculated plants with Hsw develop a lethal hypersentive necrosis. Resistance to zucchini yellow mosaic virus was located in some plants of five accessions of watermelon (Citrullus lanatus) from East Africa. This resistance is strain specific and confined to the Florida strain of the virus (ZYMV-FL), which is the most common strain occurring in the USA. Preliminary studies have indicated that the high level of resistance is conferred recessively.
Impacts
(N/A)
Publications
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Progress 01/01/87 to 12/30/87
Outputs
In Pisum sativum, resistance to a newly recognized pathotype of pea seed- borne mosaic virus (PSbMV-P4) is conferred by a single recessive gene, to which the symbol sbm-4 was assigned. This and the other genes (sbm-1, sbm- 2, and sbm-3) confer resistance to specific pathotypes of the virus. En, the gene for resistance to pea enation mosaic virus, was determined to be linked to the isozyme Adh-1 (Alcohol dehydrogenase), making this isozyme a very useful marker for breeding. In Phaseolus vulgaris, 142 cultivars were screened for resistance to broad bean wilt virus (BBWV). About 77.5% of these cultivars were resistant and 22.5% were susceptible. Inheritance studies revealed that resistance to BBWV is governed by a single completely dominant gene, to which the symbol Bbw was given. BBWV was not transmitted in 471 Red Kidney bean seeds derived from severely infected plants. In crosses between zucchini yellow mosaic virus-resistant Cucurbita moschata 'Nigerian Local'
and the susceptible 'Butternut', resistance was found to be governed by a single incompletely dominant gene. ZYMV was not transmitted in 6741 seeds of C. pepo and 434 seeds of Cucumis melo. These seeds had derived from severely ZYMV-infected plants. In Cucumis sativus, the gene (wmv-1-1) for resistance to papaya ringspot virus W (= WMV-1) was found to be closely linked to the single recessive gene (bi) for bitterness. No linkage was detected with the genes conferring resistance to scab or powdery mildew.
Impacts
(N/A)
Publications
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Progress 01/01/86 to 12/30/86
Outputs
In Pisum sativum, it was determined that the single recessive genes cyv and cyv-2 are independently able to confer resistance to the same strain of clover yellow vein virus (CYVV). Similarly, the recessive genes smb-2 and sbm-3, also independent of each other, are able to confer resistance to the lentil strain of pea seedborne mosaic virus (PSbMV). Hence, each member of the pair has the same function and may be duplicate or repetitive genetic entities. Linkage studies have established that cyv and sbm-2 are located on chromosome 2, because they are closely linked to mo, the factor for resistance to bean yellow mosaic virus. The genes cyv-2 and sbm-3 are situated in different linkage groups. Similarities in mode of inheritance, nature of resistance, extremely tight linkage and lack of complementation between genetic factors have suggested that in some cultivars of Phaseolus vulgaris, a single major locus is responsible for resistance to four viruses: bean common
mosaic virus, cowpea aphid-borne mosaic virus, blackeye cowpea mosaic virus, and watermelon mosaic virus 2. In Phaseolus vulgaris, resistance to peanut mottle virus (PMV) was found to be conferred by a single, but partially dominant gene, to which the symbol Pmv was assigned. Screening for resistance to squash mosaic virus (SqMV) among plant introductions of Cucumis melo for several areas of the world yielded a few plants with tolerance to the squash strain, but none to the melon strain of the virus.
Impacts
(N/A)
Publications
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Progress 01/01/85 to 12/30/85
Outputs
In Pisum sativum resistance to clover yellow vein virus (CYVV) was determined tobe conferred by a single recessive gene (cyv). This gene appears to be closely linked to mo, the gene for resistance to bean yellow mosaic virus (BYMV). Also in P. sativum, resistance to the lentil strain of pea seed-borne mosaic virus (PSbMV-L) was determined to be monogenically recessive. The gene for resistance, sbm-2, is also closely linked to cyv and mo. Hence, breeding for resistance to these three viruses is a relatively simple task. Resistance to zucchini yellow mosaic virus (ZYMV) in line TMG-1 of Cucumis sativus from China was established to be governed by a single recessive gene (zyv). Resistance to ZYMV found in a Cucurbita moschata from Nigeria (Nigerian Local) has been transferred through interspecific hybridization and embryo culture to cultivars of summer squash (C. pepo). No resistance to ZYMV was detected in 418 plant introductions of C. maxima. ZYMV caused
devastating epidemics in squash grown in central and western New York State in 1985. This virus was also recovered from squash, melon, cucumber, and watermelon specimens received from 12 states. Strain ZYMV-FL appeared to be the most prevalent throughout the nation. Lettuce lines resistant to cucumber mosaic virus, strain 1 (CMV-L1) and to lettuce mosaic virus, have been developed in cooperation with the Department of Horticultural Sciences. These lines are very productive and will be used more extensively in the coming years.
Impacts
(N/A)
Publications
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