Disease Resistance and Yields of Transgenic and Traditional Summer Squash

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534c-534
Author(s):  
Brent Rowell ◽  
William Nesmith ◽  
John C. Snyder

Kentucky vegetable growers exploiting a fall-harvested market window for summer squash (Cucurbita pepo L.) usually encounter severe virus and fungal disease pressure resulting in serious yield and quality reductions. Twenty-five summer squash varieties or advanced breeding lines (9 zucchini, 8 yellow straightneck, and 8 crookneck entries) were evaluated in a late summer planting for yield, quality, and disease resistance at the Univ. of Kentucky South Farm in Lexington. Both genetically engineered virus-resistant materials and new resistant/tolerant varieties from traditional breeding programs were compared with our recommended hybrids. Border rows of a virus-susceptible variety were planted alongside and between each of the four blocks to enhance virus spread throughout the trial. Virus incidence was determined visually before and after final harvest and leaf samples were collected for virus assays. Virus symptoms were absent or difficult to see on zucchini squash plants during most of the trial but became obvious near the final harvest date. Varieties from traditional breeding programs having virus tolerance were among the highest yielding zucchini types. Traditionally-bred cultivars with the precocious yellow gene and two transgenic lines were in the highest yielding group of yellow straightneck squash—in spite of high virus incidences in precocious yellow cultivars. Transgenic cultivars were clearly superior in terms of yields among yellow crooknecks with yields nearly double those of the lowest yielding traditional hybrids. Cultivars and breeding lines varied considerably in color, shape, overall appearance, and potential marketability.

1999 ◽  
Vol 9 (2) ◽  
pp. 282-288 ◽  
Author(s):  
Brent Rowell ◽  
William Nesmith ◽  
John C. Snyder

Virus and fungal disease pressures limit fall production of summer squash (Cucurbita pepo L.) in Kentucky. Twenty-five summer squash cultivars (nine zucchini, eight yellow straightneck, and eight yellow crookneck entries) were evaluated for marketable yield, appearance, and disease resistance in a late summer planting. Genetically engineered virus-resistant materials and new conventionally bred resistant or tolerant cultivars were compared with popular susceptible hybrids. Virus incidence was determined visually before and after final harvest and was also determined by enzyme-linked immunosorbent assay (ELISA). Watermelon mosaic virus (WMV) was most frequently detected and appeared to have caused most of the observed symptoms. Conventionally bred cultivars containing the precocious yellow gene and two transgenic lines were in the highest yielding group of yellow straightneck squash despite high virus incidence in precocious yellow cultivars. Among yellow crooknecks, transgenic cultivars were clearly superior for disease resistance and yields. Conventionally bred cultivars with virus tolerance were among the highest yielding zucchini types. Most transgenics were superior to their nontransformed equivalent cultivars for virus resistance and yield. Cultivars and breeding lines varied considerably in color, shape, and overall appearance. ELISA results revealed that some (but not all) transgenic cultivars tested positive for the coat protein corresponding to the virus resistance present in that cultivar. Also, mild virus-like symptoms were observed in transgenic squash plants after the conclusion of harvest.


1996 ◽  
Vol 47 (1) ◽  
pp. 1 ◽  
Author(s):  
LDJ Penrose ◽  
M Mosaad ◽  
TS Payne ◽  
G Ortiz-Ferrara ◽  
HJ Braun

This study sought to compare developmental controls in breeding a within two winter wheat improvement programs, one Australian and a CIMMYT/ICARDA program based in West Asia. Developmental controls considered were intrinsic earliness, and responses to photoperiod and to vernalization. The reliability with which each control on development had been measured was tested in separate experiments using the wheats utilized in the Australian program. Measures of intrinsic earliness showed significant agreement between experiments, better agreement being found for response to photoperiod and between integrated response to vernalization and time to double ridge after late summer sowings. The wheats utilized in the CIMMYTI/CARDA programs were found to be quick in intrinsic earliness, and to possess little response to photoperiod. While these controls varied more for the wheats utilized in the Australian program, commercial Australian winter wheats were similar to the CIMMYTI/CARDA lines. Lines utilized by both programs were represented by types with spring, facultative and winter habit. The clearest differences between programs were that CIMMYTI/CARDA winter wheats appeared to have much stronger response to vernalization than the Australian winter wheats. These findings suggest breeders would find a good proportion of segregates, from crosses between the Australian and the CIMMYTI/CARDA winter wheats, to be developmentally adapted to south-central New South Wales. This suggests CIMMYTI/CARDA winter wheats provide a matching pool from which to access germplasm to introduce new characters into Australian winter wheats.


HortScience ◽  
1996 ◽  
Vol 31 (3) ◽  
pp. 439-442 ◽  
Author(s):  
Michael P. Hoffmann ◽  
Richard W. Robinson ◽  
Margaret M. Kyle ◽  
Jonathan J. Kirkwyland

Seventy-six Cucurbita pepo L. cultivars and breeding lines were evaluated under field conditions for infestation levels and defoliation (leaf area consumed by beetles) by adult diabroticite beetles in 1992 and 1994. Striped and spotted cucumber beetles, Acalymma vittatum (F.) and Diabrotica undecimpunctata howardi Barber, respectively, were most common, but some western and northern corn rootworms, D. virgifera virgifera LeConte and D. barberi Smith and Lawrence, respectively, also were present. In general, pumpkin, delicata, acorn winter squash, scallop, and yellow straightneck summer squash types were the least infested and defoliated. Caserta/yellow, zucchini, caserta/zucchini, caserta, and precocious yellow straightneck types were the most infested and defoliated. The number of beetles per plant was correlated (r ≥ 0.72) with leaf defoliation and proportion of plants infested, indicating that beetle infestation is a good predictor of damage. The cultivars and breeding lines that were the least infested and defoliated can be used in breeding programs to develop desirable genotypes with reduced beetle preference. Conversely, those genotypes that were highly preferred have potential as trap crops for these beetle pests.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Valliappan Karuppiah ◽  
Lu Zhixiang ◽  
Hongyi Liu ◽  
Murugappan Vallikkannu ◽  
Jie Chen

Abstract Background Retention of agricultural bio-mass residues without proper treatment could affect the subsequent plant growth. In the present investigation, the co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens has been employed for multiple benefits including the enrichment of lignocellulose biodegradation, plant growth, defense potential and disease resistance. Results The Vel1 gene predominantly regulates the secondary metabolites, sexual and asexual development as well as cellulases and polysaccharide hydrolases productions. Overexpression mutant of the Trichoderma asperellum Vel1 locus (TA OE-Vel1) enhanced the activity of FPAase, CMCase, PNPCase, PNPGase, xylanase I, and xylanase II through the regulation of transcription regulating factors and the activation of cellulase and xylanase encoding genes. Further, these genes were induced upon co-cultivation with Bacillus amyloliquefaciens (BA). The co-culture of TA OE-Vel1 + BA produced the best composition of enzymes and the highest biomass hydrolysis yield of 89.56 ± 0.61%. The co-culture of TA OE-Vel1 + BA increased the corn stover degradation by the secretion of cellulolytic enzymes and maintained the C/N ratio of the corn stover amended soil. Moreover, the TA OE-Vel1 + BA increased the maize plant growth, expression of defense gene and disease resistance against Fusarium verticillioides and Cohilohorus herostrophus. Conclusion The co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens could be utilized as a profound and meaningful technique for the retention of agro residues and subsequent plant growth.


Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
Author(s):  
S. K. Gremillion ◽  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
B. G. Mullinix ◽  
R. N. Pittman ◽  
...  

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.


1999 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
A. K. Culbreath ◽  
J. W. Todd ◽  
D. W. Gorbet ◽  
S. L. Brown ◽  
J. A. Baldwin ◽  
...  

Abstract Epidemics of tomato spotted wilt, caused by tomato spotted wilt Tospovirus (TSWV), were monitored in field plots of runner-type peanut (Arachis hypogaea L.) cultivars Georgia Green and Georgia Runner and numerous breeding lines from four different breeding programs as part of efforts toward characterizing breeding lines with potential for release as cultivars. Breeding lines were divided into early, medium and late maturity groups. The tests were conducted near Attapulgus, GA and Marianna, FL in 1997 and in Tifton, GA and Marianna, FL in 1998. Epidemics in some early and medium maturing breeding lines, including some genotypes with high oleic acid oil chemistry, were comparable to those in Georgia Green, the cultivar most frequently used in the southeastern U.S. for suppression of spotted wilt epidemics. No early maturing breeding lines had lower spotted wilt final intensity ratings or higher yields than Georgia Green. However, spotted wilt intensity ratings in some late maturing lines and a smaller number of medium maturing lines were significantly lower than those of Georgia Green. Several of those lines also produced greater pod yields than Georgia Green. Results from these experiments indicated that there is potential for improving management of spotted wilt though development of cultivars that suppress spotted wilt epidemics more than currently available cultivars. There was no indication that differences in spotted wilt ratings corresponded to differences in numbers of thrips adults or larvae.


2015 ◽  
Vol 2 ◽  
pp. 81 ◽  
Author(s):  
Gilberto Antonio Peripolli Bevilaqua ◽  
Iraja Ferreira Antunes

The common bean has been object of breeding programs aiming the development of new cultivars adapted to varied production system and shown differentiated nutritional characteristics. Due a genetic diversity existent the landraces can be used directly for cropping, for present characteristics desirable. Little information exists about mineral content and other quality traits for those bean landraces. The aim of this paper was to verify the variability for grain nutricional caracters in breeding cultivars and landraces of bean from Rio Grande do Sul state, Brazil. The experiment was conducted in 2009/2010 in Experimental Station Cascata, of Embrapa Temperate Agriculture. In whole grain of 54 bean genotypes with black and no black coat were determined macroelements (nitrogen, phosphorus, potash, calcium, magnesium and sulfur), oligoelements (iron, manganese, zinc and cuprum), protein and ash content, insoluble fiber, digestive nutrient and antioxidant astragalina. The results shown that the landraces varieties presents nutritional composition of macro and oligoelements, fibers, protein and ash contents in whole grain similar than that of breeding lines and cultivars. The black coat grain from breeding programs showed better nutritional quality for macro and oligoelements content than coloured grain, highlighting TB 02-04 e TB 01-01. The landraces with coloured grains TB 02-26, TB 02-24 and TB 03-13 showed the high levels of astragaline.


2021 ◽  
Vol 47 (2) ◽  
pp. 103-109
Author(s):  
João Alberto Zago Bevenuto ◽  
José Raimundo de Souza Passos ◽  
Edson Luiz Furtado

ABSTRACT The major phytosanitary problem for rubber tree cultivation in Brazil is the disease known as South American leaf blight, caused by the fungus Microcyclus ulei. Its symptoms manifest in young leaves and cause intense defoliation, resulting in reduced latex production and even the death of susceptible plants. Thus, this disease consists in a constant threat to East Asian plantations. As worldwide traditional breeding programs have evolved, interspecific hybrid clones have currently been used for planting. They are more productive and show better resistance to pathogens. However, traditional breeding programs have not led to significant progress in resistance to South American leaf blight since the selection is directed to clones with complete resistance. In this pathosystem, horizontal or partial resistance (HR) and vertical or complete resistance (VR) can act simultaneously, evidencing their complexity and difficult quantification. This study aimed to: characterize the foliar lesion type in Hevea sp. X M. ulei pathosystem; verify the clonal susceptibility to pathogens; analyze the infection frequency for resistance quantification in Hevea sp. x M. ulei pathosystem, and recommend differentiating rubber tree clones to quantify M. ulei races in Brazil. The monocyclic parameters (latent period and lesion diameter) are applicable for resistance quantification in Hevea sp. x M. ulei pathosystem. Latent period had slight variation among clones. Lesion diameter had wide variation among clones and was a discriminating parameter for horizontal resistance and vertical resistance.


2008 ◽  
Vol 35 (2) ◽  
pp. 81-85 ◽  
Author(s):  
S. P. Tallury ◽  
H. E. Pattee ◽  
T. G. Isleib ◽  
H. T. Stalker

Abstract Several diploid wild species of the genus Arachis L. have been used as sources of resistance to common diseases of cultivated peanut (Arachis hypogaea L.). Because flavor is among the most important quality attributes for commercial acceptance of roasted peanuts, sensory attributes of interspecific hybrid derived breeding lines were evaluated to determine if transfer of disease resistance from wild species is associated with concomitant changes in flavor. Sixteen interspecific hybrid derivatives with five diploid species in their ancestries and the commercial flavor standard, NC 7 were evaluated for sensory quality. Significant variation among entries was found for the roasted peanut, sweet, and bitter sensory attributes, but not for the overall contrast between NC 7 and the wild species-derived breeding lines. The variation was either between two groups of wild species-derived breeding lines or within one or both groups. Introduction of disease and pest resistance traits from Arachis species did not result in degradation or improvement of the flavor profile. This suggests that flavor of wild species-derived germplasm will not prevent its use either as parents in peanut breeding programs or as cultivars.


Sign in / Sign up

Export Citation Format

Share Document