Contemporary Approaches to Improving Citrus Cultivars

Gmitter, Frederick G.

doi:10.21273/horttech.4.3.206

Cited by 6 publications

(4 citation statements)

References 20 publications

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“…Through sexual hybridization, trifoliate orange (Poncirus trifoliata [L.] Raf.) has been used successfully to develop several adaptable rootstocks, although it is practically difficult to breed improved scions mostly because of high heterozygosity and long juvenility and large tree size (Soost and Cameron 1975;Cameron and Soost 1984;Gmitter 1994). Table 1 lists mapping populations worldwide that have been used to develop genetic maps for genomes, genes, and quantitative trait loci (QTLs) in citrus.…”

Section: Introductionmentioning

confidence: 99%

EST-SSR genetic maps for Citrus sinensis and Poncirus trifoliata

Chen

Bowman

Choi

et al. 2007

Tree Genetics & Genomes

122

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The segregation of 141 polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers in an F1 intergeneric citrus population was studied to build the first extensive EST maps for the maternal sweet orange and paternal Poncirus genomes. Of these markers, 122 were found segregating in sweet orange, 59 in Poncirus, and 40 in both. Eleven linkage groups with 113 markers in sweet orange, 8 with 45 markers in Poncirus, and 13 with 123 markers in the cross pollinator (CP) consensus of both, were constructed. About 775.8 cM of sweet orange genome and 425.7 cM of Poncirus genome were covered. Through comparison of shared markers, three cases were found where two linkage groups in one map apparently were colinear with one group of the other map; Poncirus linkages Ar1a and Ar1b and consensus linkages CP1a and CP1b, were both collinear with one sweet orange linkage, Sa1, as were sweet orange Sa3a and Sa3b with Poncirus Ar3 and consensus CP3, and sweet orange Sa7a and Sa7b, and consensus CP7a and CP7b with Poncirus Ar7. These EST-SSR markers are particularly useful for constructing comparative framework maps for related genera because they amplify orthologous genes to provide anchor points across taxa. All SSR primers are freely available to the citrus community.

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Section: Introductionmentioning

confidence: 99%

EST-SSR genetic maps for Citrus sinensis and Poncirus trifoliata

Chen

Bowman

Choi

et al. 2007

Tree Genetics & Genomes

122

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“…Only one parental genotype with Poncirus in its pedigree (CRC3552) showed more than 14% dieback, and two parental genotypes that were Poncirus • cultivated Citrus displayed only 4% dieback. Poncirus and Citrus are sexually and graft-compatible (Gmitter, 1994;Sanghera et al, 2011). Poncirus has been used in many intergeneric crosses to increase cold tolerance, although the fruit of Poncirus itself is inedible (Barrett, 1990;Gmitter, 1994;Tignor et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…Poncirus and Citrus are sexually and graft-compatible (Gmitter, 1994;Sanghera et al, 2011). Poncirus has been used in many intergeneric crosses to increase cold tolerance, although the fruit of Poncirus itself is inedible (Barrett, 1990;Gmitter, 1994;Tignor et al, 1998). The USDA citrus breeding program has been using Poncirus in some hybridizations for many years, specifically to enhance cold-hardiness (Barrett and Young, 1982;Tignor et al, 1998) and many advanced selections now include Poncirus in their pedigree, although so far none has been released as cultivars.…”

Section: Discussionmentioning

confidence: 99%

Freeze Response of Citrus and Citrus-related Genotypes in a Florida Field Planting

Inch¹,

Stover²,

Driggers³

et al. 2014

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A test population consisting of progenies of 92 seed-source genotypes (hereafter called “parent genotypes”) of Citrus and Citrus relatives in the field in east–central Florida was assessed after natural freeze events in the winters of 2010 and 2011. Eight seedlings per parent genotype were planted in a randomized complete block design; however, as a result of mortality, the number of plants assessed in some genotype groups was reduced at some or all sampling dates. The citrus diseases huanglongbing and citrus canker were endemic in the planting and may have influenced tree response to cold temperatures. Unusually low temperatures (near –4 °C each winter) for east–central Florida were experienced during the trial period. Defoliation and dieback were significantly greater in the winter of 2011 than in the winter of 2010. The winter in 2011 was preceded by a period of extraordinarily low temperatures in mid-December with no period of cool temperatures to allow trees to acclimate. In 2010 the average defoliation was 53% ± 28% and less than 13% of the trees exhibited any noticeable dieback, whereas in 2011, the average defoliation and dieback were 93% ± 17% and 51% ± 35%, respectively. Within the genus Citrus, several progenies were identified that had 16% to 24% dieback in 2011 and these were from parent genotypes C. reticulata (CRC 2590) (23%), C. sinensis (CRC 3858) (24%), C. maxima (CRC 3945) (16%), C. hassaku (CRC 3907 and 3942) (16% and 17%), C. aurantium (CRC 628 and 2717) (18% and 7%), C. taiwanica (CRC 2588) (21%), and C. neo-aurantium (C. obovoidea + C. unshiu graft chimera) (CRC 3816) (23%). Within other genera in the Aurantiodeae, Poncirus trifoliata (CRCs 301, 3957, 3549, and 4007), Severinia buxifolia (CRC 1497), Bergera koenigii (CRC 3165), and Glycosmis pentaphylla (CRC 3285) had the least amount of dieback, all at less than 23%. The two species within the Toddalioideae subfamily of the Rutaceae (Casimiroa edulis and Zanthoxylum ailanthoides) had among the least amount of dieback (1% and 8%, respectively). When considered by groups, the Citrons and Australian natives had the greatest amount of dieback in 2011, 68% and 65%, respectively. The trifoliates (Poncirus and hybrids) had the least dieback, ranging from 4% to 40%. The information from this study may be useful in germplasm enhancement and Citrus breeding targeting greater cold tolerance.

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“…Genetic transformation has become the most attractive alternative method for improving existing grapefruit cultivars (and other citrus), as it allows the introduction of one or two specific traits while maintaining cultivar integrity (Gmitter, 1994;Bond and Roose, 1998). The first reports of citrus transformation began to appear more than a decade ago, utilizing protoplasts (Kobayashi and Uchimiya, 1989;Vardi et al, 1990;Hidaka and Omura, 1993), and Agrobacterium-mediated transformation of citrus cells (Hidaka et al, 1990) and stem segments (Moore et al, 1992), and finally particle bombardment of citrus cells (Kayim et al, 1996;Yao et al, 1996) with low transformation efficiency.…”

Section: Grapefruit Variety Improvementmentioning

confidence: 99%

Grapefruit

Grosser

Gmitter

Orbović

et al. 2008

Compendium of Transgenic Crop Plants

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This chapter summarizes the status of genetic transformation research to improve grapefruit. The chapter begins describing the history, origin, distribution and uses of grapefruit, followed by a discussion of the threats to grapefruit production, and finally a review of efforts to date in grapefruit variety improvement. Agrobacterium ‐mediated genetic transformation has become the primary method for improving existing cultivars of grapefruit, and extensive protocols for achieving this as well as information regarding the characterization of resulting transgenic plants are provided. The chapter also provides a detailed review of transgenic grapefruit plants produced to date, with focus on transformation with the various transgenes used for specific trait improvement. These include transformation with: virus‐derived genes for citrus tristeza resistance; trifoliate orange derived genes for tristeza resistance; virus‐derived genes for Citrus psororis virus resistance; spinach defensin (SoD2) and bovine lysozyme (BVLZ) antimicrobial genes for citrus canker resistance; and biosynthetic genes from the carotenoid biosynthetic pathway for fruit quality improvement. Finally, preliminary information on the field evaluation of transgenic grapefruit trees in southern Texas is provided.

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Contemporary Approaches to Improving Citrus Cultivars

Cited by 6 publications

References 20 publications

EST-SSR genetic maps for Citrus sinensis and Poncirus trifoliata

EST-SSR genetic maps for Citrus sinensis and Poncirus trifoliata

Freeze Response of Citrus and Citrus-related Genotypes in a Florida Field Planting

Grapefruit

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