`Chandler' pummelo [Citrus maxima (Burm.) Merrill] was found to be citrus tristeza virus (CTV)–resistant. The inheritance of this resistance in 84 progeny of two crosses derived from `Chandler' pummelo and trifoliate orange [Poncirus trifoliata (L.) Raf.] was controlled by a single dominant gene designated Ctv2. Progeny analysis of four molecular markers closely linked to the Ctv gene, which confers resistance to CTV in trifoliate orange, demonstrated that Ctv2 was an independently assorting gene from Ctv.
D.Q. Fang and M.L. Roose
Mikeal L. Roose, Claire T. Federici, and Gregory P. Copenhaver
To assess genetic diversity in the UC Riverside Citrus Variety Collection, all accessions of pummelo (59), citron (24), and trifoliate orange (48) were studied for RFLP variation using 11-18 cDNA probes that had previously been shown to reveal polymorphism in a broad range of citrus germplasm. Inheritance studies have shown that these probes hybridize to at least 20 loci. The taxa studied are believed to represent biological species rather than hybrids. Citrons were nearly monomorphic and most appeared homozygous at all of the loci studied. Pummelos were very polymorphic and highly heterozygous. Trifoliate orange, an important source of disease resistance in rootstock breeding, was nearly monomorphic but moderately heterozygous (17% of loci). Most accessions of trifoliate orange have evidently differentiated only by mutation. One multilocus probe separated trifoliate orange accessions into 3 groups. Two new trifoliate orange accessions had novel alleles at some loci. The use of genetic markers to recognize hybrid accessions classified as members of species will be discussed.
Yuan Yu, Chunxian Chen, Ming Huang, Qibin Yu, Dongliang Du, Matthew R. Mattia, and Frederick G. Gmitter Jr.
genetic relationships between C. sinensis , C. aurantium , and Citrus clementina with C. maxima and C. reticulata ( Wu et al., 2014 , 2018 ; Xu et al., 2013 ). The phylogenetic origin of some secondary species and important citrus cultivars
Andrew K. Miles, Malcolm W. Smith, Nga T. Tran, Timothy A. Shuey, Megan M. Dewdney, and André Drenth
Blanco; C. maxima ; C. medica L.; and C. micrantha Wester and Fortunella spp. ( Wu et al., 2018 ). An understanding of these genetic relationships is important in the development of genetic solutions to CBS because disease-resistant citrus types
Ed Stover, Randall Driggers, Matthew L. Richardson, David G. Hall, Yongping Duan, and Richard F. Lee
also indicated that the one C. maxima accession tested displayed no ACC symptoms ( Sarkar et al., 2007 ). These discrepancies may reflect diversity in Citrus germplasm or diversity of Xcc strains resulting in marked strain × genotype interactions
Lynn Jo Pillitteri, Carol J. Lovatt, and Linda L. Walling
2 Professor of Plant Physiology. 3 Professor of Genetics. The authors thank Drs. Mikeal Roose and Claire Federici (UC Riverside) for isolating and providing C. maxima `Chandler' DNA and for their thoughtful discussions. Virginia Alonzo isolated
citrus types are citron ( C. medica ), pummelo ( C. maxima ), and mandarin ( C. reticulata ). This argument was made four decades ago by several scholars ( Barrett and Rhodes, 1976 ; Scora, 1975 ) based on morphological and biochemical characteristics
Atsu Yamasaki, Akira Kitajima, Norihiro Ohara, Mitsutoshi Tanaka, and Kojiro Hasegawa
to ovules per fruit were 23.1% to 67.4%, indicating that these are seedy cultivars and lines. Table 1. Fruit weight and number of seeds, ovules, and locules in BSY lines [hybrid seedlings of ‘Southern Yellow’ ( Citrus maxima ‘Tanikawa Buntan
Yiran Li, Akiha Abe, Takuichi Fuse, Tomonari Hirano, Yoichiro Hoshino, and Hisato Kunitake
only observed in the SI-like treatment ( Fig. 1B ), we focused on these proteins as candidates for SI-related proteins. Table 3. Result of protein identification in Citrus maxima ‘Banpeiyu’ pollen tubes exposed to compatible (C)-like treatment. Table
Sharon Inch, Ed Stover, Randall Driggers, and Richard F. Lee
from 4% to 40% dieback. Within the groups of the genus Citrus , several parent genotypes had less than 25% dieback and included C. reticulata (CRC 2590), C. sinensis (CRC 3858), C. maxima (CRC 3945), C. hassaku (CRC 3907 and 3942), C