of all varieties of Citrus as well as other Rutaceae and some ornamental plants ( Heppner, 1993 ; Jacas et al., 1997 ; Pandey and Pandey, 1964 ). Larvae feed on the epidermal cell layer of developing leaves, producing a serpentine mine ( Belasque
Matthew L. Richardson, Catherine J. Westbrook, David G. Hall, Ed Stover, Yong Ping Duan, and Richard F. Lee
Catherine J. Westbrook, David G. Hall, Ed Stover, Yong Ping Duan, and Richard F. Lee
(Rutaceae: Aurantioideae) ( Bowman et al., 2001 ; Luthria et al., 1989 ; Yang and Tang, 1988 ), and it is possible that the Aurantioideae germplasm reservoir contains traits that confer specific resistance to D. citri . The Aurantioideae, one of seven
Mukadder Kayum, N. Kemal Koç, and Veli-Matti Rokka
Laser flow cytometry was used to analyze nuclear DNA contents (2C values) of five genera (Severinia Ten., Atalantia Corrèa, Fortunella Swing., Poncirus Raf., and Citrus L.) taxonomically grouped in subtribe Citrinae (citrus fruit trees) of the Rutaceae. The genotypes analyzed had 2C values ranging from 0.67 pg for diploid Severinia buxifolia (Poir.) Ten. to 1.27 pg for tetraploid Hongkong Fortunella hindsii Swing. There was no significant difference in the 2C values within the sexually compatible diploid species of 11 “true citrus fruit trees” [Citrus aurantium L., C. grandis (L.) Osbeck, C. limon (L.) Burm. f., C. limonia Osbeck, C. paradisi Macf., C. reshni Hort. ex Tanaka, C. sinensis (L.) Osbeck, C. volkameriana Ten. & Pasq., Poncirus trifoliata (L.) Raf., and the intergeneric hybrid C. sinensis × P. trifoliata]. The species Atalantia ceylanica (Arn.) Oliv. (a “near-citrus fruit tree”), sexually incompatible with Citrus spp., had a 2C value significantly different from those of the true citrus fruit tree species. The 2C value of Severinia buxifolia (a “primitive citrus fruit tree”), another species sexually incompatible with the Citrus spp., also differed from those of some of the true citrus fruit tree species. The data largely corresponds with taxonomical differences between a) the genera Citrus and Poncirus and b) the genera Severinia and Atalantia, all assigned to subtribe Citrinae.
Sharon Inch, Ed Stover, Randall Driggers, and Richard F. Lee
relatives are members of the family Rutaceae. The subtribe Citrinae is composed of Citrus (mandarins, oranges, pummelos, grapefruits, papedas, limes, lemons, citrons, and sour oranges); Poncirus (deciduous trifoliate oranges); Fortunella (kumquats
Godfrey P. Miles, Ed Stover, Chandrika Ramadugu, Manjunath L. Keremane, and Richard F. Lee
subfamily Aurantioideae, family Rutaceae, representing ≈85% of the genetic diversity within the UCR collection ( Barkley, 2003 ). Good germination was obtained from about 100 accessions, generating ≈886 seedlings. Information on the phylogenetic
Ed Stover, Randall Driggers, Matthew L. Richardson, David G. Hall, Yongping Duan, and Richard F. Lee
confidence that the same material or resulting half-sib seedlings can be obtained for future work. All material tested was in the family Rutaceae and we obtained additional seed from the subfamily Aurantioideae (which includes Citrus ), Afraegle paniculata
S. Kobayashi, I. Oiyama, K. Yoshinaga, T. Ohgawara, and S. Ishii
Kim D. Bowman, Jeffrey P. Shapiro, and Stephen L. Lapointe
Commercially used citrus rootstocks can all be seriously damaged by larvae of the sugar cane root weevil, Diaprepes abbreviatus (L.). Six greenhouse challenge experiments were used to compare the resistance of 24 selections of citrus rootstocks and related species to this weevil by measuring root damage, and larval growth and survival. The commercial rootstocks tested were found to be susceptible, while at least seven other species within the subfamily Aurantiodeae were observed to be significantly more resistant. The species Balsamocitrus dawei Stapf. was most resistant to weevil larvae, exhibited less root damage than commonly used rootstock cultivars, and significantly depressed larval growth and survival. The species Glycosmis pentaphylla (Retz.) Correa, Microcitrus australis (Planch.) Swing., Eremocitrus glauca (Lindl.) Swing., Severinia buxifolia (Poir.) Tenore, Triphasia trifolia (Burm. f.) P. Wils., and Citrus hystrix DC. suffered as much damage from the weevil as common rootstock cultivars but significantly depressed growth of larvae feeding on them. One new hybrid rootstock, HRS-801, also significantly depressed D. abbreviatus larval growth, but this effect has not yet been verified as having significance in a long-term or field situation. Several strategies are discussed for developing citrus rootstocks resistant to D. abbreviatus.
Brent Tisserat and Paul D. Galletta
Some cultivars of mandarin (Citrus reticulata Blanco), sweet orange [Citrus sinensis (L.) Osb.], and trifoliate orange [Poncirus trifoliata (L.) Raf.] were found to have adventitious juice vesicles originating from their exocarp (peel). Several hundred green vesicles may be initiated from curvilinear stylar peel depressions of immature fruit. These vesicles develop similarly to juice vesicles from the endocarp except that, as the fruit matures, exocarp adventitious vesicles die prematurely and degenerate into a fruit surface blemish. Evidence suggests that juice vesicles and oil glands are homologous and merit reconsideration in ontological studies.
Anna J. Talcott and William R. Graves
Ptelea trifoliata L. (Rutaceae) has been used as an ornamental shrub since the 18th century and has gained international favor in England and Scotland; however, it remains a rare choice among landscapers ( Harvey, 1981 ; Lancaster, 1995 ). Two