The interspecific and intergeneric relationships of eight species of Juglans (walnuts) and three other members of Juglandaceae were investigated. The following species were included: the American J. australis Griseb., J. neotropica Diels., J. olanchana Standl. et L.O. Williams, J. nigra L., and Carya illinoensis (Wang.) K. Koch.; two Juglans from South China, namely, J. sigillata Dode and an unidentified J. sp; an Engelhardia also from China and the Asian J. ailantifolia Carr., Pterocarya stenoptera var. tonkinensis Franchet and the Eurasian J. regia L. Cladistic analysis of 27 multistate morphological characters showed that the juvenile J. ailantifolia possessed similar physical traits to that of the juvenile American Juglans species. The chloroplast DNA in the trnL-trnF region indicated a close relationship between Juglans species. Pterocarya put the root of the cpDNA network among the American species. RAPD analysis was performed using eight primers. A total of 138 fragments were generated but only 78 clearly defined bands were used in the analysis. All the DNA data grouped the tropical/subtropical American Juglans with J. nigra, and the two new Asian species with J. ailantifolia and J. regia. The American species were closely related, more so than their Asian counter parts. The closeness of the investigated species predicts interspecific graft compatibility not only within the Asian and American groups, but also between them.
G. Orel, A.D. Marchant, J.A. McLeod, and G.D. Richards
M.E. Ostry and P.M. Pijut
Butternut (Juglans cinerea L.) has many fine qualities as a nut species, however, it has never been commercially important. Although the nut is very edible, only a few cultivars have been selected that have desirable nut size and cracking qualities. In the last 20 years there has been a dramatic decline in the number of butternut in native stands caused to a large extent by the lack of natural reproduction and a damaging canker disease. Evidence suggests that superior, disease resistant trees can be propagated and if isolated from areas where the disease is prevalent, may remain disease-free. It is important that the remaining genetic diversity within the species is maintained. Various butternut conservation practices and research projects to restore butternut populations are underway in the United States and Canada.
Daniel Potter, Fangyou Gao, Giovanna Aiello, Charles Leslie, and Gale McGranahan
The utility of intersimple sequence repeat (ISSR) markers for identification of English or Persian walnut (Juglans regia L.) cultivars was explored. Four cultivars were screened with 47 ISSR primers; eight of these primers, which generated reproducible and informative data, were selected for further study. Two individuals from each of 48 cultivars, including many currently important in the California walnut industry as well as accessions from Europe and Asia, were then examined with the eight ISSR primers. Polymerase chain reaction (PCR) products were separated on agarose gels and stained with ethidium bromide. Fifty-four bands were scored as present or absent in each cultivar; of these, 31 (57%) were polymorphic among the 48 cultivars. Combined data from the eight ISSR primers provided a unique fingerprint for each of the cultivars tested. Fifteen of the cultivars could be distinguished from all others with just one primer, 31 with a minimum of two primers, and two required three primers. Pairwise genetic distances between the cultivars were calculated and a dendrogram was generated using the neighbor-joining algorithm. Some of the groupings in the dendrogram corresponded to groups which, based on known pedigrees, are genealogically closely related. Others included accessions from diverse genetic and/or geographic origins. These results can be attributed to a combination of the limitations of the ISSR method for inferring genetic relationships, on the one hand, and the complex history of walnut cultivar development involving extensive exchange and breeding of germplasm from different geographic regions, on the other.
Sudheer Beedanagari* and Patrick Conner
Pecan, [Carya illinoinensis (Wangenh.) C. Koch], is a member of Juglandaceae family and is one of the most important nut crops produced in the United States. The objective of this study is to generate the first genetic linkage maps for pecan. Maps were constructed for the cultivars `Elliot' and `Pawnee' using the double pseudo-testcross mapping method whereby a separate linkage map is made for each parent using markers heterozygous in that parent. First generation maps consisted primarily of randomly amplified polymorphic DNA (RAPD) markers. We have now used fluorescently labeled amplified fragment length polymorphism (AFLP) markers to produce more complete maps. In the development of the AFLP markers, 64 primer combinations were originally screened to find the most informative combinations. Ten primer combinations were then chosen to produce markers for the maps. The maps currently consist of approximately 100 RAPD and 100 AFLP markers on each cultivar map. `Pawnee' is a high quality commercial pecan cultivar with a very early ripening date. `Elliot' possesses high levels of resistance to pecan scab, caused by the fungus Cladosporium caryigenum. The maps will be used to find markers linked to scab resistance genes and other traits of interest to the breeding program.
Juglans regia L. is typical of Juglandaceae in that it is monoecious, wind-pollinated, and self-compatible. Despite its self-compatibility, breeding and research programs have encountered difficulties acquiring sufficient quantities of pollen
Anita Solar, Robert Veberic, and Franci Stampar
shoots in Juglans regia (Juglandaceae) related to fruiting habit and environmental conditions Austral. J. Bot. 58 141 148 Solar, A. Ivančič, A. Štampar, F. Morphometric characteristics of fruit bearing shoots in Persian walnut ( Juglans regia L
Maria Florencia Babuin, Mariela Echeverria, Ana Bernardina Menendez, and Santiago Javier Maiale
). Therefore, it becomes relevant to find methods for increasing drought-tolerance to improve pecan implantation in the field. Species within the Juglandaceae are thought to be ectomycorrhizal ( Wang and Qiu, 2006 ). Moreover, under field conditions, pecans
Rohollah Karimi, Ahmad Ershadi, Kourosh Vahdati, and Keith Woeste
The family Juglandaceae consists of seven genera, comprising ≈60 monoecious tree species. The genus Juglans contains 20 species, all producing edible nuts. Among these, the English or Persian walnut ( Juglans regia ) is the most widely cultivated
Zhan Shu, Xue Zhang, Dianqiong Yu, Sijia Xue, and Hua Wang
and J. sigillata ; Juglandaceae): Species distinctions, human impacts, and the conservation of agrobiodiversity in Yunnan, China Amer. J. Bot. 97 660 671 Hoban, S. McCleary, T. Schlarbaum, S. Romero-Severson, J. 2009 Geographically extensive
Bruce W. Wood and Larry J. Grauke
(Juglandaceae) ( Manos and Stone, 2001 ) ( Table 1 ). Species differ in not only morphology and habitat, but also in ploidy (i.e., 2 n = 32 vs. 64) with Apocarya section species being diploid (100% of species) and Carya section species being either diploid (40