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  • Author or Editor: O. Gulsen x
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Chloroplast DNA (cpDNA) restriction fragment length polymorphisms were used to study the parentage of lemons [Citrus limon (L.) Burm. f.] and several other putative hybrids. The 30 citrus accessions studied included nine lemons, three pummelos [C. maxima (Burm.) Merrill], three citrons (C. medica L.), three mandarins (C. reticulata Blanco, C. clementina Hort. Ex. Y. Tan., and C. sunki Hort. ex. Tan.), and single representatives of 13 other taxa. Four different fragments of citrus cpDNA were amplified by polymerase chain reaction using four universal chloroplast primers and amplification products were digested with four endonucleases, Rsa I, Dra I, Hae III, and Mbo I. A total of 104 different restriction fragments were scored and used for phylogenetic analysis by parsimony. The three taxa which have been proposed as ancestral Citrus L. sp., C. medica, C. maxima, and C. reticulata, had distinct cpDNA patterns. Pummelo contributed the chloroplast genome to lemons, sweet orange [C. sinensis (L.) Osbeck], and Bergamot orange (C. bergamia Risso and Poit.), and mandarin contributed the chloroplast genome to rough lemons (C. jambhiri Lush.), Rangpur lime (C. limonia Osbeck), and `Mexican' lime [C. aurantifolia (Christm.) Swing.]. Data suggest that the particular accessions of these ancestral species that were studied were not directly involved in the hybridization events that created these hybrids, since they have similar but not identical cpDNA restriction fragments. Using inter-simple sequence repeat markers that amplified from nuclear genomic DNA, a set of samples including pummelos, citrons, mandarins, sour oranges (C. aurantium L.), and `Samuyao' papeda (C. micrantha Wester) were tested as possible parents of lemons. Sour orange and citron together had all nuclear and chloroplast fragments found in lemon and are therefore proposed to be the maternal and paternal parents, respectively, of many commercial lemon cultivars, including `Lisbon', `Eureka', `Villafranca', and `Monachello'.

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Inter-simple sequence repeats (ISSR), simple sequence repeats (SSR) and isozymes were used to measure genetic diversity and phylogenetic relationships among 95 Citrus L. accessions including 57 lemons [C. limon (L.) Burm. f.], related taxa, and three proposed ancestral species, C. maxima (Burm.) Merrill (pummelo), C. medica L. (citron), and C. reticulata Blanco (mandarin). The ancestry of lemons and several other suspected hybrids was also studied. Five isozyme and five SSR loci revealed relatively little variation among most lemons, but a high level of variation among the relatively distant Citrus taxa. Eight ISSR primers amplified a total of 103 polymorphic fragments among the 83 accessions. Similarity matrices were calculated and phylogenetic trees derived using unweighted pair-group method, arithmetic average cluster analysis. All lemons, rough lemons, and sweet lemons, as well as some other suspected hybrids, clustered with citrons. Most lemons (68%) had nearly identical marker phenotypes, suggesting they originated from a single clonal parent via a series of mutations. Citrons contributed the largest part of the lemon genome and a major part of the genomes of rough lemons, sweet lemons, and sweet limes. Bands that characterize C. reticulata and C. maxima were detected in lemons, suggesting that these taxa also contributed to the pedigree of lemon.

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Warm-season turfgrasses are grown throughout the warm humid, sub-humid, and semiarid regions. The objective of this study was to determine the adaptation of six warm-season turfgrass species and several of their cultivars to Mediterranean growing conditions of Turkey by evaluating turfgrass establishment rate, quality, color, and percentage of turfgrass cover. Information of this nature is lacking and would be helpful to turfgrass managers and advisers working in the region. A study was conducted over a 2-year period in two locations of the Mediterranean region of Turkey. The warm-season turfgrass species studied were bermudagrass (Cynodon dactylon), buffalograss (Buchloë dactyloides), zoysiagrass (Zoysia japonica), bahiagrass (Paspalum notatum), seashore paspalum (Paspalum vaginatum), and centipedegrass (Eremochloa ophiurioides). Tall fescue (Festuca arundinacea) was included as a cool-season turfgrass species for comparison. Twenty cultivars belonging to these species were evaluated for their establishment, turfgrass color and quality, spring green-up, and fall color retention. Bermudagrass, bahiagrass, and seashore paspalum established 95% or better coverage at 1095 growing degree days [GDD (5 °C base temperature)], buffalograss and centipedegrass at 1436 GDD, and ‘Zenith’ and ‘Companion’ Zoysiagrass had 90% and 84% coverage at Antalya after accumulating 2031 GDD. ‘Sea Spray’ seashore paspalum; ‘SWI-1044’, ‘SWI-1045’, ‘Princess 77’, and ‘Riviera’ bermudagrass; ‘Cody’ buffalograss; and ‘Zenith’ zoysiagrass exhibited acceptable turfgrass quality for 7 months throughout the growing season. ‘Argentine’ and ‘Pensacola’ bahiagrass; ‘Sea Spray’ seashore paspalum; and ‘SWI-1044’ and ‘SWI-1045’ bermudagrass extended their growing season by retaining their green color 15 days or longer than the rest of the warm-season cultivars and/or species in the fall. The warm-season species stayed fully dormant throughout January and February. Zoysiagrass and buffalograss cultivars showed early spring green-up compared to the other warm-season species studied. Results from this study support the use of warm-season turfgrass species in this Mediterranean region, especially when heat stress and water limitations exist. Tall fescue did not survive summer heat stress necessitating reseeding in fall.

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Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] has the potential for increased use as a turfgrass species due to its low maintenance and water conservation characteristics. This study was conducted to estimate diversity and relationships among naturally occurring buffalograss genotypes based on the nuclear genome, using sequence-related amplified polymorphism (SRAP) markers. The 56 genotypes studied represented five ploidy levels collected from diverse geographic locations in the North American Great Plains. In addition, blue grama [Bouteloua gracilis (H.B.K.) Lag. Ex Steud.] and perennial ryegrass (Lolium perenne L.) were included as outgroups. Twenty-five combinations of forward and reverse primers were used. Ninety-five intensively amplified markers were scored and used to infer diversity and relationships among the genotypes. All buffalograss genotypes were discriminated from each other with similarity values ranging from 0.70 to 0.95. Principal component analysis (PCA) suggested that the 56 genotypes could be reduced to 50 due to high similarity levels among some of the genotypes. The distance between buffalograsses, blue grama, and perennial ryegrass were consistent with current taxonomical distances. This research indicates that SRAP markers can be used to estimate genetic diversity and relationships among naturally occurring buffalograss genotypes.

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