Phytophthora cinnamomi, the causal agent of Phytophthora Root Rot (PRR) of avocado, is the most serious disease of avocado worldwide. The development of tolerant rootstocks to control PRR has proven to be an effective means to control the disease. However, using traditional breeding approaches can take over a decade to produce results and there has been a limited use to integrate molecular data into breeding efforts. Therefore, the objective of this work was to use amplified fragment length polymorphism (AFLP) to genetically characterize greenhouse selected PRR tolerant rootstocks, some that had been field-tested and others that had not. Sixty-one polymorphic markers were identified among the 83 cultivars/selections tested. Based on UPGMA analysis, extensive genotypic diversity was found with the closest genotypes differing by six markers. No obvious trends were observed based on the cluster analysis with regards to known tolerant and susceptible rootstocks but rootstocks that have been field-tested and determined to be very tolerant rootstocks such as Latas, Dusa, PP14 (Uzi), PP4 (Zentmyer), and PP24 (Steddom) were distributed across the tree. This suggests that the same mechanisms for resistance may not be shared among these various selections. Therefore, these best-performing and most genetically diverse rootstocks will be combined in future breeding efforts to potentially pyramid diverse sources of resistance into future selections.

Chamomilla recutita (L.) Rauschert (Asteraceae) is a well-known plant used in medicine, cosmetics, and food industry (1). Due to the content of essential oil and flavonoids, extracts of chamomile flowers exhibit antiphiogistic and antispasmodic activities. In addition, water-soluble polysaccharides have attracted scientific interest, as they are shown to be involved in antiphlogistic effects and might act also as biological response modifiers (2). Therefore the structural features of the water-soluble polysaccharides of chamomile flowers were investigated.Dried flower heads of the chemocultivar DegumilleTM of C. recatita were powdered V 0.2mm), preextracted with methanol and petroleum ether, followed by water extraction (5% w/w) at 25 °C for 8 h. After centrifugation, the polysaccharides were precipitated with ethanol (final concentration 80% v/v), redissolved in water, dialysed (Mr cut-off 3.5 kd) and freeze-dried, yielding 3.2% (w/w of dried flower heads) of a crude polysaccharide fraction (= CPS).By sequential elution of CPS on DEAE-Sephacel with water, 0.25 M and 0.5 M potassium phosphate buffer, three polysaccharide fractions could be obtained: PS I (0.8% w/w dried flower heads), PS 11(0.7%), and PS 111(0.5 %). Allfractions were analysed.Relative molecular mass was determined on GPC with SephacryPTM S 400, SuperdexTM 75 or 200, and SuperoseTM 6 or 12. Neutral sugar composition was determined by GLC of the alditol acetates (3) or alditol trimethylsilyl ethers (4) after hydrolysis with TFA or oxalic acid. Uronic acid content was measured colorimetrically by the hydroxybiphenyl assay (5). The degree of substitntion (DS) with methanol or acetic acid was evaluated photometrically after saponification and formation of 3 ,5-diacetyl-1 ,4-dihydro-2 ,6-dimethylpyridine (6) or of a chelate complex of hydroxamic acid with ferric ions (7).Analysis of sugar linkages was carried out by GLC/MS-analysis of the partially methylated alditol acetates (PMSS) (8). Prior to methylation analysis, a carboxyl reduction with carbodiimide (9) was performed, in the case of acidic polysaccharides.The major polysaccharide component of fraction PS I (85%) was a fructan with a relative molecular mass of 3.5 kd, with a main chain of 1,2-linked fructose and a few branching points (2%) via 1,2,6-fructose. In addition, fraction PS I contained small amounts (15 %) of a neutral arabinogalactan with an identical molecular mass range, mainly consisting of 1,3,6linked galactose, 1,6-linked galactose, and 1,5-linked arabinose in a ratio of 1 :0.9:0.8.Fraction PS II could be separated by GPC into three acidic polysaccharides with molecular masses of 300 kd (PS II A), 83kd (PS II B), and 11 kd (PS II C)in a ratio nfl :3:1. The oronic acid content was determined to be 50.5%, 26.0%, and 37.3%, respectively. PSII A, PSII B, and PSII C also showed differences in the DS with methanol of 52.0%, 42.5%, and 59.7%. backbone of a-1,4-linked galacturonic acid regions and ramified regions with 1, 2,4-rhamnose as branching points and side chains of 1,5-linked arab...

This is the first report of the ash sawfly, Tomostethus nigritus, in the Republic of Ireland. We observed defoliated leaves of Fraxinus excelsior L. and T. nigritus larvae at a forestry plantation in Co. Kildare. Morphological observation of the larvae and DNA analysis using mitochondrial COI barcoding confirmed the identification of this pest of ash.