Hawkes Bay Research Center

Havelock North, New Zealand

Hawkes Bay Research Center

Havelock North, New Zealand
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Knabel M.,New Zealand Institute for Plant and Food Research | Knabel M.,University of Auckland | Friend A.P.,Motueka Research Center | Palmer J.W.,Motueka Research Center | And 7 more authors.
Tree Genetics and Genomes | Year: 2017

The ease of vegetative propagation by hardwood cuttings is a critical trait for consideration by breeders of woody perennial rootstocks. This is especially so for Pyrus, because most Pyrus rootstock are known to be difficult to propagate. This report presents progress on the identification of loci controlling rooting of hardwood cuttings in European pear (Pyrus communis L.). Quantitative trait loci (QTLs) controlling the development of adventitious roots on hardwood cuttings were identified in both parents of a mapping population developed by crossing “Old Home” and “Louise Bonne de Jersey,” with the goal of investigating the genetic control of several rootstock related traits, which would be useful for rootstock breeding. A QTL for root development was identified on chromosome 7, co-located in both parents and exhibiting male and female additive and dominance effects. These results will assist in developing genetic markers that can be utilized by rootstock breeders for marker-assisted selection for this complex trait. © 2017, Springer-Verlag Berlin Heidelberg.

Prakash R.,The New Zealand Institute for Plant and Food Research Ltd | Hallett I.C.,Mount Albert Research Center | Wong S.F.,Mount Albert Research Center | Johnston S.L.,Hawkes Bay Research Center | And 5 more authors.
BMC Plant Biology | Year: 2017

Background: Unlike in abscission or dehiscence, fruit of kiwifruit Actinidia eriantha develop the ability for peel detachment when they are ripe and soft in the absence of a morphologically identifiable abscission zone. Two closely-related genotypes with contrasting detachment behaviour have been identified. The 'good-peeling' genotype has detachment with clean debonding of cells, and a peel tissue that does not tear. The 'poor-peeling' genotype has poor detachability, with cells that rupture upon debonding, and peel tissue that fragments easily. Results: Structural studies indicated that peel detachability in both genotypes occurred in the outer pericarp beneath the hypodermis. Immunolabelling showed differences in methylesterification of pectin, where the interface of labelling coincided with the location of detachment in the good-peeling genotype, whereas in the poor-peeling genotype, no such interface existed. This zone of difference in methylesterification was enhanced by differential cell wall changes between the peel and outer pericarp tissue. Although both genotypes expressed two polygalacturonase genes, no enzyme activity was detected in the good-peeling genotype, suggesting limited pectin breakdown, keeping cell walls strong without tearing or fragmentation of the peel and flesh upon detachment. Differences in location and amounts of wall-stiffening galactan in the peel of the good-peeling genotype possibly contributed to this phenotype. Hemicellulose-acting transglycosylases were more active in the good-peeling genotype, suggesting an influence on peel flexibility by remodelling their substrates during development of detachability. High xyloglucanase activity in the peel of the good-peeling genotype may contribute by having a strengthening effect on the cellulose-xyloglucan network. Conclusions: In fruit of A. eriantha, peel detachability is due to the establishment of a zone of discontinuity created by differential cell wall changes in peel and outer pericarp tissues that lead to changes in mechanical properties of the peel. During ripening, the peel becomes flexible and the cells continue to adhere strongly to each other, preventing breakage, whereas the underlying outer pericarp loses cell wall strength as softening proceeds. Together these results reveal a novel and interesting mechanism for enabling cell separation. © 2017 The Author(s).

Chagne D.,The New Zealand Institute for Plant and Food Research Ltd | Crowhurst R.N.,Mount Albert Research Center | Pindo M.,Instituto Agrario San Michele allAdige Research and Innovation Center | Thrimawithana A.,Mount Albert Research Center | And 39 more authors.
PLoS ONE | Year: 2014

We present a draft assembly of the genome of European pear (Pyrus communis) 'Bartlett'. Our assembly was developed employing second generation sequencing technology (Roche 454), from single-end, 2 kb, and 7 kb insert paired-end reads using Newbler (version 2.7). It contains 142,083 scaffolds greater than 499 bases (maximum scaffold length of 1.2 Mb) and covers a total of 577.3 Mb, representing most of the expected 600 Mb Pyrus genome. A total of 829,823 putative single nucleotide polymorphisms (SNPs) were detected using re-sequencing of 'Louise Bonne de Jersey' and 'Old Home'. A total of 2,279 genetically mapped SNP markers anchor 171 Mb of the assembled genome. Ab initio gene prediction combined with prediction based on homology searching detected 43,419 putative gene models. Of these, 1219 proteins (556 clusters) are unique to European pear compared to 12 other sequenced plant genomes. Analysis of the expansin gene family provided an example of the quality of the gene prediction and an insight into the relationships among one class of cell wall related genes that control fruit softening in both European pear and apple (Malusxdomestica). The 'Bartlett' genome assembly v1.0 (http://www.rosaceae.org/species/pyrus/ pyrus-communis/genome-v1.0) is an invaluable tool for identifying the genetic control of key horticultural traits in pear and will enable the wide application of marker-assisted and genomic selection that will enhance the speed and efficiency of pear cultivar development. © 2014 Chagné et al.

Bus V.,Hawkes Bay Research Center | Brewer L.,Motueka Research Center | Morgan C.,Motueka Research Center
Acta Horticulturae | Year: 2013

Scab is a major disease of pear worldwide. The disease is caused by two species: Venturia pirina, which infects European pear, and V. nashicola, which infects Asian pear species. The host types are mutually exclusive to the Venturia species and this phenomenon is heavily exploited in the Plant & Food Research pear breeding programme for the breeding of scab-resistant pear cultivars. In 2008 and 2009, 18 seedling families with a range of 0 to 100% Asian pear pedigree were screened in the glasshouse following artificial inoculation with V. pirina, the scab species present in New Zealand. The progenies showed a range of resistance reactions, mostly in the classes 0 (no symptoms) and 2 (necrotic reaction without sporulation). Some seedlings showed a hypersensitive response (class 1) or chlorotic reactions with limited sporulation (class 3). As expected, the seedling progenies of low Asian pear descent showed high proportions (78-91%) of susceptible seedlings. Ten families showed 100% resistant seedlings, with a further two families showing 98 and 94% resistance. We show that the average proportion of Asian ancestry of a progeny estimated from their parents is not necessarily a good predictor for the expected resistance segregations of that progeny.

Volz R.K.,Hawkes Bay Research Center | Kumar S.,Hawkes Bay Research Center | Chagne D.,Palmerston North Research Center | Espley R.,Mt Albert Research Center | And 2 more authors.
Acta Horticulturae | Year: 2013

The genetic relationships between 'Type 1' red flesh and several fruit quality traits in apple were assessed in breeding populations that segregated in the field for white and red flesh. Transgenic plants grown in the glasshouse and genetically modified with the MdMYB10 gene, responsible for the 'Type 1' red flesh phenotype, were also examined. Moderate positive genetic correlations were found in each of two seedling populations between the amount of red colour estimated in the cortical flesh of fruit (WCI) and astringent taste and an internal flesh browning disorder (IFBD) observed in fruit after medium-term cold storage. In one family, a quantitative trait locus for astringent taste and IFBD was mapped to the same position at the bottom of linkage group (LG) 9 as that for WCI and MdMYB10. Fruit from 'Royal Gala' trees that had been transformed with 35S-MdMYB10 had high flesh anthocyanin concentrations but also showed considerable IFBD after cold storage. In contrast, white flesh 'Royal Gala' control fruit did not show any cortical MdMYB10 expression or IFBD symptoms and had minimal flesh anthocyanin concentrations. These results are discussed with regards to future breeding strategies that aim to optimize fruit quality in 'Type 1' red flesh breeding lines.

Palmer J.W.,The New Zealand Institute for Plant and Food Research Ltd | Harker F.R.,Mt Albert Research Center | Tustin D.S.,Hawkes Bay Research Center | Johnston J.,Mt Albert Research Center
Journal of the Science of Food and Agriculture | Year: 2010

In the fresh apple market fruit must be crisp and juicy to attract buyers to purchase again. However, recent studies have shown that consumer acceptability could be further enhanced by improving taste. This study evaluates the use of fruit dry matter concentration (DMC) as a new fruit quality metric for apple. RESULTS: Fruit samples collected at harvest, in the two main fruit growing regions of New Zealand, showed a variation in mean fruit DMC from 130 to 156 g kg-1 with 'Royal Gala' and with 'Scifresh' from 152 to 176 g kg-1. Individual fruit DMC showed a larger range, from 108 to 189 g kg-1 with 'Royal Gala' and from 125 to 201 g kg-1 with 'Scifresh'. Fruit DMC proved a more reliable predictor of total soluble solids after 12 weeks of air storage at 0.5 °C than TSS at harvest for both 'Royal Gala' and 'Scifresh'. Fruit DMC was also positively related to flesh firmness, although this relationship was not as strong as that seen with soluble solids and was more dependent on cultivar. Consumer studies showed that consumer preference was positively related to fruit DMC of 'Royal Gala' apples. CONCLUSION: Fruit DMC can therefore be measured before or at harvest, and be used to predict the sensory potential for the fruit after storage. © 2010 Society of Chemical Industry.

Palmer J.,The New Zealand Institute for Plant and Food Research Ltd | Lozano L.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Chagne D.,Palmerston North Research Center | Volz R.,Hawkes Bay Research Center | And 8 more authors.
Acta Horticulturae | Year: 2012

The biosynthesis of anthocyanins in many plant species is affected by environmental conditions. In apple fruit, skin anthocyanin contents are lower under hot climate conditions. We have examined anthocyanin accumulation in maturing 'Royal Gala' apples grown under temperate and hot conditions. Orchard-based apple heating to temperatures comparable to hot climates was performed and found to cause fast fruit colour loss and a reduction in anthocyanin content. Lower rates of biosynthesis are suggested, as a coordinative down-regulation of gene expression of the genes encoding the anthocyanin biosynthetic pathway occurs in hot conditions. In addition, the expression of the genes encoding the transcriptional activation complex is also reduced. Heating fruit rapidly reduced expression of apple anthocyanin-related genes, which correlated with a reduction in expression of the R2R3 MYB transcription factor (MYB10/MYB1) responsible for elevating apple colour. A genetic mapping strategy was used to identify loci associated with the expression of red skin colour under high temperatures. A population of apple seedlings was phenotyped for skin colour and anthocyanin content and then genotyped using a panel of SNP markers spanning the entire apple genome. Two markers were associated with red skin colour on linkage groups 9 and 17, including a marker located close to MYB10 (LG 9). We propose that temperature-induced down-regulation of fruit anthocyanin biosynthesis is primarily due to down-regulation of the anthocyanin regulatory complex, and that the genes encoding the complex have become useful loci for the development of marker assisted breeding of new apple cultivars tolerant of warm conditions.

El-Sayed A.M.,The New Zealand Institute for Plant and Food Research Ltd | Unelius C.R.,The New Zealand Institute for Plant and Food Research Ltd | Unelius C.R.,Linnaeus University | Twidle A.,The New Zealand Institute for Plant and Food Research Ltd | And 7 more authors.
Tetrahedron Letters | Year: 2010

Headspace volatiles collected from virgin females of the citrophilous mealybug, Pseudococcus calceolariae, contain three compounds not present in the headspace of control samples. The main female-specific compound is identified as [2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methyl 2-acetoxy-3-methylbutanoate (chrysanthemyl 2-acetoxy-3-methylbutanoate). The other two compounds are identified as [2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methanol (chrysanthemol) and [2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methyl 2-hydroxy-3-methylbutanoate (chrysanthemyl 2-hydroxy-3-methylbutanoate). Traps baited with 100 μg and 1000 μg of chrysanthemyl 2-acetoxy-3-methylbutanoate captured 4- and 20-fold more males than traps baited with virgin females. © 2009 Elsevier Ltd. All rights reserved.

Ampomah-Dwamena C.,The New Zealand Institute for Plant and Food Research Ltd | Dejnoprat S.,The New Zealand Institute for Plant and Food Research Ltd | Lewis D.,Palmerston North Research Center | Sutherland P.,The New Zealand Institute for Plant and Food Research Ltd | And 3 more authors.
Journal of Experimental Botany | Year: 2012

Carotenoid accumulation confers distinct colouration to plant tissues, with effects on plant response to light and as well as health benefits for consumers of plant products. The carotenoid pathway is controlled by flux of metabolites, rate-limiting enzyme steps, feed-back inhibition, and the strength of sink organelles, the plastids, in the cell. In apple (Malus × domestica Borkh), fruit carotenoid concentrations are low in comparison with those in other fruit species. The apple fruit flesh, in particular, begins development with high amounts of chlorophylls and carotenoids, but in all commercial cultivars a large proportion of this is lost by fruit maturity. To understand the control of carotenoid concentrations in apple fruit, metabolic and gene expression analysis of the carotenoid pathway were measured in genotypes with varying flesh and skin colour. Considerable variation in both carotenoid concentrations and compound profile was observed between tissues and genotypes, with carotenes and xanthophylls being found only in fruit accumulating high carotenoid concentrations. The study identified potential rate-limiting steps in carotenogenesis, which suggested that the expression of ZISO, CRTISO, and LCY-ε, in particular, were significant in predicting final carotenoid accumulation in mature apple fruit. © 2012 The Authors.

Tustin D.S.,The New Zealand Institute for Plant and Food Research Ltd | Tustin D.S.,Hawkes Bay Research Center | Seymour S.M.,The New Zealand Institute for Plant and Food Research Ltd | Seymour S.M.,Riwaka Research Center | And 2 more authors.
Acta Horticulturae | Year: 2014

Contemporary dwarfing and semi-dwarfing rootstocks cultivated extensively worldwide lack durable resistance to economically damaging pests and diseases. In recognition of these limitations, a series of hybrid families was created in 1986-87 by crossing resistance sources Malus 'Robusta 5' and 'Aotea' (Malus seiboldii) to maternal parent 'Malling 9' (M.9) dwarf rootstock. More than 10,000 genotypes were screened as young seedlings for Phytophthora cactorum tolerance and the survivors established as individual stoolbeds. After three years, those individuals exhibiting field resistance to natural infestation by woolly apple aphid (WAA) (Eriosoma lanigerum) and freedom from spines/branches were grafted with the scion 'Gala' and planted in a replicated agronomic performance trial. The evaluation site was chosen to have a high natural disease pressure for Phytophthora cactorum and periods of waterlogging. After five years, about 15 genotypes were identified for their reduced tree stature, freedom from suckering, continued WAA resistance, freedom from Phytophthora symptoms and high floral and fruiting precocity. Currently, seven selections have been retained in advanced evaluation orchard productivity and adaptability trials, compared with standards M.9 and Geneva® 210. Five of the seven selections show immunity or resistance to fire blight (Erwinia amylovora) in shoot inoculation bioassays. Tree size, productivity and fruit quality comparisons with M.9 and Geneva 210 are presented. Three of the selections are similar in stature to M.9, three selections are semidwarfing, similar or slightly smaller than Geneva 210 and one is more vigorous than Geneva 210 but judged to be less vigorous than MM.106. International development of these rootstock selections is being conducted in collaboration with International Fruit Obtention (IFO).

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