Mt Albert Research Center

Auckland, New Zealand

Mt Albert Research Center

Auckland, New Zealand

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Henriod R.E.,Horticulture and Food Research Institute of New Zealand Ltd | Tustin D.S.,Horticulture and Food Research Institute of New Zealand Ltd | Breen K.C.,Horticulture and Food Research Institute of New Zealand Ltd | Oliver M.,Horticulture and Food Research Institute of New Zealand Ltd | And 5 more authors.
Acta Horticulturae | Year: 2011

This study investigated the effects of both crop load and time of thinning on harvest fruit size, yield and quality of 'Scifresh' (Jazz™) apple at experimental orchards in Hawke's Bay (HB) and in Nelson (NEL), New Zealand. Six-year-old 'Scifresh' trees were thinned to low, medium and high crop loads (targets of 4, 8 and 12 fruit per trunk cross sectional area (TCA), respectively) at either 0, 30, 60 or 90 days after full bloom. Fruit were assessed at harvest after 16 weeks storage at 0.5°C and 7 days at 20°C. Trees thinned early in the season to a target crop load of 4 fruit per TCA produced considerably larger fruit at harvest (mean 203 g in HB and 183 g in NEL), being approximately 9.4% (HB) and 12.1% (NEL) larger than on trees thinned to a target of 12 fruit per TCA. Allowing trees to carry a low versus a high crop load resulted in the additional fruit quality benefits of higher mean soluble solids content (13.3 v 12.5%), titratable acidity (0.62 v 0.54%) and firmness (9.7 v 8.8 kgf) at harvest. The drawbacks from reduced crop load, however, were a substantial reduction in mean yield per tree (max. 59 kg/tree down to 34.5 kg/tree) and an increased potential of up to 3.6% in post-storage bitter pit expression. Earlier timing of thinning had the benefits of increasing fruit size without overly compromising total yield per tree, and in slightly increasing (by 1.1%) mean soluble solids content (max. 13.7%). Thinning timing had minimal effect on firmness and acidity. The drawbacks from early rather than late thinning, however, were a slight reduction in mean blush coverage (by 8.1%) and a higher incidence of mean internal bitter pit (max. 5.3%). In general, superficial scald incidence overall was highest (up to 23%) in fruit from HB compared with NEL when thinning occurred early and late in the season. Thus, a medium crop load of 8 fruit per TCA employed early to mid-season is likely to provide the most favourable trade-off for production of adequate yield without unduly compromising fruit size, eating quality and disorder incidence.


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.


Bushakra J.M.,The New Zealand Institute for Plant and Food Research Ltd | Bushakra J.M.,Massey University | Bushakra J.M.,U.S. Department of Agriculture | Krieger C.,The New Zealand Institute for Plant and Food Research Ltd | And 10 more authors.
Theoretical and Applied Genetics | Year: 2013

Fruit from Rubus species are highly valued for their flavor and nutritive qualities. Anthocyanin content contributes to these qualities, and although many studies have been conducted to identify and quantify the major anthocyanin compounds from various Rubus species, the genetic control of the accumulation of these complex traits in Rubus is not yet well understood. The identification of the regions of the genome involved in the production of anthocyanins is an important first step in identifying the genes underlying their expression. In this study, ultra and high-performance liquid chromatography (UHPLC and HPLC) and two newly developed Rubus linkage maps were used to conduct QTL analyses to explore the presence of associations between concentrations of five anthocyanins in fruit and genotype. In total, 27 QTL were identified on the Rubus linkage maps, four of which are associated with molecular markers designed from transcription factors and three of which are associated with molecular markers designed from anthocyanin biosynthetic pathway candidate genes. The results of this study suggest that, while QTL for anthocyanin accumulation have been identified on six of seven Rubus linkage groups (RLG), the QTL on RLG2 and RLG7 may be very important for genetic control of cyanidin modification in Rubus. © 2012 Springer-Verlag Berlin Heidelberg.


Palmer J.,The New Zealand Institute for Plant and Food Research Ltd | Diack R.,The New Zealand Institute for Plant and Food Research Ltd | Johnston J.,Mt Albert Research Center | Boldingh H.,Ruakura Research Center
Journal of Horticultural Science and Biotechnology | Year: 2013

The supply of carbon to fruit on whole apple trees of 'Scifresh' grafted onto M.9 rootstock was altered by adjustment of the crop load [43% removal at 60 d or 90 d after full bloom (DAFB)], by three periods of 75% shading (from 60 - 90, 90 - 120, or 60 - 120 DAFB), or by a combined treatment of fruit removal at 60 DAFB and shading from 60 - 120 DAFB. Altering the timing and duration of shading, and crop load adjustment, resulted in changes in fruit dry matter concentration (DMC), with a range at harvest from 14.0 - 17.5%. Thinning to reduce the crop load enhanced fruit DMC, with greater effects on both fruit DMC and mean fruit fresh weight the earlier it was done. Shading reduced fruit DMC, with greater reductions the longer the shade was left over the trees. All treatments had greater effects on fruit DMC and fruit quality (flesh firmness and soluble solids concentration) at harvest than on mean fruit fresh weight.This trial also provided fruit samples for measurements of both the carbohydrate content and apoplastic composition of cortical tissues. Starch contents and total apoplastic sugar concentrations were increased by reductions in crop load and were decreased by shading, with starch content being the most responsive. Apoplastic sugar concentrations increased during fruit development. The relative order of abundance of sugars in the apoplast and in the symplast plus vacuole was similar, although differences in the ratios of sugars were evident, with sorbitol accounting for ≤ 10% of the total sugar content in the apoplast and ≤ 3% in the symplast plus vacuole. This work has revealed the possibility of using apoplastic sugar concentration as an indicator of the carbohydrate supply to apple fruit.


Beatson R.A.,The New Zealand Institute for Plant and Food Research Ltd | Alspach P.A.,The New Zealand Institute for Plant and Food Research Ltd | Currie A.J.,The New Zealand Institute for Plant and Food Research Ltd | Harris-Virgin P.M.,The New Zealand Institute for Plant and Food Research Ltd | White A.,Mt Albert Research Center
Acta Horticulturae | Year: 2011

The genus Actinidia contains many species that have an array of novel traits of potential commercial interest. We have initiated an interspecific hybridisation programme to introgress some of these novel traits into commercial kiwifruit. Thus we need to have an understanding of the genetic behaviour of interspecific hybrids. We report on the fruiting characteristics of two interspecific Actinidia hybrid populations. Plants were harvested over five seasons (2006-2010). Key traits measured included average fruit weight, estimated yield, dry matter, soluble solids, fruit firmness, titratable acidity and vitamin C content. A mixed modelling approach for the analysis of data was used to derive estimates of narrow sense heritability for four traits and the genetic correlations between them. In addition, empirical breeding values were obtained for each genotype and selection indices developed. The implications of these estimates in breeding for improved commercial cultivars of Actinidia species are discussed.


Horner I.,The New Zealand Institute for Plant and Food Research Ltd | Manning M.,Mt Albert Research Center | Casonato S.,Te Puke Research Center
Acta Horticulturae | Year: 2015

Pseudomonas syringae pv. Actinidiae (Psa) causes leaf spotting, cane and leader cankers, or death of kiwifruit vines. Growers require management strategies that minimise the spread of cankers or systemic infection, whilst also minimising canopy loss. This project investigated whether cauterising cankers or pruning beyond the visible canker had any long-term effect in containing progression of the pathogen within the vine. The study included 72 'Zesy002' (commonly known as Gold3) (Actinidia chinensis) vines on one orchard and 87 'Hayward' (A. deliciosa) vines on two orchards, in Te Puke, New Zealand. From one to 30 cane or leader cankers per vine were monitored. Cankers were either left untreated, cauterised using a gas blowtorch, or pruned 40 cm below the lowest symptom. Cankers were delineated initially and canker advance was measured after 1, 3, 7 and 12 months. In 'Hayward', pruning proved to be the most effective, and most pruning wounds callused and healed. Cankers spread only where pruning wounds had not callused and healed. Only 11% and 3% of pruned canes on the two orchards, respectively, showed canker advance after 7 months. In comparison, in cauterised and untreated vines the majority (over 80%) of cankers continued to expand, with no obvious difference between these two treatments, and many instances where cankers expanded beyond the 40-cm mark. In Gold3, canker expansion was greater than in 'Hayward'. Pruning 40 cm below the visible canker margin did not remove the infection from the cane, and cankers continued to expand, in 18.4% of cases. This compares with 27.6 and 27.8% of cankers that expanded beyond the 40-cm mark in the untreated and cauterised vines, respectively, with more than 80% of cankers expanded beyond the original canker margin. The experiments showed that pruning beyond the visible canker reduced the systemic spread of Psa more effectively than cauterising cankers or leaving them untreated.


PubMed | Mt Albert Research Center
Type: Journal Article | Journal: Planta | Year: 2013

Mature fruit (kiwifruit) of Actinidia deliciosa var. deliciosa (A. Chev.), (C.F.) Liang and Ferguson cv. Haywood (Chinese gooseberry) were harvested and allowed to ripen in the dark at 20 C. Changes were recorded in metabolites, starch and sugars, adenine nucleotides, respiration, and sucrose and glycolytic enzymes during the initiation of starch degradation, net starch-to-sucrose conversion and the respiratory climacteric. The conversion of starch to sucrose was not accompanied by a consistent increase in hexose-phosphates, and UDP-glucose declined. The activity of sucrose phosphate synthase (SPS) measured with saturating substrate rose soon after harvesting and long before net sucrose synthesis commenced. The onset of sugar accumulation correlated with an increase in SPS activity measured with limiting substrates. Throughout ripening, until sucrose accumulation ceased, feeding [(14)C] glucose led to labelling of sucrose and fructose, providing evidence for a cycle of sucrose synthesis and degradation. It is suggested that activation of SPS, amplified by futile cycles, may regulate the conversion of starch to sugars. The respiratory climacteric was delayed, compared with net starchsugar interconversion, and was accompanied by a general decline of pyruvate and all the glycolytic intermediates except fructose-1,6-bisphosphate. The ATP/ ADP ratio was maintained or even increased. It is argued that the respiratory climacteric cannot be simply a consequence of increased availability of respiratory substrate during starch-sugar conversion, nor can it result from an increased demand for ATP during this process.


PubMed | Mt Albert Research Center
Type: Journal Article | Journal: Journal of chemical ecology | Year: 2013

Ctenopseustis obliquana females collected from Christchurch were found to produce a mixture of (Z)-5-tetradecenyl acetate and tetradecyl acetate in their sex pheromone gland, in contrast toC. obliquana from Auckland which produce an 8020 mixture of (Z)-8-tetradecenyl acetate and (Z)-5-tetradecenyl acetate. This identification has been made on the basis of instrumental and chemical analyses. Antennae of maleC. obliquana from Christchurch gave a maximal electroantennogram response to (Z)-5-tetradecenyl acetate. A field trapping program in Christchurch using combinations of synthetic (Z)-5-tetradecenyl acetate and tetradecyl acetate caughtCtenopseustis males equally well if the latter chemical was present or absent. No males were caught in traps baited with the Auckland-type pheromone. In Alexandra,Ctenopseustis males were caught in traps baited with Auckland-type pheromone and not in traps baited with Christchurch-type pheromone. This phenomenon is ascribed to the existence of sibling species within the describedC. obliquana.


PubMed | Mt Albert Research Center
Type: Journal Article | Journal: Journal of chemical ecology | Year: 2013

(Z)-5-Tetradecenyl acetate and tetradecyl acetate were identified as sex pheromone components of an unnamedPlanotortrix leafroller moth species found onAvicennia resinifera (mangrove). An equal mixture of the two compounds used as bait gave field trap catches at least as good as those baited with caged virgin females. Traps baited with the two chemicals caught malePlanotortrix moths in a mangrove swamp not previously found to host the unnamedPlanotortrix species. Adults of the unnamedPlanotortrix species and of the greenheaded leafroller,Planotortrix excessana are morphologically indistinguishable. The sex pheromone ofP. excessana has been found previously to be a mixture of (Z)-S-tetradecenyl acetate and tetradecyl acetate, and this means that the two species may now be distinguished by sex pheromone differences.

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