A NOTE ON THE EFFECTS ON YIELDS OF SHIFTS IN THE AUSTRALIAN WHEAT BELT

Marketing, Productivity Analysis,

Variability in peach and nectarine eating quality

Meeting consumers' expectations of peaches and nectarines is paramount for the Australian peach industry. Providing consumers with fruit that have consistently high eating quality is essential for repeat purchases and increasing per capita consumption. A major problem with meeting consumers' expectations is the variability among fruit within the same tray, as there can sometimes be large differences in fruit sweetness (soluble solids content, SSC). A first step towards solving this problem is to identify and quantify this variability in fruit SSC and then begin to identify some of the factors that influence SSC. The variability of fruit SSC was measured in a range of different peach and nectarine cultivars grown in different growing regions in Australia. Fruit SSC was measured non-destructively in the field and packinghouses with near infra red (NIR) spectroscopy. Fruit SSC and size (fruit diameter) was measured in a range of orchard and packinghouse surveys, which were conducted in each of the growing regions during the harvest period. The results show for the first time the range of fruit SSC within and between different growing regions and in the wholesale/retail market during the 2007/8 season. The results from the low and medium chill growing areas showed that there is tremendous potential to increase both the average SSC and to minimise fruit to fruit variability. The overall fruit SSC in the low chill and medium chill growing regions in the 2007 season was low. The fruit from the higher chill growing regions generally had higher fruit SSC, but there were still issues with low and variable SSC identified in the market and there was inter- and intra-tree variability. Fruit was also sampled at wholesale and retail markets and the variation in fruit SSC over the entire 2007/8 season was large

VARIABILITY IN PEACH AND NECTARINE EATING QUALITY

Meeting consumers' expectations of peaches and nectarines is paramount for the Australian peach industry. Providing consumers with fruit that have consistently high eating quality is essential for repeat purchases and increasing per capita consumption. A major problem with meeting consumers' expectations is the variability among fruit within the same tray, as there can sometimes be large differences in fruit sweetness (soluble solids content, SSC). A first step towards solving this problem is to identify and quantify this variability in fruit SSC and then begin to identify some of the factors that influence SSC. The variability of fruit SSC was measured in a range of different peach and nectarine cultivars grown in different growing regions in Australia. Fruit SSC was measured non-destructively in the field and packinghouses with near infra red (NIR) spectroscopy. Fruit SSC and size (fruit diameter) was measured in a range of orchard and packinghouse surveys, which were conducted in each of the growing regions during the harvest period. The results show for the first time the range of fruit SSC within and between different growing regions and in the wholesale/retail market during the 2007/8 season. The results from the low and medium chill growing areas showed that there is tremendous potential to increase both the average SSC and to minimise fruit to fruit variability. The overall fruit SSC in the low chill and medium chill growing regions in the 2007 season was low. The fruit from the higher chill growing regions generally had higher fruit SSC, but there were still issues with low and variable SSC identified in the market and there was inter- and intra-tree variability. Fruit was also sampled at wholesale and retail markets and the variation in fruit SSC over the entire 2007/8 season was large

Feeding and development of the glassy-winged sharpshooter, Homalodisca vitripennis, on Australian native plant species and implications for Australian biosecurity.

In any insect invasion the presence or absence of suitable food and oviposition hosts in the invaded range is a key factor determining establishment success. The glassy-winged sharpshooter, Homalodisca vitripennis, is an important insect vector of the xylem-limited bacterial plant pathogen, Xylella fastidiosa, which causes disease in numerous host plants including food and feedstock crops, ornamentals and weeds. Both the pathogen and the vector are native to the Americas and are considered to be highly invasive. Neither has been detected in Australia. Twelve Australian native plant species present in the USA were observed over two years for suitability as H. vitripennis feeding, oviposition and nymph development hosts. Hosts providing evidence of adult or nymph presence were Leptospermum laevigatum, Acacia cowleana, Eremophila divaricata, Eucalyptus wandoo, Hakea laurina, Melaleuca laterita and Swainsona galegifolia. An oviposition-suitability field study was conducted with citrus, a favoured oviposition host, as a positive control. Citrus and L. laevigatum, A. cowleana, B. ericifolia×B. spinulosa, C. pulchella, E. divaricata, E. wandoo, H. laurina, and S. galegifolia were found to be oviposition hosts. Egg parasitism by the mymarid parasitoid Gonatocerus ashmeadi was observed on all Australian plants. A number of Australian plants that may facilitate H. vitripennis invasion have been identified and categorised as 'high risk' due to their ability to support all three life stages (egg, nymph and adult) of the insect in the field (L. laevigatum, A. cowleana, E. divaricata, H. laurina, and S. galegifolia). The implications of these host status and natural enemy research findings are discussed and placed in an Australian invasion context

Low dose gamma irradiation does not affect the quality, proximate or nutritional profile of 'Brigitta' blueberry and 'Maravilla' raspberry fruit

Blueberry (Northern Highbush, cv ‘Brigitta’) and raspberry (cv ‘Maravilla’) fruit were subject to low dose gamma irradiation (0, 150, 400 and 1000 Gy) and stored at 0 °C for three or ten days (blueberry) and two or seven days (raspberry) to determine the effects of irradiation on fruit quality and nutritional and proximate contents. In general, none of the irradiation doses (≤1000 Gy) significantly affected blueberry or raspberry fruit quality (overall fruit quality, colour, firmness, weight loss, TSS, TA levels or TSS/TA ratio), or the nutritional or proximate content (ash, carbohydrate, dietary fibre, energy, moisture, protein, sodium, potassium, total sugars, fructose, ascorbic acid, monomeric anthocyanin, citric and malic acids). The length of time in storage affected some fruit quality and nutritional and proximate content parameters (such as overall fruit quality, firmness, weight loss, TA levels, dietary fibre, potassium, ascorbic acid, citric and malic acids), with longer storage periods resulting in lower quality fruit, irrespective of irradiation treatment. No interaction was detected between the effects of irradiation treatment and storage time, indicating that the storage effect was consistent for all irradiation doses on both blueberry and raspberry fruit quality

Low Dose Gamma Irradiation Does Not Affect the Quality or Total Ascorbic Acid Concentration of “Sweetheart” Passionfruit (Passiflora edulis)

Passionfruit (Passiflora edulis, Sims, cultivar “Sweetheart”) were subject to gamma irradiation at levels suitable for phytosanitary purposes (0, 150, 400 and 1000 Gy) then stored at 8 °C and assessed for fruit quality and total ascorbic acid concentration after one and fourteen days. Irradiation at any dose (≤1000 Gy) did not affect passionfruit quality (overall fruit quality, colour, firmness, fruit shrivel, stem condition, weight loss, total soluble solids level (TSS), titratable acidity (TA) level, TSS/TA ratio, juice pH and rot development), nor the total ascorbic acid concentration. The length of time in storage affected some fruit quality parameters and total ascorbic acid concentration, with longer storage periods resulting in lower quality fruit and lower total ascorbic acid concentration, irrespective of irradiation. There was no interaction between irradiation treatment and storage time, indicating that irradiation did not influence the effect of storage on passionfruit quality. The results showed that the application of 150, 400 and 1000 Gy gamma irradiation to “Sweetheart” purple passionfruit did not produce any deleterious effects on fruit quality or total ascorbic acid concentration during cold storage, thus supporting the use of low dose irradiation as a phytosanitary treatment against quarantine pests in purple passionfruit

<i>Homalodisca vitripennis</i> incidence on Australian native plants in a field survey in California, USA from June–November (n = 9).

<p>Species back transformed means in each column assigned the same letter are not significantly different; citrus control with mean and standard error (n = 10) also provided.</p>∧<p>Citrus plants were not part of the randomised design and data not included in the ANOVA and not transformed.</p>†<p>Species effect not detected at p = 0.05.</p>#<p><i>Banksia ericifolia×B. spinulosa</i>.</p

<i>Homalodisca vitripennis</i> host status of Australian native plants in the field.

#<p><i>Banksia ericifolia×B. spinulosa</i>.</p

Effect of Australian native plant species on feeding rate (excreta volume) and predicted survival proportion for 2010 and 2011 for <i>Homalodisca vitripennis</i> in a no choice feeding experiment over 72 hours.

<p>Species back transformed means in each column assigned the same letter are not significantly different.</p>#<p><i>Banksia ericifolia×B. spinulosa</i>.</p