Land capability assessment for expanding irrigated horticulture around Myalup

The Department of Primary Industry and Regional Development (DPIRD, formerly Department of Agriculture and Food, Western Australia), assessed the suitability of land for expanding irrigated horticulture around Myalup, Western Australia. The assessment builds upon existing soil-landscape mapping produced by van Gool and Kipling (1992), and Barnesby and Proulx-Nixon (2000). This report provides guidance to decision-makers and investors about areas with potential for irrigated horticulture. The survey area for this assessment is east of Myalup, covering 37 800 hectares (ha). Johnston Road forms the northern boundary and the Brunswick River forms the southern boundary (Figure 1.1). The sandy soils of the Spearwood and Karrakatta series in this area are highly sought after for irrigated horticulture because their drainage and workability provide the opportunity for year-round cropping. They also have better water- and nutrient-holding capacity than other soils on the Swan Coastal Plain. We described 140 soil profiles and collected over 80 soil samples for analysis. We used this information to improve existing soil-landscape mapping. We used land qualities assigned to this mapping to generate land capability maps of the Myalup survey area, highlighting the areas with the greatest potential for irrigated horticulture

Methyl jasmonate alleviates chilling injury and regulates fruit quality in ‘Midknight’ Valencia orange

Susceptibility of sweet oranges to chilling injury (CI) restricts the utilisation of cold storage to its full potential to extend storage life and maintain fruit quality. The present investigation examined the role of postharvest methyl jasmonate (MJ) dips and different cold storage temperatures on the incidence of CI and fruit quality of ‘Midknight’ Valencia over two years. The fruit were dipped for 1 min in aqueous emulsions containing different concentrations 0.10, 0.25 or 0.50 mM of MJ and ‘Tween 20’ (0.01%) as a surfactant. The untreated fruit were used as the control. The fruit were stored at 4 °C or 7 °C for 90 d followed by 10 d simulated shelf conditions. MJ treatments, irrespective of the concentration applied, reduced CI in the fruit. The fruit treated with 0.25 mM MJ followed by 90 d cold storage and 10 d simulated shelf conditions were free from CI, irrespective of the cold storage temperatures. Dip treatments of 0.25 or 0.50 mM MJ reduced soluble solids concentration (SSC) and titratable acidity (TA); however, the SCC/TA ratio was higher when fruit was dipped in 0.25 mM MJ as compared with all other treatments. 0.25 or 0.50 mM MJ reduced concentrations of vitamin C and total antioxidants compared with all other treatments. Overall, 0.25 mM MJ is recommended as a treatment to reduce CI, while maintaining fruit quality attributes

Pre-harvest spray application of abscisic acid (S-ABA) regulates fruit colour development and quality in early maturing M7 Navel orange

Poor fruit colour development at harvest in early maturing M7 sweet orange cultivar causes economic losses to the growers. The responses of different concentrations (50, 100, 200, 300 or 500 mgL -1 ) of abscisic acid (S-ABA) and its biosynthesis inhibitor nordihydroguaiaretic acid (NDGA) (0.01, 0.02, 0.04 mM) at pre-harvest stage (6 or 3 weeks before anticipated harvest) on peel colour development particularly from yellow to deep orange and on the fruit quality of M7 were studied during 2015 and 2016 in Western Australia. S-ABA treatments during both years irrespective of the concentrations applied exhibited significantly lower hue angle (h°) with enhanced citrus colour index (CCI) and higher levels of total carotenoids in the flavedo during 2015 and 2016. Spray application of S-ABA (300 and 500 mg L -1 ) resulted in higher level of total carotenoids (35.0 and 71.5 mg kg -1 ) in the flavedo during 2015 and 2016. A single spray application of S-ABA applied at 6 weeks before anticipated harvest (WBAH) showed higher mean CCI (10.1) and level of total carotenoids (37.6 mg kg -1 ) as compared to its single application at 3 WBAH and double spray at 6 WBAH followed by 3 WBAH in 2015. However, nordihydroguaiaretic acid (NDGA) restricted colour development indicated by higher h° and reduced CCI with lower levels of total carotenoids in the flavedo during 2015. S-ABA treatments exhibited significantly reduced total organic acids in the juice, whilst total sugars were not affected by any of the treatments. S-ABA treatments (200 and 300 mg L -1 ) showed increased SSC/TA ratio (12.8%) as a result of reduction in total acidity (TA) (0.96%). In conclusion, pre-harvest spray application of S-ABA promoted fruit colour development from yellow to deep orange, indicated by reduced h° and increased CCI as well as the levels of total carotenoids in the flavedo of M7 Navel orange. Promotion of fruit colour development (yellow to deep orange) with the pre-harvest application of S-ABA and its down regulation with the application of ABA biosynthesis inhibitor (NDGA) suggested the involvement of S-ABA in flavedo colour development in M7 Navel orange fruit