Thirsty vines Summer girdling Compost teas Organic marketing The ...

Recommendations

Info

During fl owering in 2006, we selected a number of shoots and pruned them to stimulate regrowth. After fruit set we set fruit and leaf numbers to: • four leaves + one fruit • four leaves + one fruit + one regrowth • four leaves + one regrowth. All shoots were girdled so that only the leaves on the shoot could support the growth of fruit or regrowths on their shoot. Regrowths were left on all shoots until mid January when they were about 20 cm long. At this stage we removed all regrowths except those we wanted to retain. From this time onward we stripped the leaves off regrowths as the leaves expanded (Figure 2). This allowed us to measure how much of the resources being produced by the shoots was required to support elongation of regrowths. Of course in a normal orchard situation, elongation of regrowth would be supported by carbohydrate from the parent shoot for the fi rst few weeks only: as the Fruit weight (g) Length of regrowth (cm) Figure 2. During January and February, elongating regrowths were allowed to compete with fruit for carbohydrate and this reduced fruit growth by 48 per cent (top graph). <strong>The</strong> presence of a fruit did reduce elongation of regrowths, but only by 17 per cent. NZ KIWIFRUIT JOURNAL JANUARY / FEBRUARY 2008 27
28 regrowth developed larger leaves, these would return carbohydrate to the shoot and this should increase fruit growth. For this trial we wanted to make sure the regrowth was always acting as a competitor to fruit. This should give us an indication of what happens during the fi rst fl ush of regrowth on commercial orchards. We found that while regrowths were vigorously elongating, fruit growth was dramatically reduced (Figure 3). Once the regrowths stopped elongating, then fruit growth was actually faster than on the shoots with no regrowths. We also found that producing a regrowth uses about the same amount of resources as growing a fruit. By harvest, the total dry matter (DM) in fruit was 20.1g, while regrowths contained 26.2g DM. At harvest, fruit supported by four leaves were large, with an average fresh weight of 151g and DM content of 17.2 per cent. Competition from a single regrowth reduced average fruit fresh weight to 130g and DM content to 15.9 per cent. That is, regrowth resulted in a loss of 21g in the fruit weight and a loss of 1.3 per cent DM. WHAT DOES IT MEAN? We measured the competition between fruit and shoots under simplifi ed, artifi cial conditions, so our data cannot be applied directly to commercial orchards. However, our test system showed that summer regrowths can dramatically reduce both fresh weight and DM accumulation in fruit during the fi rst few weeks of growth. In orchards where there are many cycles of vegetative fl ushes followed by pruning, this may appreciably reduce fruit size and fruit quality. This confi rms recent research (Patterson et al. 2007) where it was shown that orchards that do not need summer pruning produce fruit with a higher DM. It may also explain why warm summers in the Bay of Plenty tend to lower per cent DM (Snelgar et al. 2007), since we know that higher temperatures greatly increase the rate of vegetative growth. This season we will carry out similar trials, but we will leave the leaves on some regrowths so that we can measure when shoot regrowth stops reducing fruit growth and when it resumes supporting fruit growth. REFERENCES Patterson KJ, Max. S. Woodward T, Nichols P, Barnett A, Martin P 2007. Top Dry Matter Performers – ZESPRI GREEN (Confi dential Report to ZESPRI Group Ltd, Project TZ0850). Snelgar B, Minchin P, Hall A 2007. Predicting dry matter of GREEN kiwifruit from climate. New Zealand Kiwifruit Journal:184: 29-31. ■
Page 1 and 2: Thirsty vines Summer girdling Compo
Page 3 and 4: 4 contributors BILL SNELGAR Bill Sn
Page 5 and 6: 6 GRANT THORP Dr Grant Thorp is a H
Page 7 and 8: 8 Statistic December January Februa
Page 9 and 10: 10 Fruit dry matter (%) Soluble sol
Page 11 and 12: 12 SUMMARY We now have an indicatio
Page 13 and 14: 14 Orchard Control Dry matter (%) C
Page 15 and 16: 16 Operators should also avoid cutt
Page 17 and 18: Technical Review Advertisement / Ad
Page 19 and 20: 20 Gearing up ‘Hort16A’ Returns
Page 21 and 22: 22 Table 2. Maturity attributes of
Page 23 and 24: 24 Active fungal biomass (ug/g) Fig
Page 25: 26 Hayward’s first priority: Shoo
Page 29 and 30: 30 Location Soil % C % N C:N Nelson
Page 31 and 32: 32 Mineral N (mg/kg) Figure 2. Chan
Page 33 and 34: 34 Resolving labour shortages - Is
Page 35 and 36: 36 Perceptions of the RSE Advantage
Page 37 and 38: 38 Organic O Marketing 2007 Tom McL
Page 39 and 40: 40 Customers are Impressed with tas
Page 41 and 42: 42 The Th flavour fl seesaw: balanc
Page 43 and 44: 44 aroma compounds. Dry Matter is a
Page 45 and 46: 46 Producing country On Orchard Pos
Page 47 and 48: 48 optimise their current managemen
Page 49 and 50: 50 Figure 2: Levels of actinidin en
Page 51 and 52: 52 NZKGI making its pledge in isola
Page 53 and 54: 54 Image provided by the NOAA/ESRL
Page 55 and 56: 56 Sea Surface temperature anomaly
Page 57 and 58: 58 The Taste ZESPRI TM programme wa
Page 59 and 60: 60 were either completely unconvinc
Page 61: 62 Orchard productivity remains a k

Thirsty vines Summer girdling Compost teas Organic marketing The ...

Create successful ePaper yourself

Delete template?

Save as template?