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Early Maturing ‘Valencia’ Clones for Processing






Probably the most important clones being developed in this project are early ‘Valencia’ clones, and CREC pilot plant data over the past six years from some of the more interesting selections are provided in Table 9.2. Presently, there is a signifi cant gap between optimum harvest dates for our midseason juice oranges (‘Pineapple’ and ‘Midsweet’ – usually harvested during January) and the highest quality late matur- ing standard ‘Valencia’ (harvest usually runs from March to June). This creates a gap in the processing season (usually lasting the entire month of February), resulting in inef- fi cient operation of some processing plants during this time. An earlier maturing


 

Table 9.2. Selected ‘Valencia’ somaclones with a maturity date 2–4 weeks earlier than standard ‘Valencia’: 1997–2002 data (ratio/soluble solidsa/colour).

 
 

Harvest date

  Clone 14 January 15 January 28 January 10 February 4 February 28 January
B4-70 15.30 ND 16.95 14.88 ND ND
  5.72   6.50 6.70    
  36.4   36.8 36.9    
B6-66 13.46 15.72 16.08 13.36 12.48 14.40

7.00 6.15 6.93 7.23 6.44 6.20

36.6 37.2 36.4 36.9 36.1 37.6

B6-68 13.94 15.34 13.84 13.94 10.92 14.06
  6.60 6.38 7.15 6.47 6.10 6.19
  37.9 38.4 38.2 38.0 38.1 37.7
B10-81 ND 14.58 14.98 13.51 12.54 14.06
6.34 7.01 6.70 6.31 6.48
38.3 38.7 38.5 37.7 38.3
Control 10.53 12.61 12.50 12.20 10.34 11.61
  7.15 6.96 6.89 6.65 6.11 6.43
  36.3 37.6 38.1 37.6 37.5 37.8

aPounds of solids per 90 lb box. ND = not determined.


 


 

‘Valencia’ would of course solve this prob- lem. Other advantages to having a superior early ‘Valencia’ include: (i) the possibility of harvesting grade A fruit in the event that there is a fruit-destructive freeze any time after mid-January; (ii) the availability of superior quality and highly coloured juice to blend with ‘Hamlin’ as needed to achieve grade A juice during the early–middle part of the season; (iii) expanding the NFC season; and (iv) the possibility of harvesting fruit prior to fruit set of the following season’s crop. Standard ‘Valencia’ has the new and old fruit on the tree at the same time, making it diffi cult to use abscission chemicals to facilitate mechanical harvest- ing.

The most promising early maturing ‘Valencia’ clones for processing from the fi rst group studied (Table 9.2) are B6-68 and B10-81, and the data suggest that they should be amenable to a February harvest (in Florida) during most years. The original trees of these clones are of normal size and vigour, and both appear to be yielding well. Fruits are less seedy than typical ‘Valencia’ and consistently have a high juice content. Juice of both clones has excellent colour and a typical ‘Valencia’ fl avour. This is sup- ported by sensory data that indicate that B10-81 is as acceptable as the control Midsweet as early as mid-January, well before ‘Valencia’ fruit can usually be uti-


 

lized. The two earliest clones of this group, B4-70 and B4-83, can usually be harvested in mid–late January, but often their juice content is lower than average (data not shown), and their juice colour is also less than average. The original trees of these two clones are smaller and less thrifty than typ- ical ‘Valencia’. Juice from somaclone B6-66 has an excellent rich fl avour and the fruit is totally seedless. The superior fl avour of B6- 66 is confi rmed by preliminary sensory test- ing that shows it is signifi cantly preferred to the control ‘Valencia’ at both mid-February and mid-March harvests. Unfortunately, this clone also has lower than average juice colour scores and juice content. The origi- nal tree is also smaller than average. The fi ve clones described in Table 9.2 were all regenerated from embryogenic callus.

More recently, a protoplast-derived clone SF14-62W was identifi ed that is even earlier maturing than the clones mentioned above (Table 9.3). This clone has a maturity date very comparable with that of ‘Midsweet’, the currently preferred mid- season cultivar in Florida. Somaclone SF14-62W has significantly better juice colour than ‘Midsweet’, and was favoured over ‘Midsweet’ in preliminary sensory testing. Brix: acid ratio data also indicate that SF14-62W is signifi cantly earlier than either B10-81 or B6-68. SF14-62W, there- fore, has excellent potential as a mid-season


 

 

Table 9.3. Recently selected very early maturing ‘Valencia’ somaclone (4–8 weeks earlier than standard ‘Valencia’): (Brix/ratio/colour/soluble solidsa).

 

  Harvest date  
Clone 28 January 2000 4 February 2001 15 January 2002
SF14-62W 11.0 12.8 11.8
  14.7 15.8 13.8
      37.6
  4.9 7.0 ND
Control Valencia 10.1 Valencia 11.7 Midsweet 12.0
  10.8 10.3 13.4
  37.6 37.5 36.4
  5.6 6.1 ND

aPounds of solids per 90 lb box. ND = not determined.


 

Table 9.4. Late maturing ‘Valencia’ somaclones: 1999–2000 CREC pilot plant data.

 
 

Harvest date

 
 

Clone 24 May 1999 24 May 2000

T3-56 Juice content (%) 59.8 52.4

Brix: acid ratio 19.1 14.6

Pounds of SSa/90 lb box 8.25 6.86

Juice colour score 38.5 39.3

T3-58 Juice content (%) 59.8 58.2

Brix: acid ratio 19.1 16.8

Pounds of SS/90 lb box 7.83 7.28

Juice colour score 38.2 39.7

T3-53 Juice content (%) 56.9 59.7

Brix: acid ratio 19.7 17.9

Pounds of SS/90 lb box 7.74 7.22

Juice colour score 39.0 39.7

T3-51 Juice content (%) 58.6 51.9

Brix: acid ratio 19.6 17.4

Pounds of SS/90 lb box 8.45 6.41

Juice colour score 39.3 39.6

Control fruit were not available.

aSS = soluble solids.


 

 

clone, which could be especially useful for blending with low-coloured ‘Hamlin’ juice.

 

 






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