Problems with Quality and Late Shuck Opening in Southeastern Shuck - - PowerPoint PPT Presentation

Problems with Quality and Late Shuck Opening in Southeastern Shuck Opening in Southeastern Pecans in 2010

Lenny Wells UGA Horticulture UGA Horticulture

Early 2010 Pecan Crop Predictions f G i for Georgia

Littlepage Pape Alabama NPSA Littlepage Pape Alabama NPSA 78 million 85 million 75 million 90 million

2010 Crop Maturity and D l I Development Issues

• Cool Spring Temperatures

Cool Spring Temperatures

“The temperature effect on date of nut maturity is

indirect in that springtime temperatures influence the starting date of fruit development.” Darrell Sparks UGA Horticulture

“Cool early season temperatures result in a pronounced

dela in pollen shed b t a minor dela in recepti it so UGA Horticulture delay in pollen shed, but a minor delay in receptivity, so chosen pollen shed –receptivity patterns may not match any more in a year with cool early season temperatures.” Tommy Thompson USDA pecan breeder,

Average Maximum Temperature h March

80 70 80 F) 50 60 erature ( 2010 2009 30 40

• x. Tempe

2009 2008 2007 10 20 Max 2007

Ft Valley Cordele Albany Tifton Vidalia

Green immature catkins with no evidence of anther dehiscence suggest that Stuart is a few days from pollen shed.

• Because many female

flowers on adjacent flowers on adjacent Desirable trees are already receptive, they cannot be pollinated by Stuart, b th ill l Rough, glistening fully developed stigma indicating receptivity of because they will no longer be receptive when Stuart pollen is shed. indicating receptivity of ‘Desirable’ flower is near peak. Bill Goff

Pollination Pollination

No Pollination Self-Pollination Sparks

Effect of Self‐Pollination d ‐‐‐Marquard, 1988

Self Cross Self Pollination Cross Pollination Weight 5 4g 6 5g** Weight 5.4g 6.5g Volume 7.4 ml 8.3ml** % Pops 11.7% 3.6%NS

Self Pollination results in: 17% l t t 17% less nut wt 11% smaller volume

Cool Spring Cool Spring

• Cool spring temperatures indirectly delayed
• Cool spring temperatures indirectly delayed

crop maturity as a result of the delay in budbreak budbreak

• Cool spring temperatures reduced pollination
• f ‘Desirable’ by ‘Stuart’ in some locations
• f Desirable by Stuart in some locations

(and potentially other cultivars), leading to more fruit abortion and lower quality more fruit abortion and lower quality

• Use more than one pollinator!

2010 Crop Maturity Issues 2010 Crop Maturity Issues

• Cool Spring Temperatures
• Cool Spring Temperatures
• Extreme Prolonged Heat

Average Maximum Temperature b June 1‐September 15

96 92 94 96 88 90 2010 2009 82 84 86 2009 2008 2007 78 80 82 2007 76 8

Ft Valley Cordele Albany Tifton Vidalia

Pecans, Heat, and Water Pecans, Heat, and Water

• Pecans have a very efficient water transport

Pecans have a very efficient water transport system

• Developed ability to avoid stomatal closure

Developed ability to avoid stomatal closure under high temps with adequate water

• Can tolerate temperatures of 106.5 with good

Can tolerate temperatures of 106.5 with good soil moisture

• Pecans are very inefficient users of water

Pecans are very inefficient users of water

• Require large amounts of water to support
• ptimal growth and fruit production
• ptimal growth and fruit production

• High daytime temperatures are not a serious
• High daytime temperatures are not a serious

limiting factor to pecan production UNLESS soil moisture is inadequate soil moisture is inadequate

• SE irrigation systems are designed to be

supplemental to rainfall supplemental to rainfall

• Under prolonged heat and inadequate soil

i ill ff moisture, pecans will suffer

2010 Crop Maturity Issues 2010 Crop Maturity Issues

• Cool Spring Temperatures
• Cool Spring Temperatures
• Extreme Prolonged Heat

S h

• Late Season Drought

Water Deficit b June 1‐September 15

1 3 5 ) ‐3 ‐1 1 ficit (in) 2010 2009 ‐7 ‐5 3 ater Def 2009 2008 2007 ‐11 ‐9 Wa 2007 ‐13

Ft Valley Cordele Albany Tifton Vidalia

Evapotranspiration b June 1‐September 15

24 23 24 22 in) 2010 2009 20 21 ET (i 2009 2008 2007 19 2007 18

Ft Valley Cordele Albany Tifton Vidalia

Tree Water Status 2010

120 (psi) 80 100

• tential (

20 40 60 Water Po 20

/ 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1

Stem W

6 / 4 / 2 6 / 1 1 / 2 6 / 1 8 / 2 6 / 2 5 / 2 7 / 2 / 2 7 / 9 / 2 7 / 1 6 / 2 7 / 2 3 / 2 7 / 3 / 2 8 / 6 / 2 8 / 1 3 / 2 8 / 2 / 2 8 / 2 7 / 2 9 / 3 / 2

Date Evap Pan Tensiometer Dry

Nut Drought Induced Yield Nut Retention (%) Drought Induced Nut Drop (# nuts beneath canopy) Yield (lbs/tree) (July 20) (Aug. 13) Evap Pan 61a 22.6a 59a p Tensiometer 65a 27.8a 48ab Dry 60a 122.8b 30b

Summary Summary

• Cool spring temperatures indirectly delayed

nut maturity and directly affected pollination

• f certain cultivar combinations, which led to

fruit abortion

• Prolonged heat combined with inadequate

Prolonged heat combined with inadequate soil moisture and high ET reduced photosynthesis, leading to poor quality, small photosynthesis, leading to poor quality, small nut size, low volume, and nut abortion