summary of the recently released european pear,...
TRANSCRIPT
Summary of the recently released European Pear, ‘Gem’
Todd Einhorn, Ph.D. Michigan State University
USDA Pear Breeding Objectives
• High fruit quality cultivars (Flavor, texture, appearance, size, and no physiological disorders are major traits).
• High productivity and early bearing • Wide range of maturities • Resistance to fire blight (Primarily Pyrus communis sources of resistance) • Resistance to pear psylla (Pyrus ussuriensis and East European Pyrus communis
sources of resistance) • Resistance to Fabraea leaf spot and pear scab
Background
* Slide compliments of Dr. Richard Bell, USDA-ARS Pear Breeder
USDA Pear Cultivars Notable Features 1960 Releases: ‘Magness’ High fire blight resistance and quality
‘Moonglow’ High fire blight resistance and productivity ‘Dawn’ High quality, moderate fire blight resistance
1980 – 2016 Releases: ‘Potomac’ ‘Moonglow’ X ‘Anjou’- Anjou type flavor, fire blight resistance ‘Shenandoah’ Late maturity, large size, fire blight resistance
‘Blake’s Pride’ Excellent aromatic flavor, fire blight resistance (-) size, russet ‘Sunrise’ Early August maturity, fire blight resistance,
excellent flavor/ (-) relatively no storage life/size ‘Gem’ Cultivar Release Publication
Releases
* Slide compliments of Dr. Richard Bell, USDA-ARS Pear Breeder
Potomac
Photo: Adams County Nursery
Shenandoah Sunrise
Precocious and productive Crisp/juicy texture at harvest Can be ripened to melting quality Non-russeting, smooth finish Flesh non-browning Fire blight tolerance
‘Gem’ Summary
‘Gem’ 16-April 1-Sept ‘Bartlett’ 17-April 15-Aug ‘d’Anjou’ 13-April 5-Sept
‘Gem’- Bloom and Harvest Timing
05
101520253035404550
0 2 4 6 8 10
Freq
uenc
y (%
)
Seeds/fruit
'd'Anjou'
'Bartlett'
'GR Bosc'
'Comice'
'Gem'
'Starkrimson'
• Compatible with all cultivars evaluated; bloom timing near ‘Bartlett’
• Fruits from 20 % of self-pollinated flowers were parthenocarpic
‘Gem’- Pollination
Gem: Planted 2005Leaf Yield 8x15x 6x15 6x12 5x12 4x12 Avg. fruit wt. Avg. fruit size
Year (year) (lbs/tree) 363 484 605 726 908 (g) (box sz)2007z 3 11 3.6 4.8 6.1 7.3 9.1 175 110/1202008z 4 22 7.3 9.7 12.1 14.5 18.2 175 110/1202009z 5 77 25.4 33.9 42.4 50.8 63.6 150 1352010z 6 115 38 50.6 63.3 75.9 94.9 155 1352010y 6 56 18.5 24.6 30.8 37 46.2 205 1002011z 7 120 39.6 52.8 66 79.2 99.1 150 1352011y 7 66 21.8 29 36.3 43.6 54.5 215 902012 8 n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d.
2013w 9 90 29.7 39.6 49.5 59.4 74.3 211 100/90z Unthinnedy Thinned to 4 fruits/cm2 trunk cross-sectional areaxActual spacing of orchardwThinned commerically to Bartlett levelsOptimal spacing
Bins/acre for a range of spacings and tree densities
‘Gem’- Production Central leader system- 890 trees/ha on OH X F 97
‘Gem’- Yield and Fruit Size
‘Gem’ will require thinning if size 90s and larger are desired
0
10
20
30
40
50
70 80 90 100 110 120 135 <135
Perc
ent
Fruit size (no. fruit per 44 lb box)
HeavyModerateLightCommercial
8.5 fruits/cm2
6 fruits/cm2
3 fruits/cm2
4 fruits/cm2
‘Gem’- Cropload vs. Fruit Size 890 trees/ha
‘Gem’- Harvest Timing
Delaying harvest to optimize harvest eating quality resulted in a linear improvement in fruit size
13-15% 0.3 -
0.5% 10.5 lb
(47.5 N) ~50% of
fruits 90 to 100
240 to 194 g Smooth
no russet
‘Gem’- Fruit Quality ‘Gem’ is a crisp/crunchy pear that can be consumed directly ‘off the tree’
‘Gem’ can also be ripened to a melting flesh dessert quality pear
At 10 lb harvest pressure, ~30 d of chill were required to ripen
PH (RA) storage life is 5 months
‘Gem’- Postharvest Quality
‘Gem’- Postharvest Quality
• Gem pears were processed on Duckwall’s commercial ‘Comice’ line (brushes covered by belts)
‘Gem’ -Fire Blight
• Original source of fire blight resistance was ‘Seckel’
• Inoculation of actively growing shoots showed high level of resistance
• Blossom susceptibility (observed on nursery trees in 2016)
‘Gem’ – Distribution Issues
• Infected with PVY virus- presumably due to grafting to infected rootstocks • Clean Plant Network (Prosser, WA) successfully treated PVY infected material via heat therapy • A limited supply of vf buds were available Fall 2016
• 35-40 fruits per tree after thinning
• 166 is precocious and productive
• Bartlett harvested 3-Aug
• -166 harvested 19-Aug
Other New Germplasm
84907-166 91 a 1.43 a 249.2 16.4 12.6 ‘Bartlett’ 122 a 0.83 b 222.4 18.9 11.7 ‘d’Anjou’ 5 b 0.1 c - - -
US84907-166 Parentage: Bartlett x US65062-040 Bartlett-type flavor, sweet Harvest: Aug 20 Storage: 3 months RA Fire blight resistant
- Tested positive for PVY
Other New Germplasm