APPLE FRUIT PHENOTYPING PROTOCOL

Transcription

1 APPLE FRUIT PHENOTYPING PROTOCOL OVERVIEW Apple fruits frm individuals t be evaluated will be harvested at a defined stage f maturity based n starch pattern index and evaluated fr varius at 3 times: 1. Harvest weeks pstharvest cld strage + 1 week rm temp weeks pstharvest cld strage + 1 week rm temp CROPLOAD & THINNING After any chemical thinning (if dne), trees shuld be hand-thinned (beginning 5-6 weeks after blm) t retain fruit per tree fr yunger trees, r 4 fruit per ft f branch length fr lder trees (nt including current seasn's extensin grwth) and n mre than 2 fruit per spur r cluster. 15 fruit is minimum needed t cver all evaluatin stages (5 fruit x 3 evaluatin times), and extra fruit prvides sme backup in case f fruit rt in strage. We wuld like t harvest a minimum f 10 fruit per tree t allw fr evaluatins at harvest and after 10 weeks f strage. FRUIT MATURITY & HARVEST Check trees weekly fr fruit clr changes that indicate nset f fruit maturatin changes in backgrund clr (frm green t cream r light yellw) and brightening in red blush clr develpment. When the tree lks like it may be ready fr the first harvest sampling, select 1-2 fruit with the mst advanced maturity appearance and cnduct a starch-idine test. Aim fr a maturity indicatr f SPI 3-5 n the 1-8 Crnell (Blanpied) Chart belw (available at: r n a 0-6 starch pattern chart as a generic harvesting g date. This is equivalent t cmmercial harvest, and is a gd intermediate range where it is unlikely fr any trees t be t immature r vermature.

2 If the SPI indicates nset f maturatin fr a tree, visually evaluate the remaining fruit n the tree fr their range in maturity. If ~50 % f the fruit have a harvest-mature appearance (rughly similar t the SPI-tested fruit), take the sample f fruit selectively picked t be at the crrect harvest maturity. 15 fruit is minimum t cver all evaluatin stages (5 fruit x 3 evaluatin times), and extra fruit prvides sme backup in case f fruit rt in strage. Fruit shuld be harvested wherever pssible frm well expsed areas f the tree but aviding the tp and bttm f the canpy. Avid sunburned fruit, cracked fruit, etc. if pssible. Careful harvest is als required because fruit can be readily damaged by stem pulls, finger bruising, etc.

3 Harvest int tray-lined plastic lugs fr strage, labeled with fllwing infrmatin Rw N. and Tree N. (i.e., tree lcatin) Designatin f cultivar/selectin/seedling (e.g. Hneycrisp, r WSU47, r RGxBB #23 ) Harvest date Number f fruit Transfer fruit t cld strage as sn as pssible.

4 DATA COLLECTION AT HARVEST Recrd data fr the fllwing traits at harvest: Harvest date When maturity indicatr f SPI n a 0-6 starch pattern chart r 3-5 n the 1-8 Crnell Chart Crp lad (rating) (nte: with thinning advised abve, this shuld usually be medium r less) 1=very light 2=light 3=medium 4=heavy 5=very heavy Preharvest drpping (rating) 1=nne 2=light (<5%) 3=medium (5-30%) 4=heavy (30-60%) 5=very heavy (>60%) Disease traits may als be recrded frm field plts at harvest if cnditins permit: Diseases (rated 0=nne, 1=slight, 2=medium 3=severe) Apple scab severity (rating) Fireblight severity (rating) Pwdery mildew (rating) These crpping traits can be derived frm annual harvest data Annual bearing (based n annual crp lad rating) Preccity (yr. t bearing)

5 TRAITS EVALUATED USING AGGREGATE RATING ON FIVE WHOLE FRUIT The fllwing traits are rated based n an aggregate sample five fruit at harvest and/r after 10 r 20 weeks f strage: Harvest nly Grund clr Blush/strip clr Overclr type Red/blush stripe cverage Russet lcatin Russet cverage Fruit cracking Fruit shape Calyx pening Sunburn Harvest and Strage Greasiness (nt cmmn at harvest) Shrivel (likely nly after strage) Bitter pit Scald (nt cmmn at harvest)

6 GROUND COLOR 1 GREEN 2 PALE GREEN 3 GREEN-YELLOW 4 PALE YELLOW 5 YELLOW

7 BLUSH-STRIPE COLOR 1 ORANGE 2 ORANGE RED 3 PINK RED 4 RED 5 DARK RED

8 OVER COLOR TYPE 1 STRIPED 2 STRIPED-BLUSH 3 BLUSH-STRIPED 4 BLUSHED

9 % RED BLUSH/STRIPE COVERAGE COVERAGE OF THE FRUIT WITH: 1 NONE 2 <25% % % 5 >75% RUSSET LOCATION (ALL THAT APPLY) 1 STEM CAVITY 2 SHOULDERS 3 BODY BASIN/CALYX 4 LENTICELS

10 % RUSSET 1 NO RUSSET (RARE BUT CAN OCCUR) 2 STEM CAVITY RUSSET BUT NOT EXTENDING OVER SHOULDERS OR ON BODY OF FRUIT 3 SLIGHT ONE TO 2 FRUIT WITH RUSSET EXTENDING OVER SHOULDERS OR ON BODY OF FRUIT 4 SEVERE THREE OR MORE FRUIT WITH RUSSET EXTENDING OVER SHOULDERS OR ON BODY OF FRUIT FRUIT CRACKING This will usually ccur at the stem r calyx end f the fruit. 1 NONE 2 SLIGHT ONE FRUIT AFFECTED 3 MEDIUM 2 OR 3 FRUIT AFFECTED 4 SEVERE 4 OR 5 FRUIT AFFECTED

11 FRUIT SHAPE A scale develped by INRA (France) is used. Shape is rated frm 1 t 9 as shwn based n amunt f cnicity and height/width rati. CALYX OPENING 1 ALL CLOSED 2 MIXED 3 ALL OPEN OPEN CLOSED

12 SUNBURN Use pht cllage abve as a guide: 1 NONE (GRADE 0) 2 SLIGHT (GRADE 1-2) 3 MEDIUM (GRADE 3) 4 SEVERE (GRADE 4-5)

13 GREASINESS (TACKINESS) WHEN: HARVEST AND AFTER STORAGE 1 NONE FINGER SLIDES WITH NO RESISTANCE, MAY MAKE AUDIBLE SQUEAK IF GREAT PRESSURE IS APPLIED 2 SLIGHT SLIGHT RESISTANCE AND TACKINESS 3 MEDIUM CONSIDERABLE RESISTANCE AND PERSISTENT TACKINESS THAT LINGERS ON FINGER 4 VERY GREASY EXTREME FORCE IS NEEDED TO SLIDE FINGER SHRIVEL WHEN: HARVEST AND AFTER STORAGE Nte shriveled skin indicating water lss in prtins f fruit with sund skin (ignre areas damaged by disease r mechanical cntact) 1 NONE 2 SLIGHT ONE FRUIT AFFECTED 3 MEDIUM TWO OR THREE FRUIT AFFECTED 4 SEVERE FOUR OR FIVE FRUIT AFFECTED

14 BITTER PIT WHEN: HARVEST AND AFTER STORAGE 1 NONE 2 SLIGHT AT LEAST ONE PIT OBSERVED ON ONE FRUIT 3 MEDIUM 2 OR 3 FRUITS HAVE PITS 4 SEVERE 4 OR 5 FRUITS HAVE PITS SCALD WHEN: HARVEST AND AFTER STORAGE Disclratin and may have an epxy glue-like flavr. 1 NONE 2 SLIGHT ONE FRUIT AFFECTED 3 MEDIUM 2 OR 3 FRUITS AFFECTED 4 SEVERE 4 OR 5 FRUITS AFFECTED Phts: D. Rudell, USDA-ARS

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