Introduction Methods Results

Transcription

1 North Carolina G. Craig Yencho and Mark E. Clough Department of Horticultural Science, North Carolina State University, Vernon G. James Research and Extension Center, Plymouth NC Introduction Nineteen round white, and seven red and purple clones were evaluated in two replicated yield trials at the NCSU VGJREC/NC Department of Agriculture and Consumer Sciences, Tidewater Research Station in Plymouth, NC as part of the NE-1014 Northeast Regional Potato Variety Trials Project during Methods The trials were planted in a Portsmouth fine sandy loam soil with a ph of ca. 5.5 on March 15. A randomized complete block design with 4 replicates was used for each experiment. Plots consisted of 1 row with 28 hills spaced 9 inches apart. Spacing between rows was 38 inches for both trials. Fertilizer was broadcast (648 lbs./a gal./a ) on March 14. Imidacloprid (Admire 20F at 17 oz/a) was applied to seed-pieces in the furrow at planting. The herbicides metribuzin (Sencor 75DF at 1/2 lb./a) and metalochlor (Dual Magnum at 1.5 pt/a) were applied pre-emergence. Post planting disease and pest control measures were applied in accordance with recommendations for commercial growers in NC. The trials were harvested without vine killing. The plots were dug using a two-row John Deere potato harvester modified to dig one row. The red trial was dug on July 5 th and the white trial was dug on July 8 th. Potatoes were graded to five classes: 1 s < 1 7/8 ; 2 s > 1 7/8 to 2 1/2 ; 3 s > 2 1/2 to 3 1/4 ; 4 s > 3 1/4 to 4 ; 5 s > 4. Culls were removed and weighed separately in both trials. After grading and weighing, 40 marketable tubers (10 tubers/replication) were sampled randomly from each entry, cut and scored for the presence or absence of hollow heart, heat necrosis and any other internal defects. Random subsamples of marketable tubers were then obtained from each replication and bulked by clone to provide samples for specific gravity readings and chipping. Specific gravity was determined using the weight-in-air/weight-in-water method. Chip ratings were done at the TRS/VGJREC. Results Our season started on time, though rains occurring during the middle and later parts of March caused our plantings to be spread out. Temperatures throughout the majority of the season were favorable for growth. Rains this year came in large amounts at a time or none at all, still overall quantities were adequate during the growing season for the trials. High amounts of ozone damage in trials caused premature vine decline a few weeks before harvest. In addition, rains at harvest time spread us out and caused elevated levels of soft rot in the plots. Round White Trial: B (274 cwt/a) had the highest total and marketable yield in this trial. But, none of the nineteen clones in this trial, had marketable yields significantly greater than Atlantic (257 cwt/a). Ten clones in this trial had gravities greater than Atlantic (1.075) these, sorted high to low were: AF (1.087), AF (1.084), Kennebec (1.084), AF (1.078), NY126 (1.078), AC Sunbury (1.076), Snowden (1.076), Yukon Gold (1.076), AF2206-8

2 NE1014 Report North Carolina Page 2 (1.075), and NY128 (1.075). One clone, NY127, received a chip rating of 1 (exceptionally bright). Six clones (AF2115-1, AF2211-9, Atlantic, B and Yukon Gold) were rated a 7 for overall appearance. Clones with 10% or greater incidence of IHN were: AF (10% incidence, mean rating 7.5), AF (90% incidence, mean rating 6.5), and Atlantic (53% incidence, mean rating 6.5). Clones with incidence of brown center 10% or greater were: AF and Superior. The most common culls were misshapes, sunscald, secondary growth, and skin blemishes attributed to rhizoctonia. Red Trial: The standard, Chieftain, had a marketable yield of 237 cwt/a. None of the NE-1014 clones in this trial had higher marketable yields. B and B had the highest appearance scores in the trial each rating a 6. Clones with 10% or greater IHN were: B (13% incidence, mean rating 8.0), Chieftain (40% incidence, mean rating 7.3), and NY129 (30% incidence, mean rating 7.8). Culls were due mostly to soft rot, misshapes, secondary growth, sunscald, infected lenticels, and skin blemishes attributed to rhizoctonia. Descriptions of Numbered or Recently Released White Clones under NC Conditions AC Sunbury has been evaluated for 3 years and may have some potential in North Carolina as a table-stock potato. It is early maturing and has a good appearance. Typically, it produces round to oblong tubers with a smooth, tan to white skin. Marketable yields were 74% of Atlantic this year (historically 80%), gravity was similar to Atlantic, and size was medium or slightly larger. There were no significant internal defects. Other defects included misshapes, scab, and soft rot. AF has been evaluated for two years and this clone may have some potential in North Carolina. It is a medium maturing clone with a good appearance. It produces mostly oblong, white-skinned, medium to large tubers. Marketable yields were 65% of Atlantic (84% historically) and gravity has been variable. This year specific gravity was and two years ago it was This year no incidence of internal heat necrosis was noted though last year it had 10% with a mean severity rating of 8.3. Other defects included growth cracks, misshapes, secondary growth, and skin blemishes due to rhizoctonia. AF has been evaluated for two years and it has not performed well in North Carolina due to poor appearance and low yield. It is a medium maturing clone with a poor appearance. Marketable yields were 46% of Atlantic, shape was round to oblong, and size was medium to small. Gravity is comparable to Atlantic and it rated a 2 for chipping. There were no significant internal defects, other defects included many misshapes, and some soft rot. AF has been evaluated for 5 years and this clone is not suited for North Carolina due to poor appearance and low yield. It is a mid to late maturing clone with a less than fair appearance, and it has a brown moderately to slightly netted skin, with tubers being mostly oblong. Marketable yields have averaged 76% of Atlantic in 6 trials since 2001, gravity is similar to Atlantic (historical average 1.078), it chipped good, and size tended to be medium. No internal defects were noted this year, other defects included misshapes, sunscald and soft rot.

3 NE1014 Report North Carolina Page 3 AF has been evaluated in three trials since 2001 and is not suited for North Carolina due to low yield. It is a mid to late, mostly round, clone. Its skin color is tan to light brown, texture is slightly netted and its appearance scores have been fair overall. Marketable yields in this year s trial were 66% of Atlantic and are 72% historically. Gravity is similar to Atlantic and chip color is good. In terms of internal defects, for IHN it has averaged 8% with a severity rating of 6. Incidence of hollow heart and brown center have averaged 8% since External defects included misshapes and sunscald. AF has been evaluated for 5 years in 4 trials and it is not suited for North Carolina due to low yield and appearance. This clone is mid to late maturing, and appearance is fair (less than fair score historically). It produces smooth cream-colored, medium to large tubers and shapes are oblong. Marketable yields averaged 69% of Atlantic and are historically 75%, gravity was (1.072 historically), and chip color was marginal. Minimal internal defects were recorded. External defects included sunscald, soft rot, enlarged lenticels, and high amounts of misshapes. AF has been evaluated for 5 years in 5 trials and it is not suited for North Carolina due to low yield. Maturity is medium to late, appearance this year was less than fair (historically better than fair). This clone produces medium sized, oblong, slightly netted, tan tubers. Marketable yields averaged 48% of Atlantic and historically were 73% of Atlantic, gravity was (historical average, 1.066), and it chipped acceptable. No significant internal defects were noted. External defects included misshapes, sunscald, growth cracks, and skin blemishes due to rhizoctonia. AF has been evaluated for 2 years and it is not suited for North Carolina due to poor appearance, low marketable yield, and severe IHN. This is a medium sized, late maturing, oblong clone with a slightly netted tan to light brown skin, and a less than fair appearance. Its marketable yields in all trials averaged 79% of Atlantic, gravity was 1.059, and the chip score was marginal. Internally, 90% of tubers sampled had IHN with a mean severity rating of 6.5, also it had 15% brown center. External defects included misshapes, secondary growth and skin blemishes due to rhizoctonia. B has been evaluated for 6 years and has some potential in North Carolina as a table stock variety. This is a medium sized, yellow fleshed, mid to late maturing clone. It is round to oblong, with a smooth, buff skin and a fair appearance. Marketable yields were 107% of Atlantic during 2005 and have averaged 106% historically, and gravity was No significant internal defects were recorded in this trial. Other defects included misshapes. NY125 has been evaluated for 8 years in twelve trials and has some potential in North Carolina s table stock market. This clone is mid to late maturing, with a better than fair appearance. Tubers are medium sized, mostly oblong, with a slightly netted, buff-colored skin and a light yellow flesh. Marketable yields averaged 75% of Atlantic but historically average 102% of Atlantic, and gravity was less than Superior. Internal defects were minimal. Other defects included misshapes, sunscald, and secondary growth. NY126 has been evaluated for 7 years in thirteen trials and has some potential in North Carolina as a table stock variety. It is a medium maturing clone, with a better than good appearance.

4 NE1014 Report North Carolina Page 4 Tubers are medium to large and mostly round, flesh is yellow, and the skin is brown and slightly netted. Marketable yields averaged 89% of Atlantic during 2005 and have historically averaged 98%. Gravity was 1.078, though historically it averages No internal defects were recorded. Other defects included misshapes, soft rot, and skin blemishes due to rhizoctonia. NY127 has been evaluated for 5 years and has some potential as a table stock variety though its overall appearance was less than fair in 2005 and historically have only been fair. It is a midmaturing clone, that produces medium to large, mostly round tubers with moderately smooth buff colored skin. Marketable yields averaged 97% of Atlantic, historically 109%, gravity was 1.064, and chip scores average acceptable. No significant internal defects were recorded. Other defects included sunscald misshapes, growth cracks, and soft rot. NY128 has been evaluated for 6 years and does not have potential in North Carolina, it is too netted for table stock, and though it chips well, the gravity is too low for chipping. It is a late maturing clone, and appearance is good. Tubers are medium to large in size, and mostly round, the skin is tan to light brown color and netted. Marketable yields averaged 86% of Atlantic and have a historical average of 85%, gravity was and historically is 1.071, chip scores are good. Internal defects were minimal. Other defects included misshapes. Descriptions of Numbered or Recently Released Red Clones under NC Conditions AC Red Island has been evaluated for 3 years and has some potential in NC. It is a medium to late maturing variety with a fair appearance. Tubers are medium to large and mostly round, and skins are red and moderately smooth and with good skin set. Marketable yields averaged 94% of Chieftain and historically averaged 76%. No significant internal defects were recorded. Other defects included silver scurf, fusarium, soft rot, sunscald and misshapes. B has been evaluated for 6 years in fourteen trials and has potential in North Carolina. This is a mid-maturing clone with better than fair appearance. Tubers are medium to small and shapes tend to be oblong, its skin is slightly netted to moderately smooth and purple, skin set is fair, and flesh color is medium to dark yellow. Marketable yields averaged 76% of Chieftain in 2005 and have averaged 86% historically. Internal defects included 13% IHN rated at 8.0 in It s important to note, however, that this is the first year we have seen any IHN in this clone. Other defects included misshapes. B has been evaluated for 5 years in 9 trials and has potential in North Carolina. This is an early to mid maturing clone with a better than fair appearance. Tubers tend to be one step larger than medium and round to oblong, its skin is moderately smooth and bright purple, with a less than fair skin set. Marketable yields averaged 88% of Chieftain during 2005, and have averaged 77% historically. Internal defects included 18% of cut tubers with vascular ring. External defects included misshapes, growth cracks, infected lenticels, sunscald, silver scurf. NDTX731-1R has been evaluated for 3 years and needs further evaluation in NC. Its maturity is early to mid with a fair appearance. Tubers are medium sized and mostly round with shallow eyes, skin is red and moderately smooth with a fair skin set. Marketable yields averaged 56% of

5 NE1014 Report North Carolina Page 5 Chieftain during 2005 but historically have been 97% of Chieftain. Internal defects included 13% of cut tubers with vascular ring. Other defects included misshapes, soft rot, fusarium dry rot, insect damage, infected lenticels, secondary growth, and blemishes due to rhizoctonia. NY129 has been evaluated for 6 years in fifteen trials and has some potential in North Carolina. It is mid to late maturing with a better than fair appearance. Tubers are medium to large and very round, and its skin is red with a slight netting, and skin set is fair. Marketable yields averaged 105% of Chieftain during 2005 and have averaged 91% historically. Internal defects included 30% IHN at a rating of 7.8. This is the first year we have seen significant amounts of IHN in this clone. Other defects included silver scurf, skin blemishes due to rhizoctonia, infected lenticels, growth cracks, fusarium dry rot, misshapes, and soft rot.

6 NE1014 Report North Carolina Page 6 North Carolina Table 1. Total and marketable yield, percentage of total yield by size class, specific gravity and chip color of potato clones harvested 115 days after planting at the NCSU VGJREC/NCDA TRS, Plymouth, Washington Co., NC Size Distribution by Class 1 Total Yield Marketable Yield (% of total yield) 1 7/8 2 1/2 Specific Chip Clone cwt/a cwt/a % Atl. 1's 2's 3's 4's 5's Culls to 4" to 4" Gravity 2 Color 3 AC Sunbury AF AF AF AF AF AF AF Atlantic B Katahdin Kennebec NY NY NY NY Snowden Superior Yukon Gold Grand Mean CV(%) LSD(K=100) Size classes: 1 s < 1 7/8 ; 2 s > 1 7/8 to 2 1/2 ; 3 s > 2 1/2 to 3 1/4 ; 4 s > 3 1/4 to 4 ; 5 s > 4 Culls = all defective potatoes. 2 Determined by weight in air/water method. 3 Chip Color Ratings conducted by Wise Foods Inc. and the NCSU potato breeding program at the TRS/VGJREC: 1 = no defects, exceptionally bright; 2 = excellent, bright; 3 = good, light or golden; 4 = dark defects, marginal; 5 = not acceptable.

7 NE1014 Report North Carolina Page 7 North Carolina Table 2. Plant vine type, disease and air pollution scores, maturity at ca. 3 weeks prior to harvest, and external and internal tuber attributes of potato clones harvested 115 days after planting at the NCSU VGJREC/NCDA TRS, Plymouth, Washington Co., NC Plant Data 2 Tuber Data 2 % Internal Defects 3 Clone TYPE DIS POLL MAT CLR TXT TCX TSS SHP EYE SIZE DIS APP HN HNR HH VR BC SR Comments 4 AC Sunbury CS,SR,MS,YF1 AF GC,SG,MS,RZ AF ^MS,SR AF MS,SS,SR AF MS,SS AF ^MS,SR,EL,SS AF MS,GC,SS,RZ AF RZ,MS,SG Atlantic MS,GC,SS B MS,YF1 Katahdin MS,SS,SR Kennebec MS,SS,SG NY MS,SG,YF2 NY MS,SR,RZ,YF2 NY MS,GC,SS,SR NY MS Snowden MS,SG,IL,SR Superior SR,MS Yukon Gold SR,MS,SG,YF2 1 NE1014 Standard Potato Rating Scores 2 HN=heat necrosis; HNR=average heat necrosis rating (Rating Scale: 1= very severe to 9 = absent); HH=hollow heart; VR=vascular ring discoloration; BC=brown center 3 Comment codes: AC=air cracks; BR=bruise; BS=black scurf; CPB=colorado potato beetle; CS=common scab; DAE=deep apical eyes; DSE=deep stolen end; EB=early blight; ECB= European corn borer; EL= enlarged lenticels; FS=fusarium wilt; GC=growth cracks; HI= herbicide injury; HS=heat sprouts; IL=infected lenticels; LB=late blight; LHD=leaf hopper damage; MS=mishaped tubers; PE=pink eye; PR=pink rot; PLRV=potato leaf roll virus; PTS=very pointed tubers; PS=powdery scab; PVA, PVX, PVY=potato viruses A, X, Y; RZ=Rhizoctonia; SC=star cracking; SEB=stem end browning; SG=secondary growth; SIS=silver scurf; SKN=skins; SS=sunscald; SR=soft rot; STST=sticky stolens; VW=Verticillium wilt; WSTD=weak stand; WW=wire worm; YF=yellow flesh Note:^ before code indicates high levels

8 NE1014 Report North Carolina Page 8 North Carolina Table 3. Total and marketable yield, percentage of total yield by size class, and specific gravity of potato clones harvested 112 days after planting at the NCSU VGJREC/NCDA TRS, Plymouth, Washington Co., NC Size Dist. by Class (%) 1 Total Yield Marketable Yield (% of total yield) 1 7/8 2 1/2 Specific Clone cwt/a cwt/a % Chieftain 1's 2's 3's 4's 5's Cull's to 4" to 4" Gravity 2 AC Red Island B B Chieftain Dark Red Norland NDTX731-1R NY Grand Mean CV(%) LSD(K=100) Size classes: 1's < 1 7/8"; 2's 1 7/8 to 2 1/2"; 3's 2 1/2 to 3 1/4" ; 4's 3 1/4 to 4"; 5's 4"; Culls = all defective potatoes. 2 Determined by weight in air/water method. North Carolina Table 4. Plant vine type, disease and air pollution scores, maturity at ca. 3 weeks prior to harvest, and external and internal tuber attributes of potatoes harvested 112 days after planting at the NCSU VGJREC/NCDA TRS, Plymouth, Washington Co., NC Plant Data 2 Tuber Data 2 % Internal Defects 3 Clone TYPE DIS POLL MAT CLR TXT TCX TSS SHP EYE SIZE DIS APP HN HNR HH VR BC SR Comments 4 AC Red Island SS,SR,MS,FS,SiSc B MS,SR,SG,IL,RZ B MS,GC,IL,SS,SiSc Chieftain MS,SR,SS,SG,IL,RZ Dark Red Norland RZ,MS,GC,SS,SG NDTX731-1R MS,SR,FS,SG,RZ,ID,IL NY SiSc,FS,MS,IL,SR,RZ,GC 1 NE1014 Standard Potato Rating Scores 2 HN=heat necrosis; HNR=average heat necrosis rating (Rating Scale: 1= very severe to 9 = absent); HH=hollow heart; VR=vascular ring discoloration; BC=brown center; SR=soft rot 3 Comment codes: AC=air cracks; BR=bruise; CPB=colorado potato beetle; CS=common scab; DAE=deep apical eyes; DSA=deep stolen end; EB=early blight; ECB= European corn borer; EL= enlarged lenticels; FS=fusarium wilt; GC=growth cracks; HI= herbicide injury; HS=heat sprouts; IL=infected lenticels; LB=late blight; LHD=leaf hopper damage; MS=mishaped tubers; PE=pink eye; PR=pink rot; PLRV=potato leaf roll virus; PTS=very pointed tubers; PS=powdery scab; PVA, PVX, PVY=potato viruses A, X, Y; RZ=Rhizoctonia; SEB=stem end browning; SG=secondary growth; SIS=silver scurf; SKN=skins; SS=sunscald; SR=soft rot; STST=sticky stolens; VW=Verticillium wilt; WSTD=weak stand; WW=wire worm; YF=yellow flesh Note:^ before code indicates high levels