Sweetpotato Transplant Holding Duration Effects on Plant Survival and Yield

Studies were conducted in North Carolina to determine the effect of holding durations (HDs) [0, 1, 3, 5, and 7 days before planting (DBP)] of ‘Covington’ sweetpotato (Ipomoea batatas) transplants on plant stand and storage root numbers and yield in production fields. In a second field study, the effect of preplant irrigation (PI) treatments (PI and nonirrigation) were evaluated along with the transplant HD on plant stand, storage root numbers, and yield. Transplants held for 7 DBP did not survive as well as the other treatments (lower plant stands) and had lower no. 1, marketable, and total storage root numbers and yields than other holding treatments. HD of 1 or 3 DBP resulted in higher plant stands, and no. 1, marketable, and total numbers of storage roots and yields than holding for 0, 5, or 7 DBP. This study affirms the importance of soil moisture at and shortly after planting for transplant survival and yield. Holding transplants for 1–3 DBP can improve stand establishment and yields when dry conditions occur either before or soon after planting. However, holding transplants for 7 DBP can result in reduced plant stands and yields when stress/dry conditions occur soon after planting.

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Occurrence, Severity and Initiation of Internal Necrosis in ‘Covington’ Sweetpotato

HortTechnology ◽

10.21273/horttech.25.3.340 ◽

2015 ◽

Vol 25 (3) ◽

pp. 340-348 ◽

Cited By ~ 1

Author(s):

Chen Jiang ◽

Penelope Perkins-Veazie ◽

Sylvia M. Blankenship ◽

Michael D. Boyette ◽

Zvezdana Pesic-VanEsbroeck ◽

...

Keyword(s):

North Carolina ◽

Relative Humidity ◽

Ipomoea Batatas ◽

Storage Temperature ◽

The State ◽

Storage Root ◽

Storage Roots ◽

Harvest Aid ◽

Internal Necrosis ◽

Storage Facilities

A series of studies were conducted to better understand the occurrence and causes of internal necrosis (IN) in ‘Covington’ sweetpotato (Ipomoea batatas). Assessment of the problem among the industry was done for 2 years and revealed that IN was widespread in commercial storage facilities throughout the state of North Carolina; both incidence and severity were generally low (<10% incidence with minimal severity of symptoms). A few storage rooms had a high percentage of IN with severe storage root symptoms but results were inconsistent across years and among rooms. Preharvest studies with commercially used insecticides did not induce IN, but the harvest aid ethephon consistently induced IN with an incidence higher than 50%. Internal necrosis symptoms were not detectable at harvest, and earliest consistent incidence was observed 6 days after harvest (DAH) during the curing phase. Symptoms became more prevalent and severe at 30 DAH. However, in commercial storage rooms, no relationship was found between IN incidence and postcuring storage temperature or relative humidity (RH) conditions. Sweetpotato storage roots stored in air-tight barrels and exposed to 100 ppm ethylene after curing showed no relationship between the presence of ethylene gas in storage and incidence of IN. Our results indicate that IN incidence of ‘Covington’ is erratic with no obvious cause among storage rooms and that initiation of IN may occur most frequently during the first week following harvest.

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Sweetpotato `Beauregard' Mericlones Vary in Yield, Vine Characteristics, and Storage Root Size and Shape Attributes

HortScience ◽

10.21273/hortsci.38.6.1089 ◽

2003 ◽

Vol 38 (6) ◽

pp. 1089-1092 ◽

Cited By ~ 2

Author(s):

A.Q. Villordon ◽

J.M. Cannon ◽

H.L. Carroll ◽

J.W. Franklin ◽

C.A. Clark ◽

...

Keyword(s):

Ipomoea Batatas ◽

Maximum Yield ◽

Storage Root ◽

Storage Roots ◽

Marketable Yield ◽

Methods Of Evaluation ◽

Foundation Seed ◽

Axis Length ◽

And Storage ◽

Selection Of

Yield tests and evaluation of selected storage root and vine characters were conducted among 12 `Beauregard' sweetpotato [Ipomoea batatas (L.) Lam.] mericlones. Maximum yield differences were 43%, 48%, 79%, and 40% for U.S. #1, canners, jumbos, and total marketable yield, respectively. Additive main effect and multiplicative interaction (AMMI) biplot analysis was useful in graphically presenting the yield differences and stability patterns of mericlones. Differences were also detected in vine length, internode diameter, and internode length. Digital image analysis of U.S. #1 storage roots also revealed differences in storage root minor axis length, roundness, and elongation attributes. The results provide valuable information for enhancing current methods of evaluation and selection of mericlones for inclusion in sweetpotato foundation seed programs.

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The Expression of IbMYB1 Is Essential to Maintain the Purple Color of Leaf and Storage Root in Sweet Potato [Ipomoea batatas (L.) Lam]

Frontiers in Plant Science ◽

10.3389/fpls.2021.688707 ◽

2021 ◽

Vol 12 ◽

Author(s):

Daowei Zhang ◽

Yongjun Tan ◽

Fang Dong ◽

Ya Zhang ◽

Yanlan Huang ◽

...

Keyword(s):

Sweet Potato ◽

Ipomoea Batatas ◽

Anthocyanin Biosynthesis ◽

Expression Patterns ◽

Anthocyanin Content ◽

Storage Root ◽

Storage Roots ◽

Cultivated Species ◽

Purple Color ◽

And Storage

IbMYB1 was one of the major anthocyanin biosynthesis regulatory genes that has been identified and utilized in purple-fleshed sweet potato breeding. At least three members of this gene, namely, IbMYB1-1, -2a, and -2b, have been reported. We found that IbMYB1-2a and -2b are not necessary for anthocyanin accumulation in a variety of cultivated species (hexaploid) with purple shoots or purplish rings/spots of flesh. Transcriptomic and quantitative reverse transcription PCR (RT-qPCR) analyses revealed that persistent and vigorous expression of IbMYB1 is essential to maintain the purple color of leaves and storage roots in this type of cultivated species, which did not contain IbMYB1-2 gene members. Compared with IbbHLH2, IbMYB1 is an early response gene of anthocyanin biosynthesis in sweet potato. It cannot exclude the possibility that other MYBs participate in this gene regulation networks. Twenty-two MYB-like genes were identified from 156 MYBs to be highly positively or negatively correlated with the anthocyanin content in leaves or flesh. Even so, the IbMYB1 was most coordinately expressed with anthocyanin biosynthesis genes. Differences in flanking and coding sequences confirm that IbMYB2s, the highest similarity genes of IbMYB1, are not the members of IbMYB1. This phenomenon indicates that there may be more members of IbMYB1 in sweet potato, and the genetic complementation of these members is involved in the regulation of anthocyanin biosynthesis. The 3′ flanking sequence of IbMYB1-1 is homologous to the retrotransposon sequence of TNT1-94. Transposon movement is involved in the formation of multiple members of IbMYB1. This study provides critical insights into the expression patterns of IbMYB1, which are involved in the regulation of anthocyanin biosynthesis in the leaf and storage root. Notably, our study also emphasized the presence of a multiple member of IbMYB1 for genetic improvement.

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RESPONSE OF OF SWEETPOTATO GROWN IN NFT TO DIFFERENT PHOTOPERIODS

HortScience ◽

10.21273/hortsci.27.6.665f ◽

1992 ◽

Vol 27 (6) ◽

pp. 665f-665

Author(s):

D. G. Mortley ◽

C. K. Bonsi ◽

W. A. Hill ◽

P. A. Loretan ◽

C. E. Morris ◽

...

Keyword(s):

Ipomoea Batatas ◽

Dry Weight ◽

Root Number ◽

Storage Root ◽

Growth Responses ◽

Storage Roots ◽

Area Index ◽

Chamber Studies ◽

Growth Chamber Studies ◽

And Storage

Growth chamber studies were conducted to determine growth responses of sweetpotato [Ipomoea batatas (L.) Lam) to differing photoperiods (PP) when grown by use of NFT. Four vine cuttings (15 cm length) of GA Jet and TI-155 were grown for 120 days at 12/12, 15/9, 18/6, and 21/3 light/dark PP. Irradiance averaged 427 umol m-2 s-1, with day/night temperatures of 28/22C and 70% RH. A modified half Hoagland's solution was used. Number of storage roots/plant, and storage root fresh and dry weights for GA Jet increased as PP increased from 12 to 21 h, while storage root fresh and dry weights for TI-155 increased up to 18 h PP but declined at 21 h PP. Storage root number/plant for TI-155 declined at 15 h PP but was higher at both 18 and 21 h PP. Highest foliage dry weight for GA Jet was obtained at 21 h PP while that for TI-155 was obtained at 18 h PP. Leaf area index (LAI) for GA Jet increased with increased PP, while LAI for TI-155 increased with increased PP up to 18 h then declined at 21 h PP.

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Early-season Soil Moisture Deficit Reduces Sweetpotato Storage Root Initiation and Development

HortScience ◽

10.21273/hortsci.48.12.1457 ◽

2013 ◽

Vol 48 (12) ◽

pp. 1457-1462 ◽

Cited By ~ 14

Author(s):

Bandara Gajanayake ◽

K. Raja Reddy ◽

Mark W. Shankle ◽

Ramon A. Arancibia

Keyword(s):

Soil Moisture ◽

Ipomoea Batatas ◽

Root Formation ◽

Developmental Process ◽

Root Initiation ◽

Storage Root ◽

Storage Roots ◽

Root Numbers ◽

Functional Relationships ◽

Wide Range

Sweetpotato [Ipomoea batatas (L.) Lam.] storage root formation is a complex developmental process. Little quantitative information is available on storage root initiation in response to a wide range of soil moisture levels. This study aimed to quantify the effects of different levels of soil moisture on sweetpotato storage root initiation and to develop functional relationships for crop modeling. Five levels of soil moisture, 0.256, 0.216, 0.164, 0.107, and 0.058 m3·m−3 soil, were maintained using sensor-based soil moisture monitoring and semiautomated programmed irrigation. Two commercial sweetpotato cultivars, Beauregard and Evangeline, were grown in pots under greenhouse conditions and treatments were imposed from transplanting to 50 days. Identification of storage roots was based on anatomical, using cross-sections of adventitious roots, and visual features harvested at 5-day intervals from 14 to 50 days after transplanting (DAT). Recorded time-series storage root numbers exhibited sigmoidal responses at all soil moisture levels in both cultivars. Time to 50% storage root initiation and maximum storage root numbers were estimated from those curves. Rate of storage root development was determined as a reciprocal of time to 50% storage root formation data. Time to 50% storage root initiation declined quadratically from 0.05 to 0.15 m3·m−3 soil moisture and increased slightly at the higher soil moisture levels in both the cultivars. Cultivars differed in time to 50% storage root initiation and the storage root developmental rate. Soil moisture optima for storage root initiation were 0.168 and 0.199 m3·m−3 soil, equivalent to 63% and 75% field capacity for cultivars Beauregard and Evangeline, respectively. The data and the inferences derived from the functional algorithms developed in this study could be used to advise growers to schedule irrigation more precisely, make planting decisions based on available soil moisture, and to develop sweetpotato crop models for field applications.

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Cultivar Decline in Sweetpotato: I. Impact of Micropropagation on Yield, Storage Root Quality, and Virus Incidence in `Beauregard'

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.128.6.0846 ◽

2003 ◽

Vol 128 (6) ◽

pp. 846-855 ◽

Cited By ~ 15

Author(s):

A.D. Bryan ◽

Z. Pesic-VanEsbroeck ◽

J.R. Schultheis ◽

K.V. Pecota ◽

W.H. Swallow ◽

...

Keyword(s):

North Carolina ◽

Total Yield ◽

Growing Season ◽

Storage Root ◽

Storage Roots ◽

Planting Material ◽

Field Samples ◽

And Storage ◽

Root Quality ◽

Quality Measurements

Decline in sweetpotato yield and storage root quality has been attributed to the accumulation of viruses, pathogens and mutations. To document the effects of decline on yield and storage root quality, two micropropagated, virus-indexed, greenhouse produced G1 `Beauregard' meristem-tip cultured clones, B94-14 and B94-34, were compared with 1) micropropagated B94-14 and B94-34 clones propagated adventitiously up to five years in the field (G2, G3, G4, G5); and 2) nonmicropropagated, unimproved stock of `Beauregard' seed in field trials during 1997 to 2001. At least three trials were located each year in sweetpotato producing regions in North Carolina. In 2000 and 2001, two trials were monitored weekly for foliar symptoms of Sweet potato feathery mottle virus (SPFMV) and other potyviruses, and virus-indexed for selected viruses using Ipomoea setosa and nitrocellulose enzyme linked immunosorbant assays (NCM-ELISA). Only SPFMV was detected in field samples using NCM-ELISA, but this does not rule out the presence of newly described viruses infecting sweetpotato for which tests were unavailable. Monitoring indicated that all G1 plants became infected with SPFMV by the end of the growing season, and that G2 to G5 plants were probably infected in their initial growing season. G1 plants consistently produced higher total yield, total marketable yield (TMY), U.S. No. 1 root yield and percent No. 1 yield than G2 to G5 plants. G1 plants also produced storage roots with more uniform shapes and better overall appearance than storage roots produced from G2 to G5 plants. Also, G2 to G5 storage roots tended to be longer than G1 storage roots. Rank mean yield and storage root quality measurements of each location were consistent with means averaged over locations per year and suggested a decrease in yield and storage root quality with successive seasons of adventitious propagation. Linear regression analysis used to model yield and storage root quality measurements of seed generations G1 to G5 indicated that total yield, TMY, No. 1 yield, percent No. 1 yield, shape uniformity, and overall appearance decreased gradually, and that length/diameter ratios increased gradually with generation. The rate of decline in No. 1 yield was greater for B94-34 compared to B94-14. Both viruses and mutations of adventitious sprouts arising from storage roots probably contribute to cultivar decline in sweetpotato, but further studies are needed to determine their relative importance. A simple profitability analysis for G1 vs. G2-G4 planting material conducted to facilitate better understanding of the economics of using micropropagated planting material to produce a crop in North Carolina revealed that growers have a potential net return of $2203/ha for G1 plants, $5030/ha for G2 plants, and $4394/ha for G5 plants. Thus, while G1 plants generally produce higher No. 1 yields, a greater monetary return can be achieved using G2 planting materials because of the high costs associated with producing G1 plants. Based on this analysis, the best returns are accrued when growers plant their crop using G2 and/or G3 seed.

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Potassium Fertilization Stimulates Sucrose-to-Starch Conversion and Root Formation in Sweet Potato (Ipomoea batatas (L.) Lam.)

International Journal of Molecular Sciences ◽

10.3390/ijms22094826 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4826

Author(s):

Yang Gao ◽

Zhonghou Tang ◽

Houqiang Xia ◽

Minfei Sheng ◽

Ming Liu ◽

...

Keyword(s):

Sweet Potato ◽

Ipomoea Batatas ◽

Intercellular Co2 Concentration ◽

Biomass Accumulation ◽

Starch Accumulation ◽

Storage Root ◽

Root Yield ◽

Starch Conversion ◽

And Storage ◽

Low K

A field experiment was established to study sweet potato growth, starch dynamic accumulation, key enzymes and gene transcription in the sucrose-to-starch conversion and their relationships under six K2O rates using Ningzishu 1 (sensitive to low-K) and Xushu 32 (tolerant to low-K). The results indicated that K application significantly improved the biomass accumulation of plant and storage root, although treatments at high levels of K, i.e., 300–375 kg K2O ha−1, significantly decreased plant biomass and storage root yield. Compared with the no-K treatment, K application enhanced the biomass accumulation of plant and storage root by 3–47% and 13–45%, respectively, through promoting the biomass accumulation rate. Additionally, K application also enhanced the photosynthetic capacity of sweet potato. In this study, low stomatal conductance and net photosynthetic rate (Pn) accompanied with decreased intercellular CO2 concentration were observed in the no-K treatment at 35 DAT, indicating that Pn was reduced mainly due to stomatal limitation; at 55 DAT, reduced Pn in the no-K treatment was caused by non-stomatal factors. Compared with the no-K treatment, the content of sucrose, amylose and amylopectin decreased by 9–34%, 9–23% and 6–19%, respectively, but starch accumulation increased by 11–21% under K supply. The activities of sucrose synthetase (SuSy), adenosine-diphosphate-glucose pyrophosphorylase (AGPase), starch synthase (SSS) and the transcription of Susy, AGP, SSS34 and SSS67 were enhanced by K application and had positive relationships with starch accumulation. Therefore, K application promoted starch accumulation and storage root yield through regulating the activities and genes transcription of SuSy, AGPase and SSS in the sucrose-to-starch conversion.

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Physiological and Anatomical Characterization of a Late-storage Root-forming Mutant of Sweetpotato

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.127.2.178 ◽

2002 ◽

Vol 127 (2) ◽

pp. 178-183 ◽

Cited By ~ 12

Author(s):

Makoto Nakatani ◽

Masaru Tanaka ◽

Masaru Yoshinaga

Keyword(s):

Cross Sections ◽

Ipomoea Batatas ◽

Root Formation ◽

Morphological Characteristics ◽

Zeatin Riboside ◽

Storage Root ◽

Storage Roots ◽

Physiological Mechanisms ◽

Maximum Root

A late-storage root-forming mutant (`KM95-A68') of sweetpotato [Ipomoea batatas (L.) Poir.] was characterized to clarify the genetic and physiological mechanisms of storage root formation. This mutant originated from a somaclonal mutation of `Kokei No. 14'. Storage roots of `KM95-A68' are rare and, when formed, develop 2 or 3 weeks later than those of `Kokei No. 14' from which it originated. Morphological characteristics of the canopy and leaf photosynthetic rates of `KM95-A68' were similar to those of `Kokei No. 14'. No apparent differences were observed in the anatomy of root cross sections of `KM95-A68' and `Kokei No. 14'. An apparent increase in the root zeatin riboside (ZR) levels were observed in `Kokei No. 14' at storage root formation. Root ZR levels differed between `Kokei No. 14' and `KM95-A68'. The onset of increase in root ZR levels was delayed by 2 or 3 weeks in `KM95-A68' in comparison to `Kokei No. 14'. Maximum root ZR levels in `Kokei No. 14' were 2.2 times higher in comparison to `KM95-A68'. This appeared to be a factor in delayed storage root formation of `KM95-A68'. Results of reciprocal grafts of `KM95-A68' and `Kokei No. 14' indicated that the late storage root-forming characteristic of `KM95-A68' is a characteristic that arises from the root itself.

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Sweetpotato Tip Rot Incidence Is Increased by Preharvest Applications of Ethephon and Reduced by Curing

HortTechnology ◽

10.21273/horttech.23.3.288 ◽

2013 ◽

Vol 23 (3) ◽

pp. 288-293 ◽

Cited By ~ 4

Author(s):

Ramón A. Arancibia ◽

Jeffrey L. Main ◽

Christopher A. Clark

Keyword(s):

Ipomoea Batatas ◽

Unknown Etiology ◽

Research Station ◽

Storage Root ◽

Storage Roots ◽

Induced Stress ◽

Potential Association ◽

Relationship Of ◽

On Farm

Tip rot, or restricted end rot, is a new sweetpotato (Ipomoea batatas) disease/disorder in Mississippi with unknown etiology. Since pathogen isolations have been inconsistent, a relationship of this disorder with stress is proposed. This disease/disorder is manifested as a restricted lesion at or close to the proximal end of the storage root and appears after 2 to 4 weeks in storage. In many cases, the lesion necrosis expands internally. On-farm and research station studies with preharvest foliar applications of ethephon were conducted in Mississippi to determine the potential association of tip rot with ethephon-induced stress. In addition, the effects of ethephon rate and interval between application and harvest on tip rot were investigated. After 1 to 2 months in storage, tip rot incidence was observed mostly in storage roots from ethephon-treated plants. The increase in tip rot incidence was well correlated with ethephon rate. These results suggest that preharvest applications of ethephon trigger a response that results in the tip rot disorder.

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Incidence of End Rots and Internal Necrosis in Sweetpotato Is Affected by Cultivar, Curing, and Ethephon Defoliation

HortTechnology ◽

10.21273/horttech.23.6.886 ◽

2013 ◽

Vol 23 (6) ◽

pp. 886-897 ◽

Cited By ~ 2

Author(s):

Christopher A. Clark ◽

Washington L. da Silva ◽

Ramón A. Arancibia ◽

Jeff L. Main ◽

Jonathan R. Schultheis ◽

...

Keyword(s):

Ipomoea Batatas ◽

Breeding Line ◽

Storage Roots ◽

Postharvest Storage ◽

Breeding Lines ◽

Multiple Environments ◽

Internal Necrosis ◽

Production Areas ◽

And Storage

Two distinct syndromes have emerged in some production areas that have caused losses of sweetpotato (Ipomoea batatas) storage roots during postharvest storage: a complex of fungal rots (end rots) progressing from either end of storage roots and a necrotic reaction (internal necrosis) progressing internally from the proximal end of storage roots. This study was conducted in multiple environments to evaluate whether the use of preharvest ethephon application and storage with or without curing after harvest could be used to screen sweetpotato breeding lines for susceptibility/resistance to these two disorders. Treating vines with ethephon 2 weeks before harvest and placing harvested roots directly into storage at 60 °F without curing resulted in the greatest incidence of end rots in each state and there were significant differences in incidence among the sweetpotato genotypes evaluated. However, when ethephon was not used and roots were cured immediately after harvest, the incidence of end rots was low in all the genotypes evaluated except for one breeding line. Incidence and severity of internal necrosis were greatest when ethephon was applied preharvest and roots were cured immediately after harvest, but two cultivars, Hatteras and Covington, had significantly more internal necrosis than all others.

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