Split Application under Reduced Nitrogen Rate Favors High Yield by Altering Endogenous Hormones and C/N Ratio in Sweet Potato

A process for reducing the nitrogen (N) application rate while maintaining sweet potato yield urgently needs to be determined. A two-year pot experiment was conducted with three N management strategies to explore the mechanism underlying yield increase caused by a split application under a reduced N rate through an investigation of the changes in the carbon (C)-N metabolism and endogenous hormone. Results revealed that, compared with conventional basal N management, split application under a reduced N rate increased storage root yield by 22.1% through improving the storage root number and mean storage root weight by 12.3% and 10.2%, respectively. During the storage root formation period, split application under a reduced N rate decreased the soil-available N (AV-N) content and N content in storage root, inducing elevated C content, C/N ratio, auxin (IAA) content, zeatin and zeatin riboside (Z + ZR) content and reduced abscisic acid (ABA) content in storage roots, promoting storage root formation. During the storage root bulking period, split application under a reduced N rate appropriately elevated the soil AV-N content and N content in the storage root which, together with increased ABA content, which enhanced C content and C/N ratio in the storage root, resulted in an improved mean storage root weight. These results will facilitate the generation of appropriate N management strategies to improve sweet potato productivity.

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Effect of cutting position and vine pruning level on yield of Sweet Potato (Ipomoea Batatas L.)

Journal of Aridland Agriculture ◽

10.25081/jaa.2019.v5.5255 ◽

1970 ◽

pp. 01-05

Author(s):

Ncube Netsai ◽

Mutetwa Moses, Mtaita Tuarira

Keyword(s):

Sweet Potato ◽

Root Length ◽

Ipomoea Batatas ◽

Block Design ◽

Root Diameter ◽

Root Weight ◽

Stem Cuttings ◽

Storage Root ◽

Storage Roots ◽

Significant Difference

There is significant variation in yield of storage roots and vines of sweet potato (Ipomoea batatas) among farmers due to use of different cutting positions and pruning of vines at different levels. This study was carried out to establish the cutting position and the vine pruning level that give the best yield of both the storage roots and vines. The study was conducted in a 3x3 factorial arrangement in Randomized Complete Block Design (RCBD) with three replications. Treatments included cutting position at three levels (apical cutting, middle cutting and basal cutting) and pruning at three levels, 0%, 25% and 50% respectively. Pruning was done. 50 days after planting. And storage root harvesting was done 100 days after planting. The two measurements were summed up to give the total vine weight. Storage root length, diameter and weight were measured at 100 DAP. Storage root length indicated significant difference (P<0.05) only among cutting positions with highest mean length (16.20 cm) obtained from apical cutting and the lowest (11.98 cm) from basal cutting. Storage root diameter, storage root weight and vine weight indicated significant interaction (P<0.05) of cutting position and vine pruning level. Highest mean root diameter and root weight were obtained from middle cutting and 25% vine pruning level, with the lowest being obtained from basal cutting and 50% vine pruning level. Highest vine weight was recorded from middle cutting and 50% vine pruning level, with the lowest being recorded from basal cutting and 0% vine pruning level. Both middle and apical stem cuttings can be recommended for higher storage root and vine yield. Vine pruning at 25% can be adopted for higher storage root yield while pruning at 50% can be suggested for higher vine yield.

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SWEET POTATO GROWTH AND ROOT DEVELOPMENT IN FRITTED CLAY MEDIA

HortScience ◽

10.21273/hortsci.25.8.855 ◽

1990 ◽

Vol 25 (8) ◽

pp. 855F-855

Author(s):

P. J. Ndolo ◽

E. G. Rhoden

Keyword(s):

Sweet Potato ◽

Root Length ◽

Dry Weight ◽

The Other ◽

Root Weight ◽

Storage Root ◽

Fibrous Root ◽

Storage Roots ◽

Potato Growth ◽

Fibrous Roots

Root growth of sweet potato [Ipomoea batatas (L) Lam.] cvs `TI-82-155', `Centennial' and `Rojo Blanco' in coarse fritted clay soil, was investigated under greenhouse conditions. The sweet potato cultivars were harvested at 41 and 82 days after planting. Dry weight of fibrous roots of all cultivars were similar at day 41. Fibrous root weight of `Rojo Blanco' increased by 5% while those of the other cultivars increased by 168%. Mean fibrous root length per centimeter depth was not significantly different among cultivars. Although fresh weight of storage roots of `Rojo Blanco' was significantly lower than those of the other cultivars, their dry weights were similar. `TI-82-155' and `Rojo Blanco' had fewer storage roots compared to the other cultivars, however, storage root length of `TI-82-155' or `Rojo Blanco' was greater than that of `Georgia Jet' or `Centennial'. Length to diameter ratio of the storage root of `Rojo Blanco' was significantly greater than that of `TI-82-155' and `Georgia Jet'.

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SWEET POTATO GROWTH AND ROOT DEVELOPMENT IN FRITTED CLAY MEDIA

HortScience ◽

10.21273/hortsci.25.8.855f ◽

1990 ◽

Vol 25 (8) ◽

pp. 855f-855

Author(s):

P. J. Ndolo ◽

E. G. Rhoden

Keyword(s):

Sweet Potato ◽

Root Length ◽

Dry Weight ◽

The Other ◽

Root Weight ◽

Storage Root ◽

Fibrous Root ◽

Storage Roots ◽

Potato Growth ◽

Fibrous Roots

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Response mechanism of sweet potato storage root formation and bulking to soil compaction and its relationship with yield

ACTA AGRONOMICA SINICA ◽

10.3724/sp.j.1006.2019.84084 ◽

2019 ◽

Vol 45 (5) ◽

pp. 755

Author(s):

Wen-Qing SHI ◽

Bin-Bin ZHANG ◽

Hong-Juan LIU ◽

Qing-Xin ZHAO ◽

Chun-Yu SHI ◽

...

Keyword(s):

Sweet Potato ◽

Soil Compaction ◽

Root Formation ◽

Potato Storage ◽

Storage Root ◽

Response Mechanism

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Nitrogen management strategies on plant growth and severities of Sclerotinia stem rot of canola in eastern Canada

Canadian Journal of Plant Science ◽

10.1139/cjps-2021-0160 ◽

2021 ◽

Author(s):

Fen Gao ◽

Yuanhong Chen ◽

SeaRa Lim ◽

Allen Xue ◽

Bao-Luo Ma

Keyword(s):

Plant Growth ◽

Seed Yield ◽

Management Strategies ◽

Stem Rot ◽

Sclerotinia Stem Rot ◽

Split Application ◽

Eastern Canada ◽

N Application ◽

Application Rates ◽

N Management

Effective nitrogen (N) management strategies are important for ensuring a balance between optimizing plant growth and minimizing disease damage. A field experiment was conducted for three years to (i) assess the effects of N fertilizer application on the growth and seed yield of canola, and severities of Sclerotinia stem rot (SSR), and (ii) determine a reasonable N-rate for optimizing plant growth and minimizing the loss from SSR in eastern Canada. The experiment was designed with factorial combinations of eight N treatments and two canola hybrids. All N-treatments reduced canola emergence with increasing preplant N application rates above 100 kg ha–1, but had a positive impact on plant height, fresh weight, dry weight and seed yield. The development of SSR showed differential responses to N application rates. Of all the treatments, the split application (50 kg N ha–1 at preplant plus 100 kg N ha–1 side-dressed at the 6-leaf stage) increased canola growth, and often produced the highest or similar seed yields to those of equivalent N rate applied as preplant. At the 150 kg ha–1 N rate, no severe development of SSR was observed in either preplant-only or split application. Overall, this study demonstrates that the split-N management strategy (50+100 kg ha–1) maintained a balance between enhancing plant growth and mitigating the negative impacts of SSR on canola.

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The use of humic acid urea fertilizer for increasing yield and utilization of nitrogen in sweet potato

Czech Journal of Genetics and Plant Breeding ◽

10.17221/24/2017 ◽

2017 ◽

Author(s):

Chen Xiaoguang ◽

Kou Meng ◽

Tang Zhonghou ◽

Zhang Aijun ◽

Li Hongmin

Keyword(s):

Humic Acid ◽

Sweet Potato ◽

Production Efficiency ◽

Potato Production ◽

Utilization Rate ◽

Nitrogen Accumulation ◽

Storage Root ◽

Nitrogen Absorption ◽

Storage Roots ◽

Urea Fertilizer

Humic acid urea fertilizer (HA-N) is a new type of slow-release nitrogenous fertilizer that can enhance utilization rate of urea, and consequently increases crop yield. However, there were few researches about the effect of HA-N on the nitrogen absorption and utilization in sweet potato production. Hence, the effect of HA-N on nitrogen accumulation and distribution, nitrogen use efficiency (NUE), and yield of sweet potato was studied in the field using the <sup>15</sup>N tracer technique. Results showed that HA-N significantly increased the number of storage roots per plant and the average fresh weight per storage root, as well as the yield increased by 29.6% compared with urea fertilizer. Furthermore, nitrogen accumulation of total plant was higher under the HA-N. In addition, HA-N significantly increased nitrogen production efficiency of fertilizer and nitrogen production efficiency. Results of a <sup>15</sup>N tracer experiment revealed that the percentage of nitrogen absorbed by plant from fertilizer increased from 31.1% to 38.7% and NUE increased from 33.5% to 44.8% with application of HA-N when compared with single N treatment, respectively. HA-N significantly increased sweet potato storage root yield, nitrogen absorption and NUE, as well as it reduced the loss of nitrogen fertilizer.

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Molecular Regulation of Storage Root Formation and Development in Sweet Potato

Horticultural Reviews: Volume 42 ◽

10.1002/9781118916827.ch03 ◽

2014 ◽

pp. 157-208 ◽

Cited By ~ 5

Author(s):

V. Ravi ◽

S.K. Chakrabarti ◽

T. Makeshkumar ◽

R. Saravanan

Keyword(s):

Sweet Potato ◽

Root Formation ◽

Molecular Regulation ◽

Storage Root

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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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