scholarly journals Cultivar Decline in Sweetpotato: II. Impact of Virus Infection on Yield and Storage Root Quality in `Beauregard' and `Hernandez'

2003 ◽  
Vol 128 (6) ◽  
pp. 856-863 ◽  
Author(s):  
A.D. Bryan ◽  
J.R. Schultheis ◽  
Z. Pesic-VanEsbroeck ◽  
G.C. Yencho

To determine the effects of Sweet potato feathery mottle virus (SPFMV), and possibly other newly described potyviruses, on sweetpotato yield and storage root appearance, virus-indexed `Beauregard' and `Hernandez' mericlones testing free of known viruses were compared with virus-infected mericlones in two separate experiments over two years. The experiments were arranged in a split-plot, randomized, complete-block design with the initial presence (VI+) or absence (VI-) of SPFMV as the whole plot factor and mericlone as the subplot factor. Plants were monitored weekly for symptoms of SPFMV and vine samples were taken for virus-indexing on Ipomoea setosa. Additional testing for selected sweetpotato viruses was done using a nitrocellulose membrane enzyme-linked immunosorbant assay. SPFMV was the only virus detected in the study, using available testing methodologies. Field monitoring indicated that §100% of the VI-plants were reinfected with SPFMV by 9 weeks after planting. The presence of virus before planting reduced yields of No. 1 roots by 26% and decreased overall appearance ratings for the three `Beauregard' mericlones. In addition, VI+ planting materials resulted in increased storage root length and reduced storage root width of both cultivars leading to increased storage root length/diameter ratios, further detracting from overall storage root appearance. The results of this study demonstrate that SPFMV contributes to cultivar decline in sweetpotato. However, the interaction of SPFMV with other newly described potyviruses, which may result in synergistic negative effects on sweetpotato yield and quality, needs further research.

2018 ◽  
Vol 3 (1) ◽  
pp. 644-651
Author(s):  
A.O. Adekiya ◽  
C.M. Aboyeji ◽  
T.M. Agbede ◽  
O. Dunsin ◽  
O.T.V. Adebiyi

Abstract Micro-nutrients especially zinc can not only increase the yield of sweet potato but can also improve the quality of tubers. Hence, experiments were carried out in 2015 and 2016 cropping seasons to determine the impact of various levels of ZnSO4 fertilizer on soil chemical properties, foliage and storage root yields and proximate qualities of sweet potato (Ipomoea batatas L.). The experiments consisted of 5 levels (0, 5, 10, 15 and 20 kg ha-1) of ZnSO4 fertilizer. These were arranged in a randomized complete block design and replicated three times. ZnSO4 increased (with the exception of P) soil chemical properties compared with the control. N, K, Ca, Mg and Zn were increased up to the 20 kg ha-1 ZnSO4 level in both years. ZnSO4 reduced P concentrations in soil as the level increased. For sweet potato performance, 5 kg ha-1 ZnSO4 fertilizer had the highest values of foliage yield (vine length and vine weight) and storage root yield. Using the mean of the two years and compared with the control, ZnSO4 fertilizer at 5 kg ha-1 increased storage root yield of sweet potato by 17.4%. On fitting the mean storage root yield data of the two years with a cubic equation, the optimum rate of Zn for sweet potato was found to be 3.9 kg ha-1 to achieve the maximum sweet potato yield. In this study, relative to the control, ZnSO4 fertilizer increased moisture and decreased the fibre contents of sweet potato. There were no consistent patterns of variation between the 5, 10, 15 and 20 kg ha-1 ZnSO4 treatments for proximate qualities except that the highest values of fat, protein, carbohydrate and ash was at 5 kg ha-1 ZnSO4.


2012 ◽  
Vol 26 (3) ◽  
pp. 474-479 ◽  
Author(s):  
Stephen L. Meyers ◽  
Katherine M. Jennings ◽  
David W. Monks

Studies were conducted in 2008 and 2009 to determine the effect ofS-metolachlor rate and application time on sweetpotato cultivar injury and storage root shape under conditions of excessive moisture at the time of application.S-metolachlor at 1.1, 2.2, or 3.4 kg ai ha−1was applied immediately after transplanting or 2 wk after transplanting (WATP) to ‘Beauregard’, ‘Covington’, ‘DM02-180’, ‘Hatteras’, and ‘Murasaki-29’ sweetpotato. One and three d afterS-metolachlor application plots received 1.9 cm rainfall or irrigation.S-metolachlor applied immediately after transplanting resulted in increased sweetpotato stunting 4 and 12 WATP, decreased no. 1 and marketable sweetpotato yields, and decreased storage root length to width ratio compared with the nontreated check. Sweetpotato stunting, no. 1 and marketable yields, and storage root length to width ratio in treatments receivingS-metolachlor 2 WATP were similar to the nontreated check. In 2008, Covington and Hattaras stunting 12 WATP was greater at 2.2 and 3.4 kg ha−1(11 to 16%) than 1.1 kg ha−1(1 to 2%). In 2009,S-metolachlor at 3.4 kg ha−1was more injurious 4 WATP than 2.2 kg ha−1and 1.1 kg ha−1. While cultivar by treatment interactions did exist, injury, yield, and storage root length to width ratio trends were similar among all cultivars used in this study.


HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 760g-761
Author(s):  
Jonathan R. Schultheis ◽  
Dennis E. Adams

Boron has been used to overcome the disorder blister in varieties such as `Jewel'. `Hernandez' is an attractive, good-yielding variety with uniform shape that will consistently pack out at 80% to 90%. Over time in storage, however, roots develop blister-like symptoms, rendering roots unmarketable for fresh market. Our objective was to evaluate the effect of different B rates and application times on the yield and quality of `Hernandez' roots. Rates were varied up to 2.24 kg actual B/ha 6 days after planting, while various soil and foliar application times (6, 34, and 69 days after planting) were evaluated at 1.12 kg·ha–1. In 1994, three row plots were arranged in a randomized complete block design and replicated four times. Planting was on a deep sand to maximize the effect of the B carrier Solubor. Roots were harvested, graded, and weighed 120 days after planting and storage roots evaluated for blister-like symptoms in Mar. 1995. No significant differences in yield were attributed to B rate or application method. Blister-like symptoms were more severe when no B was applied; however, application of B did not eliminate symptoms, as most roots had the blister-like appearance. Boron application did not solve the problem, but symptoms were less apparent when some B was applied.


1970 ◽  
pp. 01-05
Author(s):  
Ncube Netsai ◽  
Mutetwa Moses, Mtaita Tuarira

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.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1078a-1078
Author(s):  
E. Niyonsaba ◽  
E. G. Rhoden ◽  
P. K. Biswas ◽  
G.W. Carver

A study was conducted to assess the effects of gypsum on the early growth and storage root yield of sweet potato (Ipomoea batatas) cvs `Jewel', `Goergia Jet' and `TI-155'. Three rates of gypsum were applied (1.03, 2.06 and 3.09 tons/acre). These represented half, recommended and 1.5 recommended levels. The experiment was a randomized complete block design with a split plot arrangement of treatment. Leaf area, total dry matter, leaf dry matter and stat-age root weight were recorded at 30-day intervals. Plants receiving half the recommended levels of gypsum produced the highest total storage root dry matter (0.306 t/a) and the highest leaf dry matter (0.116 t/a). Although a positive relationship exists between leaf dry matter and storage root yield between 90 and 120 days, there was no such relationship between those parameters either at 30 and 60 days or 60 and 90 days after transplanting.


2017 ◽  
Vol 35 (1) ◽  
pp. 1
Author(s):  
Taniela K. Siose ◽  
Danilo F. Guinto

There is need to diversify crop production in Samoa which currently depends mainly on taro crop, that has proved to be susceptible to fungus and other diseases, to as safeguard against risks of crop failures and adapt to climatic changes. The potential of introducing sweetpotato as a second staple food in Samoa is explored in this study. The study analyses the suitability of sweetpotato cultivars in Samoan agro-environment and major soil types. For this purpose a twenty week pot experiment was conducted to investigate the performance of three improved sweetpotato cultivars (IB/PR/12, IB/PR/13 and IB/PH/03) on four different types of soils in Samoa (Savaia calcareous sandy loam, Matafa’a red acidic, Faleula silty clay and Saleimoa silty clay) in a factorial arrangement of treatments in randomised complete block design with three replications. Results revealed that soil type had a significant effect on vine growth, and storage root yield with the best yield obtained in the silty clay soils having high K content. Retarded plant growth observed under the acidic soil having low K content resulted in lowest storage root yield. A significant varietal difference was recorded in sweetpotato growth and yield. IB/PH/03 was inferior in vine length, but produced comparatively highest number of vines per plant, and storage root yield attesting its adaptability in all the four tested soil types of Samoa and has potentiality to be promoted for wider adoption. A follow-up field study is needed to verify our preliminary results under pot culture on different soil types of Samoa.


2019 ◽  
Vol 20 (2) ◽  
pp. 380-386
Author(s):  
RATNA DEWI ◽  
SETYO DWI UTOMO ◽  
M. KAMAL ◽  
PAUL B. TIMOTIWU ◽  
SITI NURDJANAH

Dewi R, Utomo SD, Kamal M, Timotiwu PB, Nurdjanah S. 2019. Genetic and phenotypic diversity, heritability, and correlation between the quantitative characters on 30 sweet potato germplasms in Lampung, Indonesia. Biodiversitas 20: 380-386. Local food commodities such as sweet potato is an alternative rice substitute food which has high nutritional content. Estimating the value of genetic diversity, heritability and correlation between quantitative characters with the weight of large storage root per plant, is needed in the selection program for the development of quality sweet potato varieties. The purpose of this study was to find out information about genetic diversity, heritability, and correlation between quantitative characters with the weight of large storage root in 30 local Lampung sweet potato germplasm, introduction and national superior genotypes. The study was carried out in the Politeknik Negeri Lampung experimental garden from September 2017 to January 2018. Using 30 genotypes of sweet potato germplasm. The study was arranged in a randomized block design (RBD) with two replications. The results showed that all characters (weight of large storage root, number of large storage root, storage root length, storage root diameter, vines length, segment length, vines diameter, and weight of vines) had a value of genetic diversity, whereas wide phenotypic diversity and has a high value of heritability. Genetic factors more influence all characters in this study compared to environmental factors. The results of the correlation analysis showed that the characters of the weight of large storage root, storage root length, and storage root diameter were positively correlated with the weight of the storage root. Whereas, the length of vines is negatively correlated with the weight of large storage. The character of the segment length, vines diameter and weight of vines did not correlate with the weight of large storage root. The character of the segment length, vines diameter and weight of vines did not correlate with the weight of large storage root. Cluster analysis results from 30 sweet potato genotypes were grouped into 13 clusters. Based on similarity of character and provenance. The germplasm of 30 Sweet potato genotypes found in Politeknik Negeri Lampung can be selected and crossed to create the desired superior characters.


2018 ◽  
Vol 33 (1) ◽  
pp. 128-134 ◽  
Author(s):  
Shawn C. Beam ◽  
Sushila Chaudhari ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Stephen L. Meyers ◽  
...  

AbstractStudies were conducted to determine the tolerance of sweetpotato and Palmer amaranth control to a premix of flumioxazin and pyroxasulfone pretransplant (PREtr) followed by (fb) irrigation. Greenhouse studies were conducted in a factorial arrangement of four herbicide rates (flumioxazin/pyroxasulfone PREtr at 105/133 and 57/72 g ai ha–1, S-metolachlor PREtr 803 g ai ha–1, nontreated) by three irrigation timings [2, 5, and 14 d after transplanting (DAP)]. Field studies were conducted in a factorial arrangement of seven herbicide treatments (flumioxazin/pyroxasulfone PREtr at 40/51, 57/72, 63/80, and 105/133 g ha–1, 107 g ha–1 flumioxazin PREtr fb 803 g ha–1S-metolachlor 7 to 10 DAP, and season-long weedy and weed-free checks) by three 1.9-cm irrigation timings (0 to 2, 3 to 5, or 14 DAP). In greenhouse studies, flumioxazin/pyroxasulfone reduced sweetpotato vine length and shoot and storage root fresh biomass compared to the nontreated check and S-metolachlor. Irrigation timing had no influence on vine length and root fresh biomass. In field studies, Palmer amaranth control was≥91% season-long regardless of flumioxazin/pyroxasulfone rate or irrigation timing. At 38 DAP, sweetpotato injury was≤37 and≤9% at locations 1 and 2, respectively. Visual estimates of sweetpotato injury from flumioxazin/pyroxasulfone were greater when irrigation timing was delayed 3 to 5 or 14 DAP (22 and 20%, respectively) compared to 0 to 2 DAP (7%) at location 1 but similar at location 2. Irrigation timing did not influence no.1, jumbo, or marketable yields or root length-to-width ratio. With the exception of 105/133 g ha–1, all rates of flumioxazin/pyroxasulfone resulted in marketable sweetpotato yield and root length-to-width ratio similar to flumioxazin fb S-metolachlor or the weed-free checks. In conclusion, flumioxazin/pyroxasulfone PREtr at 40/51, 57/72, and 63/80 g ha–1 has potential for use in sweetpotato for Palmer amaranth control without causing significant crop injury and yield reduction.


2014 ◽  
Vol 153 (7) ◽  
pp. 1267-1280 ◽  
Author(s):  
R. TUMUHIMBISE ◽  
P. SHANAHAN ◽  
R. MELIS ◽  
R. KAWUKI

SUMMARYCassava (Manihot esculenta Crantz) is an important storage root crop with largely unexplored and unexplained potentially valuable genetic variability. Genetic variability is important in selecting suitable genotypes for crop improvement. The present study was aimed at assessing the extent of variability in cassava storage root bulking, based on fresh storage root yield accumulated over time. Twelve cassava genotypes were evaluated in a randomized complete block design at three contrasting locations in Uganda. Assessments were done from 5 to 13 months after planting at intervals of 2 months. Genotype, harvest time, location and their interactions were significantly different for fresh storage root yield and most of the other traits assessed. Estimates of variance components revealed that a large portion of the phenotypic variance was accounted for by the genotypic component for all traits assessed indicative of substantial genetic variability among the genotypes evaluated. This genetic variability is important in a hybridization and/or selection programme because it implies that significant genetic gain through phenotypic selection is possible for the traits assessed. Fresh storage root yield was positively and significantly correlated with storage root girth, harvest index, shoot mass and storage root number. The information generated will inform future breeding initiatives to develop early-bulking cassava genotypes with farmer-preferred traits in Uganda.


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