scholarly journals 449 PS 288 EVALUATION OF SWEETPOTATO GERMPLASM FOR RESISTANCE TO THE SWEETPOTATO WEEVIL

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 495e-495
Author(s):  
Paul G. Thompson ◽  
John C. Schneider ◽  
Boyett Graves

One hundred one accessions from the U.S. germplasm collection were evaluated in field trials for sweetpotato weevil resistance. Weevils were collected from 4 separate Mississippi locations during the winter of 1992-93. They were increased in culture and 6 adult females and 6 males were applied to the crown of each plant percentage of uninjured storage roots ranged from 53 to 99. The most highly resistant control, Regal, had 79% and the most susceptible, Centennial, 60% uninjured roots. Uninjured root numbers ranged from 0.03 to 3.82 per plant. Regal had 2.1 and Centennial 1.88 uninjured roots per plant. Seventy-five accessions produced higher percentages of uninjured roots than Regal. However, 48 of those accessions produced less than one root per plant and previous results indicated that estimates with low storage root numbers lack precision. Fourteen accessions produced as many or more roots than Regal and also higher percentages and numbers of uninjured roots.

2017 ◽  
Vol 27 (6) ◽  
pp. 818-823 ◽  
Author(s):  
William B. Thompson ◽  
Jonathan R. Schultheis ◽  
Sushila Chaudhari ◽  
David W. Monks ◽  
Katherine M. Jennings ◽  
...  

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.


2018 ◽  
Vol 28 (5) ◽  
pp. 676-683
Author(s):  
Susan C. Miyasaka ◽  
Sharon Motomura-Wages ◽  
Ishakh Pulakkatu-Thodi ◽  
Michael J. Melzer ◽  
Christopher A. Clark ◽  
...  

Tissue-cultured, virus-tested (TC) plantlets of sweetpotato (Ipomoea batatas var. batatas) cultivars Okinawan, LA 08-21p, and Murasaki-29 were obtained from Louisiana State University Agricultural Center. The objectives of field trials conducted at the Kula Agricultural Park, Maui, HI, were to compare yield and pest resistance of 1) ‘Okinawan’ obtained from a commercial (C) field with TC ‘Okinawan’ and 2) TC Okinawan with the aforementioned TC cultivars. Trials were planted Oct. 2015 and Aug. 2016 and harvested 5 months later. Storage roots were graded according to State of Hawai’i standards, and marketable yields included Grades AA, A, and B. In addition, injuries due to sweetpotato weevil (Cylas formicarius elegantulus) or rough sweetpotato weevil (Blosyrus asellus) were estimated. In both trials, fresh and dry weights of marketable storage roots of TC ‘Okinawan’ were nearly twice those from commercial planting material. In both trials, marketable fresh weights differed among the three TC cultivars; however, significant interactions were found, indicating that yields of cultivars differed between years. In the first field trial, ‘LA 08-21p’ had fresh marketable yields 1.6 to 1.7 times greater than TC ‘Okinawan’ and Murasaki-29, respectively. In the second trial, fresh marketable yields of TC ‘Okinawan’ and ‘LA 08-21p’were similar and 1.7 to 1.5 times greater than that of ‘Murasaki-29’, respectively. In both trials, ‘LA 08-21p’ had greater sweetpotato weevil injury than did the other two cultivars. Interestingly, in the second year, TC ‘Okinawan’ had greater rough sweetpotato weevil injury than did the other cultivars. Our results indicate that tissue-cultured planting materials increased marketable yields of TC ‘Okinawan’ compared with C ‘Okinawan’ sweetpotato and that the other TC cultivars did not produce greater yields than TC Okinawan.


2019 ◽  
Vol 29 (6) ◽  
pp. 967-975
Author(s):  
Susan C. Miyasaka ◽  
Marisa Wall ◽  
Don LaBonte ◽  
Alton Arakaki

Twelve sweetpotato (Ipomoea batatas var. batatas) accessions/cultivars/landraces (entries) were evaluated for yield, resistance to pests, and quality in five field trials planted at Pepe`ekeo, Hawai‘i Island, and replicated over time with blocks planted on May and Oct. 2014, Feb. and July 2015, and Jan. 2016. Plots were harvested at 4.5 to 6 months after planting. In the first two field trials, local entries planted were ‘Okinawan’, ‘Mokuau’, and ‘Kona B’, as well as PI 531094, ‘Beauregard’, PI 573309, PI 573330, ‘Darby’, ‘Pelican Processor’, and ‘Picadito’. Yields of ‘Mokuau’ and ‘Kona B’ were low and were replaced in the latter three field trials with ‘Murasaki-29’ and ‘LA 08-21p’ from Louisiana State University (LSU) AgCenter, Baton Rouge. At harvest, storage roots were graded according to State of Hawai‘i standards and marketable yields included grades AA, A, and B. Then, injuries of storage roots due to infestations of sweetpotato weevil (Cylas formicarius elegantulus) in each category were estimated. Finally, sugar concentrations, anthocyanins, and β-carotene contents were measured in storage roots. Marketable fresh weight yields of entries differed significantly, with ‘LA 08-21p’ having the greatest marketable yield. However, ‘LA 08-21p’ also had the greatest incidence of damage due to sweetpotato weevil, perhaps because of its growth habit as a tight cluster of storage roots located close to the soil surface. Entries also had significantly different sugar concentrations (fructose, glucose, sucrose, maltose, and total sugars). Concentrations of sucrose ranged from 25 to 68 mg·g−1 fresh weight and were greater than those of monosaccharides analyzed. ‘Beauregard’ had the highest sucrose concentration and total sugars. Purple-fleshed cultivars Okinawan and LA 08-21p contained total monomeric anthocyanins that ranged from 34 to 37 mg/100 g dry weight. Orange-fleshed cultivars Beauregard and Darby contained β-carotene that ranged from 5485 to 8302 µg/100 g fresh weight. These results provide yields of storage roots, susceptibility to sweetpotato weevils, and amounts of antioxidants in purple- and orange-fleshed sweetpotato cultivars to growers interested in producing new sweetpotato cultivars.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1173b-1173
Author(s):  
Helen Beaufort-Murphy

Yield and insect damage of 50 potato cultivars, representative of genetic variation found in CIP germplasm collection, were evaluated over two years in a wide range of environmental conditions throughout Peru, from 4°S to 17°S, including coastal desert, cool highland and humid jungle, at altitudes from 180m to 3280m. Storage root and foliage yields were related to maximum and minimum temperature, photoperiod, precipitation, soils, and insect damage. Genotypic yield varied considerably from one location to another. Jonathan (Peruvian cultivar) produced well in Cañete (coastal desert) but not in the jungle or highlands. Jewel (US cultivar) produced well in Yurimaguas (jungle) but not in coastal deserts. Pesticides were not used but several cultivars had little or no insect damage, others were badly damaged. Some cultivars produced a reasonable yield over a wider range than did others. Results suggest that a cultivar can be strongly adapted to a particular set of environmental conditions. Data provide valuable information for growers-breeders.


HortScience ◽  
2013 ◽  
Vol 48 (12) ◽  
pp. 1457-1462 ◽  
Author(s):  
Bandara Gajanayake ◽  
K. Raja Reddy ◽  
Mark W. Shankle ◽  
Ramon A. Arancibia

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.


2017 ◽  
pp. 420-425 ◽  
Author(s):  
Christa Hoffmann

The high yield level sugar beet has reached in the past years might have altered the morphology of the storage root. The study thus aimed at analyzing storage root diameter and length in relation to yield under various environmental conditions. For that purpose, data of various field and pot experiments were included covering a broad range of storage root diameters and yield levels of sugar beet. It turned out that there was a close relationship between storage root diameter and root yield, which was not affected by different environmental conditions (site, year). Furthermore, breeding progress had obviously not changed this relation, as it was not affected by varieties. Results from pot experiments could well be compared with field trial data. In field trials, storage root length did not exceed 25cm independent of yield level, whereas in pot experiments plants formed longer storage roots with higher yield levels. It is discussed that increasing penetration resistance in soil could limit the further expansion of the storage root diameter. A more aboveground growth of the storage root with increasing yield level, however, will make yield estimates based on root diameter more difficult.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534e-534 ◽  
Author(s):  
J. Staub ◽  
Felix Sequen ◽  
Tom Horejsi ◽  
Jin Feng Chen

Genetic variation in cucumber accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. Principal component analysis of allelic variation allowed for the depiction of two distinct groupings of Chinese accessions collected in 1994 and 1996 (67 accessions). Six isozyme loci (Gpi, Gr, Mdh-2, Mpi-2, Pep-gl, and Pep-la) were important in elucidating these major groups. These groupings were different from a single grouping of Chinese 146 accessions acquired before 1994. Allelic variation in Chinese accessions allowed for comparisons with other accessions in the U.S. National Plant Germplasm System (U.S. NPGS) collection grouped by continent and sub-continent. When Chinese accessions taken collectively were compared with an array of 853 C. sativus U.S. NPGS accessions examined previously, relationships differed between accessions grouped by country or subcontinent. Data indicate that acquisition of additional Chinese and Indian cucumber accessions would be strategically important for increasing genetic diversity in the U.S. NPGS cucumber collection.


Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Michael Gomez Selvaraj ◽  
Maria Elker Montoya-P ◽  
John Atanbori ◽  
Andrew P. French ◽  
Tony Pridmore

Abstract Background Root and tuber crops are becoming more important for their high source of carbohydrates, next to cereals. Despite their commercial impact, there are significant knowledge gaps about the environmental and inherent regulation of storage root (SR) differentiation, due in part to the innate problems of studying storage roots and the lack of a suitable model system for monitoring storage root growth. The research presented here aimed to develop a reliable, low-cost effective system that enables the study of the factors influencing cassava storage root initiation and development. Results We explored simple, low-cost systems for the study of storage root biology. An aeroponics system described here is ideal for real-time monitoring of storage root development (SRD), and this was further validated using hormone studies. Our aeroponics-based auxin studies revealed that storage root initiation and development are adaptive responses, which are significantly enhanced by the exogenous auxin supply. Field and histological experiments were also conducted to confirm the auxin effect found in the aeroponics system. We also developed a simple digital imaging platform to quantify storage root growth and development traits. Correlation analysis confirmed that image-based estimation can be a surrogate for manual root phenotyping for several key traits. Conclusions The aeroponic system developed from this study is an effective tool for examining the root architecture of cassava during early SRD. The aeroponic system also provided novel insights into storage root formation by activating the auxin-dependent proliferation of secondary xylem parenchyma cells to induce the initial root thickening and bulking. The developed system can be of direct benefit to molecular biologists, breeders, and physiologists, allowing them to screen germplasm for root traits that correlate with improved economic traits.


1990 ◽  
Vol 115 (4) ◽  
pp. 696-699 ◽  
Author(s):  
Ki-Cheol Son ◽  
Ray F. Severson ◽  
Richard F. Arrendale ◽  
Stanley J. Kays

Methodology was developed for the extraction of surface components of sweetpotato [Ipomoea batatas (L.) Lam.] storage roots. Surface components of storage roots were quantitatively extracted with methylene chloride using 8-minute ultrasonication. After removal of the solvent, the extract was treated with 3 Tri Sil-Z:1 trimethylsilylimidazol (v/v) to convert components with hydroxyl moieties to silyl ethers and then separated on a SE-54 fused silica capillary column. Distinctly different gas chromatography profiles were found between lines displaying moderate levels of resistance (`Resisto', `Regal', `Jewel') to the sweetpotato weevil [Cylas formicarius elgantulus (summers)] and weevil-susceptible lines (`Centennial', SC 1149-19, W-115), indicating a possible role of surface components in insect response. Chromatographic fractionation techniques were developed for separation of major components or groups of components. The results will allow subsequent bioassaying for the presence of an ovipositional stimulant(s) and other weevil behavior-modulating compounds and their chemical characterization.


HortScience ◽  
2016 ◽  
Vol 51 (9) ◽  
pp. 1079-1086 ◽  
Author(s):  
Rolland Agaba ◽  
Phinehas Tukamuhabwa ◽  
Patrick Rubaihayo ◽  
Silver Tumwegamire ◽  
Andrew Ssenyonjo ◽  
...  

The amount of genotypic and phenotypic variability that exists in a species is important for selection and initiating breeding programs. Yam bean is grown locally in tropical countries of the Americas and Asia for their tasty storage roots, which usually have low dry matter content. The crop was recently introduced in Uganda and other East and Central African countries to supplement iron (Fe) and protein content in diets. This study aimed to estimate genetic variability for root yield and quality traits among 26 yam bean accessions in Uganda. A randomized complete block design was used with two replications across two ecogeographical locations and two seasons during 2012 and 2013. Near-infrared reflectance spectroscopy (NIRS) was used to determine quality of storage root samples. Significant differences among genotypes were observed for all traits except root protein, zinc (Zn), and phosphorus contents. Genotypic variance components () were significant for storage root fresh yield (SRFY), storage root dry matter (SRDM), storage root dry yield (SRDY), vine yield (VNY), fresh biomass yield (FBY), and storage root starch (STA) and Fe contents. For traits with significant the broad sense heritability estimates ranged from 58.4% for SRDY to 83.6% for FBY; and phenotypic coefficients of variation were high for SRFY (66%), SRDY (53.3%), VNY (60.5%), and FBY (59%), but low to medium for SRDM (22.6%), STA (15.1%), and Fe (21.3%). Similarly, the genotypic coefficients of variation were high for SRFY (56.7%), SRDY (53.3%), VNY (55%), and FBY (53.9%); and low for SRDM (20%), STA (12.4%), and Fe (17.8%). There were strong positive correlations between SRFY and both SRDY (r = 0.926) and FBY (r = 0.962), but low-to-moderate correlations among quality traits. It should be possible to breed for high dry matter yam beans by using low dry matter accessions due to the observed genetic variation ( = 9.3%2), which is important if the high dry matter Pachyrhizus tuberosus accessions (known as chuin) from Peru cannot be accessed. This study indicated substantial genetic variation for yield and quality traits in yam bean, demonstrating potential for adaptability to growing conditions and consumer needs in East and Central Africa and for genetic improvement through selection.


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