Storage roots of `Beauregard' and `Centennial' were used to identify varietal differences in fatty acid composition in plasmalemma lipids during storage conditions. Total plasmalemma fatty acid composition of glycolipids and phospholipids in storage roots of `Beauregard' and `Centennial' did not differ. The fatty acid composition of MGDG and DGDG in storage root plasmalemma was >50% unsaturated fatty acids in `Beauregard'. The high percentage of 18:2 (65.44%) fatty acid compared to `Centennial' (19.70%) and 79.35% total unsaturated fatty acid content in MGDG may contribute to low temperature tolerance in `Beauregard'. The higher percentages of 16:1 and 22:1 fatty acids in `Centennial' compared to `Beauregard' contributed to MGDG fatty acid unsaturation. However, these fatty acids have not been related to chilling tolerance.
Arambage Abesinghe and James O. Garner
Kalavathy Padmanabhan, Daniel J. Cantliffe, Roy C. Harrell and Dennis B. McConnell
A comparison of external morphology captured via a computer vision system and a study of internal anatomy of sweetpotato somatic embryos identified five different major morphological variants among torpedo and cotyledonary stage embryos. These included 1) Perfect Type, 2) Near Perfect Type, 3) Limited/No Meristematic Activity Type, 4) Disrupted Internal Anatomy Type, 5) Proliferating Type. Perfect and Near Perfect types of somatic embryos were categorized as competent, while Limited/No Meristematic activity, Disrupted Internal Anatomy, and Proliferating types were categorized as noncompetent with respect to their conversion ability. Lack of organized shoot development in somatic embryos of sweetpotato was attributed to the following abnormalities: 1) lack of an organized apical meristem, 2) sparsity of dividing cells in the apical region, 3) flattened apical meristem, 4) multiple meristemoids and/or diffuse meristematic activity throughout the embryo. A morphological fate map of most of the torpedo and cotyledonary embryo variants was identified, which will be beneficial in synthetic seeding and transgenic research and development of sweetpotato.
V.A. Khan, C. Stevens, M.A. Wilson, J.Y. Lu, E.G. Rhoden, D.J. Collins and J.E. Brown
In 1995 a study was conducted in split-split-plot design to determine the effect of single, double, and equilateral planting configurations with a single and double recommended rate of fertilizer (NPK), would have on the yield of four sweetpotato cultivars. TU-1892, Jewel, TU-82-155, and Georgia Jet were planted on a raised shaped bed 2 ft wide. Fertilizer was banded in the center of the bed and plants were then placed 6 inches away on both sides of this band for the double and equilateral configurations and on one side for the single configuration. Plants were spaced 12 inches apart within rows and the rate of fertilizer used for both single and double rows was the recommended rate for single rows. All plots were side dressed with an additional 80 lbs/acre of K at the time of flowering. Marketable yield data showed that by doubling the recommended rate of fertilizer yield increased for all cultivars which ranged from 26%-41% for single, 35%-88% for double, and 64%-104% for equilateral configurations, respectively. The results also indicated that net returns for TU-1892 was 217%, Jewel 136%, TU-82-155 203%, and Georgia-Jet 171%, for double and equilateral configurations, respectively, when the rate of fertilizer was doubled.
A.Q. Villordon, C.A. Clark, R.A. Valverde, R.L. Jarret and D.R. LaBonte
Previous work by our group has detected the presence of a heterogeneous population of Ty1-copia-like reverse transcriptase retrotransposon sequences in the sweetpotato genome. Recently, we detected the presence of putatively active Ty1-copia-like reverse transcriptase sequences from a virus-infected `Beauregard' sweetpotato clone. In the current study, we report the differential detection of putatively stress-activated sequences in clones from seedling 91-189. The clones were infected with different combinations of virus isolates followed by extraction of leaf RNA samples at three sampling dates (weeks 2, 4, and 6) after inoculation. After repeated DNAse treatments to eliminate contaminating DNA, the RNA samples were subjected to first strand cDNA synthesis using random decamer primers followed by PCR analysis utilizing Ty1-copia reverse transcriptase-specific primers. Through this approach, we detected amplified fragments within the expected size range (280-300 bp) from clones infected with isolates of sweetpotato leaf curl (SPLC) and feathery mottle viruses (FMV) (week 2 and 6) and FMV (week 4). We were unable to detect PCR products from the noninfected clones or the other infected samples. The data suggests that specific viruses may be involved in the expression of these Ty1-copia-related reverse transcriptase sequences. It also appears that sampling at various dates is necessary to detect putative activity over time. This preliminary information is essential before proceeding to the construction and screening of cDNA libraries to isolate and fully characterize the putatively active sweetpotato Ty1-copia-like retrotransposon sequences. Through the partial or complete characterization of sweetpotato Ty1-copia elements, sequences that correspond to cis-regulatory element(s) can be identified and further studied for their roles in responding to specific stress factors.
Benard Yada, Phinehas Tukamuhabwa, Bramwell Wanjala, Dong-Jin Kim, Robert A. Skilton, Agnes Alajo and Robert O.M. Mwanga
. Delacy, I.H. 1994 Interpretation of random amplified polymorphic DNA marker data for fingerprinting sweetpotato [ Ipomoea batatas (L.) Lam] genotypes Theor. Appl. Genet. 88 332 336 Diaz, J. Schmiediche, P
Malkeet S. Padda and D.H. Picha
.J. Lin, Y.H. 2004 Antioxidant and antiproliferative activities of sweet potato [ Ipomoea batatas (L.) Lam ‘Tainong 57’] constituents Bot. Bul. Academia Sinica 45 179 186 Islam, S. 2006 Sweetpotato ( Ipomoea
William B. Thompson, Jonathan R. Schultheis, Sushila Chaudhari, David W. Monks, Katherine M. Jennings and Garry L. Grabow
adventitious roots in sweetpotato ( Ipomoea batatas ) Austral. J. Bot. 52 551 558 Beyene, K. Nebiyu, A. Getachew, M. 2015 Effect of number of nodes and storage duration of vine cuttings on growth, yield and yield components of sweet potato ( Ipomoea batatas L
Arthur Villordon, Wambui Njuguna, Simon Gichuki, Philip Ndolo and Don Labonte
://www.viazivitamu.org/index.php >. Gichuki, S.T. Berenyi, M. Zhang, D. Hermann, M. Schmidt, J. Glössl, J. Burg, K. 2003 Genetic diversity in sweetpotato [ Ipomoea batatas (L.) Lam.] in relationship to geographic sources as assessed with RAPD markers Genet. Resources Crop Evol. 50 429 437
Bandara Gajanayake, K. Raja Reddy, Mark W. Shankle and Ramon A. Arancibia
the field. Literature Cited Acquaah, G. 2007 Principles of plant genetics and breeding. Blackwell, Malden, MA Belehu, T. Hammes, P.S. Robbertse, P.R. 2004 The origin and structure of adventitious roots in sweetpotato ( Ipomoea batatas ) Aust. J. Bot
Howard F. Harrison Jr, Trevor R. Mitchell, Joseph K. Peterson, W. Patrick Wechter, George F. Majetich and Maurice E. Snook
caffeoylquinic acid compounds from Ipomea pandurata stele ( A ) and I. batatas ‘Jewel’ cortex ( B ). Isolation of dcqa for bioassay and identification. Ipomoea pandurata stele was the source of 3,4-DCQA and 4,5-DCQA. Freeze-dried stele (30 g