Eight sweetpotato [Ipomoea batatas (L.) Lam.] clones were evaluated for the digestibility of their starch in animals with a simple in vitro screening method. Starch digestibility varied significantly among clones. After dry-heat treatment at 100C for 30 minutes, digestibility of the most heat-sensitive clone increased only 37.8%. Excellent repeatable results were obtained with a simple weight-loss method. This assay procedure can be used as a screening method in breeding digestible sweetpotatoes for animal feed.
Dapeng Zhang, Wanda W. Collins and Suzanne Belding
Antal Szőke, Erzsébet Kiss, László Heszky, Ildikó Kerepesi and Ottó Toldi
sucrose and starch synthesis during photosynthesis ( Stitt, 1990 ; Stitt et al., 1987 ). As a signal metabolite it regulates the interconversion between fructose 1,6-bisphosphate and fructose 6-phosphate, the crucial step of carbon partitioning ( Nielsen
Karen Mesa, Sara Serra, Andrea Masia, Federico Gagliardi, Daniele Bucci and Stefano Musacchi
growth until leaves have developed the photosynthetic capacity to independently support net carbon assimilation ( Flore and Layne, 1999 ; Regier et al., 2010 ; Whiley et al., 1996a ). During the dormant period (fall-winter), hydrolysis of starch and
Sylvia M. Blankenship, Donna D. Ellsworth and Ronald L. Powell
A starch staining technique using pictures to rate starch disappearance has been developed to determine banana pulp maturity. The disappearance of starch from the pulp shows linear correlation with peel color (r 2 = 0.76) and soluble solids content (r 2 = 0.81). Pulp pH shows a poor correlation with starch disappearance (r 2 = 0.38). Staining banana pulp starch with an iodine solution is a quick and easy method for estimation of pulp maturity.
Fhatuwani N. Mudau, Ambani R. Mudau, Mpumelelo Nkomo and Wonder Ngezimana
at or above the levels in their control, suggesting that sugar levels were maintained through the hydrolysis of starch reserves, whereas no starch replenishment occurred shortly after pruning. Besides genetic factors, plant physiological responses can
Maurizio Giolo, Stefano Macolino, Erica Barolo and Filippo Rimi
., 1927 ; Macolino et al., 2010 ). Nonstructural carbohydrates (starch and WSC) are used for maintaining respiration when photosynthesis is not sufficient to sustain metabolism and for supporting new shoot growth in the spring ( Stier and Fei, 2008 ). In
Dapeng Zhang, Wanda W. Collins and Maria Andrade
Two experiments that included 25 sweetpotato [Ipomoea batatas (L.) Lam] genotypes were planted in various environments across North Carolina, and an in vitro screening method was used to investigate genotypic and environmental variance and genotype × environment (G × E) interactions of starch digestibility in sweetpotato. Significant genotypic variation of starch digestibility was found in both experiments. Some clones have starch digestibility equivalent to that of corn. Variance analysis from both experiments indicated that genotypic variance was the dominant component in starch digestibility. G × E interaction only accounted for 6.8% of the phenotypic variance in one experiment and for 5.9% in the other one. These results suggested that starch digestibility of sweetpotato could be improved to a level as that of corn through conventional breeding.
Teryl R. Roper and John S. Klueh
The dwarfing potential of apple interstems has long been recognized. This study was undertaken to examine the relationship between the dwarfing effect of apple interstems and interstem starch concentration. In 1981 apple trees with P2 or P22 interstems on clonal Antonovka rootstock using Jerseymac or Starkspurmac as scion were planted. In 1989 and 1990 core samples from the interstems and root samples were analyzed for starch concentration. Roots always had higher starch concentrations than interstems. In the spring, P22 interstems had higher starch levels than P2 interstems, but in the fall the reverse was found. No difference in starch concentration was found between the Antonovka rootstock under the same interstem. However, root starch concentration was more stable under P22 than P2. Further, roots under P22 were lower in starch in the fall than in the spring. This suggests that P22, the more dwarfing interstem, may interfere with the transport of carbohydrates through the trunk, which may be a factor in dwarfing.
Nathan Phillips, Andrew Reynolds and Frederick Di Profio
), but little work describing relationships between the two has been conducted. Starch is directly involved in callus formation and vegetative growth of rootstocks during callusing ( Hunter et al., 2004 ). Rootstock cultivars affect starch levels in
T. Casey Garvey and John D. Hewitt
A study using Lycopersicon cheesmanii Riley LA 1449 (typicum), a low soluble solids content (SSC) accession, and L. cheesmanii f. minor LA 528 (minor), a high SSC accession, was undertaken to characterize the accumulation of starch, sugar, and total SSC. Fruit of each accession was sampled throughout development to identify differences in SSC, starch accumulation, and sugar distribution. Osmetric analysis indicated that the minor race had higher SSC content throughout the ontogeny of fruit development than the typicum. Typicum contained more starch than minor, and both accessions showed a rapid decline in percent starch as the fruit ripened. Sucrose remained low throughout all stages of fruit development for both accessions. Glucose increased in the minor and declined in the typicum. Fructose increased in both accessions. Total reducing sugar content at the full ripe stage was higher in minor than the typicum.