The relationship between specific gravity and percentage dry matter in potato tubers

1976 ◽  
Vol 53 (4) ◽  
pp. 111-122 ◽  
Author(s):  
P. A. Schippers
1984 ◽  
Vol 103 (2) ◽  
pp. 475-476
Author(s):  
P. K. Ray ◽  
S. Mishra ◽  
S. S. Mishra

In the recent past, specific gravity of tubers has been considered an easy means of estimating yield potential of sweet potato cultivars (Bryant, 1979) and their quality characters like starch value and dry-matter content (Ishikawa & Sakai, 1973). Bryant (1979) separated sweet potato tubers with low and high specific gravity at planting time by determining whether or not they floated in water, and observed that the floaters gave 20% higher yield than the sinkers. As this simple test claimed to hold promise for selecting higher-yielding sweet potato genotypes, it was decided to scan its usefulness at the College of Agriculture, Dholi, where a large collection of sweet potato germ plasm is being maintained for research needs.


2020 ◽  
Vol 17 (2) ◽  
pp. 173-184
Author(s):  
J Ferdous ◽  
TS Roy ◽  
R Chakraborty ◽  
M Mostofa ◽  
R Noor ◽  
...  

The effect of vermicompost on dry matter and specific gravity of potato tubers under ambient storage condition was studied. Vermicompost was used at four rates viz. 0, 2, 4 and 6 t ha-1 over the four varieties of potato viz. BARI TPS-1, BARI Alu-28 (Lady Rosetta), BARI Alu-25 (Asterix) and BARI Alu-29 (Courage). Results demonstrated that processing parameters such as dry matter percentage (%) and specific gravity increased with increasing vermicompost levels while they decreased with the increasing storing period. Lady Rosetta and Asterix potato varieties can be safely stored at normal room temperature up to 60 days. There was no interaction between vermicompost rates and crop varieties. Hence, the potato growers of Bangladesh can use vermicompost at 6 t ha-1 for achieving better yield without affecting processing quality. SAARC J. Agri., 17(2): 173-184 (2019)


1989 ◽  
Vol 29 (6) ◽  
pp. 869 ◽  
Author(s):  
NA Maier ◽  
KA Potocky-Pacay ◽  
AP Dahlenburg ◽  
CMJ Williams

The effect of phosphorus banded at planting, at rates up to 240 kg/ha, on the specific gravity of tubers of cvv. Kennebec (10 sites) and Coliban (5 sites) was investigated using field experiments conducted during 1984-85, 1985-86 and 1986-87. The relationship between specific gravity and phosphorus concentration in petioles of youngest fully expanded leaves (P-YFEL) was also determined. As the rate of applied phosphorus increased there were significant positive and negative trends in specific gravity. However, the size of the effect varied between sites; for example, the maximum and minimum ranges in specific gravity (based on treatment means) due to phosphorus application were 1.0762-1.0869 (site 13) and 1.0753-1.0772 (site 24), respectively for the cv. Kennebec and 1.0598-1.0683 (site 22) and 1.0715-1.0753 (site 17), respectively for the cv. Coliban. Rates of applied phosphorus, which resulted in maximum specific gravity, also varied between sites. Maximum specific gravities occurred at phosphorus rates in the ranges 0-100 and 40-240 kg/ha for cvv. Kennebec and Coliban, respectively. There were significant relationships (5 quadratic and 1 negative linear) between phosphorus concentration in P-YFEL and specific gravity for cv. Kennebec at all 6 responsive sites. Phosphorus concentrations in P-YFEL associated with maximum specific gravities were in the range 0.29-0.51%. For cv. Coliban, over similar tissue phosphorus concentration ranges, there were significant (P<0.05) positive linear relationships for 1 responsive and 2 non-responsive sites. When data for cv. Kennebec were pooled for all sites, there was a significant (P<0.05) quadratic relationship between specific gravity and tissue phosphorus concentration (range 0.22-0.77%). For the cv. Coliban the trend was not significant (P>0.05). We have concluded that the rate of phosphorus banded at planting can affect specific gravity and that the cvv. Kennebec and Coliban differ in their sensitivity to this effect.


2020 ◽  
Vol 5 (1) ◽  
pp. 63-74
Author(s):  
Lemma Tessema ◽  
Wassu Mohammed ◽  
Tesfaye Abebe

AbstractA field experiment was conducted in the central highlands of Ethiopia to evaluate the performance of potato varieties for tuber yield and to identify a superior variety in tuber yield and yield components. The experiment was laid out in a randomized complete block design with three replications at two locations in the central highlands of Ethiopia during the 2017 main cropping season. The results of analysis of variance (ANOVA) showed the presence of highly significant (P<0.01) differences among varieties over all traits studied. The mean squares for location were also significant in indicating the influence of environments on the traits of the studied varieties. However, the interaction between variety and environment had no significant effect on the performances of the potato varieties to attain 50% flowering, specific gravity and dry matter content indicating a similar performance of these traits across all locations. The variety Belete produced the maximum total tuber yield of 32.8 t ha -1 and marketable tuber yield of 29.1 t ha-1. Conversely, farmers` variety Nech Abeba produced the minimum total tuber yield of 13.8 t ha-1 and marketable tuber yield of 8.4 t ha-1. For most tuber quality traits, viz., tuber specific gravity, dry matter content, starch percentage and total starch yield, varieties Belete and Menagesha were the maximum and minimum producers, respectively. Thus, it could be concluded that varietal and environmental variations as well as their interaction had considerable influence on tuber yield and the potato’s attributes.


2012 ◽  
Vol 1 (4) ◽  
pp. 55 ◽  
Author(s):  
Trygve Helgerud ◽  
Vegard H. Segtnan ◽  
Jens P. Wold ◽  
Simon Ballance ◽  
Svein H. Knutsen ◽  
...  

<p>The dry matter is one of the main quality parameters of raw and processed potatoes. In the present study, the potential of utilizing high throughput commercially available NIR interactance systems for dry matter determination in whole unpeeled potato tubers is investigated. The performance of a 2D NIR interactance instrument was compared with that of a 1D NIR interactance instrument and a traditional underwater weight apparatus. A total of 114 tubers were assessed individually with both of the NIR instruments (760-1040 nm), the underwater weight and an external reference method (freeze drying). The 1D interactance instrument obtained better prediction results than what the 2D instrument could achieve (R<sup>2</sup>=0.95, RMSECV=0.91, and R<sup>2</sup>=0.83, RMSECV=1.65, respectively). The underwater weight obtained the highest explained variance (R<sup>2</sup>=0.97), but the estimation was biased by approximately 1.5% (by weight). The poorer prediction performance of the 2D NIR interactance system can be partly explained by the lower penetration depths of the light compared to the 1D NIR interactance systems.</p>


2001 ◽  
Vol 72 (3) ◽  
pp. 595-606 ◽  
Author(s):  
J.G. M. Houdijk ◽  
I. Kyriazakis ◽  
F. Jackson ◽  
R. L. Coop

AbstractA nutritional hypothesis for the occurrence of the periparturient relaxation of immunity (PPRI) to gastrointestinal nematodes was tested within the bounds of a nutrient partitioning framework. It was hypothesized that at times of a scarce supply of metabolizable protein (MP), an increase in MP supply or a reduction in MP demand (having singles instead of twins) should lower the extent of PPRI in sheep. Twenty-one single- and 21 twin-bearing and -rearing Finn-Dorset ewes, 2 to 7 years old, and repeatedly infected withTeladorsagia circumcincta, were given one of three pelleted foods (no. = 7). The foods were formulated to supply 0·8 (L), 1·0 (M) and 1·2 (H) times the MP requirements during lactation, and were offeredad libitumfrom d–21to d35(d0 is day of parturition). Faecal egg counts (FEC) were assessed twice weekly as an indicator for host resistance. Dry-matter intake (DMI) during late pregnancy was higher than expected, and MP supply did not limit performance at this stage. In accordance with the hypothesis, there were no indications of a breakdown of immunity toT. circumcinctaduring late pregnancy. DMI during lactation did not differ between the single- and twin-rearing ewes. Calculated milk production was lower for the L than for the M and H ewes, especially for the twin-rearing ewes. A temporarily elevated FEC was observed during the first few days in lactation, which was probably mainly due to changes in faecal output rather than to PPRI. The FEC returned to low, late pregnancy levels at d12and remained low for the single- but not for the twin-rearing ewes (P< 0·001). Overall, the L ewes had higher FEC than the M and H ewes from d19onwards; this effect was more pronounced for the twin- than for the single-rearing ewes. It was postulated that DMI achieved overcame MP scarcity and thus prevented breakdown in immunity in the single-rearing ewes. The data support the view that, at times of MP scarcity, an increase in MP supply and reduction in MP demand can lower the extent of the breakdown in immunity towardsT. circumcincta.


2016 ◽  
Vol 8 (1) ◽  
pp. 20 ◽  
Author(s):  
M. Bänziger ◽  
G. O. Edmeades ◽  
J. Bolaños

The amount of dry matter produced during various stages of corn growth is a important variable to be taken into consideration. However, the lack of drying facilities makes its measurement a difficult task in the fields. A simple method to convert the fresh weight of a crop in the field into dry weight, could be an answer to that problem. In this study, we calculated the relationship between fresh and dry weight of corn stovers, over several, growth, stages of eight corn cultivars of different vigour and maturity period, at two Mexican locations. The differences between cultivars were for percent stover dry weight (%SDW) most evident in the second half of the grain growth stage, when late cultivars showed less humidity than the early ones. The % SDW was regressed against the phenological developmental stage and expressed as a ratio against antesis (R, days to sampling /days to 50% antesis). The equations (R2 = 0.97 - 0.99) with best results were: Early maturing cultivars: %SDW = 12.6 + 0.94R2 + 1.68R4; Late: %SDW = 16.1 - 4.00 R2 + 3.36R4. There were no consistant differences among cultivars with different vigour levels, even though certain differences were noted among the locations and they were attributed to differences in relative humidity. We describe a protocol for determining the dry weight of corn stover by area unit (t/ha) when drying conditions are not available, by utilizing only a scale and a ruler.We also suggest a method to calculate percent dry matter for a real plant parts (including grain).


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