Studies on the use of mutagenic agents in plant breeding. II. The effects of dose and seed moisture content on mutation production in Lupinus angustifolius by X-Rays

1965 ◽  
Vol 16 (3) ◽  
pp. 301 ◽  
Author(s):  
JS Gladstones ◽  
CM Francis

Seeds of Lupinus angustifolius were given X-ray doses of 2.5, 5, 10, and 20 kr at each of 12 moisture contents ranging from 6.1 to 18.1 % (wet weight basis). Various measures of injury were recorded in the X1 generation, and the types and rates of mutations in the X2. At moisture contents below 16%, total mutation rates were closely correlated with X1 injury. Injury and mutation rate decreased with increasing moisture up to 11–12% moisture, and thereafter remained at a constant minimum up to 16%. Between 16 and 18% moisture there was again an increase in X1 injury, but not in mutation rate. Between 6 and 12 % moisture, a linear relationship was found between moisture content and the logarithm of the dose required to cause a given level of injury or mutation. A possible mechanism for such a pattern of protection is discussed. Lethal mutations increased as a proportion of all mutations as dose and mutation rate increased. There were also proportionately more lethals at high moisture contents than in lower moisture treatments giving the same mutation rates. It is concluded that lethal and seedling chlorophyll-deficient mutations could be misleading when used as indicators of total and viable mutation rates, and that, contrary to the conclusions of some previous authors, no advantage is likely to be gained in practical breeding work from irradiating at high seed moisture contents.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 577c-577
Author(s):  
Noël Pallais

True potato seed of Atzimba × 104.12LB (intermediate dormancy) was dried to seed moisture contents ranging from 3.85 to 12.5% (dry wt basis) and was stored for 2 years at 30, 15 and 5°C. Seed was tested for various germination and seedling vigor criteria at 4 month intervals. Seed dormancy and viability were better preserved at seed moisture levels below 7% and as temperature decreased. High moisture (>9%) was lethal to seed stored at 30°C. TPS should be stored at <5% seed moisture content. Under this condition seed dormancy in the genotype studied was lost after about 12 months at 30°C.


1958 ◽  
Vol 9 (2) ◽  
pp. 171 ◽  
Author(s):  
JS Gladstones

Freshly harvested seeds of L. digitatus were stored for up to 11 months at all combinations of six constant temperatures and five constant relative humidities. Testing for hard-seededness was by soaking in water at 15°C, and for viability by emergence tests in seed boxes. Permeability was found to be governed by seed moisture content. All seeds with more than 14 per cent. moisture (wet weight basis) remained fully permeable. Below 14 per cent., permeability decreased with decreasing moisture content until at 11 per cent. all seeds were virtually impermeable. Impermeability was readily reversible under humid conditions down to 12 per cent. moisture content, but practically irreversible below 9 per cent. Softening of semi-hard seeds took place no more rapidly at 94 per cent. R.H. than at 76 per cent. Seed which was air-drying in the laboratory remained fully soft for about 1 week after harvest, and thereafter hardened only slowly. Seed which had been kept permeable for 12 months hardened at the same rate. Viability was impaired by both high moisture content and high temperature.


1963 ◽  
Vol 14 (1) ◽  
pp. 12 ◽  
Author(s):  
CM Francis ◽  
JS Gladstones

Seeds of Lupinus angustifolius were subjected to X-ray doses of 2.5, 5, 10, and 20 kr at each of 12 moisture contents ranging from 6.1 to 18.1% (fresh weight basis). X1 plant damage was measured in terms of reduction in height at 110 days from sowing, delay in flowering, and reduction in mean seed yield per plant. The three measures were found to be highly correlated. Survival was not significantly affected within the range of treatments used. Sensitivity increased progressively with decreasing moisture contents below 11.6%, seeds with 6.1–7.6% being four to five times as sensitive as those with 11.6–16% moisture content. The latter range represented a "plateau" of minimum sensitivity. Between 16.0 and 18.1% moisture, sensitivity again increased.


1992 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
D. Gray ◽  
J. R. A. Steckel ◽  
L. J. Hands

AbstractThe effects of development of leek seeds at 20/10°, 25/15° and 30/20°C (day/night) and drying of seed harvested at different developmental stages on subsequent performance were examined in each of 3 years. An increase in temperature from 20/10° to 30/20°C reduced mean seed weight from 2.90 to 2.55 mg as a result of a reduction in the duration of seed growth from 80 to 55 days; seed growth rate was unaffected. Seed moisture content reached a minimum, up to 35 days after the attainment of maximum seed dry weight and 115, 90 and 70 days after anthesis at 20/10°, 25/15° and 30/20°C, respectively. The curves relating seed moisture to time for each temperature regime were mapped onto a single line accounting for >90% of the variation in moisture content, using accumulated day-degrees >6°C instead of chronological time. Seeds were capable of germinating when seed moisture contents were >60% (fresh weight basis), but maximum viability and minimum mean time to germination were not attained until seed moisture contents at harvest had fallen to 20–30%. Germination was little affected by temperature of seed development. Drying immature seeds increased percentage germination. Growing seeds at 30/20°C and drying at 35°C and 30% RH raised the upper temperature limit of germination compared with growing at 20/10°C and drying at 15°C and 30% RH.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 758D-759
Author(s):  
Seung-Hee Lee* ◽  
Jin-Seok Kim ◽  
Jung-Myung Lee

Dry heat treatment (DHT), a powerful and agrochemical-free means of inactivating seed-borne virus and other pathogens, has been extensively used for value-added vegetable seeds in Korea, Japan, and some other countries. Since seeds are treated with extremely high heat (75 °C or higher) for a long time (72 h or longer), heat-induced phytotoxicity symptoms are frequently observed. Even though various internal and external factors, such as seed maturity and vigor, maximum temperature and duration of DHT, are known to influence the severity of phytotoxicity, precise control of seed moisture contents during DHT is regarded as one of the most important factors for successful DHT. In an ideal condition using a specifically designed DTH machine, seed moisture content of bottle gourd, initially around 6.20% to 0.64% when stored in a storage room with 50% RH, decreased by 1% after 24 h at 35 °C (5.20% to 0.23%), and further decreased below 4% after 24 h pretreatment at 50 °C (3.64% to 0.37%). The seed moisture content was further reduced down to about 2% after 72 h DHT at 75 °C (2.16% to 0.28%). During the post-treatment conditioning at 50 °C and 70% RH for 24 h, the moisture contents were raised to about 6%(5.94% to 0.45%), thus approaching the initial moisture content of 6% to 7%. During the germination period, treated seeds showed slower absorption of water as compared to the intact seeds, thus suggesting that this slow absorption of initial moisture absorption may be responsible for the slow initial germination frequently observed in treated seeds. Final germination and seedling vigor were not affected by DHT.


2018 ◽  
Vol 5 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Marcos Altomani Neves Dias ◽  
André Kitaro Mocelin Urano ◽  
Deborah Bueno Da Silva ◽  
Silvio Moure Cicero

Seed treatment (ST) is an important practice for soybean crop. This research had the objective to evaluate the influence of seed moisture content in the response to different spray volumes (SV) used for seed treatment in soybean, considering effects on seed physiological quality. Three seed lots with distinct moistures were used: 7.2%, 10.1% and 13.0%. Untreated seeds (control) and three SV were tested: 8, 13 and 18 mL kg-1. All lots received the same treatment combination, containing insecticide, fungicide, fertilizer and biostimulant. This combination represented 8 mL kg-1 of SV; the doses of 13 and 18 mL kg-1 were obtained by adding 5 and 10 mL kg-1 of water, respectively. Evaluations of seed physiological quality consisted of electrical conductivity, seed respiration, germination and vigor tests. Results of all tests demonstrates that low-moisture soybean seeds (7.2%) are negatively affected by seed treatment within an SV range of 8 to 18 mL kg-1, while untreated seeds with equal moisture are not affected. Oppositely, high-moisture seeds (13.0%) are not affected by the SV tested, while intermediate-moisture seeds (10.1%) are affected by the higher SV. This result highlights seed moisture as a key parameter to be managed before soybean ST, aiming to maintain a high physiological quality.


2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Temidayo C. Esenamunjor ◽  
Ugwu H. Ubabuike

Performance evaluation of an electric motor and a fuel-engine powered machine used for shelling melon seeds was performed in this study to determine the effects of shelling speed and moisture content on machine productivity. The melon seeds used for the evaluation of the existing melon shelling machine were sourced locally from Umungasi market in Aba, Abia state, Nigeria. The unshelled melon seeds as used were weighed (25g each), sprinkled with water and partially dried with natural air for 25 minutes. This enabled the skin coat became slightly softened and the cotyledon easily detached from the shell, thus making the shelling more efficient. To evaluate the parameters (machine productivity, throughput capacity and percentage seed damage), the melon seeds were employed. For the shelling performance, melon seeds of five different moisture contents (7.48, 10.24, 13.92, 18.36, 21.44%) dry basis (d.b.) at different shelling speeds (850, 1000 and 1200 rpm) were utilized in the evaluation. From the evaluation, results revealed that the machine has an optimal productivity of over 83% and percentage seed damage of 14.2% at seed moisture content of 21.44% and drum speed of 1200 rpm for both power sources. Maximum machine throughput capacity of over 940 kg/h was recorded at 1200 rpm and 21.44% moisture content for both power sources. Overall, results obtained indicated that the machine can effectively shell melon seeds and that seed moisture contents and shelling speed affected the machine productivity.Keywords— Performance operation, evaluation, motorized, melon, shelling machine


1987 ◽  
Vol 27 (3) ◽  
pp. 377 ◽  
Author(s):  
GB Taylor

An improved technique for the determination of seed moisture content in small-seeded annual legumes is described. Changes in weight of permeable and impermeable seed of Medicago truncatula, M. polymorpha and Trifolium subterraneurn, which were either left intact or cut in half, were measured in air-ovens at 105 and 130�C. Drying intact seeds for 1 h at 130�C, as specified by the International Seed Testing Association, seriously underestimated moisture content in most seed samples. Seeds dried to approximately constant weight at 130�C appeared to overestimate moisture contents by about 1%, presumably because of volatilisation losses of material other than unbound water. At 105�C, halved seeds lost weight rapidly during the first day then slightly gained weight for several days before resuming a gradual weight loss. Drying intact seeds of M. truncatula and T. subterraneurn at 105�C for 2 days gave seed moisture contents similar to those obtained from halved seeds. Intact impermeable seeds of M. polymorpha were very much slower than those of the other species to lose weight. taking 14 days to approach an apparent moisture content close to that of halved seeds. Drying halved seeds for 24 h at 105�C appears the most reliable technique.


1978 ◽  
Vol 58 (2) ◽  
pp. 557-560
Author(s):  
R. M. DE PAUW

The after-ripening requirement of three fall rye (Secale cereale L.) cultivars, harvested at three seed moisture contents (50, 42, and 32%), was assessed by monitoring the changes in seedling emergence from sowings made over a period of 60 days. All cultivars exhibited a short after-ripening requirement of 1–7 days. The absolute duration of the after-ripening requirement was not affected by the range of seed moisture contents studied. Seed treatment with captan [N[(trichloromethyl) thiol]-4-cyclohexene-1,2-dicarboximide] significantly increased percent seedling emergence. The captan treatment had the greatest effect on seeds harvested at the lowest moisture content.


HortScience ◽  
1995 ◽  
Vol 30 (5) ◽  
pp. 1003-1006 ◽  
Author(s):  
William J. Carpenter ◽  
Eric R. Ostmark ◽  
John A. Cornell

Various combinations of temperature and moisture contents were used in evaluating the seed storage of nine genera of annual flowers. Relative humidity (RH) levels of 11%, 32%, 52%, and 75% provided wide ranges in seed moisture during storage at 5, 15, and 25C. At each temperature, total germination percentages (G) generally declined as seed moisture content increased during storage. The seed moisture range giving the highest G after 12 months of storage was determined for each temperature and plant genus. For all genera, seed moisture contents during storage increased as storage temperatures increased at constant RH levels. Moisture contents at 25C storage were 37%, 34%, 29%, and 20% higher than at 5C when RH levels were at 11%, 32%, 52%, and 75%, respectively.


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