scholarly journals Improvement in rice seed storage longevity from high-temperature drying is a consistent positive function of harvest moisture content above a critical value

2018 ◽  
Vol 28 (4) ◽  
pp. 332-339 ◽  
Author(s):  
K.J. Whitehouse ◽  
F.R. Hay ◽  
R.H. Ellis

AbstractDrying reduces seed moisture content, which improves subsequent seed survival periods. Diverse maximum temperatures have been recommended to limit or avoid damage to seeds, but some high-temperature drying regimes may improve subsequent seed quality. Seeds from 20 different accessions of five rice (Oryza sativaL.) variety groups (aromatic, Aus, Indica, temperate Japonica, tropical Japonica) were harvested over several seasons at different stages of maturation and either dried throughout at 15°C/15% relative humidity (RH) or for different initial periods (continuous or intermittent) in different drying regimes at 45°C before final equilibrium drying at 15°C/15% RH. Subsequent seed longevity in hermetic storage at 45°C with 10.9% moisture content was determined. In no case did initial drying at 45°C provide poorer longevity than drying at 15°C/15% RH throughout. There was a split-line relation, which did not differ amongst investigations, between longevity after initial drying at 45°C relative to that at 15°C/15% RH throughout and harvest moisture content, with a break point at 16.5% (a seed moisture status of about –14 MPa). Below 16.5%, relative longevity did not differ with harvest moisture content with little or no advantage to longevity from drying at 45°C. Above 16.5%, relative longevity showed a positive relation with harvest moisture content, with substantial benefit from drying at 45°C to subsequent longevity of seeds harvested whilst still moist. Hence, there are temporal (immediatelyex plantacf. subsequent air-dried storage) and water status discontinuities (above cf. below 16.5%) in the effect of temperature on subsequent air-dried seed longevity.

2020 ◽  
Vol 48 (3) ◽  
pp. 413-418
Author(s):  
T.M. Jones ◽  
O.A. Oyatomi ◽  
B.O. Akinyele ◽  
A.C. Odiyi ◽  
M.T. Abberton ◽  
...  

In this paper, we considered the effects of different drying regimes on the subsequent longevity of Bambara groundnut seeds. Freshly harvested Bambara groundnut seeds from 27 genebank accessions were divided into five samples. One sample (control) was immediately dried at 17°C/15% RH and the other samples were dried at 45°C/35% RH for up to eight days, before transfer to 17°C/15% RH. After drying, seed moisture content was raised to 10.9% before packing the seeds in aluminium foil packets and placing at 45°C. Samples were removed at regular intervals for germination tests to compare seed longevity. Initial drying at the higher temperature resulted in a faster reduction in seed moisture content. The effect of the different drying regimes on subsequent longevity was not significant for most accessions. Nonetheless, the seed longevity of smaller-seeded accessions was perhaps enhanced by initial drying at a higher temperature; in contrast, initial drying at 17°C appeared to be the best drying treatment for larger-seeded accessions. Overall, the results suggest that initial drying at a higher temperature was beneficial for reducing processing time and for some accessions would be beneficial for seed longevity, but further work is required to understand for which seed lots.


1989 ◽  
Vol 69 (3) ◽  
pp. 749-761 ◽  
Author(s):  
ULRICH HERTER ◽  
JOSEPH S. BURRIS

Mechanical drying has frequently caused injury in corn seed. Changes in seed moisture, temperature, and quality were determined for inbred lines A632, B73 and Mo17 to define the relationship between these variables. Ears harvested at ca. 48 and 38% seed moisture could be dried at 50 °C for 4–15 h and 18–24 h, respectively, before germination started to decline linearly with prolonged 50 °C drying. Drying time at 50 °C, seed moisture, or embryo moisture after 50 °C drying could be used equally well for prediction of seed quality. Seedling dry weights often declined even when seed was dried for only a few hours at 50 °C. Temperature measurements within seeds indicated that evaporation cooled the seed no more than 5 °C. Drying susceptibility of seed parents varied greatly between years.Key words: Moisture, temperature changes, seed corn, drying


1987 ◽  
Vol 27 (1) ◽  
pp. 179 ◽  
Author(s):  
MA Siddique ◽  
G Somerset ◽  
PB Goodwin

Trials on the cultivars Canyon and Gallatin 50 in 1978 and Cascade in 1979 were run in North Queensland to examine ways of improving seed quality of snap beans. The trials concentrated on the maturation period, since this is a critical period for the development of seed quality. We found that seed quality was poor when the crop was cut at the stage when the leaves had fallen and all the pods were dry, or if the plants were cut at any stage and allowed to dry on the ground in single rows. This poor seed quality was associated with high pod temperatures during seed maturation. Cutting the crop before leaf fall, at a seed moisture content close to 50% (20-40% of pods dry) and windrowing immediately in 5 or 10 rows to 1 windrow gave low pod temperatures during seed maturation and high seed quality. Seed harvested and threshed directly off the crop was of good quality provided the seed moisture content in the crop had fallen to less than 25%.


1991 ◽  
Vol 1 (4) ◽  
pp. 243-249 ◽  
Author(s):  
R. J. Probert ◽  
S. V. Bogh ◽  
A. J. Smith ◽  
G. E. Wechsberg

AbstractPriming in polyethylene glycol (PEG, −1.5 MPa) for 7 d followed by drying, led to a 4–5 fold increase in mean longevity when achenes (seeds) of Ranunculus sceleratus L. were subsequently stored at 35°C and 9.2% moisture content on a fresh weight basis (67.1% equilibrium relative humidity). The increase in longevity was due to an increase in the standard deviation of the frequency distribution of individual seed lifespans (decrease in the slope of transformed survival curves) and to a lesser extent to an increase in the intercept of survival curves. Priming for 1 d resulted in a smaller but significant increase in longevity independent of whether seeds were primed in PEG, distilled water or a saturated atmosphere (100% RH).The effects of priming were not due to the prevention of imbibition injury, and there was no evidence that the water relations of whole achenes was affected by priming. The effects of a 7 d priming treatment were dependent on the temperature and nature of the priming medium. However, no differences were recorded between corresponding treatments which were primed in PEG or distilled water. Moreover, the survival and responsivity to priming of R. sceleratus seeds was not related to dormancy status. The effects of priming on the longevity of R. sceleratus seeds are apparently unrelated to seed quality as the response of seeds previously aged for 8 d at 35°C and 7.9% moisture content was similar to that for unaged seeds.Priming followed by drying did not increase seed longevity in the related species R. acris L. The promotive effects of priming on seed survival appear to be species specific and may be related to ecological factors.


2020 ◽  
Vol 48 (2) ◽  
pp. 201-207
Author(s):  
Y.K. Fan ◽  
M. Liu ◽  
J.X. Hu ◽  
M.Y. Ji ◽  
Q.Y. Lan

The present study examined the effect of temperature (15, 20, 25, 30 and 20/30°C) on germination and the storage behaviour of freshly harvested mature seeds of Calamus palustris var. cochinchinensis. Seed desiccation tolerance and the effects of storage temperature (4 and 15°C), perlite water content (120, 180 and 240%) and seed moisture content (27.8, 38.2 and 49.2%) on viability were observed. Seeds had a higher germination at 25°C (88.3%) than at the other tested temperatures. Germination decreased as the seed moisture content decreased during desiccation. The germination of seeds stored at 15°C was higher than that of seeds stored at 4°C. Germination of seeds stored at 15 and 4°C was <65% and with extension of storage time, the germination decreased, indicating that neither temperature can be used for long-term conservation. For short-term storage, the seeds can be stored at 15°C with perlite with 180% water content in plastic bottles or at 15°C with 49.2% moisture content sealed inside aluminum foil bags.


Wood Research ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 427-436
Author(s):  
Jiangyi Chu ◽  
Jinghui Jiang ◽  
Chusheng Qi ◽  
Yongdong Zhou

The purpose of this paper is to investigate the influence of kiln temperature, relative humidity and wood moisture content on the content of acid and alcohol released in the drying process of high temperature kiln by studying the radiated pine sawn timber of 40mm thickness. The drying temperature was between 101°C and 115°C, the relative humidity in the drying kiln was reduced from 86.1% to 39.6%, the moisture content of the lumber was reduced from 106.16% to 11.98%, and gas extraction was executed nine times with an extraction speed of 1.0 L•min-1 and a sampling time of 30 min. The concentrations of acids and alcohols were analyzed by HPLC. The results showed that the concentrations of formic acid, acetic acid, and methanol emitted in the kiln during drying were 215.6-748.2, 4148.8-16803.2, and 6381.9-15648.9 mg•m-3, respectively, and these concentrations were significantly higher than the relevant standards. The concentrations of the emitted formic acid and acetic acid were proportional to the drying temperature, the concentrations of the emitted formic acid and acetic acid were inversely proportional to the relative humidity in the kiln and the moisture content of the lumber. The concentration of the emitted methanol was independent of the drying temperature, relative humidity in the kiln, and moisture content of the lumber. It is therefore suggested that formic acid, acetic acid, and methanol be separately recovered during the high-temperature drying of Pinus radiata lumber.


2020 ◽  
Vol 21 (2) ◽  
Author(s):  
Yongkriat KU-OR ◽  
NISA LEKSUNGNOEN ◽  
CHATCHAI NGERNSAENGSARUAY ◽  
TUSHAR ANDRIYAS

Abstract. Ku-or Y, Leksungnoen N, Ngernsaengsaruay C, Andriyas T. 2020. Seed longevity of Buchanania siamensis Miq. in reclaiming salt-affected areas in Thailand. Biodiversitas 21: 743-747. Inland salinity is a grave threat to soil fertility as it causes loss of arable land. Salt-tolerant species, such as Buchanania siamensis Miq., can be used for the reclamation of land affected by salinity. We investigated the appropriate conditions to store the seeds of B. siamensis and the storage duration after which the seeds can still germinate. Storage methods included cooling at 4°C and storing at room temperature (between 25-30°C). Seeds kept at 4°C had low germination (6.75% ± 1.71), with longevity of only up to a week, compared to seeds stored at room temperature, which had germination of 94% ± 4.00 and could be stored for more than 200 days. Seed-longevity test was conducted at 14 levels (the number of storage days). Germination was reduced by 50% after 3.5 months, indicating that the seed could only be stored for the short term. The seeds were classified as having an intermediate behavior in which the germination increased exponentially with increasing seed moisture content. We recommend that seeds be stored at a temperature between 25 and 30°C, with sowing done within 3.5 months to obtain germination at or above 50%.


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