Standard Germination Research Articles

Machine vision based alternative testing approach for physical purity, viability and vigour testing of soybean seeds (Glycine max).

The conventional methods for seed quality testing have several limitations as they involve visual assessment and are destructive. In this context, a study was performed to assess the suitability of non-contact, non-destructive type imaging techniques such as visible imaging and X-ray imaging for conducting physical purity, viability and vigour tests of soybean seeds. The seeds that appeared healthy in external surface examination using visible tests as well as in internal assessment using X-ray tests were classified as sound seeds while the other seeds were marked as not-sound seeds. The obtained results were then correlated with the results of the standard germination tests. The high correlation results between the imaging tests and the standard conventional germination tests indicate the effectiveness and usability of the proposed image analysis based technique as an attractive alternative to the existing quality assessment methods for soybean seeds.

GERMINATION AND VIGOR OF Bixa orellana L. SEEDS PRE-SOAKED IN A PLANT BIOSTIMULANT

The aim of this study was to assess the germination and vigor of Bixa orellana seeds that were pre-soaked in different concentrations of Stimulate® plant biostimulant. For the standard germination test, Bixa orellana seeds from the Embrapa 37 Cultivar were pre-soaked (for periods of four and eight hours) in the following concentrations of Stimulate® aqueous solution: 3.0; 6.0; 9.0; and 12.0 mL L-1. Seeds that were pre-soaked in distilled water were used as control. The following parameters were tested: germination; first germination count; abnormal seedlings; length; and seedling dry mass. The experimental design was completely randomized and a 2 x 5 + 1 factorial design was used (with two pre-soaking periods, five Stimulate® concentrations, and one additional control without pre-soaking). Four replicates of 50 seeds were performed for each treatment. Water immersion treatments for four and eight hours were efficient for breaking dormancy in Bixa orellana seeds, since they promoted better germination in relation to the intact seeds that were not pre-soaked. The pre-soaking of Bixa orellana seeds for eight hours in a 12.0 mL L-1 Stimulate® concentration presented the best results in terms of germinative performance and seedling growth, with greater accumulation of dry mass. Therefore, this practice is recommended for the production of seedlings of this species.

Evaluation of Seed Vigor Tests for Predicting Seedling Establishment at Low Temperature in Rice (Oryza sativa L.)

This study was carried out to develop an evaluation method to predict rice seedling establishment (SE) under low-temperature conditions. Two Korean-bred japonica cultivars, Shindongjin and Hopum were used in the experiment. Fresh seeds were treated with an accelerated aging (AA) at 40°C and 100% RH for 1-15 days. The SEs of the fresh and AA seeds were evaluated in nursery beds at 17°C, and their correlation coefficients with seed vigor values measured by 9 test methods including standard germination test (SGT), cool germination test (CLT), cold germination test (CDT), seedling growth rate test (SGRT), ascorbate peroxidase (APX), peroxidase (POX), superoxide dismutase (SOD), catalase (CAT), and α ‐amylase (AMY) activities. The percentage of SE decreased slowly from 75 to 0% with an increasing of AA period from 0 to 15 days. The result of nine vigor tests showed different correlations with the SE. SGT, CLT, SGRT, and POX were significantly correlated with the SE. In the correlation analysis with only short-term aging seeds (1-7 days), the SE was very highly correlated with SGT, CLT, CDT, SGRT, POX, and CAT. These results suggest that seed vigor values measured by several methods including SGT and POX could be used as a reference value to secure SE at low temperatures in nursery bed rice seedling culture.

Germinación in vitro de biznaga cabuchera


 
 
 Ferocactus pilosus [(Galeotti ex Salm-Dyck) Werdermann] es una cactácea conocida como biznaga, la cual muestra crecimiento lento y se encuentra catalogada como una especie en riesgo de extinción. El objetivo del presente estudio fuel el realizar un ensayo in vitro con el fin de estudiar el efecto de tratamientos químicos y reguladores de crecimiento, como promotores de la germinación de semillas colectadas en dos años consecutivos. Los productos químicos que se estudiaron fueron el H2SO4 y H2O2 y como los fitoreguladores AG3, AIA y ANA, bajo diferentes tiempos de inmersión y concentración, respectivamente. La asignación de tratamientos fue bajo un diseño completamente al azar. Durante 30 días se registró número de semillas germinadas cada 2 días y se determinó la germinación estándar. Se utilizó la regresión logística para estudiar el efecto de los factores de estudio sobre la proporción de semillas germinadas. La germinación estándar de la biznaga es 82% con el tratamiento H2SO4, mientras que la germinación de la semilla inicia entre 2 y 6 días después de la siembra en ambos años y la fase logarítmica representativa se tiene entre 8 y 20 días con H2SO4 en 2015. Las semillas de biznaga muestreadas el año 2016 muestran mayor lentitud para cubrir la fase inicial de la germinación, cubierta en 16 días. La aplicación de H2SO4 acortó 4 días el tiempo de germinación y aumentó 82% la germinación estándar, mientras que el H2O mantuvo constante la germinación estándar (±50%) y el tiempo de respuesta de la germinación se localizó entre 6 y 10 días de la siembra in vitro.
 
 

Near-infrared spectroscopy used to predict soybean seed germination and vigour

AbstractRapid, non-destructive methods for measuring seed germination and vigour are valuable. Standard germination and seed vigour were determined using 81 soybean seed lots. From these data, seed lots were separated into high and low germinating seed lots as well as high, medium and low vigour seed lots. Near-infrared spectra (950–1650 nm) were collected for training and validation samples for each seed category and used to create partial least squares (PLS) prediction models. For both germination and vigour, qualitative models provided better discrimination of high and low performing seed lots compared with quantitative models. The qualitative germination prediction models correctly identified low and high germination seed lots with an accuracy between 85.7 and 89.7%. For seed vigour, qualitative predictions for the 3-category (low, medium and high vigour) models could not adequately separate high and medium vigour seeds. However, the 2-category (low, medium plus high vigour) prediction models could correctly identify low vigour seed lots between 80 and 100% and the medium plus high vigour seed lots between 96.3 and 96.6%. To our knowledge, the current study is the first to provide near-infrared spectroscopy (NIRS)-based predictive models using agronomically meaningful cut-offs for standard germination and vigour on a commercial scale using over 80 seed lots.

DNA Replication during Seed Germination, Deterioration, and Its Relation to Vigor in Alfalfa and White Clover

Differences in seed vigor that arise due to seed aging, even in seeds with high levels of germination, can result in differences in field emergence. Current test methods to identify vigor differences in commercial seed lots with high standard germination take several days to complete. DNA replication, measured using flow cytometry as the ratio of 4C/2C DNA, during early germination of unaged and aged seeds of alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.) was examined as a potential rapid and accurate method of assessing seed vigor. The relationship between 4C/2C DNA during germination of 10 commercial seed lots of both species and their field emergence was also determined. Most of the nuclei in dry mature seeds were arrested in the 2C DNA stage, with only a small proportion of 4C DNA nuclei. The proportion of 4C nuclei increased during germination of seeds, although the increase was lower and delayed in aged seeds with slower and lower germination. The 4C/2C ratio after 24‐h imbibition predicted the field emergence of all seed lots, but particularly of the lots with high standard germination (SG) (SG ≥ 75%, alfalfa, R2 = 0.815; SG ≥ 80%, white clover, R2 = 0.771; P < 0.01). Thus, DNA replication marks an advancement of germination in alfalfa and white clover seed, and the 4C/2C DNA ratio after 24‐h imbibition has potential to predict the seed vigor of both species.

Changes in respiration and structure of non-heading Chinese cabbage seeds during gradual artificial aging

Abstract The aging of seeds is a major problem in the agricultural sector. It is also a complex biological question that remains unclear for many crop seeds. In this experiment, we investigated how different ageing levels influence seeds germination, storage components, structure, respiration metabolism, and whether respiration is a promising indicator that can non-destructively evaluate seed aging. First, we obtained non-heading Chinese cabbage seeds with varying ageing levels by applying artificial aging treatments over a period of six days (0 d–6 d). Subsequently, respiration related indexes and ultrastructural observations were conducted. Our results showed that the respiratory rate remains low when seeds have a low water content. With the increased water content, the activities of respiratory-related enzymes, phosphohexose isomerase (PGI) and malate dehydrogenase (MDH), reached maximum levels when seeds were aged for two days. Respiration rates peaked one day later, followed by a rapid decline with increasing age. The ageing process consumed a large amount of storage components (e.g. soluble sugar, sucrose, and starch), leading to the degradation of mitochondria, proteasomes, fat bodies and cell nuclei in the aged seeds, which resulted in the reduction of respiratory rates. This, in turn, negatively affected seed germination. When seeds germinated (1 h–6 h, 1 d–6 d) under standard germination condition, the germination rate and respiratory rate showed significant correlation. Especially for 5 h and 6 h, the correlation coefficients reached 0.954 and 0.976 respectively. Measured at those times, respiratory rate should be a promising indicator for seed aging.

Nanoscale Zinc Oxide Particles for Improving the Physiological and Sanitary Quality of a Mexican Landrace of Red Maize.

In this research, quasi-spherical-shaped zinc oxide nanoparticles (ZnO NPs) were synthesized by a simple cost-competitive aqueous precipitation method. The engineered NPs were characterized using several validation methodologies: UV–Vis spectroscopy, diffuse reflection UV–Vis, spectrofluorometry, transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR). A procedure was established to coat a landrace of red maize using gelatinized maize starch. Each maize seed was treated with 0.16 mg ZnO NPs (~7.7 × 109 particles). The standard germination (SG) and accelerated aging (AA) tests indicated that ZnO NP-treated maize seeds presented better physiological quality (higher percentage of normal seedlings) and sanitary quality (lower percentage of seeds contaminated by microorganisms) as compared to controls. The application of ZnO NPs also improved seedling vigor, correlated to shoot length, shoot diameter, root length, and number of secondary roots. Furthermore, shoots and roots of the ZnO NP-treated maize seeds showed a marked increment in the main active FTIR band areas, most notably for the vibrations associated with peptide-protein, lipid, lignin, polysaccharide, hemicellulose, cellulose, and carbohydrate. From these results, it is concluded that ZnO NPs have potential for applications in peasant agriculture to improve the quality of small-scale farmers’ seeds and, as a result, preserve germplasm resources.

Inheritance of Seed Longevity and Its Association with Other Seed-Related Traits in Soybean (Glycine max)

Soybean seeds are highly susceptible to field weathering and mechanical damage during storage, thereby adversely affecting their longevity. To study the inheritance of seed longevity crossing was undertaken between two well-adopted genotypes (DS-228 and MAUS-71) having low seed longevity and two genotypes (Birsa Soya-1 and Kalitur) having high seed longevity and their total of 1138 F2 segregants were subjected to accelerated ageing test. F2 population data for seed longevity trait fitted in 3:1 Mendelian ratio indicated that it was governed by a single major gene in all the four crosses was further confirmed by test cross which fits the ratio 1:1. The segregants obtained from this study could be utilized for the development of high seed longevity soybean breeding program. The results of various six generations (P1, P2, F1, F2, B1 and B2) of four crosses exhibited varietal differences in seed vigour as clearly evident by standard germination after 8 days of accelerated ageing (ranged from 53.16 to 83.09%). Seed longevity had a positive association with germination percentage, seed density, proportion of the seed coat and lignin content in all four crosses, while seed coat permeability had negative association. The black-seeded parents were found to inherit good storability trait to their yellow-seeded progenies.

Effects of some chemical treatments on standard germination, field emergence and vigour in hybrid maize seeds

Effects of some chemical treatments on standard germination, field emergence and vigour in hybrid maize seeds

Tolerance against ageing in different varieties of Brassica rapa var toria, B. rapa var yellow sarson and B. juncea( L.)

Seed deterioration is a serious problem in developing countries where seeds are stored in places usually without a proper control of humidity and temperature. In this investigation, an effort was made to identify crops as well as varieties of brassica spp. tolerance to ageing and predicting loss of seed viability at regular interval through standard germination under laboratory condition. Analysis of variance showed that mean squares due to crops, ageing periods and crop× ageing period were significant for % seed germination. Result revealed that standard germination declined from 95.63 to 37.54% in toria, 92 to 28.96 in yellow sarson, and 93.79 to 30.92% in mustard. Similar changes in germination % were observed at 9 and 12 months of observation. After 6 months, germination % declined from 95.13 to 35.50% in toria, 91.87 to 28% in yellow sarson and 93.33 to 29% in mustard. Analysis of variance showed significant differences for %seed germination due to varieties, ageing period and interaction of varieties × ageing periods. At varietal level AP2, AP3 and AP4 aged seed, Bhawani (82.66%, 68.16% and 28.17%) showed higher seed germination % respectively than other three varieties of toria. In case of yellowsarson and mus-tard least deterioration for standard germination were observed in B-9 and Kranti respectively.This study indicates that toria seeds have better storability than yeloowsarson and mustard. At varietal level good storage potential was found in Bhawani, B-9 and Krantivariety of toria, yellow sarson and mustard respectively than other three varieties of studied crops.

EFFECT OF SOLAR DRYING ON THE QUALITY OF CORN SEEDS

The main objective of this investigation was carried out to study the ability of utilizing greenhouse solar dryers for drying of corn in order to obtain the best quality of dried grains for using it as seeds with the least drying time, and comparing with the natural sun drying method. Thus, contributing to increase the productivity. Corn cv. (Giza 168) was used for the experimental work at initial moisture content of 31.73% on dry basis (d.b). Two different drying methods of corn were tested for drying of ear and shelled corn. The two methods were natural sun drying and solar drying using greenhouse type solar dryers at different air velocities (0.5, 1.0 and 1.5 m/s). The experiments were carried out in rice mechanization center at Meet El- Dyba, Kafr El-Sheikh Governorate, Egypt during September 2016. Experiment included the flowing variables Two different drying methods (Solar drying method using greenhouse type solar dryer and natural sun drying method). Two different conditions of corn (complete ear-shelled corn). Three different air velocity (0.5, 1.0 and 1.5 m/s). High moisture ear and shelled corn was dried by using solar energy for heating air inside a greenhouse and compared with natural sun drying method. The results of quality tests that included standard germination test, vigor test and tetrazolium test for both drying methods for ear and shelled corn recorded high percentages for all treatments except solar drying of ear corn at air velocities 0.5 and 1.0 m/s. The average air temperature inside the solar dryer at air velocities 0.5 and 1.0 m/s reached to 43.9 and 42.4 ˚C respectively. High temperatures killed the germ of corn so the quality tests were reduced. Germination percentage of natural sun dried ear corn was 97 % and for solar dried samples at air velocities 0.5, 1.0 and 1.5 m/s was 79, 81, and 89%, respectively. The corresponding values for shelled corn were 93, 97 and 98 %.and 95 % for natural sun dried ones. The vigor test of dried ear corn recorded 90 for natural sun drying method and 34, 45, and 66% for solar drying at air velocities of 0.5, 1.0 and 1.5 m/s, respectively. The corresponding values for shelled corn were 86, 96 and 97% respectively, and 82 for natural sun dried samples. The recorded drying times were 26, 24 and 28 hours to reduce the moisture content from an initial level of 31.73 to final level of 14.07% (d.b.) for ear corn and for shelled corn were 20, 16 and 24 hours to reduce the moisture content from an initial level of an initial level of 31.73 to final level of 14.07% (d.b.) for ear corn and for shelled corn were 20, 16 and 24 hours to reduce the moisture content from an initial level of 27.23% to 14.12% compared with 46 and 38 hours for ear and shelled corn dried by natural sun drying method. Hourly costs of ear corn drying were 0.95, 0.88, 1.00 and 1.03 L.E/ kg for solar drying at air velocities 0.5, 1.0 , 1.5m/s and natural sun drying respectively. The corresponding values for shelled corn were 0.74, 0.58, 0.89 and 0.96 L.E/ kg.

Respuesta fisiológica de la semilla de chile habanero (Capsicum chinense Jacq.) al almacenamiento

El objetivo del presente estudio consistió en evaluar el efecto del tiempo y la temperatura de almacenamiento de la semilla de chile Habanero en la germinación estándar total y vigor de la semilla. Los factores estudiados fueron: a) Variedades de semilla de chile habanero (H-244, H-243, H-259, H-228, H-256); b) Temperatura de almacenamiento (10 °C y 26 °C) y; c) Tiempo de almacenamiento (tres, seis y nueve meses). Los tratamientos fueron organizados en las cámaras germinadoras bajo un diseño completamente al azar, con arreglo factorial. Los resultados indican que, a los tres meses de almacenamiento en condiciones controladas, las semillas se mantuvieron inmaduras y, a los nueve meses, se deterioran y pierden viabilidad. Almacenar la semilla de chile Habanero por seis meses a 26 °C, garantiza mayor porcentaje de germinación estándar total y permite obtener mayor número de plántulas normales de las variedades H-228 y H-259.

Screening of soybean germplasm standard germination and seed vigour test

The present investigation was conducted on Seed Testing Laboratory at Department of Seed Science and Technology, V.C.S.G. Uttarakhand University of Horticulture and Forestry, College of Forestry, Ranichauri Campus with twenty diverse genotypes of soybean including two checks viz., PS-1347 and PS-1092. Analysis of variance revealed significant differences for all seed quality parameters among all soybean genotypes. The genotype PS-1347 had high speed of germination and cold test. The genotype PS-1589 showed high standard germination. The maximum root and shoot length were recorded in PS-1586 and PS-1596. The highest seedling fresh and dry weight were observed in PS-1588 and PS-1602. The minimum moisture content was recorded in PS-1588 and maximum germination per cent through accelerated ageing test was recorded in PS-1092. Hence, these genotypes can be used in breeding programme for development of high yielding variety.

Evaluating the Role of Temperature on the Germination of Sesame (Sesamum indicum L.)

The experiment was conducted in September 2016 at Ethiopian Biodiversity Institute genebank, germination laboratory, Ethiopia to investigate the effect of temperature on the three accessions of sesame indicum L. viz., 9015, 9026 and 241335 and (25oc, 30oc, 35oc, 40oc) were used as the constant temperature gradient. The experiment was comprised of two factors, accession and temperature. And it was designed in factorial CRD with four replications. Analysis of variance showed that the main effects and the interaction effect were highly significant (P<0.001) for standard germination percentage. The result showed that, the highest germination (94%) was recorded at a temperature of 35oc though it was at par with the germination percentage obtained at a temperature of 30oc. However, at 40oc germination percentage decreased (86%). Whereas the lowest germination percentage (53%) was recorded at room temperature (25oc).This means that, higher temperatures are more suitable for germination of sesame accessions. Among the three sesame accessions considered for the study, the highest and the lowest germination percentage was obtained by (9015) and the (241335) respectively. This indicated that there is variation among the sesame accession.

Physiological quality of parsley seeds in relation to doses of nitrogen and potassium

Parsley seeds [Petroselinum crispum (Mill.) Nyman ex AW Hill] must have germinations higher than 70%. But seed companies have found difficulties to get the minimum standards of germination established for this species, because of the slow and irregular germination after harvesting. The aim of this study was to evaluate the effect of nitrogen and potassium fertilization on the physiological quality of parsley seeds. The experiment was conducted in Bozano – RS. Factorial arrangement was 3x3 (3 doses of N and 3 doses of K2O). Increasing doses of potassium (0, 50 and 100 kg ha-1 of K2O) and nitrogen (0, 100 and 200 kg ha-1 of N) were applied. For the evaluation of the physiological quality of the lots in laboratory, a completely randomized design experiment was performed with the following tests: 1,000-seed weight, standard germination test, first-count germination, germination speed index, and electrical conductivity. Nitrogen and potassium coverage interfere with the physiological quality of parsley seeds. The best lots were obtained using the dose of 100 kg ha-1 nitrogen and 50 kg ha-1 potassium. Dosage of 200 kg ha-1 N will increase vigor and seed weight.

Ponašanje atipičnih klijanaca kukuruza u poljskoj proizvodnji

The aim of this study was to investigate field emergence parameters, number of plants that reached reproductive stage and yield of seed lots with different count of abnormal seedlings. In standard germination test these seedlings are discarded from the count of germinated seed, presuming that they will not develop into normal plants. Five lots of hybrid NS 640 with different percentage of abnormal seedlings were tested. Results showed that in favourable environment conditions, large number of abnormal seedlings emerged, reached reproductive stage and participated in yield formation. However, emergence of seed lots with high percentage of abnormal seedlings was longer than for lots with small number of abnormal seedlings. Laboratory germination and germination energy were more correlated with indicators of field emergence rate, while total percentage of germinated seedlings (normal and abnormal) was more correlated with grain yield. However, it can be expected that in adverse environment conditions, abnormal seedlings are less likely to develop into normal plants.

Seed Rate and Sowing Method Effects on Seed Quality of Bread Wheat (triticum aestivum L.) Varieties in Horo District, Western Ethiopia

Although wheat varieties were released with recommended seed rates, farmers usually apply their specific seed rates for various reasons. A study was conducted in Horo District to determine the effect of seeding rate and sowing methods on the seed quality of bread wheat using field and laboratory experiments, in the 2011 cropping season. The field experiment was conducted at Shambu, Bako agricultural research center sub-site while the seed quality analysis was performed at seed laboratory of Holetta Agricultural Research Center. The field experiment consisted of three factors in a factorial combination of two levels of variety (Molgo which is local and Digelu or HAR-3116 which is an improved one), two levels of sowing methods (broadcast and row) and four levels of seed rate (125, 150, 175 and 200 kg/ha) arranged in RCBD with three replications. Samples of harvested seed from those treatment combinations were subjected to seed quality analysis according to procedures described by ISTA 2003. The result of Seed quality analysis showed that physical purity, standard germination, the speed of germination, vigor index-I and II, and field emergence index were significantly affected by treatment effects. All these parameters were higher in Digelu than in Molgo at the lowest seed rate (125 kg/ha) studied in row except the mean value of speed of germination which was higher for Molgo at a seed rate of 150 kg/ha. Six fungi and one bacterium species were associated with the seed samples studied. The results indicated that good quality seed was produced when both varieties were sown in row at a seed rate of 125 kg/ha. Moreover, variety Digelu was better in terms of seed quality than variety Molgo at all seed rates and both sowing methods.

Vigour Test to Predict Seed Germination and Normal Seedling Emergence of Acacia mangium in Nursery

Standard germination does not always indicate seed lot potential performance, especially if field germination conditions are less than optimal. Seed vigour tests therefore have been proposed to detect more accurate differences in potential seed lot performance. This study is aimed to obtain more precise method to assess Acacia mangium seed vigour correlated to germination success in a greenhouse and normal seedling emergency in a nursery. Tests were conducted on 13 seed lots collected from some certified seed sources. Seed testing and nursery activities were carried out at the Seed Laboratory of Forest Tree Seed Technology Research & Development Centre, Bogor. Experimental designs were arranged in a completely randomized design with four replications for laboratory tests (standard germination, germination index, number of normal seedling in the first count, radicle length, tetrazolium test, controlled deterioration test, accelerated aging, conductivity test), germination in a greenhouse and direct sowing in a nursery. Results showed that all tests were significantly different for ranking seed vigor in the different seed lots. Seed lot from Subanjeriji-2 provided the best germination performance in the greenhouse and direct sowingin the nursery, followed by seed lot from Parungpanjang, while seed lot from Kenangan had the lowest germination performance. The relationship between some laboratory tests, i.e. top paper test, germination index, and electrical conductivity test, and the greenhouse and nursery tests were significant. The electrical conductivity test had the highest accuracy with R 2 = 0,6278 for greenhouse test and R 2 = 0,4057 for nursery test. Overall, among all the laboratory tests, electrical conductivity test showed seeds well, so the usage of the electrical conductivity test for predicting normal seedling emergence could be suitable in A. mangium nursery programs.

The ideal harvest time for seeds of hybrid maize (Zea mays L.) XY335 and ZD958 produced in multiple environments

To identify the ideal harvest time (IHT) for the seed production of XY335 and ZD958, six seed-related traits were evaluated in seeds harvested at 11 harvest stages in 8 environments. Standard germination (SG), accelerated aging germination (AAG) and cold test germination (CTG) were vigor traits; hundred-seed weight (HSW) and seed moisture content (SMC) were physiological traits; and ≥10 °C accumulated temperature from pollination to harvest (AT10ph) was an ecological trait. All the traits were significantly affected by harvest stage. The responses of SG, AAG, CTG and HSW to postponing harvest stage fit quadratic models, while SMC and AT10ph fit linear models. The IHT (indicated by the last date to reach maximum SG, AAG and CTG) were 57.97 DAP and 56.80 DAP for XY335 and ZD958, respectively. SMC and AT10ph at IHT were 33.15% and 1234 °C for XY335, and 34.98% and 1226 °C for ZD958, respectively. The period to reach the maximum HSW was 5 days later than the IHT. Compared to HSW and SMC, AT10ph had a closer relationship to the seed vigor traits. Together with the fact that AT10ph was less affected by environment, these results suggested that AT10ph may be a novel indicator for determining the IHT.