(pp. 7-13)
Germination Properties and Cardinal Temperatures of Blue Panic Grass (Panicum antidotale)
Hamid Reza Javanmard*and Hamid Reza Eshghizadeh
ABSTRACT:
Understanding the cardinal temperatures for germination and seedling growth of new crops is important in determining potential production areas.In order to evaluate seed germination responses of blue panic grass (Panicum antidotale) to different temperatures, an experiment was conducted using eight temperature regimes of 5 °C intervals, from 10–45 °C.
Seed germination was complete within a 15–40 °C range, with the highest percentage and rate of germination at 30 °C. The shortest mean germination time was recorded at 35 °C. The best model describing cardinal temperatures for this species was the quadratic polynomial model; according to this model, the most favorable temperature for seed germination was 29.6 °C. The highest and lowest acceptable temperatures were 10.4 and 48.9 °C, respectively. This extended temperature range for germination, and the ability to germinate rapidly, suggested a high probability for successful blue panic grass establishment as a new forage crop in arid regions, such as those of Iran.
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(pp. 15-27)
Screening Oilseed Rape Germination for Thermotolerance Using a Laboratory-Based Method
Salim Farzaneh, Elias Soltani*, Ebrahim Zeinali and Farshid Ghaderi-Far
ABSTRACT:
The objective of this study was to screen oilseed rape (OSR) cultivars for cold and heat stress tolerance. OSR cultivars were classified into cold or heat tolerant groups based on the summation of individual temperature response index values for seed germination and germination rate.
Cardinal temperatures varied among cultivars. The base (Tb), optimum (To) and ceiling (Tc) temperatures ranged from 1–5, 11–24 and 35–40 °C for mean seed germination (MSG), and from 0–5, 21–35 and 41–46 °C for germination rate (GR), respectively. Each cultivar was classified as either cold or heat tolerant using cumulative temperature response indices (CTRI), based on its heat CTRI (H-CTRI) and cold CTRI (C-CTRI) index score. Talayeh was the most tolerant cultivar to cold stress, and Option 501, Hyola 420, Hyola 401, Okapi and P.Ft were tolerant to heat, with Hyola 420 having the highest HCTRI score. Tb for GR and MSG had a positive relationship with H-CTRI, while a negative relationship existed between Tb for GR and C-CTRI. There was an inverse relationship between H-CTRI and C-CTRI.
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(pp. 29-40)
Soybean Seed Pre-Harvest Desiccation and Physiological Quality from an Indeterminate Growth Cultivar
Mariana Zampar Toledo*, Altair Carlos Dubay, Rafaela Alenbrant Miggliavacca and Jaqueline Cazado Felix
ABSTRACT:
Desiccation of soybean plants often advances harvests by reducing the time needed for seeds to reach physiological maturity, but few studies have examined the efficacy of this management practice on indeterminate growth cultivars. This study evaluated the physiological quality of seeds from an indeterminate cultivar, ‘BMX Potência RR’, harvested on different days after plant desiccation.
The experiment was laid out in a split plot design, desiccation treatments (presence or absence of desiccation with paraquat at physiological maturity) as main plots, and harvest times (0, 3, 6, 9, 12, 15 and 18 d after the application of desiccant), based on developmental stages established for determinate cultivars, as sub-plots. Following harvest, seeds were evaluated for moisture content, seed weight, germination, and vigor tests. Low quality soybean seeds at physiological maturity, under environmental stresses during filling and maturation stages, were enhanced by delayed harvest. The highest quality seeds were those harvested close to the 9th and 12th d after physiological maturity, in the presence and absence of plant desiccation, respectively.
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(pp. 41-49)
Evaluating Seed Quality of Amburana cearensis Using X-Ray Scanning
Roberta S. Guedes*, Francisco G. Gomes-Junior,Julio Marcos-Filho and Edna U. Alves
ABSTRACT:
Legume seeds are commonly damaged by mechanical trauma invisible to the human eye, making other testing methods such as X-ray scanning useful for injury evaluation. The present study used X-ray and germination testing to detect alterations in the internal morphology of Amburana cearensis seeds and to relate their effects to seed quality.
Amburana cearensis seed lots were collected from 8 locations. Four replicates of 25 seeds were used from each seed lot. Following radiographic analysis, individually identified seeds were placed between moist paper towels and incubated for 12 d at 30 °C and a 12-h photoperiod, and their germination parameters evaluated. It was possible to use X-rays to identify the different types of internal tissues of A. cearensis seeds, as well as detect the presence of morphological and physical damage. Radiographic analysis proved to be an effective method of monitoring A. cearensis seed lot quality. This non-destructive analysis allowed for the prediction of seedling performance and could ensure high-quality seed standards for use in precision agriculture.
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(pp. 51-59)
Germination Characteristics of Abies × borisii-regis
Georgios K. Varsamis*, Ioannis A. Takos, Theodora P. Merou, Spiridon A. Galatsidas and Dimopoulos D. Panayiotis
ABSTRACT:
This study examined the effects of storage duration, light, stratification temperature, and their interaction, on seed germination of Abies × borisiiregis, a native Balkan species. Stratification temperature significantly affected germination of fresh seeds.
Seeds stratified at 0 °C exhibited the highest germination, especially under continuous light, even though A. × borisii-regis is known as a shade-tolerant species. Stratification also affected germination of seeds stored for 1 y, but not those stored for 2 y. Light affected germination of fresh and 1 y stored seeds, but only after stratification. Storage of seeds for 1 y reduced germination in most treatments, compared to fresh seeds, but seed storage for 2 y did not cause greater reduction in germination compared to 1 y of storage. Generalized linear model analysis indicated that each of the studied factors had a significant effect on seed germination, with significant interactions only between stratification temperature and storage time or light conditions. Results of the present study could explain the observed age polyvariation structure type of forest that A. × borisii-regis forms, in which continuous regeneration produces populations of individuals of various ages.
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(pp. 61-72)
Germination Constraints on Ricinodendron heudelotii in Cameroon
F.J. Djeugap*, L. Bernier, D. Dostaler, D.A. Fontem and M.L. Avana
ABSTRACT:
Ricinodendron heudelotii is a woody forest plant in the process of domestication in Cameroon. Due to its flavor and good nutritional value, demand for its seeds has increased both within the region and beyond. This study investigated the major factors hindering germination of the species.
Seeds collected in 2011 and 2012 were subjected to mechanical and chemical scarification, and fungicide treatments, in addition to different storage periods. Results revealed that seed coat dormancy, storage duration, and diseases were major factors affecting germination. Hammer-based mechanical scarification, followed by soaking seeds in water for 24 h significantly improved seed germination (88%), while thermal and sulphuric acid scarification did not improve germination compared to the control (3%). The interval between planting date and first germination was 8 d, while mean germination period for seeds that were scarified with a hammer was 13 d. An ideal storage period of 6 months for R. heudelotii seeds is recommended for best germination results. Although thiram fungicide application had no significant effect on germination, it reduced the number of infected seeds and seedlings after emergence. The presence of necrotic cotyledons, seed rot, and necrosis on cotyledonal leaves after germination was indicative of the susceptibility of R. heudelotii seeds to various pathogens. Results of this study provided additional information to address germination constraints of R. heudelotii in Cameroon.
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(pp. 75-79)
Temperature Effects on Seed Germination Potential of Holy Basil (Ocimum tenuiflorum)
Birendra Kumar*, Ekta Gupta, Richa Yadav, S.C. Singh and R.K. Lal
ABSTRACT:
Holy basil (Ocimum tenuiflorum) is an important herb used by Indians in their indigenous system of medicine, and commercially cultivated in hot and humid regions of the country. For development of quality seed standards, four parameters should be determined: optimum germination potential, optimum temperature at which maximum percent of seeds germinate, as well as first and final count days for germination and vigor testing.
In this study, seed germination and two vigor indices of two holy basil varieties, CIM-Angana and CIMAyu, were evaluated at 20, 25, 30, 35 and 40 °C, coupled with 16 h light and 8 h dark photo periods. Maximum germination was observed at 30 °C (88%) for CIM-Angana, and at 25 °C (72%) for CIM-Ayu. Seedling vigor index I,based on seedling length and germination, was highest at 20 and 25 °C for CIM-Angana and CIM-Ayu, respectively, while seedling vigor index II, based on seedling mass and germination, was highest at 30 °C for both varieties. At 40 °C, seeds germinated but most developed into abnormal seedlings. The study revealed that holy basil seed germination should be carried out at a temperature of 30 ± 5 °C, and tests evaluated 5 to 6 d after seed sowing.
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(pp. 81-88)
Seed Size Does Not Affect Germination or Seed Vigor of Common Bean
Vitor Henrique Vaz Mondo*, Clarindo Alves Costa Neto, Marco Túlio Machado Costa, Adriano Stephan Nascente and Mábio Chrisley Lacerda
ABSTRACT:
In Brazil, common bean (Phaseolus vulgaris) seed lots are classified using sieves into lots of small, medium and large seed size, which are then separately sold in standard 40-kg bags. However, the effect of seed size on common bean performances remains inconclusive, and therefore the objective of this research was to study the effects of common bean seed size on seed physiological potential.
Three common bean varieties, BRS Estilo, BRS Horizonte and BRS Madrepérola, were each sorted by size using oblong sieves, resulting in small, medium and large seed lots per variety. Seed lots were classified according to thousand seed mass, and their physiological potential assessed using several tests. Thousand seed mass indicated wide differences among seed lots, but within each variety, no differences in seed physiological potential were observed based on seed size. Only one variety, BRS Horizonte, showed significant differences in germination among seed lots of
different sizes, but all size classes had high germination of 92% or more. Germination first counts showed little variation among seed lots, and results of the other vigor tests based on seedling growth agreed with first count results. Although vigor tests based on seedling growth indicated a possible size effect on early field development of plants from large seeds, seed size of common bean does not appear to affect seed physiological potential.
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