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Components of phenotypic variance of

seed traits and germination characteristics

of 20 ponderosa pine half-sib families

Componentes de varianza fenotípica de características de semilla y

germinación de 20 familias de medios hermanos de pino ponderosa

ÉSAR

H. R

IVERA

-F

IGUEROA

1,4

, J

OHN

G. M

EXAL

AND

ENNIS

L. C

LASON

Abstract

Received: February 19, 2019 Accepted: March 1, 2019

Resumen

A study was conducted to estimate phenotypic variance components of

seed traits and seed vigor of 20 ponderosa pine seed lots. A high

intraspecific within-group variation in seed germination and seedling

growth has been observed in both half-sib and full-sib families of

conifers. Some seed traits may influence seed lot quality and seedling

survival. Wind-pollinated cones were collected from 20 ponderosa pine

maternal trees, 10 cones per tree, in a stand located in Fort Defiance,

Arizona. Air-dried seeds were sown under laboratory conditions, by

using a completely randomized design to estimate components of

phenotypic variance for seed weight (SW), seed coat weight (SCW), seed

imbibition (IMB), five germination characteristics, and three Weibull

parameters (

and

). About 80% of size classes had a seed weight

(SW) e» 41 mg and e» 97% final germination. The within-plot (within-

family) variance component for SW (64.5%) and IMB (70.4%) was

higher than among-family variation (35.3 and 24.8%, respectively). The

among-family component varied from 35.1% (Weibull parameter

) to

62.3% (Peak Value). Results suggest a significant maternal contribution

and a high within-family genetic influence on seed quality and

germination characteristics. Finally, heavier seeds (SW e» 60 mg), whose

time of germination (TOG) occurred at day 3, increased 38.3% of their

seed weight due to water absorption before reaching 50% germination;

on the other hand, seeds whose SW was e» 45 mg and TOG = 7, showed

102.2% increase in SW before reaching 50% germination.

Keywords:

germination timing, peak value, Weibull parameters, within-

family variation.

Se realizó un estudio para estimar componentes de varianza de

características y vigor de 20 lotes de semilla de pino ponderosa. En

familias de hermanos completos y medios hermanos la varianza dentro

de grupos es elevada para la germinación y crecimiento de plántulas de

coníferas. Algunas características de semilla pueden influir en la calidad

del lote y la supervivencia de plántulas. Diez conos de polinización abierta

fueron colectados de cada uno de 20 árboles madre, en una población

localizada en Fort Defiance, Arizona. Semillas secadas al aire fueron

sembradas en el laboratorio, en un diseño completamente aleatorizado,

para estimar las componentes de varianza fenotípica de: peso (SW) y

cubierta de la semilla (SCW); imbibición de la semilla (IMB), cinco

características germinativas y tres parámetros de Weibull (

a, b

Un 80% de la semilla tuvo peso e» 41 mg y germinación e» 97%. La

varianza dentro de progenie/dentro de familia para las características

SW (64.5%) e IMB (70.4%) fue mayor que la varianza entre familias

(35.3 y 24.8%, respectivamente). La varianza entre familias varió de

35.1% (parámetro

a de Weibull) a 62.3% (Peak Value). Los

resultados sugieren

contribución materna y componente genética alta

dentro de familias que influyen en la calidad y características

germinativas de la semilla. Semillas con SW e» 60 mg y TOG=3,

incrementaron 38.3% de su peso por agua absorbida para alcanzar

50% de germinación. Las semillas cuyo SW fue e» 45 mg and TOG = 7,

mostraron un incremento de 102.2% en SW antes

de completar 50%

de germinación.

Palabras clave: tiempo para germinación, valor pico, parámetros

Weibull, variación dentro de familias.

_________________________________

1 UNIVERSIDAD AUTÓNOMA DE CHIHUAHUA. Facultad de Ciencias Agrotecnológicas. Ciudad Universitaria s/n, C.P. 31170. Chihuahua, Chihuahua.

México.

2 NEW MEXICO STATE UNIVERSITY. College of Agriculture. Department of Agronomy and Horticulture. Las Cruces, NM.

3 UNIVERSITY OF CINCINNATI BLUE ASH COLLEGE. Department of Mathematics. Physics and Computer Science. Cincinnati, OH.

4 Corresponding autor: crivera@uach.mx

Medio Ambiente y Desarrollo Sustentable Artículo arbitrado

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CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

characteristics of 20 ponderosa pine half-sib families

Introduction

onifers are considered one of the most variable plant groups for many morphological

and physiological characteristics of seeds and seedlings. A high intraspecific within-

group variation in seed germination and seedling growth has been observed in both

half-sib and full-sib families, and this variability increases with age (Maze and Banerjee, 1989;

Matziris, 1998; Parker et al., 2006).

Some authors indicate that variation in seed

weight and seedling phenology is due to four major

factors: (1) genotype of seeds (Bramlett et al., 1983;

Sorensen and Campbell, 1985; Davidson et al., 1996;

Barnett, 1997); (2) maternal effects (Perry, 1976;

Perry and Hafley, 1981; (3) environmental conditions

such as chilling duration, incubation temperatures,

and soil moisture (McLemore, 1966; Gossling, 1988;

Bai et al., 2004; Pasquini and Defossé, 2012); and (4)

cultural practices such as fertilization, irrigation, and

pest control (More and Kidd, 1982; Gummerson, 1989;

Heidmann and Haase, 1989; Benjamin 1990; St. Clair

and Adams, 1993).

Seedling quality and the success of seedling

establishment are strongly correlated with

germination and emergence of seeds planted in the

nursery (Silen and Osterhaus, 1979; Mexal and Fisher,

1987; Davidson et al., 1996). It is apparent from

documented literature that seed mass, a maternally-

determined characteristic, seems to be correlated

with total germination and time of germination

(Roach and Wulf, 1987). In ponderosa pine, genetic

variation in seed morphology appears to be associated

with climatic gradients (mostly precipitation,

temperature and soil moisture); high estimates of

within-population variation seem to be associated to

adaptive mechanisms to environmental changes

(Parker et al., 2006). In addition, evidence suggests

that selective forces (temperature, soil moisture,

birds) are responsible for the origin of ecotypes

possessing unique variation in seed morphology (Ager

and Settler, 1983).

Little information exists about the genesis of

variation of germination characteristics and seeds

traits in Pinus ponderosa (Weber and Sorensen, 1992;

Matziris, 1998; Parker et al., 2006), which have

influence on quality of seed lots and seedling survival.

This study was conducted a) to estimate

phenotypic variance components of seed traits and

germination parameters of seed lots; b) to compare

seed vigor and germination characteristics of 20 half-

sib families and c) to analyze correlations of seed size

with germination and other seed traits.

Materials and methods

Study site and cone collection. The genetic

material was supplied by the Department of Navajo

Forestry Reforestation and Disease Control. Two

hundred wind-pollinated cones were collected from

twenty maternal trees, randomly selected from a stand

of ponderosa pine (Pinus ponderosa Dougl. Ex Laws.).

Trees of the ponderosa pine stand are located on the

Defiance Plateau (35° 40’ N, 111° 49’ W, at an

elevation between 2200 and 2500 meters (ASL), on

Fort Defiance, Arizona, USA. Mature cones were

collected in fall (October) and dried at room

temperature (20 °C ± 2 °C) for one month. Seeds were

then dewinged, cleaned, placed them in polyethylene

bags and stored five months in a refrigerator at 4 °C

until sown (Long and Jones, 1996; Parker et al., 2006;

Pasquini and Defossé, 2012). Seed traits of collected

cones and some morphological characteristics were

recorded for selected maternal trees (Table 1). In this

study, a seed lot is the progeny derived from each

maternal tree, each of which will be also named

subsequently as half-sib family.

Seed traits measurements. A bulked seed lot of

400 seeds was formed by combining cleaned seed

from 20 half-sib families (20 seeds randomly selected

from each half-sib family); then, seeds were weighed

and categorized into five size weight classes: a) < 31;

b) 31-40; c) 41-50; d) 51-60, and e) > 60 mg. Seed

weights (SW) were used to build an histogram of

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

characteristics of 20 ponderosa pine half-sib families

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frequencies (Figure 1). Seed coats of germinants were

removed, dried at 100 °C for 24 hours, weighed and

recorded (SCW). Values of seed imbibition (IMB),

expressed as amount of daily absorbed water (mg),

were calculated with the formula (Durzan, 1983;

Woodstock, 1988; Terskikh et al., 2005): IMB= [(SW2-

SW1)/SW1], where SW2=Seed weight at time 2 and

SW1=Seed weight at initial time. For each individual

seed, daily measurements of seed fresh weight changes

were registered.

Experimental design and treatments. Twenty

half-sib families, which represent 20 treatments, were

compared in a completely randomized design (give a

reference for this experimental design, e.g., Steel and

Torrie, 1980), with two replicates. The experimental

unit (EU) and sampling unit (SU) for all germination

parameters were represented by a Petri dish with 10

seeds. The SU for seed weight traits and seed

imbibition, on the other hand, was represented by a

single seed.

Table 1. Elevation (masl) and traits of mother trees from which 20 half-sib families were collected from Navajo Forest located on

Defiance Plateau (Fort Defiance, Arizona. USA).

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

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p w e f

w e f

Germination test. This study was conducted

under laboratory conditions (20 ºC ± 2 ºC) at the

Department of XXX, New Mexico State University, to

estimate variance components of several seed quality

traits of 20 half-sib families. Two replicates of ten

seeds of each half-sib family were sown on Petri

dishes containing three layers of filter paper

(Whatman No. 2). After sowing the seeds, 10 ml of

deionized water were applied in each Petri dish, and

5 ml were added every other day to replace the water

lost by evaporation.

Germination parameters. The criterion to define

seed germination was when radicle protrusion

occurred (if possible, give a reference) and extended

about 5 mm. In this study, several criteria were

included to measure germinative characteristics of

seed lots. Germination capacity (GC), which is also

named final or total germination, was measured as

germination percentage at the end of the test (G) and

transformed into Arc Sine (G* 0.01). Time of

germination (TOG), which is usually named

between groups or treatments, is a random sample

derived from a ponderosa pine population; the error

term (e2), it is also known as within group

component, which represents the variation among

experimental units (EU), while the component of

variance within-plot (w2) is the variation among

individuals within each EU (Steel and Torrie, 1960).

Since at each EU were sown seeds selected from a

given family, the within-plot component of variance

is also named within-family variation. The numbers

of families, replications, and individuals/plot

(progeny size/family) were, respectively, 20 (f), 2

(r) and 10 (p). Phenotypic variance is =  2 =  2 + 2 +  2.

Table 2. ANOVA model and expected means squares (EMS).

1/ 2,  2,  2 are the within-plot, error, and family components of

w e f

germination timing, was described as the number of

days to reach 50% germination. Germination speed

(GS), it is the reciprocal of time of germination (1/

TOG). Peak value (PV), it is the highest quotient when

dividing the maximum cumulative germination

percentage by number of days to reach this percentage.

Germination value (GV), it is the result of multiplying

PV*MDG data, where MDG=Mean daily germination

= number of seeds germinating per day (Czabator,

1962; Larson, 1963; Ranal and Garcia de Santana,

2006). Weibull parameters, other seed characteristics

associated with germinative capacity of seeds, were

estimated for all half-sib families. The parameter «a»,

for instance, indicates the point in which germination

begins. Parameter «b», on the other hand, is the scale

factor. Finally, «c» defines the shape of the curve (Rink

et al., 1979; Bahler et al., 1989).

Statistical analysis and variance components.

The model of analysis of variance (ANOVA) for

estimating components of phenotypic variance of seed

traits is shown in Table 2. Sources of variation

(Source), degrees of freedom (DF), and the expected

mean squares (EMS) were calculated for a completely

randomized design (Kuehl, 1994). The family

component of variance (f2), which it is usually

named in experimental design terminology as

variance, respectively.

Phenotypic variance = p

2 =  2 +  2 +  2. f=20 families; r=2

replicates, and p=10 individuals/family.

Results and discussion

Characteristics of mother trees and seeds of half-

sib families. Recorded data for selected maternal trees

(Table 1) confirm the existence of morphological

variation among half-sib families, as it has been

mentioned by other authors (Maze and Banerjee,

1989; Barnett, 1997; Matziris, 1998); for instance,

height of trees varied from 10.7 (family 20) to 24.4 m

(family 4); diameter at breast height (DBH), on the

other hand, showed a range between 25 (family 14)

and 63 cm (family 12). Number of seeds per cone,

among families, varied from 32 (family 16) to 123

(family 3). Average seed weight showed a range from

29 to 60 mg, respectively, for family 7 and family 19.

Seed moisture content (dry weight basis), averaged

7.6%, a minimum of 7.0% (family 9) and a maximum

of 8.1% (family 18). Since most means were close to

the average seed moisture content, this suggests

similar seed maturity conditions, as it was expected

because all cones were harvested on the same day of

October. Similar results were documented in other

pine species (Durzan, 1983; Terskikh et al., 2005;

Pasquini and Defossé, 2012).

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

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• Vol. XII, Núm. 3 • Septiembre-Diciembre 2018 •

Figure 1. Frecuency distribution of seed size of a 400-seeds

balanced bulk of 20 half-sib families.

Seed weight sizes and germination capacity. The

histogram of frequencies for seed weight shows a

normally distributed curve (Figure 1); the value of

the mode corresponds to seed size 41-50 mg, since it

is the class of the highest frequency (41%). The

heavier seed weight (> 60 mg) represents 7.5% o

the seeds, while the lighter (< 31 mg) only 2.1%.

About 80% of seeds weighed 41 mg and showed .

96.9% germination (Figure 2); lighter seeds, on the

other hand, had only 10.9% germination because

89.1% were empty seeds; these results, however,

contrast studies conducted in others tree species,

under controlled environmental conditions, have

observed that seed mass effects on germination and

early seedling growth depend on resource availability

(Parker et al., 2006; Mtambalika et al., 2014);

however, results of this study agree with some

researchers who have stated that embryo abortion is

the main cause of empty seeds (Matziris, 1998).

IMB, SW and TOG relationships. Four curves of

seed imbibition (IMB), selected from the balanced

bulk of half-sib families (Figure 3), show seed weight

increases and their relationships with time of

germination 50% (TOG) and initial seed weight (SW).

As it was mentioned before, lighter seeds (seed weight

< 31 mg) showed a low percent of germination,

because they had a higher percent of empty seeds;

moreover, ungerminated small seeds increased their

weight from 26 to 35 mg (increment = 57.7%). This

could be related to damage on seed coat produced by

pathogens (fungi and bacteria), seed coat layers

structure, insects, high temperature, wind and other

environmental factors (Timonin, 1964; Tillman-Sutela

and Kaupin, 1995). On the other hand, seeds whose

TOG occurred 3, 5 and 7 days after sowing, showed

at day 3, respectively, SW increments of 38.3, 29.4

and 40%. Studies in Pinus monticola (Dougl. Ex D.

Don) seeds have been reported weight increases of

30% one day after sowing, and it has been indicated

that seeds should reach a desirable seed moisture

content before germination begins (Terskikh et al.,

2005). Barnett (1997) indicated that in Pinus taeda

(L.) seeds must reach a moisture content of 36% to

split the seed coat and to initiate germination, while

longleaf pine (Pinus palustris Mill.) seeds require

around 55% moisture content (seed dry weight basis)

before starting germination.

Figure 2. Seed size effect on percent germination (bulk of 20

half-sib families).

Table 3. Components of phenotypic variance (%) for seed fresh

weight (SFW), seed coat fresh weight (SCFW) and seed

imbibition (IMB).

** Highly significant (P 0.01).

Increases in seed weights, which were recorded

during the seven-day imbibition period (Figure 3),

showed three imbibition stages described by other

researchers (Terskikh et al., 2005): 1) Phase I (0-1

day after sowing); 2) Phase II (2-3 days after sowing);

and 3) Saturation Phase or Phase III (4-7 days after

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

characteristics of 20 ponderosa pine half-sib families

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• Vol. XII, Núm. 3 • Septiembre-Diciembre 2018 •

sowing). Phase III is characterized by the highest

water-uptake rate and a fast increase in seed coat

permeability; important changes in SW occurred in

Phase I, since it was observed increases of 16, 12 and

13 mg, respectively, for TOG 3 (from 60 to 76 mg),

TOG 5 (from 51 to 63 mg) and TOG 7 (from 45 to 58

mg). In Phase II, on the other hand, small SW changes

were recorded from day 1 to day 2 (2-3 mg) and from

day 2 to day 3 (1-4 mg). Finally, the Saturation Phase

is characterized for another high increase and a linear

trend, whose pattern continues from day 3 to day 7. It

is also marked the superiority of seeds whose TOG is

3 and their average seed weight increases from 83 to

128 mg (day 3 to day 7). Patterns of imbibition curves

observed in this study agree with those described by

Woodstock (1988) and Terskikh et al. (2005).

Figure 3. Imbibition of seeds associated to Time of Germination

50% (TOG).

Components of variance for seed traits. Highly

significant differences (P < 0.001) were observed

among families for seed weight (SW), seed coat weight

(SCW), and seed imbibition (IMB); estimates of

components of variance, associated to family

differences (genetic variation), were 35.5, 50.1 and

24.8%, respectively, for SW, SCW and IMB (Table 3).

Within-plot (Within-family) variances estimated for

seed traits: SW, SCW and IMB were, respectively, 64.5,

41.8 and 70.4%; in most cases, the extent and magnitude

of this component is higher than family variance;

which may represent another source of genetic

variation associated to differences among individuals

of same family (within-family variance), resulting from

cross pollination between mother tress (female

parents) and male parents genetically divergent. The

great amount of among and within family variation,

observed for most characteristics analyzed, confirms

the results found by several researchers in other

species (Banerjee and Maze, 1988; Maze et al., 1989).

The existence of a high within-family variation, equal

in magnitude to within-population variance, seems to

be genetic in origin (Banerjee and Maze, 1988). As in

other conifers, germination parameters are clearly

under maternal control because a high percentage of

the phenotypic variance was determined by family

variation (Bramlett et al., 1983; St. Clair and Adams,

1993; Sorensen and Cress, 1994). On the other hand,

variation among-plots is mainly caused by

environmental differences associated to experimental

units.

Components of phenotypic variance. Significant

differences among half-sib families were found for

all germinative characteristics (Table 4); means

varied from 35.1% (parameter a) to 89.2%

(parameter b). In the former case, a low percentage

also indicates a low genetic contribution involved in

germination onset; the higher amount of variance,

associated to the scale factor «b», on the other hand,

strongly suggests that differences among seedlots

reflect a significant genetic influence on that

parameter, regardless the small number of half-sib

families compared in this study.

Table 4. Components of phenotypic variance (%) of germinative traits and Weibull´s parameters for 20 half-sib ponderosa pine families.

*Significant (P 0.05); ** Highly significant (P 0.01)

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

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LSD mean comparison test. For all seed traits and

germination parameters was used the Fisher´s Least

Significant Level (LSD) test, a multiple comparison

procedure, and the significant level of 5% (P = 0.05).

Percent seed germination (G), expressed as angular

transformation ArcSin G*0.01, varied from 45

(families 7 and 16) to 90 (families 14 and 15);

moreover, means of families with the highest

germination capacity included in group a (Table 5),

varied from 67.5 to 90, while group d, which included

families of the lowest germination capacity showed

averages between 45 and 67.5. Three groups of

significance were found for time of germination 50%

(TOG); group c, which showed the fastest

germination of them (TOG = 4), included 17 families;

while the slowest germination group consisted of

families 19, 11 and 4, whose TOG means were,

respectively, 5.5, 5 and 5 days. The Czabator´s

germination value (GV) describes completeness and

speed of germination process, so then it is a good

criterion to compare family performance. More

variation was observed in GV means (Table 5),

because seven significant groups were formed; group

a, for instance, included seven of better performance

families with the highest GV values; on the other hand,

group g included eight of lower performance families

with the smallest GV values.

Time of germination for 50% (TOG) in all

families took place 4-5.5 days after sowing. These

results agreed with other general findings in which

southern pine populations did not require pre-

chilling treatment (Larson, 1963; Hoff, 1987;

Gossling, 1988). Number of days required to start

germination was statistically the same for all half-sib

families; this result was expected because seeds were

non-dormant when running the germination test; in

other words, stratification treatments were not

required, by any seed lot compared here, to begin

germination.

Families 15, 14, and 6 had the best performance

by comparing the germination capacity (Arcsine),

TOG, and GV. Those germination parameters are

indicators of high quality seed lots, thus, they measure

germinative energy of seeds via percentage of

viability, completeness and rate of germination. Peak

Value means of ten families were statistically superior

to population mean (17.0) and families 3, 6, 14 and

15 were statistically superior to any progeny whose

mean was < 17.2. Most half-sib families (60%) had

fast germination because their average GS values were

superior to the population mean. In this germination

test, family 14 was the fastest germinating seedlot

(0.252), while family 19 performed as the slowest

germinating seedlot (GS = 0.183).

Table 5. Mean comparison test1 (LSD) for seed germination

[expressed as ArcSin (% germination)*0.01], time of

germination 50% (TOG), and germination value (GV).

1/Means with the same letters are not significantly different

(P 0.05).

The means of Weibull parameters for the seed

lots are listed (Table 6). Ten means of parameter «a»,

one of parameter «b» and 12 of parameter «c» belong

to group a and they were statistically superior to most

population means. The shape parameter «c» has a

strong genetic influence from maternal parent.

Significant effects of family component found in this

experiment, are indicative of genetic variation among

half-sib families. It was initially discussed that mean

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

characteristics of 20 ponderosa pine half-sib families

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• Vol. XII, Núm. 3 • Septiembre-Diciembre 2018 •

parameter «c» describes among half-sib families. It

was initially discussed that mean parameter «c»

describes the shape of the curve. Values of «c» near

3.6 (Table 6), like those for families 1 and 13 (3.5),

describe a symmetrical curve (approximately

normal), which also means a more uniform

germination; if «c» decreases below that value

(families 2, 19 and 20), the shape of the curve will be

possibly skewed (the pronounces tail to the right);

shapes negatively skewed, on the other hand, are

correlated with values of «c» greater than 3.6

(Families 3, 5, 6 and 7). Several authors (Bonner and

Dell, 1976; Bahler et al., 1989) stated that an increase

in parameter «a» and decrease in «b» and «c» are

correlated with a decrease in seed quality. The scale

factor «b» is inversely associated to increase in

germination capacity and germination rate of seed

lots, so a faster or more vigorous germination will be

reflected in lower values of the parameter «b».

Comparing the larger scale parameter of family 19

(2.8) with that of family 6 (1.0), it can be suggested

that the firs progeny has a lower seed quality. In this

sense, GS and GV parameters suggest the same

conclusion.

Table 6. Mean comparison test1 (LSD) of seed germination traits and Weibull’s parameters for 20 half-sib ponderosa pine families.

1/Means with the same letters are not significantly different (P 0.05)

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

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• Vol. XII, Núm. 3 • Septiembre-Diciembre 2018 •

Conclusions

1. There was among-family and within-family

significant variation associated for all seed traits and

Weibull parameters. These findings suggest that

analyzed characters are under control of both genetic

and environmental control.

2. Czabator´s GV and Weibull´s parameters were

useful criteria to compare overall performance of

seed lots. Half-sib families 6, 14, and 15 were

consistently superior to the rest of seed lots for

germination parameters Arcsine, TOG, PV and GV.

3. Seed weights e» 60 mg were positively

correlated with high percentages of sound and viable

seeds, fast germination (TOG = 3) and higher

imbibition rates (IMB).

Literature cited

AGER, A.A. and R.F. Stettler. 1983. Local variation in seeds of

ponderosa pine. Can. J. Bot. 61:1337-1344.

BAHLER, C., R.R. Hill, Jr., and R.A. Byers. 1989. Comparison of logistic

and Weibull functions: The effect of temperature on

cumulative germination of alfalfa. Crop Sci. 29:142-146.

BAI, Y., D. Thompson, and K. Broersma. 2004. Douglas fir and

ponderosa pine seed dormancy as regulated by grassland

seedbed conditions. J. Range Manage. 57:661-667.

BANERJEE, S. and J. Maze. 1988. Variation in growth within and

among families of Douglas-fir through a single season. Can. J.

Bot. 66:2452-2458.

BARNETT, J.P. 1997. Relating pine seed coat characteristics to speed

of germination, geographic variation, and seedling

development. Tree Planters´ Notes 48:38-42.

BENJAMIN, L.R. 1990. Variation in time of seedling emergence within

populations: A feature that determines individual growth and

development. Adv. Agron. 44:1-25.

BONNER, F.T. and T.R. Dell. 1976. The Weibull function: A new

method of comparing seed vigor. J. Seed Technol. 1:96-103.

BRAMLETT, D.L., R.R. Dell, and W.D. Pepper. 1983. Genetic and

maternal influences on Virginia pine seed germination. Silvae

Genet. 32:1-4.

DAVIDSON, R.H., D.G.W. Edwards, O. Sziklai, and Y.A. El-Kassaby. 1996.

Genetic variation in germination parameters among

populations of pacific silver fir. Silvae Genet. 45:165-171.

DURZAN, D.J. 1983. Metabolism of tritiated water during imbibition

and germination of jack pine seeds. Can. J. For. Res. 13:1204-1218.

GOSSLING, P.G. 1988. The effect of moist chilling on the subsequent

germination of some temperate conifer seeds over a range of

temperatures. J. Seed Technol. 12:90-98.

GUMMERSON, R.J. 1989. Seed-bed cultivations and sugar-beet

seedling emergence. J. Agric. Sci. Camb. 112:159-169.

HEIDMANN, L.J. and S.M. Haase. 1989. Causes of mortality in

outplanted ponderosa pine container seedlings in the

southwest. Tree Planters´ Notes 40:16-19.

HOFF, R.J. 1987. Dormancy in Pinus monticola seed related to

stratification time, seed coat, and genetics. Can. J. For. Res.

17:294-298.

KING, J.E. and D.J. Gifford. 1997. Amino acid utilization in seeds of

loblolly pine during germination and early seedling growth.

Plant Physiol. 113:1125-1135.

KY-DEMBELE, C., M. Tigabu, J. Bayala, and P.C. Odén. 2014. Inter-

and intra-provenances variations in seed size and seedling

characteristics of Khaya senegalensis A. Juss in Burkina Faso.

Agroforestry Syst. 88:311-320.

KUEHL, R.O. 1994. Statistical principles of research design and

analysis. Duxbury Press. Belmont, C.A.

LARSON, M.M. 1965. Initial root development of ponderosa pine

seedlings as related to germination date and size of seed. For.

Sci. 9:456-460.

LONG, T.J. and R.H. Jones. 1996. Seedling growth strategies and

seed size effects in fourteen oak species native to different

soil moisture habitats. Trees 11:1-8.

MATZIRIS, D. 1998. Genetic variation in cone and seed

characteristics in a clonal seed orchard of Aleppo pine grown

in Greece. Silvae Genet. 47:17-41.

MAZE, J., S. Banerjee, and Y.A. El-Kassaby. 1989. Variation in growth

rate within and among full-sib families of Douglas-fir

(Pseudotsuga menziesii). Can. J. Bot. 67:140-145.

MAZE, J. and S. Banerjee. 1989. A comparison of variation of

Pseudotsuga menziesii seedlings from genetically defined and

undefined sources. Can. J. Bot. 67:945-947.

MCLEMORE, B.F. 1966. Temperature effects on dormancy and

germination of loblolly pine seed. For. Sci. 12:284-289.

MEXAL, J.G. and J.T. Fisher. 1987. Size hierarchy in conifer seedbeds.

1. Time of emergence. New Forests 3:187-196.

MOORE, M.B. and F.A. Kidd. 1982. Seed source variation in induced

moisture stress germination of ponderosa pine. Tree Planters´

Notes 33:12-14.

MTAMBALIKA, K.,C. Munthali, D. Gondwe, and E. Missanjo. 2014.

Effect of seed size of Afzelia quanzensis on germination and

seedling growth. Int. J. For. Res. 2014:1-5.

PARKER, W.C., T.L. Noland, and A.E. Morneault. 2006. The effect of

seed mass on germination, seedling emergence, and early

seedling growth of eastern white pine (Pinus strobus L.). New

Forests 32:33-49.

PASQUINI, N.M. and G.E. Defossé. 2012. Effects of storage conditions

and pre-chilling periods on germinability of Pinus ponderosa

seeds from Patagonia, Argentina: preliminary study. Bosque

33(1):99-103.

PERRY, T.O. 1976. Maternal effects on the early performance of

trees progenies. pp. 474-481. IN: M.G.R. Cannell and F.T. Last

(eds.). Tree physiology and yield improvement. Academic?

Press, New York.

PERRY, T.O. and W.L. Hafley. 1981. Variation in seedling growth

rates: Their genetic and physiological bases. pp. 288-301. IN:

Proceedings: Southern Forest Tree Improvement Conference.

Louisiana State University, Division of Continuing Education

in Cooperation with Southern Forest Experimental? Station,

USDA, Forest Service.

RANAL, M. and D. Garcia de Santana. 2006. How and why to measure

the germination process?. Revista Brasil. Bot. 29:1-11.

CÉSAR H. RIVERA-FIGUEROA, JOHN G. MEXAL AND DENNIS L. CLASON: Components of phenotypic variance of seed traits and germination

characteristics of 20 ponderosa pine half-sib families

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• Vol. XII, Núm. 3 • Septiembre-Diciembre 2018 •

RINK, G., R.R. Dell, G. Swuitzer, and F.T. Bonner. 1979. Use of the

Weibull function to quantify sweetgum germination data.

Silvae Genet. 7:319-329.

ROACH, D. and R. Wulff. 1987. Maternal effects in plants. Ann. Rev.

Ecol. Sys. 18:209-235.

SILEN, R. and C. Osterhaus. 1979. Reduction of genetic base by

sizing of bulked Douglas-fir seed lots. Tree Planters´ Notes

30:24-30.

SORENSEN, F.C. and R.K. Campbell. 1985. Effect of seed weight on

height growth of Douglas-fir [Pseudotsuga menziesii (Mirb.)

Franco var. menziesii] seedlings in a nursery. Can. J. For. Res.

15:1109-1115.

SORENSEN, F.C. and D.W. Cress. 1994. Effects of sib mating on cone

and seed traits in coastal Douglas-fir. Silvae Genet. 43:338-345.

ST. CLAIR, J.B. and W.T. Adams. 1993. Family composition of Douglas-

fir nursery stock as influenced by seed characters, mortality,

and culling practices. New Forests 7:319-329.

STEEL, R. y J.H. Torrie. 1960. Principles and Procedures of Statistics.

John Willey & Sons.

TILLMAN-SUTELA, E. and A. Kauppi. 1995. The morphological

background to imbibition in seeds of Pinus sylvestris L. of

different provenances. Trees 9:123-133.

TIMONIN, M.I. 1964. Interaction of seed-coat microflora and soil

microorganisms and its effects on pre- and post-emergence

of some conifer seedlings. Can. J. Microbiol. 10(1):17-22.

TERSKIKH, V.V., J.A. Feurtado, C. Ren, S.R. Abrams, and A.R. Kermode.

2005. Water uptake and oil distribution during imbibition of

seeds of western white pine (Pinus monticola Dougl. Ex D.

Don). Planta 221:17-27.

WEBER, J.C. and F.C. Sorensen. 1992. Geographic variation in speed

of seed germination in central Oregon ponderosa pine (Pinus

ponderosa Dougl. Ex Laws.). Pacific Norwest Forest & Range

Experiment Station. Res. Pap. PNW-RP-444. Portland, OR:

USDA, Forest Service, 12 p.

WOODSTOCK, L.W. 1988. Seed imbibition: A critical period for

successful germination. J. Seed Technol. 12:1-15.

Cite this paper as:

Rivera-Figueroa, C. H., J. G. Mexal and D. L. Clason. 2018. Components of phenotypic variance of seed traits and germination

characteristics of 20 ponderosa pine half-sib families. TECNOCIENCIA Chihuahua 12(3):150-159.

DOI: https://doi.org/10.54167/tch.v12i3.189