Genotype-By-Environment Interaction (VG X E) wth ExamplesZohaib HUSSAIN
Introduction
Phenotypic variation can be caused by the combination of genotypes and environments in a population. Genotypes are all equally sensitive to their environments, meaning that a change of environment would impact the phenotype of all genotypes to the same extent. In fact, genotypes very often have different degrees of sensitivity to environmental conditions. This cause of phenotypic variance is called genotype by- environment interaction and is symbolized by VG x E. This adds another term to the expression for the independent causes of total phenotypic variation in a population
Ve = VG + VE + VG xE
Knowledge of the magnitude of genetic variability, heritability and genetic gains in selection of desirable characters could assist the plant breeder in ascertaining criteria to be used for the breeding programmes. Ten open pollinated maize varieties were evaluated at the Teaching and Research farm, University of Ilorin, Nigeria, during 2005 and 2006 cropping seasons to estimate genetic variability, heritability and genetic advance of grain yield and its component characters. The effect of genotype and genotype by year interaction were significant for ear weight and grain yield, while the effect of year was highly significant (P< 0.01) for all the characters. High magnitude of phenotypic and genotypic coefficient of variations as well as high heritability along with high genetic advance recorded for grain yield, number of grains ear-1, ear weight, plant and ear heights provides evidence that these parameters were under the control of additive gene effects and effective selection could be possible for improvement for these characters. Tze Comp3 C2, Acr 94 Tze Comp5, Tze Comp 4-Dmr Srbc2 and Acr 90 Pool 16-Dt were identified as outstanding genotypes for maize grain yield and should be tested at multilocation for their yield performance.
Genotype-By-Environment Interaction (VG X E) wth ExamplesZohaib HUSSAIN
Introduction
Phenotypic variation can be caused by the combination of genotypes and environments in a population. Genotypes are all equally sensitive to their environments, meaning that a change of environment would impact the phenotype of all genotypes to the same extent. In fact, genotypes very often have different degrees of sensitivity to environmental conditions. This cause of phenotypic variance is called genotype by- environment interaction and is symbolized by VG x E. This adds another term to the expression for the independent causes of total phenotypic variation in a population
Ve = VG + VE + VG xE
Knowledge of the magnitude of genetic variability, heritability and genetic gains in selection of desirable characters could assist the plant breeder in ascertaining criteria to be used for the breeding programmes. Ten open pollinated maize varieties were evaluated at the Teaching and Research farm, University of Ilorin, Nigeria, during 2005 and 2006 cropping seasons to estimate genetic variability, heritability and genetic advance of grain yield and its component characters. The effect of genotype and genotype by year interaction were significant for ear weight and grain yield, while the effect of year was highly significant (P< 0.01) for all the characters. High magnitude of phenotypic and genotypic coefficient of variations as well as high heritability along with high genetic advance recorded for grain yield, number of grains ear-1, ear weight, plant and ear heights provides evidence that these parameters were under the control of additive gene effects and effective selection could be possible for improvement for these characters. Tze Comp3 C2, Acr 94 Tze Comp5, Tze Comp 4-Dmr Srbc2 and Acr 90 Pool 16-Dt were identified as outstanding genotypes for maize grain yield and should be tested at multilocation for their yield performance.
Stability analysis and G*E interactions in plantsRachana Bagudam
Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. Stability refers to the performance with respective to environmental factors overtime within given location. Selection for stability is not possible until a biometrical model with suitable parameters is available to provide criteria necessary to rank varieties / breeds for stability. Different models of stability are discussed.
Genotype by environment interactions and effects on growth and yield of cowpe...Premier Publishers
Cowpea is widely grown in the humid tropics as staple and is largely affected by genotype by environment interaction (GEI). Data obtained from field trials were subjected to genotype (G) by environment (E) interaction (GEI Biplot) analysis and was applied to examine the nature and magnitude of GEI and quantify their effects on cowpea performance in seven experimental trials in a rainforest and derived savanna agroecologies of south-west Nigeria. Results showed that genotype x environment interactions effects were significant on cowpea growth and yield characters. The differential performance of cowpea varieties as early- and late- rainy season crops at both locations were attributable to variability in the soil, weather and biotic factors of the test environments. Determination of winning genotype(s) and yield ranking across environments showed that cowpea varieties depicted differential performance for the test environments and hence the interaction was crossover type. Varieties IT97K-568-18, IT97K-568-18 and Oloyin Brown are high yielding while IT96D-610 and IT98K-205-8 are poor. Oloyin Brown and IT98K-573-2-1 won in Akure 1, 2, 3 and 4 and Ado 1 while IT97K-568-18 won in Ado 2 and Akure 5. IT96D-610 and IT98K-205-8 did not win in any environment. The best performing varieties, Oloyin Brown, IT97K-568-18 and IT98K-573-2-1 combined both high yield and stable performance across test environments and were characterized as ideal genotypes while most unstable variety, IT96D-610, performed poorly in test environments. It is concluded that Ado-Ekiti was best for the late rainy while Akure location was best for early rainy season cropping.
GGEBiplot analysis of genotype × environment interaction in Agropyron interme...Innspub Net
In order to identify genotypes of Agropyron intermedium with high forage yield and stability an experiment was carried out in the Research station of Kermanshah Iran.The 11 accessions were sown in a randomized complete block design with three replications under rainfed and irrigated conditions during 2013-21-014 cropping deasons. Combined analysis of variance indicated high significant differences for location, genotype and G × E interaction (GEI) at 1% level of probability. Mean comparisons over environments introduced G4, G3 and G5 with maximum forage yield over rainfed and irrigated conditions. Minimum forage yield was attributed to genotype G1. GGEbiplot analysis exhibited that the first two principal components (PCA) resulted from GEI and genotype effect justified 99.37% of total variance in the data set. The four environments under investigation fell into two apparent groups: irrigated and rainfed. The presence of close associations among irrigated (E1 and E3) and rainfed (E2 and E4) conditions suggests that the same information about the genotypes could be obtained from fewer test environments, and hence the potential to reduce testing cost.The which-won-where pattern of GGEbiplot introduced genotypes G3 and G4 as stable with high forage yield for rainfed condition, while G5 was stable with high yield for irrigated condition. According to the comparison of the genotypes with the Ideal genotype accessions G4, G3 and G9 were more favorable than all the other genotypes. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Ecophysiological Yield Components In Wheat Cultivars Under Variable Phosphoru...Agriculture Journal IJOEAR
Abstract— Effects of P deficiency and interactions Cultivar x P available, on wheat yield and ecophysiological components were analysed, considering that the grain number m-2 is the product of the length of spike growth period, crop growth rate during this phase, the proportion of growth for spikes (partitioning) and spike fertility (grain number produced per unit of spike dry weight). Four cultivars with different strategy to generate yield (i.e. combinations of ecophysiological yield components) were compared with and without P fertilization, during two years in Azul, Buenos Aires, Argentina. The soil was moderately P deficient (7-9 mg P kg-1 soil) and P fertilization treatments (50 kg P ha-1) were established at sowing. P deficiencies affected yield and most of its components, the exceptions were: partitioning to spike, spike growth period and radiation use efficiency. The interaction Cultivar x P fertilization was not significant in all cases. The lack of interaction between cultivar and P level suggest that improvements in any crop physiological component will express in both, moderately deficiencies or high P environment.
Influence of some site factors on germinative parameters of Quercus seedsAI Publications
The genus Quercus has a high economic and ecological potential in Mexico. Nonetheless, its populations are reducing yearly, which demands the implementation of efficient management strategies to preserve them. To determine germinating capacity of seeds, and to learn about their relationship with some conditions of collecting sites (latitude N, accumulated degree-days >5 C in the frozen-free period (AD), precipitation of growing season (PGS)) we used information of seeds and collecting sites for natural populations of Quercus crassifolia, Q. jonesii, Q. polymorpha and Q. potosina. We determined that Q. potosina, the northernmost population; showed higher values of seeds mean weight, percentage of germinated seeds (PGS), average germination time (AGT), peak value (PV), and germination energy (GE), than other species. Q. polymorpha also showed high mean values of seeds weight, PGS, PV, and GE and it was collected at northern latitudes near those of Q. crassifolia and Q. jonesii. Q. jonesii was the southernmost population and showed lower values in these parameters. On the other hand, the analysis also determined that Q. jonesii, Q. plymorpha, and Q. potosina had quicker germination than Q. crassifolia. We inferred that for the species in the analyzed sites, increasing PGS improves sites conditions, which promotes better germination of germplasm.
Stability analysis and G*E interactions in plantsRachana Bagudam
Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. Stability refers to the performance with respective to environmental factors overtime within given location. Selection for stability is not possible until a biometrical model with suitable parameters is available to provide criteria necessary to rank varieties / breeds for stability. Different models of stability are discussed.
Genotype by environment interactions and effects on growth and yield of cowpe...Premier Publishers
Cowpea is widely grown in the humid tropics as staple and is largely affected by genotype by environment interaction (GEI). Data obtained from field trials were subjected to genotype (G) by environment (E) interaction (GEI Biplot) analysis and was applied to examine the nature and magnitude of GEI and quantify their effects on cowpea performance in seven experimental trials in a rainforest and derived savanna agroecologies of south-west Nigeria. Results showed that genotype x environment interactions effects were significant on cowpea growth and yield characters. The differential performance of cowpea varieties as early- and late- rainy season crops at both locations were attributable to variability in the soil, weather and biotic factors of the test environments. Determination of winning genotype(s) and yield ranking across environments showed that cowpea varieties depicted differential performance for the test environments and hence the interaction was crossover type. Varieties IT97K-568-18, IT97K-568-18 and Oloyin Brown are high yielding while IT96D-610 and IT98K-205-8 are poor. Oloyin Brown and IT98K-573-2-1 won in Akure 1, 2, 3 and 4 and Ado 1 while IT97K-568-18 won in Ado 2 and Akure 5. IT96D-610 and IT98K-205-8 did not win in any environment. The best performing varieties, Oloyin Brown, IT97K-568-18 and IT98K-573-2-1 combined both high yield and stable performance across test environments and were characterized as ideal genotypes while most unstable variety, IT96D-610, performed poorly in test environments. It is concluded that Ado-Ekiti was best for the late rainy while Akure location was best for early rainy season cropping.
GGEBiplot analysis of genotype × environment interaction in Agropyron interme...Innspub Net
In order to identify genotypes of Agropyron intermedium with high forage yield and stability an experiment was carried out in the Research station of Kermanshah Iran.The 11 accessions were sown in a randomized complete block design with three replications under rainfed and irrigated conditions during 2013-21-014 cropping deasons. Combined analysis of variance indicated high significant differences for location, genotype and G × E interaction (GEI) at 1% level of probability. Mean comparisons over environments introduced G4, G3 and G5 with maximum forage yield over rainfed and irrigated conditions. Minimum forage yield was attributed to genotype G1. GGEbiplot analysis exhibited that the first two principal components (PCA) resulted from GEI and genotype effect justified 99.37% of total variance in the data set. The four environments under investigation fell into two apparent groups: irrigated and rainfed. The presence of close associations among irrigated (E1 and E3) and rainfed (E2 and E4) conditions suggests that the same information about the genotypes could be obtained from fewer test environments, and hence the potential to reduce testing cost.The which-won-where pattern of GGEbiplot introduced genotypes G3 and G4 as stable with high forage yield for rainfed condition, while G5 was stable with high yield for irrigated condition. According to the comparison of the genotypes with the Ideal genotype accessions G4, G3 and G9 were more favorable than all the other genotypes. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Ecophysiological Yield Components In Wheat Cultivars Under Variable Phosphoru...Agriculture Journal IJOEAR
Abstract— Effects of P deficiency and interactions Cultivar x P available, on wheat yield and ecophysiological components were analysed, considering that the grain number m-2 is the product of the length of spike growth period, crop growth rate during this phase, the proportion of growth for spikes (partitioning) and spike fertility (grain number produced per unit of spike dry weight). Four cultivars with different strategy to generate yield (i.e. combinations of ecophysiological yield components) were compared with and without P fertilization, during two years in Azul, Buenos Aires, Argentina. The soil was moderately P deficient (7-9 mg P kg-1 soil) and P fertilization treatments (50 kg P ha-1) were established at sowing. P deficiencies affected yield and most of its components, the exceptions were: partitioning to spike, spike growth period and radiation use efficiency. The interaction Cultivar x P fertilization was not significant in all cases. The lack of interaction between cultivar and P level suggest that improvements in any crop physiological component will express in both, moderately deficiencies or high P environment.
Influence of some site factors on germinative parameters of Quercus seedsAI Publications
The genus Quercus has a high economic and ecological potential in Mexico. Nonetheless, its populations are reducing yearly, which demands the implementation of efficient management strategies to preserve them. To determine germinating capacity of seeds, and to learn about their relationship with some conditions of collecting sites (latitude N, accumulated degree-days >5 C in the frozen-free period (AD), precipitation of growing season (PGS)) we used information of seeds and collecting sites for natural populations of Quercus crassifolia, Q. jonesii, Q. polymorpha and Q. potosina. We determined that Q. potosina, the northernmost population; showed higher values of seeds mean weight, percentage of germinated seeds (PGS), average germination time (AGT), peak value (PV), and germination energy (GE), than other species. Q. polymorpha also showed high mean values of seeds weight, PGS, PV, and GE and it was collected at northern latitudes near those of Q. crassifolia and Q. jonesii. Q. jonesii was the southernmost population and showed lower values in these parameters. On the other hand, the analysis also determined that Q. jonesii, Q. plymorpha, and Q. potosina had quicker germination than Q. crassifolia. We inferred that for the species in the analyzed sites, increasing PGS improves sites conditions, which promotes better germination of germplasm.
DOI: 10.21276/ijlssr.2016.2.3.1
ABSTRACT- Genetic variability studied for eleven characters viz., number of leaves, branches, clusters, pods, pod
length (cm), seed per plant, plant height (cm), 100 seed weight (g), days to flower, maturity and yield per plant (g) in
group of forty two genotypes of French bean (Phaseolus vulgaris L.) revealed highly significant difference for all the
characters. High heritability not only guideline for breeding improvement must to associated with genetic advance
expressed a wide range of variability for all the traits. Heritability estimated and expected genetic advance were high
for number of leaves (95.46< 97.00), branches (45.85 > 14.00), clusters (89.45< 92.00), pods (92.84< 99.00), pod length
(88.94< 99.00), seeds per plant (92.20> 32.00), plant height (96.41< 106.00), 100 seed weight (99.22> 72.00), days to
flower (94.82 > 32.00), maturity (56.26> 13.00) and yield per plant (80.13 < 140.00) suggesting that these are more
useful traits for varietal improvement programme.
Key-words- French bean (Phaseolus vulgaris L.), Genetic Variability, Heritability, Phenotypic coefficient of variation,
Genotypic coefficient of variation
Out Crossing, Heterozygosis and Inbreeding with Environments Interaction in R...paperpublications3
Abstract:The progenies of five sorghum heterozygous populations’ cycles were tested under main and off-season on two different environments irrigated and rainfall conditions for their outcrossing, heterozygosity and inbreeding coefficient using SSR markers,the marker combinations were optimized according to their fragment size. Multi-locus outcrossing rate (tm) and average single-locus (ts) outcrossing rates were estimated using the MLTR software, and TFPGA computer program. The outcrossing rate effected directly by the temperature and relative humidity (RH) during the initial flowering period, which the low temperature with high RH under main season is revealed positive increased in outcrossing than off-season. Progenies outcrossing rate revealed same trend with main population outcrossing and the same trend was observed heterozygosity with decreased in inbreeding coefficient. Higher levels in outcrossing rate and heterozygosity was detected under rainfall environment in two based population progenies, but in three advanced population cycles the outcrossing rate was higher under irrigated than rainfed environment. Inbreeding coefficient revealed negative relation with outcrossing rate and heterozygosity in different population’s progenies.
Out Crossing, Heterozygosis and Inbreeding with Environments Interaction in R...paperpublications3
Abstract:The progenies of five sorghum heterozygous populations’ cycles were tested under main and off-season on two different environments irrigated and rainfall conditions for their outcrossing, heterozygosity and inbreeding coefficient using SSR markers,the marker combinations were optimized according to their fragment size. Multi-locus outcrossing rate (tm) and average single-locus (ts) outcrossing rates were estimated using the MLTR software, and TFPGA computer program. The outcrossing rate effected directly by the temperature and relative humidity (RH) during the initial flowering period, which the low temperature with high RH under main season is revealed positive increased in outcrossing than off-season. Progenies outcrossing rate revealed same trend with main population outcrossing and the same trend was observed heterozygosity with decreased in inbreeding coefficient. Higher levels in outcrossing rate and heterozygosity was detected under rainfall environment in two based population progenies, but in three advanced population cycles the outcrossing rate was higher under irrigated than rainfed environment. Inbreeding coefficient revealed negative relation with outcrossing rate and heterozygosity in different population’s progenies.
Keyword:environment, recurrent selection, outcrossing, sorghum, progenies.
Genetic diversity enhances the resistance of aseagrass ecosyMatthewTennant613
Genetic diversity enhances the resistance of a
seagrass ecosystem to disturbance
A. Randall Hughes* and John J. Stachowicz
Section of Evolution and Ecology, One Shields Avenue, University of California, Davis, CA 95616
Edited by G. David Tilman, University of Minnesota, St. Paul, MN, and approved May 4, 2004 (received for review April 14, 2004)
Motivated by recent global reductions in biodiversity, empirical
and theoretical research suggests that more species-rich systems
exhibit enhanced productivity, nutrient cycling, or resistance to
disturbance or invasion relative to systems with fewer species. In
contrast, few data are available to assess the potential ecosystem-
level importance of genetic diversity within species known to play
a major functional role. Using a manipulative field experiment, we
show that increasing genotypic diversity in a habitat-forming
species (the seagrass Zostera marina) enhances community resis-
tance to disturbance by grazing geese. The time required for
recovery to near predisturbance densities also decreases with
increasing eelgrass genotypic diversity. However, there is no effect
of diversity on resilience, measured as the rate of shoot recovery
after the disturbance, suggesting that more rapid recovery in
diverse plots is due solely to differences in disturbance resistance.
Genotypic diversity did not affect ecosystem processes in the
absence of disturbance. Thus, our results suggest that genetic
diversity, like species diversity, may be most important for enhanc-
ing the consistency and reliability of ecosystems by providing
biological insurance against environmental change.
There is growing recognition that humans are highly depen-dent on natural ecosystems for a variety of goods and
services (1). Maintaining the provision of these goods and
services in the face of natural and anthropogenic disturbances is
critical to achieving both conservation and economic goals.
Motivated by accelerating rates of worldwide decline in biodi-
versity (2), considerable research has focused on the conse
quences of local species loss for goods and services provided by
ecosystems (2– 8). Much of this work focuses on the effects of
declining species richness on short-term processes such as pro-
duction, community respiration, and nutrient cycling (2). Al-
though the results are far from unequivocal and subject to
varying interpretation (e.g., ref. 9), it does appear that, in some
systems, reductions in local species diversity contribute to a
decline in ecosystem properties such as productivity and resis-
tance to disturbance (see review in ref. 2).
Nevertheless, many important ecosystems, such as kelp forests,
cattail marshes, and fir forests, are dominated by, and dependent
on, one or a few key plant species (10). Furthermore, individual
predator and herbivore species often play a disproportionate role in
determining ecosystem processes, overwhelming any effect of spe-
cies diversity (11). Dominant, numerically abundant s ...
Genetic control and heterosis depend directly on genetic divergence among the parents in generating promising hybrids
required by plant breeders. The purpose of this study was to determine the relative importance of heterosis, combining
abilities, regression and correlation estimates in order to develop hybrid cultivars in maize. The 28 F1 hybrids obtained by
partial diallel cross of 8 inbreds in a randomized complete block design were evaluated at the Lower Niger River Basin
Authority, Oke-Oyi, Nigeria in three years. General (GCA) and specific combining abilities (SCA) produced significant (P
< 0.01) effects for all the characters, while non-additive genetic effects were predominant. The levels of heterosis for grain
yield varied widely among crosses, ranging from -16.83 to 9.76%. Positive and significant genotypic and phenotypic
correlations among grain yield and some related characters (days to anthesis and silking; plant and ear heights; number of
ears plant-1 and 1000 seed weight) showed that each character could be used indirectly to selection of grain yield. These
results also indicated that SCA was more effective than heterosis for describing hybrid performance. The regression of
actual hybrid characters on the expected hybrid characters, based on parental GCA values, was highly significant.
Regression analysis also showed that all the agronomic characters jointly contributed 19.4% to grain yield of maize. The
inbreds (Pop 66 SR and 2000 EV DT-Y STRC4) and crosses (Pop 66 SR x, 2000 EV DT-Y STRC4, Pop 66 SR x KU1409
and 9006 x KU1409) featured prominently with respect to better GCA × Year and SCA × Year effects with high heterotic
values for maize grain yield and associated characters. These inbreds could serve as donors to obtain early and short
statured hybrids with higher yield, while the crosses may be exploited and adapted to the Nigerian Savannas. This study
also affirmed that genotypic and phenotypic correlation coefficients as well as combining abilities, heterosis and regression
analyses were found to be suitable models for yield improvement in maize breeding.
Diversity of drought tolerance and seed yield in sunflower (Helianthus annuus...Innspub Net
Randomized complete block design with four replications in two drought and non-drought environments was used for this study. Drought resistance indices were calculated based on seed yield in stress and non-stress conditions. The results showed that GMP and STI were the best drought resistance indices so had the positive and significant correlation with Yp and Ys. Three dimensional graph showed that RFG5*AF80, G-543 and Farokh were the drought resistant hybrids. These hybrids had the highest amount of Yp, Ys, GMP and STI that revealed the highest yield potential as well as drought tolerance in these genotypes. Because of that these hybrids have promised potential to cultivate in drought prone environments. Regression analysis revealed that the traits grain filling rate, grain filling duration and water use efficiency accounted for 97.0% of total variation exist in seed yield. Path coefficient analysis demonstrated the highest and positive direct effect of grain filling rate and grain filling duration on seed yield in sunflower hybrids. Water use efficiency had low direct effect while high indirect effects via grain filling duration on seed yield. Therefore, the study revealed the importance of total grain filling rate and grain filling duration as indirect selection criteria for genetic improvement of seed yield in sunflower breeding programs especially in early generations. On the other hand, indirect effects of water use efficiency through grain filling duration on seed yield have promising result in selection programs. Get the full articles at: http://www.innspub.net/volume-6-number-5-may-2015-jbes/
The Effects of Coconut Milk on the Rooting Of Two Types of Cutting of Termina...ijsrd.com
Objectives: The trial investigated the effects of coconut milk on stem and root cuttings of Terminalia catappa. Methodology and results: Each cutting type treated with three coconut milk concentrations (0%, 50% and 100%).The experiment was a 2x3 factorial set, six treatment combinations replicated four times and laid out in a completely randomized design. The results showed that root cuttings produced significantly more cuttings with roots, number of roots on rooted cuttings and rooted cuttings with the longest roots (P<0.05)>0.05) than those treated with 50% and 0% coconut milk. There was a significant interaction (P<0.05)><0.05)><0.05) between cutting type and coconut milk concentration on the number of leaves produced. It was recommend that root cuttings treated with 100% coconut milk should be used for vegetative propagation programs of the species.
1. 1. Riginos, C., M.S. Herschel, and J. Schmitt. 2007. Am. J. Bot. 94(12): 1984-1991
2. Sultan, S.E., K. Barton, and A.M. Wilczek. 2009. Ecology 90(7): 1831-1839
3. Sultan, S.E. 1996. Ecology 77(6): 1791-1807
4. Weiner, J., S. Martinez, H. Muller-Scharer, P. Stoll, and B. Schmid. 1997. J. Ecol. 85(2): 133-142
5. Jakobsson, A. & Eriksson, O 2000.. Oikos 88: 494-502.
Experiment Conclusions
Results
In plants, ‘maternal effects’ refer to the effect of the maternal
environment on offspring phenotype. For example, some
studies have shown that parents in good environments produce
larger, healthier seeds.
Despite clear examples of maternal effects in some species,
there has been no systematic study of their importance for a
broad suite of species1,2. In addition, the type of maternal effect
can differ – species have shown differences in terms of the
quality and quantity of offspring, but the potential trade-off in
these responses has not been tested.
In our study, we examined the generality of maternal effects for
Mediterranean annual plants found in California. This large
group of species commonly faces drought conditions, with
highly variable rainfall from one year to the next. Our goal was
to test the generality of maternal effects among these species,
using ecologically relevant conditions. In this study, we asked:
1) Are drought induced maternal effects still prevalent at
the community level?
2) Does phylogeny and area of origin (native to California
or Spain) account for any variation in maternal effects?
Drought
*
*
*
*
-4
-3
-2
-1
0
1
2
3
4
5
C. Seed mass vs. number (negative values indicate a trade-off)
*
*
*
* *
*
*
-6
-5
-4
-3
-2
-1
0
1
2
3
4
B. Number of seeds per plant
*
*
*
*
*
-4
-3
-2
-1
0
1
2
3
4
5
A. Seed mass
Figure 2: a) t-values for mass per seed testing null hypothesis μDry – μWet = 0, b) t-values for total number of seeds per plant testing
null hypothesis μDry – μWet = 0, c) t-values testing null hypothesis that the linear relationship between seed mass and number is equal
to zero. All tests showed significant species x environment interactions, indicating different responses among species.
* Significant P-value with 0.05 significance level
Native species
Non-Native species
Performanceindry-wetenvironments(t-values)
Maternal effects to drought were negligible for 58% of the
species, with five and seven species responding significantly
through seed mass and seed number, respectively (Fig. 2)
Seed mass varied in direction. However, seed number was
mainly increased in wet compared to dry environments.
Phylogeny and area of origin does not appear to play a
significant role in species’ drought responses, except for some
grouping of significant seed mass effects in the Poales order.
Many species had one favourable environment (seed mass or
seed number effect with a positive or no relationship between the
two). However, for those species that do show a trade-off, it is
unclear if gain in seed size offsets loss in seed number, and vice
versa, in response to the environment.
Despite many studies showing the importance of maternal
effects on specific species, these effects are not consistent in
magnitude or direction within a community4.
Maternal effects are expressed at several nodes across a
diverse phylogeny, suggesting that their expression is not
constrained by recent evolutionary relationships.
Similarly, maternal effects do not seem to be related to the
geographical origin of the plant.
The importance of different types of effects (seed size and
seed number) and their trade-offs remains an important area of
research5. Our ongoing study is designed to address these
questions.
ACKNOWLEDGMENTS
Ecological community: 29 species from Mediterranean climates
native to California or Spain comprising taxonomic orders
Asterales, Lamiales, Fabales, Caryophyllales, Ranunculales and
Poales
Maternal plants were grown in dry (5.8 % soil moisture) or wet
(11.1% soil moisture) greenhouse conditions, which are known to
be important to Mediterranean species3. Seeds were counted and
weighed, and a subset were planted to examine seedling
performance (Fig. 1).
We used generalized linear models to examine the effect of
maternal environment on seed size, seed number and any
potential trade-off.
Figure 1: Growing plants and processing seeds.
Hvulg Vmyur Pcamp
Figure 3: Seed morphology of three species used in this experiment.