scholarly journals Fertility variation among individuals in natural stands of Acacia leucophloea

2016 ◽  
Vol 65 (1) ◽  
pp. 20-30
Author(s):  
V.N. Mutharaian ◽  
R. Kamalakannan ◽  
V. Narmatha Bai ◽  
A. Mayavel ◽  
D.-Y. Kim ◽  
...  

AbstractGrowth characteristics and fertility variations were evaluated at four natural stands of tropical arid zone species,A. leucophloeain southern India. Three stands (TNL 1, TNL 2 and PDM) were situated in dry upland regions while one stand (RKP) was at waterlogged site. The tree height and girth at breast height did not vary between stands in two years. Fertility variation (sibling coefficient, ψ) was estimated based on flowering abundance and fruit set collected for two consecutive years. Fruit production per tree was generally lower in the RKP stand than the other three stands. No year-to-year variation was observed on fruit set in all stands. Growth and flower production showed a weak-positive correlation in both years (R2= 0.39 to 0.1). The correlation to check if the larger inflorescence size, the higher number of fruit production was also failed. Male fertility variation did not vary much among stands (ψm= 1.28 ~ 1.62). Female fertility variation was low (ψf= 1.71 ~ 2.02) in the three stands situated in dry upland regions than the RKP stand (ψf= 4.09 ~ 4.16). The cumulative contribution of trees to the overall fertility was deviated from the ideal situation (equal contribution) in all stands, especially the RKP stand showed a skewed distribution (R2≤ 6.5). The effective population size was low in the RKP predicting a high genetic drift when compared with other sites. Similarly high group coancestry and low gene diversity were observed in the stand RKP. The implications of fertility variation on gene diversity of the species and future management of the natural stands were also discussed.

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ji-Min Park ◽  
Hye-In Kang ◽  
Da-Bin Yeom ◽  
Kyu-Suk Kang ◽  
Yousry A. El-Kassaby ◽  
...  

Abstract Background Gender and fertility variation have an impact on mating dynamics in a population because they affect the gene exchange among parental members and the genetic composition of the resultant seed crops. Fertility is the proportional gametic contribution of parents to their progeny. An effective number of parents, derivative of effective population size, is the probability that two alleles randomly chosen from the gamete gene pool originated from the same parent. The effective number of parents is directly related to the fertility variation among parents, which should be monitored for manipulating gene diversity of seed crops. We formulated a fundamental equation of estimating the effective number of parents and applied it to a seed production population. Results Effective number of parents (Np) was derived from fertility variation (Ψ) considering covariance (correlation coefficient, r) between maternal and paternal fertility. The Ψ was calculated from the coefficient of variation in reproductive outputs and divided into female (ψf) and male (ψm) fertility variation in the population under study. The Np was estimated from the parental Ψ estimated by the fertility variation of maternal (ψf) and paternal (ψm) parents. The gene diversity of seed crops was monitored by Ψ and Np. in a 1.5 generation Pinus koraiensis seed orchard as a case of monoecious species. A large variation of female and male strobili production was observed among the studied 52 parents over four consecutive years, showing statistically significant differences across all studied years. Parental balance curve showed greater distortion in paternal than maternal parents. The Ψ ranged from 1.879 to 4.035 with greater ψm than ψf, and the Np varied from 14.8 to 36.8. When pooled, the relative effective number of parents was improved as 80.0% of the census number. Conclusions We recommend the use of fertility variation (i.e., CV, Ψ), Person’s product-moment correlation (r), and effective number of parents (Np) as tools for gauging gene diversity of seed crops in production populations. For increasing Np and gene diversity, additional management options such as mixing seed-lots, equal cone harvest and application of supplemental-mass-pollination are recommended.


2020 ◽  
Author(s):  
Kyu-Suk Kang ◽  
Ji-Min Park ◽  
Hye-In Kang ◽  
Da-Bin Yeom ◽  
Yousry A. El-Kassaby ◽  
...  

Abstract Background: Gender and fertility variation have an impact on mating dynamics in a population because they affect the gene exchange among parental members and the genetic composition of the resultant seed crops. Fertility is the proportional gametic contribution of parents to their progeny. An effective number of parents, derivative of effective population size, is the probability that two alleles randomly chosen from the gamete gene pool originated from the same parent. The effective number of parents is directly related to the fertility variation among parents, which should be monitored for manipulating gene diversity of seed crops. We formulated a fundamental equation of estimating the effective number of parents and applied it to a seed production population.Results: Effective number of parents (Np) was derived from fertility variation (Y) considering covariance (correlation coefficient, r) between maternal and paternal fertility. The Y was calculated from the coefficient of variation in reproductive outputs and divided into female (yf) and male (ym) fertility variation in the population under study. The Np was estimated from the parental Y estimated by the fertility variation of maternal (yf) and paternal (ym) parents. The gene diversity of seed crops was monitored by Y and Np. in a 1.5 generation Pinus koraiensis seed orchard as a case of monoecious species. A large variation of female and male strobili production was observed among the studied 52 parents for four consecutive years, showing statistically significant across all studied years. Parental balance curve showed greater distortion in paternal parents than maternal parents. The Y ranged from 1.879 to 4.035 with greater ym than yf, and the Np varied from 14.8 to 36.8. When pooled, the relative effective number of parents was improved as 80.0% of the census number. Conclusions: We recommend the use of fertility variation (i.e., CV, Y), Person’s product-moment correlation (r) and effective number of parents (Np) as tools for gauging gene diversity of seed crops in production populations. For increasing Np and gene diversity, additional management options such as mixing seed-lots, equal cone harvest and application of supplemental-mass-pollination are recommended.


2004 ◽  
Vol 53 (1-6) ◽  
pp. 202-206 ◽  
Author(s):  
K. S. Kang ◽  
D. Lindgren ◽  
T. J. Mullin

AbstractClonal differences in the number of male and female strobili were determined for five consecutive years in a clonal seed orchard of Pinus thunbergii in Korea. The effects of relatedness and clonal differences in reproductive development on gene diversity of seed (in terms of accumulated relatedness by status number) were estimated. While clonal differences were found, fertility variation was not large through all studied years. The orchard clones were divided into different regions and locations based on the geographical distribution and distance of natural stands that plus trees were selected from. Assuming that there was no relatedness among regions, locations and clones, the status number (Ns) was varied from 47.6 to 55.5 for five successive years. On average (pooling), Nswas 92% of census number (N). Assumed relatedness among regions, locations and/or clones decreased the status number. Effect of parental selection on relatedness and orchard management was also discussed.


2019 ◽  
Vol 68 (1) ◽  
pp. 29-40
Author(s):  
P.G. Suraj ◽  
K. Nagabhushana ◽  
R. Kamalakannan ◽  
M. Varghese

Abstract Fertility and gene diversity were estimated in three second generation (F2) seed stands (SPA 1-3) and two clone trials (CSO 1&2) of Eucalyptus camaldulensis to assess the impact on seed crop. F2 seedlots were evaluated in comparison to native provenances, ten commercial clones and interspecific hybrids at diverse sites. SPA 1&2 were genetic gain trials of five first generation (F1) orchard seedlots, SPA 3 a plantation of one F1 orchard seedlot, and CSOs were clone trials of 21 commercial clones established at two contrasting sites. Fertility variation, as indicated by sibling coefficient, was high (Ψ, 9-14) in the SPAs as only about 26 % trees were fertile compared to 81 % trees in CSOs. Effective population size was higher in SPA 1 and 2 (Ns, 95 and 74, respectively) than SPA 3 (Ns = 39). Fertility was highly skewed in CSO 2 resulting in low effective population size (Ns = 2) compared to CSO 1 (Ns = 11). Constant seed collection enabled 3-fold increase in relative population size and 22 % higher predicted gene diversity in CSO 2. Genetic diversity (He) estimated using SSR markers was higher in SPA 1&2 and native provenances (NAT), compared to SPA 3 and CSO 1, whereas CSO 2 and clones had lower values. There was a high positive correlation between estimated He and predicted gene diversity values of SPAs and CSOs. He was positively correlated to mean field survival and negatively correlated to kraft pulp yield (KPY), evaluated at three years in progeny trials across three locations. Number of alleles per locus was higher in SPAs and native provenances compared to CSOs and clones. Discriminant principal component analysis clustered CSO, NAT and SPA seedlots in different groups while commercial E. camaldulensis clones clustered close to NAT. Multilocus outcrossing rate was generally high (tm, 91-100 %), though selfing was observed in two families of SPA 3 and CSO 2. Selected interspecific hybrid families of commercial E. camaldulensis clones (with E. urophylla and E. pellita) evaluated at two of the sites had higher He and KPY than clones at three years.


2020 ◽  
Author(s):  
Nebi Bilir ◽  
Kyu-Suk Kang

Abstract Background Seed stand is one of the important seed sources that is essential for global seed production programs. The primary objective of seed stands is to produce seeds as fast as possible. Characteristics of seed stand seeds depend mainly on stand quality, fertility variation and mating system. Individual fertility is an ability to produce progeny to next generation. Prediction of fertility variation is useful for seed production, genetic resources management and gene conservation. In this study, we report how to estimate fertility variation and gene diversity, and discuss its effect on the management of natural stands of Taurus cedar. Results Fertility variation and gene diversity were estimated based on the differences of strobilus production in female and male parents from three seed stands of Taurus cedar. A total of 50 trees were randomly chosen from each seed stand, and the female and male strobili were counted for three consecutive years. The coefficients of variation for female and male strobilus production were subjected to estimation female and male fertility variation. The total fertility variation (Ψ) was then estimated from the female and male fertility variation. The effective number of parents (Np) was calculated based on the Ψ. The mean of female strobili ranged from 31 to 150, and that of male strobili ranged between 77 and 828. The Ψ in a good crop year was smaller than in a poor year and the Np varied from 34.7 to 44.2. The Ψ was improved and the Np was increased when strobilus productions were pooled across three years or populations. The equal cone harvest could mitigate the fertility variation among individuals but caused loss of seed production. Conclusions The effective number of parents could estimate gene diversity of seeds from natural stands, which was based on the function of correlated fertility variation between female and male parents. Mixing seeds from different years could improve the fertility variation among individuals and increase the gene diversity of seeds. However, a balancing between the effective number of parents and the number of mixed years or populations should be carefully considered for maintaining the gene diversity.


2020 ◽  
Author(s):  
Ji-Min Park ◽  
Hye-In Kang ◽  
Da-Bin Yeom ◽  
Kyu-Suk Kang ◽  
Yousry A. El-Kassaby ◽  
...  

Abstract Background: Gender and fertility variation have an impact on mating dynamics in a population because they affect the gene exchange among parental members and the genetic composition of the resultant seed crops. Fertility is the proportional gametic contribution of parents to their progeny. An effective number of parents, derivative of effective population size, is the probability that two alleles randomly chosen from the gamete gene pool originated from the same parent. The effective number of parents is directly related to the fertility variation among parents, which should be monitored for manipulating gene diversity of seed crops. We formulated a fundamental equation of estimating the effective number of parents and applied it to a seed production population.Results: Effective number of parents (Np) was derived from fertility variation (Y) considering covariance (correlation coefficient, r) between maternal and paternal fertility. The Y was calculated from the coefficient of variation in reproductive outputs and divided into female (yf) and male (ym) fertility variation in the population under study. The Np was estimated from the parental Y estimated by the fertility variation of maternal (yf) and paternal (ym) parents. The gene diversity of seed crops was monitored by Y and Np. in a 1.5 generation Pinus koraiensis seed orchard as a case of monoecious species. A large variation of female and male strobili production was observed among the studied 52 parents over four consecutive years, showing statistically significant differences across all studied years. Parental balance curve showed greater distortion in paternal than maternal parents. The Y ranged from 1.879 to 4.035 with greater ym than yf, and the Np varied from 14.8 to 36.8. When pooled, the relative effective number of parents was improved as 80.0% of the census number.Conclusions: We recommend the use of fertility variation (i.e., CV, Y), Person’s product-moment correlation (r), and effective number of parents (Np) as tools for gauging gene diversity of seed crops in production populations. For increasing Np and gene diversity, additional management options such as mixing seed-lots, equal cone harvest and application of supplemental-mass-pollination are recommended.


2004 ◽  
Vol 53 (1-6) ◽  
pp. 164-168 ◽  
Author(s):  
M. Varghese ◽  
D. Lindgren ◽  
A. Nicodemus

Abstract Two seedling seed orchards each of C. equisetifolia and C. junghuhniana established by thinning provenance trials in coastal and inland locations in South India were evaluated for sex expression and fertility variation at four years. More than 80% of the trees in C. equisetifolia orchards were fertile in both sites with a similar pattern of more (almost 2 times) female trees and equal proportion of monoecious and non-flowering trees. In C. junghuhniana, the coastal orchard had twice the proportion of fertile trees as that of the inland. Orchards established in coastal environment had less fertility variation and hence maintained lower coancestry values in both species. Coastal site has more trees contributing effectively to seed production than inland locations and the orchards maintain higher (almost two times) effective population sizes. Genetic drift is also 3 times higher in inland locations in both species. Male and female trees in inland orchards of both species however had greater reproductive output than coastal trees. Monoecious Casuarina equisetifolia trees showed a different trend of greater male fertility in coastal site, but seed output was the same in both locations. Gene diversity values of all orchards are high though it is marginally higher in coastal sites. Measures like constrained seed collection from large number of trees and promoting representation of superior provenances with low fertility would be useful in checking diversity loss during domestication.


2012 ◽  
Vol 61 (1-6) ◽  
pp. 79-84
Author(s):  
Kyu-Suk Kang ◽  
Chang-Soo Kim

Abstract The numbers of female and male flowers were assessed in a clonal seed orchard of Fraxinus rhynchophylla for four consecutive years from 2004 through 2007. The female and male flowers of the grafts from 48 clones were counted individually over the crown. Fertility variation was calculated by sibling coefficient that is related to the coefficient of variation in parental flower assessment. Estimated maternal and paternal fertilities were not constant but varied from year to year, and they were also found to be weakly correlated. The effective numbers of clones serving as male and female parents were calculated from the sibling coefficients of maternity and paternity. We applied two theoretical approaches to estimate the clonal effective population sizes based on 1) fertility variation (i.e., effective number of parents, N(c)) and 2) gender balance (effective population size, Nee) among parental genotypes. The values of Ne(c) were higher in the years with abundant flowering and seed production, while sibling coefficients were lower. On average (pooled), the maternal, paternal and clonal values of Ne(c) were calculated to be 17.3, 21.0 and 38.1 respectively. The Ne(c) for maternal gamete gene pool was ranged from 9.8 to 16.7. The values of Ne for paternal gamete gene pool were generally higher (ranged from 14.9 to 21.9) than those for maternal. When pooled, the Ne was 47.2 and the values of Ne were higher when the gender ratio was more balanced. An option of equal seed harvest might be good to mitigate fertility variation and to improve gene diversity of seeds.


2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Nilüfer Yazici ◽  
Nebi Bilir

There are many environmental and biological factors on forestry practices as known. Aspect called as slope faces is one of the most important environmental factors in these practices because of its easy application for managers. Fertility variation defined as an individual ability to give progeny and gene diversity estimated based on effective number of parents were investigated as the proportion of numbers of cones counted from individuals in natural stands sampled aspectual of Taurus cedar (Cedrus libani A. Rich.) for three consecutive years. The averages of cone number were 19.4, 47.2, and 75.5 for the years. It was the highest in flat (23.5) for 2013, in south (92.1) for 2014, and in flat (95.7) for 2015, while it was lowest in south (16.3), in east (18.2), and in north (39.4) for the years, respectively. Significant correlations (p≤0.01) were estimated among years for cone production in polled aspect. Estimated fertility variations changed for the years and stands. It could be generally acceptable level for typical natural stands except of west of 2014. Fertility variations were 1.55, 3.05, and 1.64 in polled stands for the years. Gene diversity was 0.99 for the years in polled stands. North aspect could be taken into consideration in establishment and selection of seed sources and gene conservation areas based on fertility variation and gene diversity.


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