Search

Objective: To increase the germination percentage of Abies religiosa by immersion in water with different temperatures and periods. Design/Methodology/Approach: A completely randomized factorial experiment was carried out with five temperatures (10, Room temperature (Rt), 30, 40, and 50 °C) and 13 periods expressed in seconds (10, 20, 40, 60, 600, 1200, 1800, 2400, 3000, 3600, 7200, 14400, and 21600), with a total of 65 treatments and 30 repetitions per treatment. The seeds were dipped in water with the temperatures and periods of each treatment to obtain the highest germination percentage. Results: The best pre-germination treatment (73% germination) was obtained with the combination of 40 °C and 7,200 s. Meanwhile, the treatments with the lowest percentage (14%) were the combinations 10 °C20 s and 10 °C40 s. Twenty-six treatments recorded a 50% germination, reaching a peak value of 8.56 at 11.7 days. Study Limitations/Implications: Keeping the water temperature and the immersion period constant during the experiment was more difficult in the longer treatments, with the lowest and highest temperatures. Findings/Conclusions: Abies religiosa registers acceptable germination percentages with the highest temperature (50 °C). [ABSTRACT FROM AUTHOR]

Copyright of Agrociencia is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agrociencia is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seed orchards are important to produce germplasm for forest plantation establishment. The objective of this study was to evaluate the variation of reproductive characteristics of cones and seeds in a Pinus patula Schiede ex Schltdl. et Cham at a sexual orchard. The reproductive characteristics variation was considered to be influenced by the genetic constitution of the trees and by environmental differences. The study was conducted in an orchard at Cuaunepantla, Acaxochitlán, Hidalgo, México. The experimental design was completely random and cones were the minimum experimental unit. The number of sampled cones varied with the production of three years in 19 sampled trees. The analyzed variables were dry cone weight, potential seeds number, percentage of aborted ovules, inbreeding index, seed weight, reproductive efficiency and full, empty and plagued seeds. All the variables showed differences between trees (p≤0.01) and between production years (p≤0.05). The number of damaged seeds (3 %) was higher in 2012. Dry cone weight (32 g), seed potential (117 seeds per cone), full seeds percentage (58 %), seed weight (9.5 mg) and reproductive efficiency (22 mg g-1) were higher in 2013. The percentage of aborted ovules and average inbreeding index (0.25) were higher in 2014. The variation levels were high in the reproductive characteristics of P. patula. The low inbreeding rate indicated low selffertilization. [ABSTRACT FROM AUTHOR]

Pinus johannis M.-F. Robert-Passini is an endemic pinion nut pine of Mexico that grows in small populations. The objective of this study was to estimate the level of genetic diversity and degree of differentiation among populations in the natural distribution of P. johannis. Mature strobili were collected from 130 tree of four populations. The genotype of each tree was determined in a sample of six megagametophytes, and nine enzyme systems with 16 loci were analyzed. In the four populations the number of alleles varied from 31 to 35. The average number of alleles per locus was 2.1, and the average percentage of polymorphic loci was 88 %. Average heterozygosity was 0.231, and expected average heterozygosity was 0.245. A deficit of heterozygous individuals (FIS=0.116 and FIT=0.176) was found in the four populations together and in each of them. The genetic differentiation among populations was moderate (FST =0.062). Genetic diversity of P. johannis was high with a moderate level of differentiation among populations. [ABSTRACT FROM AUTHOR]