Physical, plant growth regulators and TiO2 nanoparticles priming treatments to improve seed germination of endangered asafoetida (Ferula assafoetida L.)

Purpose: Ferula assafoetida (L.) is one of the most important medicinal plants with many applications in food, pharmaceutical and cosmetic industries.  It has been endangered due to overharvesting from natural habitat and long period of seed dormancy. Knowledge of seed germination behavior leads to the development of its conservation and cultivation. Research methods: We conducted this research as a factorial experiment in Completely Randomized Design (CRD) to evaluate seed germination in response to low temperature, plant growth regulators (kinetin, gibberellin, carrageenan as plant bio-stimulant) and TiO2 nanoparticles (TiO2 NPs). The germination percentage and rate, mean germination time, and radicle elongation were measured. Findings: The results showed that the cold (4 °C), GA3, carrageenan, kinetin and TiO2 NPs increased seeds germination rate and percentage. Maximum seed germination percentage (86% or 23% more than control) and minimum mean germination time (26 days or 12.6 days shorter than control) obtained with seeds pretreated by kinetin soaking and TiO2 NPs treatment at 4 °C. Furthermore, most treatments produced healthier and stronger radicles compared to the control which is vital for better establishment and growth. Research limitations: No limitations were found. Originality/Value: The price and demand of asafoetida products have been increased dramatically. The most important constrain to hinder reliable supply of the products is the shortage of plant or difficulty to access its products. Here, we showed the cost effective and environmentally friendly methods to provide high seeds germination with vigorous roots

Construction of an almond linkage map in an Australian population Nonpareil × Lauranne

Background: Despite a high genetic similarity to peach, almonds (Prunus dulcis) have a fleshless fruit and edible kernel, produced as a crop for human consumption. While the release of peach genome v1.0 provides an excellent opportunity for almond genetic and genomic studies, well-assessed segregating populations and the respective saturated genetic linkage maps lay the foundation for such studies to be completed in almond. Results: Using an almond intraspecific cross between ‘Nonpareil’ and ‘Lauranne’ (N × L), we constructed a moderately saturated map with SSRs, SNPs, ISSRs and RAPDs. The N × L map covered 591.4 cM of the genome with 157 loci. The average marker distance of the map was 4.0 cM. The map displayed high synteny and colinearity with the Prunus T × E reference map in all eight linkage groups (G1-G8). The positions of 14 mapped gene-anchored SNPs corresponded approximately with the positions of homologous sequences in the peach genome v1.0. Analysis of Mendelian segregation ratios showed that 17.9% of markers had significantly skewed genotype ratios at the level of P < 0.05. Due to the large number of skewed markers in the linkage group 7, the potential existence of deleterious gene(s) was assessed in the group. Integrated maps produced by two different mapping methods using JoinMap® 3 were compared, and their high degree of similarity was evident despite the positional inconsistency of a few markers. Conclusions: We presented a moderately saturated Australian almond map, which is highly syntenic and collinear with the Prunus reference map and peach genome V1.0. Therefore, the well-assessed almond population reported here can be used to investigate the traits of interest under Australian growing conditions, and provides more information on the almond genome for the international community.Iraj Tavassolian, Gholmereza Rabiei, Davina Gregory, Mourad Mnejja, Michelle G Wirthensohn, Peter W Hunt, John P Gibson, Christopher M Ford, Margaret Sedgley, and Shu-Biao W

Construction of a microsatellite based genetic linkage map of almond.

Almond (Prunus dulcis) is the most important nut crop in terms of world production. Due to its health benefit and high nutritional value the consumption and world supply of almond is increasing. To remain competitive in the world market, the Australian almond breeding program was established to produce cultivars with better adaptation to Australian conditions. As part of this program an almond mapping population consisting of 93 F₁ progeny derived from a cross between the American cultivar ‘Nonpareil’ (NP) and the European self-compatible cultivar ‘Lauranne’ (LA) was produced to construct the genetic linkage maps. The first almond linkage map developed prior to the commencement of this project failed to produce the eight linkage groups similar to the basic chromosome number of almond (x = 8) and many large gaps were also observed on the linkage groups. Therefore, more markers were needed to saturate the maps. Microsatellite markers are considered one of the best choices for mapping studies. 195 microsatellite markers isolated from Prunus species were obtained from published papers or by personal communication. Polymorphism was revealed by three different methods, and in general, polyacrylamide gel electrophoresis (PAGE) compared to the fluorescent labelled marker detection using an automated DNA sequencer or agarose gel electrophoresis, showed the most efficient and cost effective method of genotyping. A subset of 54 markers which produced reliable and easily interpretable polymorphic bands was selected to screen the whole mapping population. Microsatellites originally isolated from almond species showed the highest rate of amplification and polymorphism followed by peach microsatellites and the least informative markers were isolated from cherry. It seems that the level of transportability and usefulness of microsatellite markers is related to the genetic distance of the closely related species. Almond and peach belong to the same subgenus (Amygdalus) and other Prunus species are classified in Prunophora subgenus. The nut, or kernel, is the commercial part of the almond tree, thus to improve the quality of fruit an understanding of environmental influence, heritability and correlation of traits is required. Pomological and quality characters such as: shell hardness, kernel size, shape, taste, pubescence, colour, and percentage of doubles were measured during three consecutive years (2005-2007) on the total mapping population, but data analysis (ANOVA) was performed only on trees that survived for all three years. Most of the traits showed high broad-sense heritability and kernel shape showed the highest heritability of H² = 0.92 suggesting high genetic control of this trait. Occasionally larger kernels than either parent were found in the progeny indicating potential for improvement of this trait even with smaller kernel size parent that encompass many desirable characters. High correlation was also found between the in-shell and kernel weight (r = 0.74), kernel length / kernel width (r = 0.67), kernel weight to kernel length (r = 0.78) and kernel width (r = 0.80). This correlation estimation pointed out in this study indicates that the improvement of one character may result the progress in another trait. Neither of the parents in the mapping population had bitter or obvious slightly bitter taste but slightly bitter kernels were observed among the progeny. Amygdalin was assumed to be responsible for bitter taste in almond; therefore we measured the amount of amygdalin in sweet and slightly bitter kernel progeny by HPLC. However, the results showed that amygdalin exists in sweet kernels as well. Although the average amount of amygdalin in slightly bitter kernels (20.34 mg kg⁻¹ FW) was higher than sweet kernels (3.67 mg kg⁻¹ FW), some sweet kernels had higher amounts of amygdalin suggesting the impact of other components on slightly bitter kernel. The highest variability within the traits was observed in the percentage of double kernel, which showed the highest standard error. Strong environmental effects, particularly low temperature at pre-blossom time is speculated to produce much higher double kernels. Three genetic linkage maps, one for each parent and an integrated map were constructed by the addition of 54 new microsatellite markers to the previous dataset. All the data was scored and coded according to the coding system necessary by JoinMap3 which was used for map construction. 131 markers including microsatellite, ISSR, RAPD, SCAR and S-allele markers were placed on the integrated map covering 590.7 cM with the average density of 4.5 cM/marker. The minimum number of six microsatellite markers was placed on linkage group 8 and the linkage group 1 which is the longest linkage group has 14 microsatellite markers. Comparative mapping study with other Prunus maps, especially with the highly saturated reference map showed complete synteny and minor changes in the order of four markers on linkage groups compared with Prunus reference map. The conservation of molecular marker order observed in this study supports the idea of looking at Prunus genome as a single genetic system and practical application of this similarity would be in cross-transportability of microsatellite markers from well developed linkage maps to the less studied species in Prunus. Ten microsatellite loci placed on our map have not been reported before and could be used to improve the density of other Prunus maps, especially the reference map. This study contributed to the better understanding of the mode of inheritance and environmental effect on morphological traits and the effect of amygdalin on kernel taste. The most saturated microsatellite based almond linkage map developed in this study can serve as a framework for future almond breeding program in Australia and benefit Prunus improvement programs internationally.Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 200