scholarly journals An Overview of the Practices and Management Methods for Enhancing Seed Production in Conifer Plantations for Commercial Use

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 252
Author(s):  
Yan Li ◽  
Xiang Li ◽  
Ming-Hui Zhao ◽  
Zhong-Yi Pang ◽  
Jia-Tong Wei ◽  
...  

Flowering, the beginning of the reproductive growth, is a significant stage in the growth and development of plants. Conifers are economically and ecologically important, characterized by straight trunks and a good wood quality and, thus, conifer plantations are widely distributed around the world. In addition, conifer species have a good tolerance to biotic and abiotic stress, and a stronger survival ability. Seeds of some conifer species, such as Pinus koraiensis, are rich in vitamins, amino acids, mineral elements and other nutrients, which are used for food and medicine. Although conifers are the largest (giant sequoia) and oldest living plants (bristlecone pine), their growth cycle is relatively long, and the seed yield is unstable. In the present work, we reviewed selected literature and provide a comprehensive overview on the most influential factors and on the methods and techniques that can be adopted in order to improve flowering and seed production in conifers species. The review revealed that flowering and seed yields in conifers are affected by a variety of factors, such as pollen, temperature, light, water availability, nutrients, etc., and a number of management techniques, including topping off, pruning, fertilization, hormone treatment, supplementary pollination, etc. has been developed for improving cone yields. Furthermore, several flowering-related genes (FT, Flowering locus T and MADS-box, MCMI, AGAMOUS, DEFICIENCES and SRF) that play a crucial role in flowering in coniferous trees were identified. The results of this study can be useful for forest managers and for enhancing seed yields in conifer plantations for commercial use.

1987 ◽  
Vol 11 (1) ◽  
pp. 6-9 ◽  
Author(s):  
Robert C. Hare

Abstract A single foliar spray with either antiethylene compounds or cytokinins shortly after anthesis reduced conelet abortion by half and doubled seed production. Spraying with boric acid plus Cytex® , a relatively economical form of cytokinin derived from seaweed, was equally effective,and addition of certain antiethylene compounds further improved seed yield. South. J. Appl. For. 11(1):6-9.


1986 ◽  
Vol 26 (1) ◽  
pp. 59 ◽  
Author(s):  
MDA Bolland ◽  
WJ Collins

On sandy soil near Esperance, W.A., prevention of burr burial compared with covering developing burrs with sand drastically reduced the seed production of three subspp. of Trifolium subterraneum (brachycalycinum, subterraneum and yanninicum) and of T. israeliticum by reducing burr production and seed weight. However, T. globosum produced similar amounts of seed from unburied and buried burrs. On sandy soil at Shenton Park, Perth, W.A., prevention of burr burial also reduced seed production of T. subterraneum subspp. brachycalycinum and subterraneum, this being due to fewer burrs, fewer seeds per burr and lighter seed. For subsp. brachycalycinum, seed yields were two to five times greater from burrs which developed within loose gravel than from those developed over sand (in which fewer burrs were able to bury) as a result of increased production of burrs, more seeds per burr and heavier seed. However, for subsp. subterraneum seed yields were similar from burrs whether developed over gravel or sand.


1993 ◽  
Vol 33 (3) ◽  
pp. 299 ◽  
Author(s):  
GM Lodge

Plots sown in 1983 were used to examine the seed production and reserves (residual hardseeds) of 15 annual legumes over 5 years at Tamworth in northern New South Wales. Seed production characteristics were measured in 1983 for these annuals, and for 6 perennial legumes. After the annuals had set seed in 1983, an area of the plots was sprayed to prevent flowering in subsequent years, and the rates of decline in seed reserves were compared with those from areas that seeded annually. Seed yields of the perennials were often significantly lower than those of the annuals except Trifolium glomeratum. Seed yields of T. subterraneum var. subterraneum cvv. Seaton Park and Woogenellup were significantly higher than those of cv. Nungarin and T. subterrarzeum var. brachycalycinum cv. Clare. Seed numbers were lowest for Medicago scutellata cv. Sava among the annual medics, and for Nungarin among subterranean clovers. There was little relationship between the mean number of seeds produced from 1983-86 and maturity grading, and between seed numbers and relative dry matter yield. Seed reserves decreased over 5 years by more than 90% in the sprayed treatments of all species. This decrease was not continuous, with the largest declines occurring from December 1983 to August 1984. In the sprayed treatments of Seaton Park, Woogenellup, and Clare, and in both treatments of Astragalus hamosus cv. Ioman, Vicia dasycarpa var. villosa cv. Namoi, and T. hirtum cv. Hykon, none of the original 1983 seed was recovered in 1987. For the annual medics and Nungarin, the number of residual hardseeds in the sprayed treatments in 1987 was about 3-5% of the seed produced in 1983. From 1983 to 1987, seed numbers in the unsprayed treatments declined by 7040% for the annual medics and by 85-95% for Seaton Park, Woogenellup, and Clare. Long-term persistence of annual medics and Nungarin depended on seed production in most years and the maintenance of a high number of residual hardseeds in the soil. In contrast, the mid- and late-maturing subterranean clovers Woogenellup and Clare had low seed reserves and were dependent on seed production in most years for their continued regeneration.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mingkang Yang ◽  
Liping Wang ◽  
Chumin Chen ◽  
Xu Guo ◽  
Chuanglie Lin ◽  
...  

AbstractAutophagy is a highly conserved process of degradation of cytoplasmic constituents in eukaryotes. It is involved in the growth and development of plants, as well as in biotic and abiotic stress response. Although autophagy-related (ATG) genes have been identified and characterized in many plant species, little is known about this process in Medicago truncatula. In this study, 39 ATGs were identified, and their gene structures and conserved domains were systematically characterized in M. truncatula. Many cis-elements, related to hormone and stress responsiveness, were identified in the promoters of MtATGs. Phylogenetic and interaction network analyses suggested that the function of MtATGs is evolutionarily conserved in Arabidopsis and M. truncatula. The expression of MtATGs, at varied levels, was detected in all examined tissues. In addition, most of the MtATGs were highly induced during seed development and drought stress, which indicates that autophagy plays an important role in seed development and responses to drought stress in M. truncatula. In conclusion, this study gives a comprehensive overview of MtATGs and provides important clues for further functional analysis of autophagy in M. truncatula.


2020 ◽  
Author(s):  
Mingkang Yang ◽  
Liping Wang ◽  
Xu Guo ◽  
Chuanglie Lin ◽  
Wei Huang ◽  
...  

Abstract Background: Autophagy is a highly conserved degradation process of cytoplasmic constituents in eukaryotes. Autophagy is known to be involved in the regulation of plant growth and development, as well as biotic and abiotic stress response. Although autophagy-related genes (ATGs) have been identified and characterized in many plant species, little is known about the autophagy process in Medicago truncatula. Results: In this study, 39 ATGs were identified in M. truncatula (MtATGs), and the gene structures and conserved domains of MtATGs were systematically characterized. In addition, many cis-elements which are related to hormone and stress responsiveness were identified in the promoters of MtATGs. Furthermore, phylogenetic analysis and interaction network analysis suggested that the function of MtATGs is evolutionarily conserved in Arabidopsis and M. truncatula. Gene expression analysis showed that most MtATGs were largely induced during seed development, but repressed by nodulation. Moreover, MtATGs were up-regulated in response to salt and drought stresses.Conclusion: These results provide a comprehensive overview of the MtATGs, which provided important clues for further functional analysis of autophagy in M. truncatula.


2003 ◽  
Vol 83 (1) ◽  
pp. 189-197 ◽  
Author(s):  
W. E. May ◽  
H. A. Loeppky ◽  
D. C. Murrell ◽  
C. D. Myhre ◽  
J. J. Soroka

Preharvest applications of glyphosate have been shown to be effective in controlling Canada thistle in annual crops, but may reduce alfalfa seed yield depending on time and rate of application. The objective of this study was to determine the effect of preharvest applications of glyphosate on subsequent alfalfa seed yield and quality. The effects of timing, 1, 26, 51 and 76% alfalfa seed pod maturity, and rate, 0, 440, 880, 1320, and 1760 g a.i. ha-1, of a preharvest application of glyphosate on alfalfa seed yield and quality in the year of application, and regrowth and seed yield in the following year were determined. The rate of glyphosate applied did not affect seed yield in the application year; however, in the following year, growth and seed yield were reduced as rates increased. Delaying the application of glyphosate increased seed yields in the application year, but decreased alfalfa regrowth and flowering the following year. Germination and seedling emergence were not affected by the rate or timing of the glyphosate. A preharvest application of glyphosate at 1760 g a.i. ha-1 at 76% pod maturity is a viable option in the last year of seed production. Key words: Alfalfa (Medicago sativa L.), glyphosate, abnormal seeds, seed quality, and seedling vigour


Author(s):  
K.R. Brown ◽  
M.P. Rolston ◽  
W.J. Archie

'Grasslands Wana' cocksfoot (Dactylis glomerata), a new cultivar, produced highest seed yields (405 kg/ha over three years) at 30 cm row spacing in Canterbury. Wider rows (45 and 60cm) produced more seed heads/m* but lower yields, whereas with 15 cm rows there were fewer seed heads and lower yields. In the Manawatu, Wana yields averaged 605 kg/ha over three years, although the North Island is not recognised as a cocksfoot seed producing area. Seed weights range from 0.65 to 0.85 g/l000 seeds, lighter than Apanui and Kara cocksfoots. With two autumn sowings, Wana produced 325 and 170 kg/ha 10 months after sowing. Controlling weeds, especially Poa annoa, is important for high yields from autumn sowings. Plots treated with ethofumesate yielded up to 7 times more than untreated plots. Management, fertiliser use, and rules for changing cocksfoot cultivars are discussed. Keywords: Dactylis glomerata, row spacing, weed control, ethofumesate, terbicil, nitrogen.


1980 ◽  
Vol 1 ◽  
pp. 26-30
Author(s):  
L. Corkill ◽  
W. Rumball

The problems of seed production of amenity grasses in New Zealand are considered from two aspects - (a) increasing seed potential by breeding; (b) achieving that potential by good management as practised in the Netherlands, (a) In terms of breeding, the strategies to increase seed yield depended to some degree on the species concerned. With browntop it was necessary to discard about two-thirds of the most promising genotypes because of poor heading, but the remaining genotypes flowered freely and in unison, and gave good seed yields. With fescue even the best original plants were sparsely heading, so direct selection for prolificacy has been needed. This was also carried out for perennial ryegrass, as well as selection of early-heading genotypes to avoid infection by stem rust. (b) It is suggested that areas for seed of amenity grasses in New Zealand should be used for seed production only rather than for both forage and seed as is the usual practice. Techniques used in the Netherlands could serve as guidelines to procedures. The implications of low seeding rates, good weed control, high fertilizer applications and minimum cutting or grazing in promoting strong individual plants capable of high seed yields are discussed. Keywords: Amenity grass, seed production, New Zealand, breeding, management, Netherlands, Agrostis tenuis, Festuca rubra, Lolium perenne


1959 ◽  
Vol 39 (3) ◽  
pp. 364-374 ◽  
Author(s):  
Bronius Povilaitis ◽  
J. W. Botes

Evidence that red clover plants of the Dollard variety differ in production of fertile ovaries is presented. The amount of ovary sterility arising through failure of the embryo sac to complete its development is apparently controlled by genetic factors and influenced by environmental conditions. Consideration of the data on frequencies of ovary fertility of plants in nursery lines and in progenies of crosses, together with data on their seed production, leads to the conclusion that ovary sterility is an important limiting factor on the ability of a plant to produce seed. Even under adverse environmental conditions; appreciable ovary sterility is still the primary limiting factor in restricting seed production and hence, among plants affected by ovary sterility, it is not surprising that we found significant correlation between the percentages of ovary fertility and seed yields.


1977 ◽  
Vol 57 (3) ◽  
pp. 891-896 ◽  
Author(s):  
K. K. KROGMAN ◽  
E. H. HOBBS

In field plot experiments conducted in southern Alberta over a 6-yr period, highest seed yields of alfalfa (Medicago sativa L. cv. Beaver) were obtained with one or two irrigations in the first half of the growing season. In outdoor lysimeters protected from rain, moisture stress for more than 8 days before seed ripening severely reduced seed production. Under field conditions, stored soil moisture from irrigation during the vegetative stage of growth plus occasional rain in July and August permitted irrigation of alfalfa for seed to be stopped at the bud to early bloom stage (June to early July).


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