Novel perennial ryegrass-Neotyphodium endophyte associations: relationships between seed weight, seedling vigour and endophyte presence

Symbiosis ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Stuart D. Card ◽  
M. Philip Rolston ◽  
Catherine Lloyd-West ◽  
David E. Hume
2010 ◽  
Vol 14 ◽  
pp. 67-73
Author(s):  
J.A.K. Trethewey ◽  
M.P. Rolston

In cereals, the importance of the flag leaf for contributing carbohydrate during seed fill is well documented. However, in ryegrass this relationship is not so clear. This paper reports on an investigation of the effect on seed yield components of reduced photosynthetic capacity to the flag leaf, stem and head of perennial ryegrass (Lolium perenne). The hypothesis was that reduced photosynthetic capacity of the flag leaf does not affect seed yield components in perennial ryegrass. Following flowering, photosynthetic capacity was reduced by defoliation or shading the flag leaf, stem, or head of individual tillers. Seed yield components were measured at harvest. Reduced photosynthetically active radiation (PAR) to the flag leaf and stem did not affect thousand seed weight or seed yield when compared with control plants whereas reducing PAR to the head had a significant effect. The seed head itself may be more important than the flag leaf during seed fill, but when the seed head is shaded substantial re-mobilisation of stored carbohydrates can occur. Keywords: flag leaf, green leaf area, Lolium perenne, photosynthetically active radiation, seed fill, seed yield, thousand seed weight, water-soluble carbohydrates


2003 ◽  
Vol 43 (5) ◽  
pp. 481 ◽  
Author(s):  
K. F. Smith ◽  
N. M. McFarlane ◽  
V. M. Croft ◽  
P. J. Trigg ◽  
G. A. Kearney

Genetic variation for seed mass and components of early vigour were measured on 120 seedlings of each of 18 diploid and 27 tetraploid perennial ryegrass (Lolium perenne L.) cultivars. Seeds of tetraploid cultivars were on average heavier (3.8 mg) than seed of diploid cultivars (2.4 mg). However, there was variation for mean seed mass both within and between ploidy classes and within cultivars. The components of early vigour measured on each of the seedlings were: date of emergence, leaf appearance rate, seedling height (10 days after germination), leaf length and width and dry matter at 33 days after emergence. Mean seed mass of a cultivar was significantly (P<0.05) positively correlated with seedling height, leaf length, leaf width, shoot length and shoot mass. Individual seed mass within a cultivar was significantly associated with all components of early vigour, except the date of emergence of the second true leaf. There was no difference in the rate of emergence of tetraploid and diploid cultivars, although tetraploid cultivars tended to have longer and wider leaves, greater seedling lengths and fewer leaves and tillers than diploid cultivars. There was also evidence of genetic variation for seedling vigour components in perennial ryegrass after seed mass and ploidy effects had been removed during analysis. These data suggest that seed mass has a large positive effect on early vigour of both diploid and tetraploid cultivars of perennial ryegrass and that, in the absence of any specific knowledge of the early vigour characteristics of a given cultivar, seed mass could be used as a surrogate when choosing between cultivars with similar adaptation and performance.


1960 ◽  
Vol 40 (2) ◽  
pp. 268-280 ◽  
Author(s):  
W. E. Tossell

Variability in early seedling vigour was studied in polycross progenies from highly selected plants rated as good in other agronomic characters and in open-pollinated progenies from previously unselected So plants. Differences were found in both groups in rate and per cent emergence, and in height and vigour at 28 days. Considering the variability observed in these characters and the favourable associations found, it appears that early seedling vigour in bromegrass can be improved by selection within the species.Seed weight was closely associated with early seedling vigour. Plants differed widely in seed weight, and in breeding for early seedling vigour it appears that most rapid progress can be made by screening breeding material for seed weight. Because seed weight did not account for all of the differences among progenies in seedling vigour, progenies from high seed weight plants or families should be subjected to a seedling vigour test to further select for this character. The close relationship found between greenhouse and field trials indicates that at least the initial screening can be done in the greenhouse.


1959 ◽  
Vol 39 (3) ◽  
pp. 355-363 ◽  
Author(s):  
R. S. Fulkerson

The effects of six seeding rates and five row spacings on seed yield, seed quality and the yield components—number of fertile culms per square foot, number of seeds per culm and seed weight were studied in orchard grass.Row width had a marked effect on seed yield each year. Rate of seeding affected seed yield to a lesser extent and a row width × seeding rate interaction did occur. Seeding rates and row width caused small relatively unimportant differences in seedling establishment and early seedling vigour only in the third harvest year. Considering seed yield, seed quality and the ease of weed control, the best treatment combination appeared to be a seeding rate in the area of [Formula: see text] in 14-in. rows for stands to produce for 2 or 3 years.Seed yield was positively and closely correlated with the number of fertile culms in the first 2 crop years but a negative relationship was found in the third crop year. Seed weight was negatively correlated with seed yield. The number of seeds per panicle was closely associated with yield in the third crop year and negatively correlated with seed weight and culm numbers.


2007 ◽  
Vol 87 (2) ◽  
pp. 385-393 ◽  
Author(s):  
R. H. Elliott ◽  
L. W. Mann ◽  
O. O. Olfert

A 3-yr study was conducted on three synthetic Brassica rapa L. cultivars to determine the effects of seed size and seed weight on seedling establishment, seedling growth and susceptibility to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysomelidae). Seed lots of AC Boreal, Fairview and Hysyn 110 were sieved to obtain small, medium and large seeds (1.4–1.6, 1.6–1.8 and 1.8–2.0 mm, respectively). In the laboratory, seedlings grown from large seeds had the largest cotyledons, highest shoot dry weight and highest biomass. Shoot weights increased as seed size increased. Sized seeds of the three cultivars were grown in the field without insecticides in 1998–2000. Seedlings of small seeds had the highest flea beetle damage and poorest seedling establishment. Shoot dry weight and biomass 14–35 d after planting increased as seed size and seed weight increased. Compared with small seeds, large seeds improved shoot dry weight, biomass and seed yield by 13–43, 25–57 and 12%, respectively. Results indicated that seedlings of medium and large seeds are more vigorous and tolerant to flea beetle damage than seedlings of small seeds. Tolerance was due to a higher initial seedling weight rather than higher relative growth rate. Shoot dry weights, biomass and yield of the three cultivars were more strongly correlated with 1000-seed weight than with seed diameter. Key words: Canola, flea beetles, seed size, seedling vigour, tolerance, seed weight


1974 ◽  
Vol 25 (1) ◽  
pp. 33 ◽  
Author(s):  
RJ Clements ◽  
BDH Latter

Significant responses were obtained to three cycles of directional selection for seed weight, seedling weight, leaf size, and rate of leaf appearance in a broadly based P. tuberosa population. The responses were linear in both the high and low directions, and the realized heritabilities of the characters were 0.35, 0.12, 0.61, and 0.38 respectively. Leaf size was positively correlated with seedling weight and negatively correlated with rate of leaf appearance. Selection for high seed weight resulted in marked correlated increases in seedling weight and leaf size, but selection for heavy seedlings or large leaves did not significantly increase seed weight. Selection for light seedling or small leaves, on the other hand, led to a correlated decrease in seed weight. A hybrid population obtained by crossing the parents of the high leaf size line with those of the high rate of leaf appearance line had seedlings nearly as heavy as those of the high seedling weight line and significantly heavier than the mean of the two parent lines. This effect, together with other evidence of the effect of inbreeding on all characters, indicated some degree of directional dominance, particularly for leaf size. Plants in the high seed weight line matured earlier and had fewer heads. However, because they had heavier seeds and more seeds per head, there was no apparent decrease in seed yield per plant in this line, compared with the control population. Areas of the spikelets and leaf sheaths were greater in the high seed weight line, but areas of the flag and penultimate leaves were unchanged, and there was no evidence that increases in seed weight were accompanied by increases in the amount of photosynthetic area available to each developing seed. It was concluded that selection for large leaves is a relatively efficient means of increasing seedling weight, but results in a reduced rate of leaf appearance and possibly a slower rate of tillering. Selection for seed weight, though inefficient, exploits a source of variation largely untapped by direct selection for seedling weight.


Genetika ◽  
2013 ◽  
Vol 45 (2) ◽  
pp. 553-563
Author(s):  
Zeljko Lakic ◽  
Dejan Sokolovic ◽  
Snezana Babic ◽  
Svetko Vojin ◽  
Jela Ikanovic ◽  
...  

The aim of this study was to examine genetic variability, heritability and correlation of seed yield components and seed yield of progenies of autochthonous populations and cultivars of perennial ryegrass, and that on the basis of these results distinguish genotypes that would be later used in the creation of new local cultivars of perennial ryegrass. Research was carried out on experimental fields and laboratories of the Agricultural Institute of Republic of Srpska in Banja Luka in 2007. and 2008., on 6 natural populations of perennial ryegrass collected in Bosnia and Herzegovina and two cultivars, Maja and Calibra as standard. Following parameters were analyzed: number of generative tillers per plant, time of flowering, spike length, number of spikelets per spike, seed yield per spike and plant and 1000 seed weight. Analysis of the results of the number of generative tillers per plant indicates a statistically significant difference in the studied populations and cultivars of perennial ryegrass. The highest average number of tillers per plant was found in the cultivar Maja (193.8), and the least number was detected in population Dragocaj (78.9), so statistical differences were highly significant. The longest period to beginning of flowering was determined in cultivar Calibra (56.5 days) and the shortest in population Laminci (43 days). The average length of spike of perennial ryegrass in the studied population was 22.78 cm and was significantly lower than cultivar Maja. Statistically significant differences between populations and variety Maja in the number of spikelets per spike were detected. The average seed yield per spike of studied populations was in level with cultivar Maja and 37.5% higher compared with variety Calibra. In the studied populations of perennial ryegrass seed yield ranged from 5.21 g (Dragocaj population) to 15.40 g (Kupres population). Weight of 1000 seeds was highest in the variety Calibra (2.60 g) and lowest in population Maglajani (1.94 g). Proportion of genetic to phenotypic variance for time of flowering, the number of generative tillers, seed yield per spike and plant and 1000 seed weight indicate that the variability of these traits in this collection of genotypes, largely derived from plant genotype. In this investigation, the presence of a highly significant positive genetic correlation was found between time of flowering and spike length (0.98), time of flowering and 1000 seed weight (0.97), number of generative tillers and seed yield per plant (0.91) and spike length and 1000 seed weight (0.98).


1960 ◽  
Vol 40 (1) ◽  
pp. 21-28 ◽  
Author(s):  
J. E. Winch ◽  
W. E. Tossell

Higher seed yields of Redon red clover were produced from the aftermath following an early hay crop than from the first crop itself. Red clover-timothy mixtures produced more hay in June and more seed from the aftermath than did pure stands of red clover or red clover-bromegrass mixtures. Seeding rates of 3, 6, 9 and 12 lb. per acre had no effect on red clover seed yield but did affect hay yield. With 2 lb. of timothy, no increase in hay yield was obtained with red clover seeding rates above 6 lb. per acre.Red clover alone produced more seed per acre than red clover-timothy or red clover-brome mixtures when seed was harvested from the first crop. First-crop seed was higher in seed weight than second-crop seed and this was reflected in increased early seedling vigour.


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