Genetic variability and tradeoffs among reproductive traits in white clover (Trifolium repens)

1995 ◽  
Vol 73 (3) ◽  
pp. 505-511 ◽  
Author(s):  
B. Kahn ◽  
J. A. Silander Jr. ◽  
H. L. Reynolds ◽  
M. L. Cain
Keyword(s):  
Temporal Variation ◽  
Seed Yield ◽  
White Clover ◽  
Trifolium Repens ◽  
Yield Components ◽  
Seed Weight ◽  
Spatial And Temporal Variation ◽  
Phenotypic Correlation ◽  
Seed Yield Components ◽  
Reproductive Characters

There is much spatial and temporal variation for reproductive output in white clover (Trifolium repens L.), yet little is known about the control of this variation or whether there exist tradeoffs among components of seed yield. To examine these issues, seed yield components and vegetative biomass were measured on replicates of seven white clover genotypes planted in a common garden plot. Significant genetic differences among clones were found for biomass and for five of seven reproductive characters, including number of inflorescences, number of florets per inflorescence, number of fruits per infructescence, number of (late-maturing) seed per fruit, and seed weight in early-maturing fruits. Thus, there is considerable potential for natural or artificial selection to act on vegetative and reproductive characters in white clover. In addition to these genetic effects, we observed temporal variation for number of florets per inflorescence, number of fruits per infructescence, and seed weight in late-maturing fruits. Finally, analyses of phenotypic, genetic, and microenvironmental correlation coefficients revealed few pairs of traits with significant negative correlations. This suggests that few tradeoffs in resource allocation patterns existed for the phenotypic characters examined. Key words: Trifolium repens, genetic variation, seed yield components, tradeoffs, phenotypic correlation, genetic correlation.

SEED YIELD COMPONENTS IN WHITE CLOVER

1979 ◽  
Vol 59 (3) ◽  
pp. 713-715 ◽  
Author(s):  
D. M. HUXLEY ◽  
V. C. BRINK ◽  
G. W. EATON
Keyword(s):  
Seed Size ◽  
Seed Yield ◽  
White Clover ◽  
Trifolium Repens ◽  
Yield Components ◽  
Yield Component ◽  
Seed Yield Components ◽  
Significant Yield ◽  
Trifolium Repens L

Components of seed yield were studied in white clover (Trifolium repens L.). Head number and seed size were the major components of yield. Seeds per head was not a significant yield component and was independent of head number.

Is the flag leaf important in perennial ryegrass seed production?

2010 ◽  
Vol 14 ◽  
pp. 67-73
Author(s):  
J.A.K. Trethewey ◽  
M.P. Rolston
Keyword(s):  
Seed Yield ◽  
Perennial Ryegrass ◽  
Yield Components ◽  
Seed Weight ◽  
Photosynthetic Capacity ◽  
Flag Leaf ◽  
Active Radiation ◽  
Seed Yield Components ◽  
Seed Fill ◽  
Thousand Seed Weight

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

Genotypic variation for seed yield components in white clover (Trifolium repens L.)

2000 ◽  
Vol 51 (6) ◽  
pp. 657 ◽  
Author(s):  
M. Z. Z. Jahufer ◽  
F. I. Gawler
Keyword(s):  
Seed Yield ◽  
White Clover ◽  
Yield Components ◽  
Early Stage ◽  
Genotypic Variation ◽  
Principal Component ◽  
Positive Association ◽  
Genotypic Correlation ◽  
Yield Attributes ◽  
Seed Yield Components

Seed yield is an important criterion that determines the commercial acceptability of new cultivars. Often, the seed yielding capacity of a forage cultivar is tested only in the final stages of its development. A more efficient strategy would be to screen and select plants for seed yield at an early stage of breeding. An important objective of the National White Clover Breeding Program based at the Agriculture Victoria Pastoral and Veterinary Institute, Hamilton, is to assess the genetic diversity for important morphological attributes among germplasm accessions. A set of 53 accessions, which included germplasm collected from Morocco and Tunisia and a range of commercial cultivars, was characterised for seed yield components. The seed yield components were number of ripe inflorescences, number of florets per ripe inflorescence, number of seeds per pod, floret size, and inflorescence height. Potential seed yield was estimated. The magnitude of genotypic variation, together with the accession mean repeatability estimates, indicated the presence of genetic variation among the 53 accessions for all attributes. Both phenotypic and genotypic correlation coefficients indicated a strong positive association between total number of ripe inflorescences and seed yield. There was also a positive phenotypic and genotypic correlation between seed yield and number of florets per inflorescence. Cluster analysis of the 53 accessions based on seed yield components resulted in the generation of 6 groups. Principal component analysis helped to identify 5 accessions that could be potentially useful in improving the seed yield of white clover germplasm selected for superior agronomic and herbage yield attributes.

Irrigation and Nitrogen Studies in s. 23 Ryegrass Grown for Seed: 1. Growth, Development, Seed Yield Components and Seed Yield

1977 ◽  
Vol 88 (3) ◽  
pp. 605-614 ◽  
Author(s):  
P. D. Hebblethwaite
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Seed Weight ◽  
Dry Matter ◽  
Field Experiments ◽  
Unit Area ◽  
Yield Response ◽  
Seed Yield Components ◽  
Seed Yields ◽  
Number Of Seeds

SUMMARYThe effects of irrigation and nitrogen on S. 23 perennial ryegrass grown for seed were investigated in a series of field experiments from 1972 to 1974. Irrigation significantly increased seed yield by 16% in 1972 and 52% in 1974 but had no effect in the wet year of 1973. In 1972 maximum deficit reached 110 mm at the end of July and coincided with anthesis. Consequently the yield response was due to an increase in number of seeds per unit area and no other seed yield component was affected. In 1974 peak deficit also reached about 100 mm but started to build up rapidly very early in the season and had reached 80 mm by the time that the first ears emerged. Consequently the yield response was due to increases in number of fertile tillers, number of seeds per unit area and 1000-seed weight.Irrigation had no significant effect on number of florets or seeds, except in 1974 when percentage of florets which produced seed was increased by 2%.Irrigation had some effect on threshed straw yields, total dry matter, harvest index and total number of tillers but where this occurred the response was much smaller than that of seed yield which indicates that irrigation had greater effects on the reproductive development of the crop than on yield of dry matter and tillering patterns. Increasing the quantity of nitrogen from 0 to 80 kg/ha increased seed yields, all seed yield components except 1000-seed weight, threshed straw yields and total dry matter and number of tillers at most sampling dates. Increasing the quantity of nitrogen from 80 to 160 kg/ha had little further effect on the above components except in 1972 where seed yields were significantly decreased.In 1972 number of florets was increased and percentage of florets which produced seed decreased with increasing quantities of nitrogen.

scholarly journals Genetic variability of seed yield and seed yield components of autochthonous Lolium perenne L. populations

Genetika ◽  
2013 ◽  
Vol 45 (2) ◽  
pp. 553-563
Author(s):  
Zeljko Lakic ◽  
Dejan Sokolovic ◽  
Snezana Babic ◽  
Svetko Vojin ◽  
Jela Ikanovic ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Seed Yield ◽  
Perennial Ryegrass ◽  
Yield Components ◽  
Seed Weight ◽  
Average Length ◽  
Spike Length ◽  
Phenotypic Variance ◽  
Seed Yield Components ◽  
Significant Difference

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).

scholarly journals Heterosis in soybeans for seed yield components and associated traits

2002 ◽  
Vol 45 (4) ◽  
pp. 401-412 ◽  
Author(s):  
Fábio Pandini ◽  
Natal Antonio Vello ◽  
Ângela Celis de Almeida Lopes
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Seed Weight ◽  
Aerial Part ◽  
Agronomic Traits ◽  
Indirect Selection ◽  
Seed Yield Components ◽  
Per Se ◽  
Selection For ◽  
Number Of Seeds

The objective of this research was to quantify heterosis of agronomic traits and evaluate direct and indirect correlations among seed yield and other traits. A diallel involving six parents was grown in two localities. Seed yield (PG), one-hundred seed weight (PCS), number of pods per plant (NV), weight of aerial part of the plant (PPA), harvest index (IC) and number of seeds per pod (NGV) were evaluated. Positive values of heterosis were detected for all traits. Estimates of heterosis components were significative for most traits, showing effects of aditivity and dominance. The specific heterosis was more important than the variety heterosis, mainly in the locality Anhembi. MTBR-95-123800 presented the best potential per se and as parent in crosses, but it was excelled by some of the hybrids in the two localities. Number of pods per plant demonstrated to be suitable for indirect selection for PG.

Effect of time of tiller emergence and nitrogen fertiliser on seed yield components of Digitaria eriantha cv. Premier

1996 ◽  
Vol 36 (2) ◽  
pp. 189 ◽  
Author(s):  
L Ramirez ◽  
JB Hacker
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Seed Weight ◽  
Seed Set ◽  
Spikelet Number ◽  
Nitrogen Fertiliser ◽  
Seed Yield Components ◽  
Seed Harvest ◽  
Digitaria Eriantha ◽  
Total Seed

The effect of fertiliser nitrogen (N) and season (spring or autumn seed harvests) on tiller appearance, development and survival, and seed production in D. eriantha was investigated in a trial in south-east Queensland. In both spring and autumn, rate of tillering was maximal within the first week after cutting and declined rapidly thereafter, regardless of the level of applied N. Rate of tillering was greater in spring than in autumn. Tiller survival decreased as tiller emergence was delayed, and with increasing levels of applied N. At seed harvest, early-emerged tillers were consistently taller, heavier, thicker, and more fertile than late-emerged tillers, and they contributed most of the inflorescences. Fertility of all tillers was increased by application of N, particularly in spring. Seed yield, percentage seed set, and 1000-seed weight were larger in early-emerged tillers, which also bore the biggest inflorescences with the most spikelets per inflorescence, although spikelet number per unit raceme length was lower than on inflorescences borne on late-formed tillers. In general, the effect of N on seed yield components (inflorescence size, 1000-seed weight and seed set) was not significant. Early-emerged tillers contributed more than 70% of the total seed yield in both seasons.

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