The effect of defoliation on seed production by capeweed (Arctotheca calendula)

1973 ◽  
Vol 13 (65) ◽  
pp. 676 ◽  
Author(s):  
JG McIvor ◽  
DF Smith

Two experiments were done in pots to assess the effect of defoliation at different times on the seed yield of capeweed (Arctotheca calendula). Yield components measured were: number of seedheads per plant, number of seeds per seedhead, number of seeds per plant, and weight of individual seeds. Of the components of yield, number of florets per seedhead and individual seed weight were maintained under all treatments; number of seedheads and number of seeds per seedhead were more affected by defoliation. Whether grown as spaced plants or in swards, leaf removal did not significantly reduce the number of seeds produced unless combined with bud and flower removal at late flowering only. The results are discussed in relation to the growth and persistence of capeweed in pastures.

1977 ◽  
Vol 88 (3) ◽  
pp. 605-614 ◽  
Author(s):  
P. D. Hebblethwaite

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.


1978 ◽  
Vol 58 (4) ◽  
pp. 1103-1105 ◽  
Author(s):  
J. M. CLARKE

The effects of time of leaf removal on Brassica napus L. were studied under field conditions at Saskatoon in 1976 and at Swift Current in 1977. Leaf removal at the start of flowering reduced the number of pods per plant, increased seed weight, and reduced seed yield. Leaf removal at the end of flowering did not affect yield or its components.


2002 ◽  
Vol 45 (4) ◽  
pp. 401-412 ◽  
Author(s):  
Fábio Pandini ◽  
Natal Antonio Vello ◽  
Ângela Celis de Almeida Lopes

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.


1973 ◽  
Vol 81 (3) ◽  
pp. 445-448 ◽  
Author(s):  
T. E. Yassin

SUMMARYEstimates of genotypic and phenotypic variances and covariances were determined for yield and yield components in ten field beans varieties grown at two locations over three seasons.Substantial amounts of genotypic variance were obtained for yield/plot, 1000-seed weight and number of pods/plant. Variability in number of seeds/pod and much of the variation in yield/plant was attributable to environmental effects and their interaction with the varieties. Seed yield/plot was closely and positively correlated with number of pods/plant and yield/plant, while it was closely and negatively correlated with 1000-seed weight.The implications of these correlations for selection are discussed.


1972 ◽  
Vol 52 (4) ◽  
pp. 613-618 ◽  
Author(s):  
R. S. FULKERSON

Orchard grass, timothy, and bromegrass were grown for seed production in 35.5- and 71.0-cm row widths, containing plants in a solid or in a 35.5-cm thinned row arrangement. Seed yield, head numbers, head length, seed per head, and seed weight data were collected for 3–5 crop years. Orchard grass produced its highest yield of seed from the 71.0-cm thinned rows. Yield differences were present for the first 3 years only. Yield components were affected to a larger extent by row width than by thinning. However, with timothy, row widths did not influence yield and components some years. The production methods affected the bromegrass seed crop in the 1st crop year but had no influence by the 3rd year. Although some relations were established between seed yield and the components with the species studied, none appeared to clarify the physiological relations involved.


2007 ◽  
Vol 55 (3) ◽  
pp. 339-345 ◽  
Author(s):  
A. Göksoy ◽  
Z. Turan

This study was made in order to determine the correlations between seed yield and some yield components, and the direct and indirect effects of these characters on seed yield in sunflower. Four experimental synthetic varieties (Syn 1s), their parental mixtures (Syn Os) and two standard varieties (open pollinated: Vniimk 8931, and commercial hybrid: Sunbred-281) were evaluated in replicated field trials under Turkish conditions in 1995, 1996 and 1997. Agronomic characteristics such as plant height, head diameter, number of seeds per head, 1000-seed weight and seed yield were observed for correlations and path coefficient analysis.According to the results, seed yield gave significant positive correlations with plant height, head diameter, number of seeds per head and 1000-seed weight. The highest positive correlation was observed between seed yield and number of seeds per head (r=0.890**). Path analysis indicated that the number of seeds per head gave the greatest direct effect (+0.7269) on seed yield, followed by 1000-seed weight (+0.3215) and head diameter (+0.1689). The percentage of direct effects on seed yield was 80.8%, 50.6% and 24.0% for number of seeds per head, 1000-seed weight and head diameter, respectively.


2016 ◽  
Vol 8 (6) ◽  
pp. 109
Author(s):  
Natalia Anastasova Georgieva ◽  
Valentin Ivanov Kosev

<p>Adaptive potential of forage pea and vetch accessions was estimated based on seed yield and yield components. А varietal-specific reaction of the studied accessions to environmental conditions was established. The conducted assessment of selective value of genotypes gave accurate data for breeding of highly productive forms. Among studied pea varieties the following were characterized to possess adaptive ability and selective value - Glyans for numbers of seeds (1000 seed weight and seed yield), Kamerton for plant height, and Svit for seed yield. In terms of general adaptive ability and stability in plant height with the greatest value as a starting material was vetch variety Vilena. Moldovskaya was of interest in terms of 1000 seed weight. Liya is preferred vetch genotype for improving the number of seeds per plant and for selection of new forms for improving grain yield.</p>


2020 ◽  
Author(s):  
S. Kalauni

Abstract This research aims to determine the relationship between yield and yield components of French bean using multivariate statistical techniques. The study was conducted at Horticulture Research Station, Dailekh, Nepal for consecutive three year of 2016-2018. In this study, six French bean genotypes were used. The following measurements and observations were made: germination (%), pod length (cm), pod diameter (mm), individual pod weight and number of seeds pod-1, number of dry pods plant-1, dry pod yield plant-1 and dry pod yield (t/ha), 100 seed weight (g) and seed yield (t/ha). Highly significant and positive correlation was recorded between seed yield and individual pod weight (r=0.659***), number of seed pod-1 (r=0.548**) and pod length (0.459*). Conversely, pod diameter showed a negative and non-significant (-0.025) correlation on seed yield. Based on simple regression analysis, linear regression of individual pod weight, number of seed pod-1 and pod length leads to an increase in the seed yield (t/ha) by 0.188, 0.285 and 0.103 units respectively. From the path coefficient analysis maximum positive direct effect on seed yield was recorded by number of seeds pod-1 (0.767) followed by 100 seed weight (0.530) and individual pod weight (0.429). Also, stepwise multiple linear regression analysis revealed that three traits including individual pod weight, 100 seed weight and number of dry pod plant-1 with R2 = 68.22% showed their overall contribution towards seed yield. The rest of the variance (R2 = 31.78%) was contributed by the variables that were not included in the study. Results concerning four statistical methods showed that individual pod weight appeared to be most effective contributor of seed yield followed by the number of seed pod-1, 100 seed weight, and pod length. Therefore, attention should be paid to these characters in any breeding program during the selection criteria for improving the seed yield.


1990 ◽  
Vol 115 (3) ◽  
pp. 347-352 ◽  
Author(s):  
I. H. Williams ◽  
A. P. Martin ◽  
S. J. Clark

SUMMARYThe phenology of anthesis, anther dehiscence, fertilization and petal fall in the linseed cultivar Antares and its response to supplementary pollination when grown in a glasshouse were investigated. Anthesis commenced 15–30 min after the onset of the photophase and was complete within 2 h. Anthers dehisced when buds were in the tube stage of opening and produced a mean of c. 4·5 × 103 pollen grains per flower. Most ovules were fertilized within 6 h of the onset of the photophase. Flowers self pollinated naturally and, although supplementary pollination increased the percentage of flowers that produced capsules and the number of seeds per capsule, it decreased flower production and individual seed weight and conferred no increase in seed yield. Flowers retained their petals for at least 2 h after the onset of the photophase but, by 10 h, 97% of hand-pollinated flowers had shed their petals; those naturally self pollinated or shaken retained their petals for longer.


2019 ◽  
Vol 18 (3) ◽  
Author(s):  
Vahid Rahimi ◽  
Mehdi Mohebodini ◽  
Mahdi Behnamian ◽  
Shiva Azizinia

In order to evaluate the relationship between traits affecting the seed yield of the garden cress, phenotypic correlations between seed yield and yield components were detected, direct and indirect effects of yield components on yield and its role in the description of diversity were estimated, and the experiment was conducted in a randomized complete block design with three replications in 2017. The ANOVA showed that the difference among accessions was significant for all traits. There was a significant phenotypic correlation between yield and most of the traits. The highest value of phenotypic correlation was obtained between seed yield and the ‘thousand seed weight’ (0.97). The regression analysis showed that the seed yield was highly in- fluenced by the ‘thousand seed weight’, leaf height and the number of seeds per silique of the lateral branches and the main axis. These three traits constituted about 89% of changes in the total yield, while the ‘thousand seed weight’ was the most effective trait that entered the model and explained 51% of the variation. The path analysis of phenotypic correlation showed that the ‘thousand seed weight’ had the greatest direct effect on the yield (7.21). The ‘thousand seed weight’ had a positive indirect impact on other traits as well. As a result of the factor analysis, 3 independent factors explained about 79.33% of the yield variation. These factors con- sisted of the number of seeds per silique of the lateral branches, the number of seeds per silique of the main axis and the ‘thousand seed weight’.


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