Seed size influences the coleoptile length of wheat

1988 ◽  
Vol 28 (4) ◽  
pp. 521 ◽  
Author(s):  
PS Cornish ◽  
S Hindmarsh

Variation in coleoptile length within and between 2 cultivars of semidwarf wheat (Triticum aestivum) was related to seed size. Seeds of cvv. Banks and Kite were separated by sieving for width into the size classes of >2.75, 2.75-250, 2.50-2.25 and 2.25- 2.00 mm. The mean grain weights of ungraded samples were 43.1 mg (Kite) and 34.3 mg (Banks), and for the subsamples were 52.4, 37.9, 30.4 and 20.7 mg (Kite) and 41.4, 33.2, 25.8 and 19.1 mg (Banks). The effect of size class on coleoptile length was significant (P<0.01). Over both cultivars, coleoptile length declined by 0.37 mm per mg reduction in seed weight. Kite produced the longer coleoptiles overall, 87.5 mm compared with 59.0 mm for Banks. However, only 3.3 mm of this difference can be accounted for by the mean difference in seed weight (8.8 mg) and the effect of seed weight on coleoptile length (0.37 mm/mg). Genetic differences, apart from adult plant height, appear to explain most of the difference in coleoptile length between the cultivars. There was considerable genetic variability within genotypes. In Banks, with seed width >2.75 mm (41.4 mg per seed), the lengths of coleoptiles ranged from 24-89 mm (mean 65.1 mm), suggesting considerable scope for the selection of genotypes with longer coleoptiles.

2017 ◽  
Vol 6 (2) ◽  
pp. 5256
Author(s):  
Daryoush Shafiei ◽  
Prof. Basavaiah*

In mulberry (Morus spp.), the process of selection of promising hybrids from F1 population requires the screening of a large number of progenies and a long period. To develop a simple and faster approach for screening, studies were conducted using F1 seeds of two crosses. The details of screening studies conducted in relation to seed-size and seedling-size are reported separately in two parts. In this part, the F1 seeds were size-graded as small, medium and large seeds; their progenies were raised separately and screened in nursery. There was a considerable degree of variation in size of seeds and medium-size class seeds were in high percentage in both the crosses. The length, width and weight of seeds were also varied between the seed size classes significantly in both the crosses. The seed size classes differ with high significance in shoot length and Root collar diameter and also differ significantly in root length and weight of seedlings. The positive correlation between the seed size and growth of seedlings, seed size and germination, seed size and seedling survival in nursery indicated that size-grading of seeds and rejection of small seeds in the beginning of screening process may help to increase the efficiency of screening by increasing the chances of getting superior hybrids from limited progenies. However, confirmation on the performance of large seedlings from small seed size class may help to draw conclusion. Hence, the studies are continued with size- grading of seedlings in the next part of screening study.


2004 ◽  
Vol 60 (4) ◽  
Author(s):  
M. Conradie ◽  
E. Smit ◽  
M. Louw ◽  
M. Prinsloo ◽  
L. Loubser ◽  
...  

Background and purpose: Physiotherapists frequently use central posterior-anterior (PA) joint mobilization techniques for assessing and managing spinal disorders. Manual examination findings provide the basis for the selection of treatment techniques. From the literature it is evident that the level of reliability varies when physiotherapists perform different mobilization techniques. Repeatability of mobilization techniques is important for better physiotherapy management. The aim of the study was to determine whether experienced physiotherapists apply equal magnitude of force during a grade I central PA mobilisation technique on the cervical spine. Another aim was to determine the variation in the magnitude of forceapplied by each individual physiotherapist. Subjects: Sample of convenience, consisting of sixteen (n=16) selected qualified physiotherapists with experience inOrthopaedic Manual Therapy.Methods: A grade I central PA was performed on the Flexiforce TM sensors positioned on C6 of the same asymptomatic model to measure the applied magnitude of force. Two separate measurements, each lasting 30-seconds, were obtained.Results: The average maximum peak force applied by the majority of physiotherapists (87.5%) was between 10.95gand 72g. The difference in the forces applied for the two measurements ranged between 0.64g and 24.4g. The BlandAltman scatterplot determined the mean of the difference between measurement one and two, calculated for the group, was zero. When comparing the two measurements, little variation was noted in the forces applied, as well as the coefficient of variation for each physiotherapist.Conclusion and Discussion: Current results demonstrated good intra-therapist and moderate to good inter-therapist repeatability. Further research is required to generalize results.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Idah Mkwezalamba ◽  
Chimuleke R. Y. Munthali ◽  
Edward Missanjo

Sclerocarya birrea(A. Rich.) Hochst. is a multipurpose fruit tree which is very useful in providing food security and meeting nutritional and economic needs. This study was conducted to assess eighteen provenances ofSclerocarya birreaplanted in Mangochi, Malawi. The trial was assessed for fruit traits at fifteen years of age. There were significant (P<0.001) variations among the provenances in number of fruits, fruit weight, pulp weight, seed weight, fruit length, and diameter. Magunde provenance from Mozambique had the highest mean number of fruits, 2196 ± 200. Mangochi and Moamba provenances from Malawi and Mozambique were the most outstanding in the other parameters measured attaining the mean fruit weight of 20.89 ± 0.25 g and 25.67 ± 0.67 g, pulp weight of 25.70 ± 0.08 g and 21.55 ± 0.83 g, seed weight of 4.81 ± 0.35 g and 4.12 ± 0.18 g, fruit length of 2.61 ± 0.14 cm and 2.33 ± 0.07 cm, and fruit diameter of 2.33 ± 0.15 cm and 1.97 ± 0.08 cm, respectively. There was no significant (P>0.05) correlation between number of fruits and the other fruit traits. However, there were significant (P<0.05) and strong positive relationships between fruit weight and pulp weight (r=0.987) and fruit length and diameter (r=0.775). This suggests that fruit weight can be used indirectly for selection of pulp. Further studies should investigate fruit taste quality of products from the fruits.


2014 ◽  
Vol 69 (1) ◽  
pp. 44-54
Author(s):  
NASER SABAGHNIA ◽  
MOHSEN JANMOHAMMADI ◽  
ADEL BASHIRI ◽  
REZA ASGHARI-SHIRGHAN

The genetic diversity among 56 bread wheat (Triticum aestivum L.) genotypes was evaluated by 18 agronomical traits in the experimental field at Maragheh, Iran. Significant differences among bread wheat genotypes in all of the measured traits i.e. stem diameter, plant height, leaf number, leaf length, leaf width, tiller number, internode length, peduncle length, spike length, floret number, spikelet number, grain number, length of awn, grain diameter, grain length, the number of days to flowering, thousand seed weight and grain yield. The coefficient of variation (CV) was high for grain yield (25.61%), number of tillers per plant (22.06%) and number of grains per spike (21.45). The other remaining traits recorded moderate to low CV estimates from 14.30% in grain number per spike to 4.81% in days to flowering. The largest thousand seed weight was 45.93 g, the lowest thousand seed weight was 26.16 g and the mean thousand seed weight was 37.85 g. The mean performance of grain yield was 5031.2 kg ha-1, the minimum grain yield was 2835.0 kg ha-1 and the maximum grain yield was 7125.3 kg ha-1. Ward’s minimum variance cluster analysis based on squared Euclidian distance on the raw data of 18 agronomic traits clearly separated five clusters. In general, cluster analysis of the 56 genotypes based on the selected agronomic traits was consistent with known information. Our plant materials could be important germplasm resources for enriching the genetic background of commercial cultivars. Such genetic differences of bread wheat traits studied in this investigation can be applied as a new source of variation in other breeding programs and crossing nurseries in breeding program


Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 184
Author(s):  
Yonghui Cao ◽  
Benzhi Zhou ◽  
Xiaoming Wang ◽  
Lianhong Gu

In 2008, an unexpected and severe ice storm affected the forest of southern China. This storm caused damage in regeneration of an important dominant tree, Schima superba (Gugertree). To study this damage, we set up permanent monitoring plots in an ice-storm-damaged subtropical evergreen broad-leaved secondary forest dominated by S.superba in Jianglang Mountains, China. We surveyed the damage to all trees with a minimum basal diameter of 4 cm and monitored their growth for 6 consecutive years. We analyzed the degrees and types of damage for S.superba and their relationships with resprouting characteristics. The results revealed that the main damage types of S.superba were decapitation (45.45%) and uprooting (28.41%). The distribution percentage for both decapitated and uprooted trees were commonly highest in the range of 10–16 cm basal diameter (BD) size class. A great number of individuals sprouted vigorously after the storm. The mean total sprout number and sprout biomass per tree for S.superba varied by tree BD size class. During the first three years after the ice storm, decapitated trees of larger BD classes produced more sprouts per tree than trees of smaller BD classes. However, the opposite trend was seen in uprooted and leaning trees. There was a trade-off between the total number and length of the sprouts. The difference of mean sprouts number and biomass per tree with size class was mainly related to the damage types. As the recovery progressed since the ice storm, the number of sprouts and sprout biomass in uprooted trees was found mainly on the middle trunk sections of uprooted trees, but in the upper sections of decapitated trees. After six years, the mean number of sprouts per tree, on different parts of the tree and for the three types of damaged trees all declined; however, sprout biomass per tree all increased. The mean number of sprout and sprout biomass per tree on different sections for decapitated trees was always highest over time since the storm. Our study will help to provide data on resprouting ability to develop a predictive model for resprouting.


Author(s):  
Divya Ghorawat ◽  
Ravina Madan

The main aim of this study was to find out whether the color shade preferences of individuals, grouped according to their personality types are alike or not. The researchers also tried to study the difference in color shade preferences based on gender differences. The objective was to understand whether the color shade preferences of individuals are affected by their individual personality types or not and whether gender plays any role in selection of color shades of individuals. The study sample consisted of a total of 80 subjects, randomly selected from within the age group of 18-25. An attempt was made to maintain a balance between two genders and across the ages. The research instruments used were Eysenck’s Personality Test (to measure the personality types) and a separate Colour Bar- Colour Preference Test was designed to serve the purpose of this study. The subjects were made to fill both the questionnaires and then the items were scored and results were analyzed. Positive scoring was done for Eysenck’s personality questionnaire and negative scoring was used to score the Colour Bar-Colour Preference Test. The data collected was divided into: Introverts (female, male) and Extroverts (female, male). From the data collected the mean, standard deviation and correlation between extraversion scores and the most preferred colour scores, for all the four groups. The mean, standard deviation, and correlation for the four groups was found to be 436.4 (IF), 529.2 (IM), 504 (EF), 453.4 (EM); 5.47 (IF), 6.52 (IM), 5.48 (EF), 6.93(EM); -0.3 (IF), -0.1 (IM), 0.1 (EF) and 0.5 (EM) respectively. From this the conclusion was drawn that there was no significant correlation found between the personality types and colour shade preferences of the subjects except in the case of extroverted males. Recommendations: Increase the sample size as that proved to be a limitation to this study. A study across ages is also possible and might give different results.


1985 ◽  
Vol 15 (6) ◽  
pp. 1142-1148 ◽  
Author(s):  
Carl W. Mize ◽  
Richard C. Schultz

Many researchers set up an experiment, make measurements, do an analysis of variance, calculate the mean response for each treatment, and then try to decide if the treatment means are significantly different and why. Duncan's multiple-range test is frequently used to test the difference among treatment means. It is, however, only one of a number of techniques that can be used to examine treatment means. Some researchers are unaware of the different techniques and that the interpretation of the results of an experiment can be strongly influenced by the technique used. In fact, using an inappropriate technique can lead to making incorrect recommendations and to completely missing major treatment effects. Selection of the appropriate technique to use for a particular experiment depends upon the nature of the treatments and the objectives of the research. This paper discusses four techniques (ranking treatment means, multiple comparison procedures, fitting response models, and using contrasts to make planned comparisons) that can be used to examine treatment means and presents examples of each one.


2013 ◽  
Vol 111 (4) ◽  
pp. 578-585 ◽  
Author(s):  
John P. Goopy ◽  
Alastair Donaldson ◽  
Roger Hegarty ◽  
Philip E. Vercoe ◽  
Fay Haynes ◽  
...  

In the present study, following the measurement of methane emissions from 160 mature ewes three times, a subset of twenty ewes was selected for further emission and physiological studies. Ewes were selected on the basis of methane yield (MY; g CH4/kg DM intake) being low (Low MY: >1 sd below the mean; n 10) or high (High MY: >1 sd above the mean; n 10) when fed a blended chaff ration at a fixed feeding level (1·2-fold maintenance energy requirements). The difference between the Low- and High-MY groups observed at the time of selection was maintained (P= 0·001) when remeasured 1–7 months later during digesta kinetics studies. Low MY was associated with a shorter mean retention time of particulate (P< 0·01) and liquid (P< 0·001) digesta, less amounts of rumen particulate contents (P< 0·01) and a smaller rumen volume (P< 0·05), but not apparent DM digestibility (P= 0·27) or urinary allantoin excretion (P= 0·89). Computer tomography scanning of the sheep's rumens after an overnight fast revealed a trend towards the Low-MY sheep having more clearly demarcated rumen gas and liquid phases (P= 0·10). These findings indicate that the selection of ruminants for low MY may have important consequences for an animal's nutritional physiology.


2000 ◽  
Vol 125 (4) ◽  
pp. 466-475 ◽  
Author(s):  
Soon O. Park ◽  
Dermot P. Coyne ◽  
Geunhwa Jung ◽  
Paul W. Skroch ◽  
E. Arnaud-Santana ◽  
...  

Our objective was to identify quantitative trait loci (QTL) for seed weight, length, and height segregating in a recombinant inbred line population derived from the common bean (Phaseolus vulgaris L.) cross `PC-50' × XAN-159. The parents and progeny were grown in two separate greenhouse experiments in Nebraska, and in field plots in the Dominican Republic and Wisconsin. Data analysis was done for individual environments separately and on the mean over all environments. A simple linear regression analysis of all data indicated that most QTL appeared to be detected in the mean environment. Based on these results, composite interval mapping (CIM) analysis was applied to the means over environments. For seed weight, strong evidence was indicated for five QTL on common bean linkage groups (LGs) 3, 4, 6, 7, and 8. Multiple regression analysis (MRA) indicated that these QTL explained 44% of the phenotypic variation for the trait. Weaker evidence was found for three additional candidate QTL on bean LGs 4, 5, and 8. All eight markers associated with these QTL were significant in a MRA where the full model explained 63% of the variation among seed weight means. For seed length, CIM results indicated strong evidence for three QTL on LG 8 and one on LG 2. Three additional putative QTL were detected on LGs 3, 4, and 11. The markers associated with the three seed length QTL on LG 8, and the QTL on LGs 2 and 11 were significant in a MRA with the full model explaining 48% of the variation among seed length means. For seed height, three QTL on LGs 4, 6, and 11 explained 36% of the phenotypic variation for trait means. Four of the seven QTL for seed length and two of three QTL for seed height also appeared to correspond to QTL for seed weight. Four QTL for common bacterial blight resistance [Xanthomonas campestris pv. phaseoli (Smith Dye)] and for smaller seed size were associated on LGs 6, 7, and 8. The implications of these findings for breeders is discussed.


Sign in / Sign up

Export Citation Format

Share Document