Variability in seed size selection by granivorous passerines: effects of bird size, bird size variability, and ecological plasticity

Oecologia ◽  
1994 ◽  
Vol 99 (1-2) ◽  
pp. 1-6 ◽  
Author(s):  
Mario Díaz
Keyword(s):  
Seed Size ◽  
Ecological Plasticity ◽  
Size Selection ◽  
Size Variability

scholarly journals Back to Basics: Does Seed Size Affect Germination and Plant Uniformity in Broccoli (Brassica Oleracea var Italica)?

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 181
Author(s):  
Celia van Sprang ◽  
Gayathri Rajagopal
Keyword(s):  
Brassica Oleracea ◽  
Seed Size ◽  
Abiotic Factors ◽  
Crop Growth ◽  
Significant Difference ◽  
Field Uniformity ◽  
Direct Seeded ◽  
Subsequent Crop ◽  
Size Variability ◽  
The Impact

Hand harvested crops, such as brassicas and lettuce, are prone to high levels of variability during growth and at harvest. This necessitates multiple harvest passes and substantially increased labour costs for the grower. Both biotic and abiotic factors contribute to this lack of field uniformity. The main objective was to evaluate the impact of broccoli (Brassica oleracea var. Italica) seed size variability on germination, subsequent crop growth and harvest uniformity. An initial experiment was conducted where germination counts across three seed-size categories including, 2.0mm (SS1), 2.3 mm (SS2) and 2.45 mm (SS3), were recorded at 3, 7, 10 and 14 days after sowing (DAS). At 14 DAS, germination was greater in the SS1 (95%) and SS2 (91%) than the SS3 (66%) (P < 0.005). A second experiment evaluated the same seed categories planted under direct seeded (DS) and transplanted (TR) conditions to identify differences in crop growth and development. At 49 DAS, DS plant counts per plot were lowest for the SS3 (54.5 plants plot−1) compared with the SS1 (70.5 plants plot−1) and SS2 (64 plants plot−1). This could be attributed to the reduced seed coat thickness evident in the SS3 (66.3 μm) which can potentially lead to increased damage and mortality of the seed, compared with the SS1 (79.3 μm) and SS2 (73.1 μm). The TR treatment gave greater uniformity with no significant difference (P < 0.05) in plant populations across seed size categories (SS1 = 95, SS2 = 90 and SS3 = 96 plants plot−1).

Seed size selection by olive baboons

Primates ◽  
2008 ◽  
Vol 49 (4) ◽  
pp. 239-245 ◽  
Author(s):  
Britta Kerstin Kunz ◽  
Karl Eduard Linsenmair
Keyword(s):  
Seed Size ◽  
Size Selection ◽  
Olive Baboons

Resource Allocation and Seed Size Selection in Perennial Plants under Pollen Limitation

2017 ◽  
Vol 190 (3) ◽  
pp. 430-441 ◽  
Author(s):  
Qiaoqiao Huang ◽  
Martin Burd ◽  
Zhiwei Fan
Keyword(s):  
Resource Allocation ◽  
Seed Size ◽  
Pollen Limitation ◽  
Perennial Plants ◽  
Size Selection

Germination and early seedling growth in some northern wild rice (Zizania palustris) populations differing in seed size

1991 ◽  
Vol 69 (4) ◽  
pp. 689-696 ◽  
Author(s):  
R. L. Counts ◽  
P. F. Lee
Keyword(s):  
Seed Size ◽  
Field Survey ◽  
Viable Seed ◽  
Substantial Variation ◽  
Zizania Palustris ◽  
Early Seedling Growth ◽  
Early Seedling ◽  
Size Variability ◽  
Viable Seeds ◽  
Prolonged Dormancy

A field survey of eight northern Zizania palustris populations indicated that there is substantial variation in seed size. Variability is partitioned approximately equally among populations and among individuals within populations. Germination dynamics and temperature sensitivity of germination differed among four populations tested, but the differences were not apparently related to mean population seed size. Mean population seed size did appear to influence the germinability of viable seeds, such that a greater proportion of larger seeds exhibited prolonged dormancy. In a test using three populations differing in mean seed size, those with large seeds produced larger seedlings than populations characterized by small seeds. It appears that in Z. palustris seed size influences whether or not a viable seed will germinate and the size of the resulting seedling, but not the rate at which germinable seeds are recruited to form a seedling population. Key words: Zizania, seed size, germination.

Effect of Continuous Seed Size Selection Among Two Runner-Type Peanut Cultivars1

1999 ◽  
Vol 26 (1) ◽  
pp. 53-56 ◽  
Author(s):  
W. D. Branch ◽  
A. K. Culbreath
Keyword(s):  
Seed Size ◽  
Coastal Plain ◽  
Selection Pressure ◽  
Field Performance ◽  
Continuous Selection ◽  
Effective Control ◽  
Size Selection ◽  
Tomato Spotted Wilt ◽  
Arachis Hypogaea L ◽  
The U.S

Abstract The major peanut (Arachis hypogaea L.) producing regions in the U.S. are currently faced with an increasing tomato spotted wilt tospovirus (TSWV) problem, and the most effective control is the use of resistant cultivars. This study was conducted to compare the field performance and TSWV disease intensity among different seed sizes of two runner-type cultivars. For three consecutive years, 1995–97, the effect of continuous seed size selection on yield, grade, and TSWV intensity among the two runner cultivars Georgia Green and Florunner was evaluated at the Univ. of Georgia Coastal Plain Exp. Sta. Sound mature kernels from both cultivars were divided into four seed sizes (jumbo, medium, No. 1, and the combined mill run check). Seed size selection pressure was applied to both cultivars each year. Seed stock for planting each year was obtained from the corresponding seed size produced the previous year. The results showed that the Georgia Green cultivar significantly out-performed the Florunner cultivar in yield, grade, dollar value, and had significantly less TSWV. Georgia Green had a similar percentage of jumbo seed, more medium seed, and fewer No. 1 seed than Florunner. Both runner-type cultivars responded similarly to continuous selection pressure with small but significant changes in seed size distribution over a relatively short 3-yr period.

scholarly journals Seed size variability: from carob to carats

2006 ◽  
Vol 2 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Lindsay A Turnbull ◽  
Luis Santamaria ◽  
Toni Martorell ◽  
Joan Rallo ◽  
Andy Hector
Keyword(s):  
Natural Selection ◽  
Seed Size ◽  
Seed Weight ◽  
Natural Variation ◽  
Ceratonia Siliqua ◽  
Size Variability

The seeds of various plants were used as weights because their mass reputedly varies so little. Carob ( Ceratonia siliqua ), which has given its name to the carat, is particularly famous in this regard. But are carob seeds unusually constant in weight and, if not, how did the myth arise? The variability of seeds sampled from a collection of carob trees (CV=23%) was close to the average of 63 species reviewed from the literature (CV=25%). However, in a perception experiment observers could discriminate differences in carob seed weight of around 5% by eye demonstrating the potential for humans to greatly reduce natural variation. Interestingly, the variability of pre-metrication carat weight standards is also around 5% suggesting that human rather than natural selection gave rise to the carob myth.

scholarly journals Phenotypic (Fruit and Seed Characters) Selection of Dacryodes edulis (Don. G. Lam H. J.) Tree for Vegetative Propagation

2021 ◽  
Vol 5 (2) ◽  
pp. 347-353
Author(s):  
H.O. Okonkwo ◽  
R.E. Ubaekwe ◽  
A.N. Okeke ◽  
L.C. Malizu
Keyword(s):  
Seed Size ◽  
Vegetative Propagation ◽  
Fruit Size ◽  
Pairwise Comparison ◽  
Phenotypic Characters ◽  
Normality Test ◽  
Randomized Design ◽  
Significant Difference ◽  
Size Variability ◽  
Rivers State

The study was conducted to identify superior D. edulis trees using phenotypic characters (fruit and seed size) as the criteria to select candidate trees for subsequent multiplication through vegetative propagation. Five D. edulis compound trees were randomly selected within Onne community in Eleme LGA Rivers state in a preliminary effort to assist households in the selection and multiplication of desirable tree phenotypes. Seeds were extracted by softening fruit with warm water at 57oC. Fruit and seed length (mm), breadth (mm), and thickness (mm) were taken using veneer caliper. Size of fruit and seed was calculated as: length × breadth × thickness. The experiment was a completely randomized design in its layout and data analysis was carried out using analysis of variance and regression after a normality test was conducted using Shapiro-Wilk. The results showed that highest mean fruit size (79.38 ± 3.99 mm) was recorded in tree 3 and the lowest was tree 5 (29.60 ± 1.48 mm): while, highest seed size (34.78 ± 2.47 mm) was recorded in tree 3 and the lowest in tree 4 (15.58 ± 0.99 mm). Highest within tree fruit size variability was recorded in tree 1 (24%) and the lowest in tree 4 (12%): while the highest within tree seed size variability was recorded in tree 2 (28%) and the lowest in tree 5 (15%). There was however a significant difference in fruit and seed size between the trees. Pairwise comparison showed that tree 1 was not significantly different from tree 2 in fruit and seed size. There was a significant positive correlation between fruit and seed size among the trees. This implies that selection for large fruit size automatically selects for large seeds size. Large fruited trees can therefore be multiplied from these trees using vegetative propagation.

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