Factors Affecting Seed Production and Viability in Threatened Species of Encephalartos: Comparative Tests of Pollen Viability and Synchrony with Pollination Drop Formation in E. latifrons Lehm. and E. altensteinii Lehm.

2018 ◽  
Author(s):  
Phakamani Xaba ◽  
John S. Donaldson
Keyword(s):  
Seed Production ◽  
Threatened Species ◽  
Pollen Viability ◽  
Drop Formation ◽  
Factors Affecting ◽  
Comparative Tests ◽  
Pollination Drop

A Method of Measuring Pollinator Populations on Field Crops

1952 ◽  
Vol 84 (10) ◽  
pp. 314-316 ◽  
Author(s):  
M. V. Smith ◽  
G. F. Townsend
Keyword(s):  
Seed Production ◽  
Large Degree ◽  
Factors Affecting ◽  
Field Crops ◽  
Pollinating Insects ◽  
Pollinator Populations

The seed production of many field crops, and in particular of legumes, depends to a large degree upon the number of pollinating insects present in the field during the blooming period. A study of the various factors affecting seed production requires, among other things, a knowledge of the population of pollinating insects present, and a ready means of comparing pollinator populations from one field to another. To obtain this information some means must be employed to count and classify the pollinating insects in the field.

Factors affecting fruit and seed production of Paeonia ostii “Feng Dan”, an economically important oil tree

2021 ◽  
Vol 36 (2) ◽  
pp. 258-268
Author(s):  
Guo‐Xing Cao ◽  
Hong‐Qiang Lin ◽  
Yue‐Hong Cheng ◽  
Xie Wang
Keyword(s):  
Seed Production ◽  
Factors Affecting

Inflorescence development and seed production in Lolium spp. × Festuca pratensis tetraploid hybrids

1975 ◽  
Vol 85 (2) ◽  
pp. 301-307 ◽  
Author(s):  
P. Cremades ◽  
E. W. Bean
Keyword(s):  
Seed Production ◽  
Lolium Perenne ◽  
Lolium Multiflorum ◽  
Pollen Viability ◽  
Festuca Pratensis ◽  
Inflorescence Development ◽  
Tetraploid Hybrid ◽  
Pollen Release ◽  
Sufficient Variation ◽  
Reproductive Characters

SUMMARYThe reproductive development and seed production characters of a Lolium multiflorum × Festuca pratensis tetraploid hybrid and a Lolium perenne × Festuca pratensis tetraploid hybrid were compared with those of their tetraploid parental cultivars. Experiments were carried out under glasshouse and natural conditions; single plants were studied as only small quantities of seed were available from the breeder. The lowtemperature/short-day requirements for inflorescence induction of the two hybrids were in between those of the corresponding parental species. The variance of the date at which vegetative primordia changed to the reproductive condition was greater in the hybrids than in the parental cultivars, but the variance of the dates of inflorescence emergence were similar for the hybrids and parental cultivars. Inflorescences ranged from the Lolium type with only sessile spikelets to the Festuca type with primary branches. Inner glumes, which are absent in the Lolium parents but present in Festuca pratensis, were found in the hybrids, though not in all spikelets. In the Lolium perenne × Festuca pratensis hybrid pollen release, potential pollen viability and floret fertility were low, but the Lolium multiflorum × Festuca pratensis hybrid produced large amounts of pollen with a higher potential viability and had floret fertilities similar to those of its two parental cultivars. There was sufficient variation in reproductive characters for further selection, particularly in the Lolium perenne × Festuca pratensis hybrid.

FACTORS AFFECTING SCALE OF ENTERPRISE

1985 ◽  
Vol 2 ◽  
pp. 37-40
Author(s):  
Logan Freeman
Keyword(s):  
Seed Production ◽  
White Clover ◽  
Trifolium Repens ◽  
Factors Affecting ◽  
Alternative Crops ◽  
New Cultivars

White clover is undersown in the spring with wheat, barley and peas. Irrigation is used in order to achieve a heavy flowering in the white clover crop over one month. Three barley crops must be grown successively in some paddocks to eliminate yarrow. Lupins, peas and soybeans are alternative legumes to white clover, but white clover is still the preferred legume to grow, especially with new cultivars becoming available. Keywords: White clover, Trifolium repens, seed production, yarrow, alternative crops, overseas markets.

Pollen–pistil interaction, pistil histology and seed production in A×B grain sorghum crosses under chilling field temperatures

2009 ◽  
Vol 148 (1) ◽  
pp. 73-82 ◽  
Author(s):  
M. E. CISNEROS-LÓPEZ ◽  
L. E. MENDOZA-ONOFRE ◽  
H. A. ZAVALETA-MANCERA ◽  
V. A. GONZÁLEZ-HERNÁNDEZ ◽  
G. MORA-AGUILERA ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Seed Production ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Vascular Tissue ◽  
Pollen Viability ◽  
Tube Growth ◽  
Male Sterile ◽  
Pollen Diameter

SUMMARYSix pairs of isogenic lines of sorghum (Sorghum bicolor L. Moench) were sown in field plots in Montecillo, State of México (2240 m altitude), in 2005 and 2006. Crosses A (♀)×B (♂) were done in each pair. In A-lines, the length of pistil, stigma, style and ovary, as well as the ovary width, were measured. In B-lines, pollen diameter, viability (cytoplasm density) and production were evaluated. Pollen germination and pollen tube growth in the pistils of the A-lines, were quantified in vivo with aniline blue and epifluorescence 18 h after pollination (HAP), while fertilized pistils were counted at 96 HAP. Histological studies on both pollinated and non-pollinated pistils were performed in one male-sterile line. Seed yield, mean-seed weight, seeds per panicle and seed set (SS; seeds/flower/panicle) were determined at harvest. Pollen viability was the variable most related to pollen germination and pollen tube growth. Stigma receptivity was not associated with its morphology. Growth of the pollen tube in stigma, style and ovary was observed in the transmitting tissue 18 HAP, running parallel to the vascular tissue. Yield under chilling field temperatures (minimum average of 6 and 8°C) prevailing during flower development and pollination ranged from 7 to 12 g/panicle. The differences in seed production and SS among A×B crosses did not depend on the amount and viability of pollen.

Studies of seed production in two Austrodanthonia grass cultivars

2002 ◽  
Vol 53 (11) ◽  
pp. 1197 ◽  
Author(s):  
G. M. Lodge
Keyword(s):  
Seed Germination ◽  
Seed Production ◽  
Early Stage ◽  
Early Flowering ◽  
Harvest Time ◽  
Flowering Stage ◽  
N Application ◽  
Factors Affecting ◽  
The Mean ◽  
Early Harvest

Studies were conducted in 1993–94 on 2 native grass cultivars, Austrodanthonia richardsonii (Link) H.P.�Linder (syn. Danthonia richardsonii Cashmore) cv. Taranna and A. bipartita (Link) H.P. Linder (syn. D. linkii Kunth) cv. Bunderra, to quantify the important morphological factors affecting seed production (as measured by seed weight, g/plant). Experiments also examined the influence of nitrogen (N) application and investigated the effects of time and method of harvest on seed production and subsequent germination. For both cultivars, inflorescence and floret number accounted for the highest proportion of the variation in seed production per plant (R2 = 0.873 and 0.686 for Taranna and Bunderra, respectively). Although N applied (0, 25, and 50 kg/ha) at the late vegetative or early flowering stage, or split applications at both times, had no significant effect (P > 0.05) on the seed production per plant of Taranna and Bunderra, further studies of N effects are required. In 1993 and 1994, time of inflorescence harvest and method of harvest had no significant effect on inflorescence number and seed production of Taranna and Bunderra and no significant effect on the subsequent germination of Bunderra seed. However, in 1993, harvesting at an early stage of flowering (10% of florets white and fluffy) reduced Taranna seed production by 17% compared with the mean and decreased (P < 0.05) seed germination by about 10%. In 1994, harvesting at early flowering (5% florets white and fluffy) reduced Taranna seed production by a mean of around 55% compared with harvesting at 50% maturity, and subsequent seed germination was also lower (P < 0.05) for the early harvest time. Application of 1 L/ha of paraquat (a.i. 200 g/L of paraquat dichloride) at mid-flowering to desiccate the crop in 1993 had no significant effect on the germination of Taranna and Bunderra caryopses. The implications of these data for commercial seed production are discussed.

Seed production and persistence of Carnamah and other early strains of Trifolium subterraneum in the wheatbelt of Western Australia

1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Western Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Early Flowering ◽  
The Other ◽  
Factors Affecting ◽  
Seed Yields

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.

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