scholarly journals VARIABILITY AND SELECTION IN AN INTERSPECIFIC HYBRID POPULATION OF PACHYRRHIZUS EROSUS X P. AHIPA (YAM BEAN)

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 610g-611
Author(s):  
Richard W. Hartmann
Keyword(s):  
Interspecific Hybrid ◽  
Growing Season ◽  
Flowering Plants ◽  
Early Flowering ◽  
Hybrid Population ◽  
Root Size

F3 seeds from a cross of P. erosus (indeterminate, daylength sensitive) X P. ahipa (determinate, daylength insensitive) were received from M. Sorensen of the Royal Veterinary and Agricultural University in Copenhagen, Denmark and sown in Hawaii in April, 1989 to increase the seed. The F4 seed were planted in March, 1990 and in October, 1990 (the normal time). All F4 progeny included both bush and vine plants in the summer planting, with more bush plants in the progeny of F3 bushes than vines. Likewise, the progeny of earlier-flowering F3 plants had a higher percentage of plants in flower in June than progeny of later-flowering ones. Root sizes and shapes were variable. The F4 progenies of the lines with the highest percentage of bushes and early-flowering plants were regrown in the summer of 1991 and selected for summer-flowering bush plants with acceptable root size. The selections were then grown in the winter of 1991 to test for performance during the normal growing season.

The effects of grazing on the phosphorus requirement of an annual pasture

1971 ◽  
Vol 22 (1) ◽  
pp. 81 ◽  
Author(s):  
PG Ozanne ◽  
KMW Howes
Keyword(s):  
Subterranean Clover ◽  
Growing Season ◽  
Maximum Growth ◽  
Grazing Pressure ◽  
Light Interception ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Phosphorus Requirement ◽  
Root Size

The applied phosphorus requirement of a pasture sown to subterranean clover was measured with and without grazing. Under moderate grazing pressure, in the year of establishment, the pasture required about 50 % more phosphorus than when ungrazed. In the following season, at a higher stocking rate, the grazed areas needed twice as much phosphorus as the ungrazed to make 90% of their maximum growth. In both years this difference in requirement between stocked and unstocked treatments was present throughout the growing season. Increased phosphorus requirement under grazing is associated with the need for greater uptake of phosphorus under conditions where redistribution of absorbed phosphorus within the plant is prevented by defoliation. It does not appear to be due to effects of defoliation on root size. Nor does it depend on differential light interception or on changes in botanical composition.

scholarly journals A Novel Pear Scab (Venturia nashicola) Resistance Gene, Rvn3, from Interspecific Hybrid Pear (Pyrus pyrifolia × P. communis)

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2632
Author(s):  
Sewon Oh ◽  
Hyeondae Han ◽  
Daeil Kim
Keyword(s):  
Resistance Gene ◽  
Resistance Genes ◽  
Interspecific Hybrid ◽  
Dominant Gene ◽  
Apple Scab ◽  
Scab Resistance ◽  
Hybrid Population ◽  
Pyrus Pyrifolia ◽  
Pear Scab ◽  
Venturia Nashicola

Asian pear scab is a fungal disease caused by Venturia nashicola. The identification of genes conferring scab resistance could facilitate the breeding of disease-resistant cultivars. Therefore, the present study aimed to identify a scab-resistance gene using an interspecific hybrid population ((Pyrus pyrifolia × P. communis) × P. pyrifolia). Artificial inoculation of V. nashicola was carried out for two years. The segregation ratio (1:1) of resistant to susceptible individuals indicated that resistance to V. nashicola was inherited from P. communis and controlled by a single dominant gene. Based on two years phenotypic data with the Kruskal–Wallis test and interval mapping, 12 common markers were significantly associated with scab resistance. A novel scab resistance gene, Rvn3, was mapped in linkage group 6 of the interspecific hybrid pear, and co-linearity between Rvn3 and one of the apple scab resistance genes, Rvi14, was confirmed. Notably, an insertion in pseudo-chromosome 6 of the interspecific hybrid cultivar showed homology with apple scab resistance genes. Hence, the newly discovered Rvn3 was considered an ortholog of the apple scab resistance gene. Since the mapping population used in the present study is a pseudo-BC1 population, pyramiding of multiple resistance genes to pseudo-BC1 could facilitate the breeding of pear cultivars with durable resistance.

scholarly journals How does timing of flowering affect competition for pollinators, flower visitation and seed set in an early spring grassland plant?

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sandra Kehrberger ◽  
Andrea Holzschuh
Keyword(s):  
Species Interactions ◽  
Seed Set ◽  
Weather Conditions ◽  
Early Spring ◽  
Flowering Plants ◽  
Early Flowering ◽  
Flower Visitation ◽  
Floral Longevity ◽  
Visitation Rates ◽  
Phenological Shifts

Abstract Knowledge on how the timing of flowering is related to plant fitness and species interactions is crucial to understand consequences of phenological shifts as they occur under climate change. Early flowering plants may face advantages of low competition for pollinators and disadvantages of low pollinator abundances and unfavourable weather conditions. However, it is unknown how this trade-off changes over the season and how the timing affects reproductive success. On eight grasslands we recorded intra-seasonal changes in pollinators, co-flowering plants, weather conditions, flower visitation rates, floral longevity and seed set of Pulsatilla vulgaris. Although bee abundances and the number of pollinator-suitable hours were low at the beginning of the season, early flowers of P. vulgaris received higher flower visitation rates and estimated total number of bee visits than later flowers, which was positively related to seed set. Flower visitation rates decreased over time and with increasing number of co-flowering plants, which competed with P. vulgaris for pollinators. Low interspecific competition for pollinators seems to be a major driver for early flowering dates. Thus, non-synchronous temporal shifts of co-flowering plants as they may occur under climate warming can be expected to strongly affect plant-pollinator interactions and the fitness of the involved plants.

Osmiarufa L. (Hym. Megachilidae) as a Pollinator of Plants in Greenhouses

1974 ◽  
Vol 4 (3) ◽  
pp. 217-224 ◽  
Author(s):  
SVEND NØRGAARD HOLM
Keyword(s):  
Sex Ratio ◽  
Considerable Increase ◽  
Flowering Plants ◽  
Early Flowering

Abstract Osmiarufa has been successfully used as a pollinator of early flowering plants in an unheated greenhouse. This species showed a favourable sex ratio which enhanced propagation; it readily occupied artificial domiciles, hibernated well at 4–-5°C in a refrigerator, and could be available for immediate use as pollinator. The bees were easily trapped in nature by means of cardboard tubes. The females preferred tubes of 6 mm diameter, but also nested in 8 mm tubes. The latter tubes gave a considerable increase in sex ratio both in nature and under greenhouse conditions. The value of O. rufa as a pollinator is 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.

scholarly journals Application of a high-speed breeding technology to apple (Malus × domestica) based on transgenic early flowering plants and marker-assisted selection

2011 ◽  
Vol 192 (2) ◽  
pp. 364-377 ◽  
Author(s):  
Henryk Flachowsky ◽  
Pierre-Marie Le Roux ◽  
Andreas Peil ◽  
Andrea Patocchi ◽  
Klaus Richter ◽  
...  
Keyword(s):  
Malus Domestica ◽  
Marker Assisted Selection ◽  
High Speed ◽  
Flowering Plants ◽  
Early Flowering ◽  
Breeding Technology

QTL analyses of fiber components and crude protein in an annual × perennial ryegrass interspecific hybrid population

2006 ◽  
Vol 18 (4) ◽  
pp. 327-340 ◽  
Author(s):  
Yanwen Xiong ◽  
Shui-zhang Fei ◽  
E. Charles Brummer ◽  
Kenneth J. Moore ◽  
Reed E. Barker ◽  
...  
Keyword(s):  
Perennial Ryegrass ◽  
Interspecific Hybrid ◽  
Crude Protein ◽  
Hybrid Population ◽  
Fiber Components

scholarly journals The seed productivity and similarity of seeds of early flowing plants

2021 ◽  
pp. 55-60
Author(s):  
O. N. Kurdyukova
Keyword(s):  
Plant Species ◽  
Flowering Plants ◽  
High Potential ◽  
Early Flowering ◽  
Seed Productivity ◽  
Potential Productivity ◽  
Field Germination ◽  
Natural Flora

Seed productivity of 22 early flowering plants of the natural flora of the Kamensky geobotanical region, introduced into the culture and used in landscaping, has been established. It was shown that the actual average seed productivity of one individual of various plant species varies from 12 to 373 pcs., And the maximum - from 20 to 448 pcs. seeds, which is 10 to 90% of the potential. In most species, high actual seed productivity is combined with high potential productivity. Field germination of seeds of all plant species was higher when sowing with freshly harvested seeds within 5-14 days after ripening. Storage of seeds at a temperature of 18,0-20,0ºС followed by sowing them in the spring led to a significant decrease in germination.

scholarly journals Use of bulk hybrid populations to select for adaptation to contrasting environments in subterranean clover

2006 ◽  
Vol 12 ◽  
pp. 157-162
Author(s):  
Phillip Nichols ◽  
Philip Cocks
Keyword(s):  
Subterranean Clover ◽  
Farming Systems ◽  
Growing Season ◽  
Fine Tuning ◽  
Hybrid Population ◽  
Population Changes ◽  
Trial Management ◽  
Pasture Legumes ◽  
Different Populations ◽  
Selection For

Population changes were measured over 17 years within a highly variable bulk hybrid population of subterranean clover in a short and long growing season mediterranean-type environment in Western Australia. Flowering time was used as an indicator of evolutionary change and was highly responsive to environment. Markedly different populations evolved, with rapid selection for early flowering at the short growing season site and later flowering at the long growing season site. The use of bulk hybrid populations is suggested as a low-input means of breeding and selecting annual pasture legumes adapted to target environments and farming systems. While adapted genotypes can be selected after just 3 seasons, further adaptive fine-tuning occurs with increased homozygosity. The success of the method hinges on the original parents containing genes for desirable characters, trial sites being representative of target environments and trial management being representative of typical farm practice

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