Genetic Variation, G*E Interactions and Selection Response for Hagberg Falling Number in Triticale

ABSTRACT Abdominal bristle selection lines (three high and three low) and controls were founded from a marked homozygous line to measure the contribution of sex-linked "mutations" to selection response. Two of the low lines exhibited a period of rapid response to selection in females, but not in males. There were corresponding changes in female variance, in heritabilities in females, in the sex ratio (a deficiency of females) and in fitness, as well as the appearance of a mutant phenotype in females of one line. All of these changes were due to bb alleles (partial deficiencies for the rRNA tandon) in the X chromosomes of these lines, while the Y chromosomes remained wild-type bb+. We argue that the bb alleles arose by unequal crossing over in the rRNA tandon.—A prediction of this hypothesis is that further changes can occur in the rRNA tandon as selection is continued. This has now been shown to occur.—Our minimum estimate of the rate of occurrence of changes at the rRNA tandon is 3 × 10-4. As this is substantially higher than conventional mutation rates, the questions of the mechanisms and rates of origin of new quantitative genetic variation require careful re-examination.

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The impact of supply, demand and grain quality on the UK bread and feed wheat price differential in the UK

The Journal of Agricultural Science ◽

10.1017/s0021859606006307 ◽

2006 ◽

Vol 144 (5) ◽

pp. 411-419 ◽

Cited By ~ 2

Author(s):

P. D. HOLLINS ◽

P. S. KETTLEWELL ◽

S. T. PARSONS ◽

M. D. ATKINSON

Keyword(s):

Statistical Model ◽

Bread Wheat ◽

Interannual Variation ◽

Grain Quality ◽

Quality Criterion ◽

Falling Number ◽

Hypothetical Model ◽

The Uk ◽

The Impact ◽

Hagberg Falling Number

The difference between the bread wheat and feed wheat prices in the UK (the premium) is an important influence on behaviour throughout the entire grain chain. The aim of the present study was to quantify the influence of grain quality and other factors on interannual variation in the premium calculated as a proportion of the feed price. A hypothetical model of the UK wheat economy was devised, appropriate annual national data from 1982 to 2000 were collected for each component and multiple regression was used to develop a statistical model for the premium.The statistical model included livestock numbers (calculated as pig equivalents), Hagberg falling number and wheat stocks, which together explained 0·80 of the interannual variation in the premium. A high premium was associated with high livestock numbers, low Hagberg falling number and low wheat stocks. These variables were included in the hypothetical model because: livestock numbers represent demand for feed wheat; Hagberg falling number is a quality criterion for purchase of bread wheat with a low value indicating poor quality and thus a smaller supply of bread wheat; wheat stocks are one of the sources of supply of wheat. It was concluded that of the 16 supply, demand or price variables in the hypothetical model the main variables associated with the premium from 1982 to 2000 were demand for feed wheat, quality of the wheat harvest and carry-over of wheat from the previous harvest.

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The evolution of Daphnia pulex in a temporally varying environment

Genetics Research ◽

10.1017/s0016672398003322 ◽

1998 ◽

Vol 72 (1) ◽

pp. 25-37 ◽

Cited By ~ 43

Author(s):

SAMUEL M. SCHEINER ◽

LEV Yu YAMPOLSKY

Keyword(s):

Genetic Variation ◽

Temperature Change ◽

Local Population ◽

Daphnia Pulex ◽

Selection Response ◽

Clonal Variation ◽

Offspring Size ◽

Malthusian Parameter ◽

Offspring Number ◽

Variable Environments

We investigated three aspects of adaptation to variable environments in Daphnia pulex (Cladocera: Crustacea): (1) effects of temporal variation on the evolution of phenotypic plasticity ; (2) plasticity in sexual versus asexual lineages; (3) maintenance of genetic variation in variable environments. We performed a 72-day quasi-natural selection experiment comparing three patterns of variation: constant temperatures, varying but predictable temperature change, and unpredictable temperature change. All populations were begun with an identical array of 34 clones. During selection clonal variation declined in all populations and different patterns of environmental variation had little effect on amounts of genetic variation. Sexual and asexual lineages differed in size and growth rate, but did not differ in amounts of plasticity or in adaptation to variable environments. The primary target of selection was the Malthusian parameter (r) and life history traits of development time, offspring size and offspring number. The heritability of plasticity was generally lower than trait heritability. Because of this difference, the selection response on the mean of the traits overwhelmed the selection response on plasticity. Lower heritabilities of plasticity are very typical, suggesting that our results will be typical of responses to selection in nature. Our results suggest that selection will act mostly on trait means within environments and that plasticity will evolve often as a correlated trait. Because selection on plasticity is based on its across-deme, global fitness, this process will usually be slow. Comparative studies need to shift from closely related, local population differences to those of more distantly related populations or even different species.

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Alpha-amylase activity of wheat grain from crops differing in grain drying rate

The Journal of Agricultural Science ◽

10.1017/s0021859696004066 ◽

1997 ◽

Vol 128 (2) ◽

pp. 127-134 ◽

Cited By ~ 12

Author(s):

P. S. KETTLEWELL ◽

M. M. CASHMAN

Keyword(s):

Amylase Activity ◽

Potential Evapotranspiration ◽

Analysis Of Covariance ◽

Alpha Amylase ◽

Drying Rate ◽

Falling Number ◽

Seasonal Differences ◽

Year Effect ◽

Grain Drying ◽

Hagberg Falling Number

The hypothesis was tested that slow grain drying stimulates pre-maturity alpha-amylase activity in wheat (Triticum aestivum L.). Grain drying rate in 91 commercial crops of cultivars Avalon or Mercia grown over the years 1988–90 was estimated from the slope of linear regressions of moisture content on time. Incipient sprouting was detected in some samples from 1988 using the fluoroscein dibutyrate test, but results from a beta-limit dextrin gel assay indicated that pre-maturity alpha-amylase was probably the major source of alpha-amylase activity in these samples. Although year-to-year differences in ln alpha-amylase activity and Hagberg falling number tended to be associated with seasonal differences in drying rate, there was no evidence of a relationship between either ln alpha-amylase activity or Hagberg falling number and drying rate after the year effect was removed by an analysis of covariance. A second dataset from one crop in each of 14 years at one site showed significant positive linear relationships between cumulative potential evapotranspiration calculated over different periods during grain ripening and Hagberg falling number (excluding 3 years when incipient sprouting was thought to occur). It was concluded that pre-maturity alpha-amylase activity was stimulated by an unknown environmental factor differing between seasons and associated with seasonal differences in drying rate and cumulative potential evapotranspiration.

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AC Remington winter rye

Canadian Journal of Plant Science ◽

10.4141/p99-158 ◽

2000 ◽

Vol 80 (3) ◽

pp. 605-607 ◽

Cited By ~ 1

Author(s):

J. G. McLeod ◽

Y. T. Gan ◽

J. F. Payne

Keyword(s):

Secale Cereale ◽

Agricultural Research ◽

Kernel Weight ◽

Research Centre ◽

Winter Rye ◽

Falling Number ◽

Lodging Resistance ◽

Canadian Prairies ◽

Secale Cereale L ◽

Hagberg Falling Number

AC Remington, a cultivar of winter rye (Secale cereale L.), was developed at the Semiarid Prairie Agricultural Research Centre, Research Branch, Agriculture and Agri-Food Canada, Swift Current, Saskatchewan. AC Remington is a semidwarf with 20 to 25% shorter straw and improved lodging resistance compared with tall cultivars. AC Remington has good winter survival and is well adapted to the Canadian Prairies. AC Remington has improved grain yield, test weight, kernel weight and Hagberg Falling Number compared with those of the semidwarf cultivar AC Rifle. Plant height, heading, maturity and ergot infection of AC Remington are similar to those of AC Rifle. Key words: Cultivar description, semidwarf, rye (winter), Hagberg Falling Number, Secale cereale L.

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