studies on the breeding of self pollinating cereals
TRANSCRIPT
STUDIES ON THE BREEDINGOF SELF POLLINATING CEREALS
4. ENVIRONMENT AND THE INHERITANCE OF QUALITY IN SPRING WHEATS
J. B. THOMPSON *) AND R. N . H. WHITEHOUSEPlant Breeding Institute, Cambridge
With 2 figures
Received 2 Nov . 1961
ABSTRACT
A survey of the genetic control of seven aspects of wheat quality shows the presenceof complex genotype x environment interactions . The demonstration of theseinteractions emphasises the need for an effective sampling of environments during thetesting of breeding material and the importance of consistency of performance ofselections over the range of environments .
INTRODUCTION
It has long been accepted that the heritable component of the suitability of Triticumaestivum for milling and subsequent baking is sufficient to make it possible for plantbreeders to produce varieties with quality as one of their special attributes . The positionin Great Britain at present is that most of the flour used for the production of biscuitsand a small proportion of that used for bread baking is home grown, and with this inmind part of the wheat breeding work at the Plant Breeding Institute is devoted toproducing quality wheats . Wheat quality is its suitability to be put through a series ofcomplex milling, mixing, moulding and baking processes, and a character such as thismust certainly be a complex one. Attempts to measure quality objectively on a singlenumerical scale are therefore unlikely to prove successful, numerical measurementsif made at all must be made on component characters and these components thenintegrated in the final assessment of quality .
In breeding for complex characters progress can be and has been made by handlingthe material subjectively, but it is generally felt that a more objective approach, whereit can be made, is more satisfactory . In recent years GRAFIUS (1956), GRAFIUS & WIEBE(1959) and GRAFIUS and KIESLING (1958) have proposed geometrical models forhandling complex characters, these models demanding the breakdown into componentswhich are simple in their inheritance. FISHER (1936), SMITH (1937), HAZEL (1943) andothers have developed methods using discriminant functions, these methods againrequiring the breakdown of the complex character into components which mustbear certain relationships to each other and to the complex character, and these methodsare at present being widely used in cotton breeding in Uganda (MANNING, 1956 ;WALKER, 1960) .
The components into which quality can most obviously be split as far as the British*) present adress : The Unit of Applied Plant Genetics, Kells Ingram Farm, Drogheda, Ireland .
Euphytica 11 (1962) : 181-196
1 81
J . B. THOMPSON AND R. N . H. WHITEHOUSE
crop is concerned are milling, nitrogen content, water absorption, and dough physico-chemical properties (BINGHAM, 1961b), and there is reason to believe that to a fairlylarge extent they are inherited independently of each other . The physicochemicalproperties of the dough can be measured by standard laboratory tests which giveresults that can be interpreted subjectively in terms of the behaviour of known varieties .These results can also be broken down into component characters which may bemore objectively measured .BINGHAM (1961a) has shown that in winter wheat grown at Cambridge these com-
ponents of quality are controlled by relatively simple gene systems, and that it shouldtherefore be possible to handle them objectively in a breeding programme . The purposeof this investigation is to examine the system of inheritance of the same componentsof quality in spring wheat and at the same time to survey the complexities of theinterrelationship of genotype and environment .
MATERIAL, METHOD AND CHARACTERS
The material to be discussed comprises the spring wheat varieties Apu, Carpo,Fasan, Jufy I, Peko and Svenno and the F2 of a diallel set of crosses between thesevarieties . Reciprocal crosses were not made. Apu, Fasan and Svenno are acceptable asbread wheats, Peko and possibly Jufy I as biscuit wheats, whilst Carpo has the millingproperties of a biscuit wheat combined with the flour characteristics of a bread wheat .
The material was grown in 1959 in four localities, i .e . on the Institute trial groundsat Cambridge and at the National Institute of Agricultural Botany trials centres atHeadley Hall, Yorkshire ; Seale Hayne, Devon ; and Sprowston, Norfolk . The labo-ratory quality tests were done in the winter of 1959/60 .
For laboratory analysis the wheat was milled on a "Brabender" laboratory stonemill, the nitrogen content of the flour was estimated by micro-Kjeldahl methods andthe water absorption and dough physicochemical properties were measured by the"Simon" Extensometer Equipment .
The analysis of the genetic control of the various characters follows the methodsof analysis of diallel sets of crosses developed by JINKS and HAYMAN (see JINKS, 1956and WHITEHOUSE, THOMPSON & RIBEIRO, 1958) and the analysis of the environmentalinteractions follows ALLARD (1956) .
The characters to be studied have been discussed by HALTON (1948) and more recentlyby BINGHAM (1961b) . They are
1 . Dough physicochemical propertiesThe Simon extensometer equipment plots the relationship of resistance and ex-
tensibility of a disc of dough and produces graphs as shown in figure 1 . A bread wheathas a high resistance whilst a biscuit wheat has a low resistance and high extensibility,and on the shape of the graphs the flours can be classified subjectively . The two basiccomponents to physicochemical properties are thus
Maximum Resistance andExtensibilityArea under curve is a character which is frequently used to integrate these two, and
provided the graphs retain the same basic shape this is satisfactory . However inter-
182
uJUZQF-toInWM
QUALITY IN SPRING WHEATS
SVENNO
EXTENSI BILITY
EXTENSIBILITY
FIG. 1 . Extensometer curves from samples of a bread wheat (Svenno) and a biscuit wheat (Peko)grown at Cambridge .
mediate graphs and graphs of different basic shapes are difficult to interpret on thismeasure .
Maximum stress . Another way of integrating resistance and extensibility is to takethe maximum value of the product resistance x extension (BINGHAM, unpublished) .This should be high for bread wheats and low for biscuit wheats, and has some ad-vantages over area under curve by being less affected by minor fluctuations in theprocedure used in the extensometer test .
2. Percentage Bran
The percentage of bran is taken as an indication of the milling properties of thewheat. Although it is almost entirely independent of the actual suitability of the flourfor baking when milled, commercial practice demands that bread wheats shall be hardmilling and thus, under the testing system used, have a low percentage of bran whilstbiscuit wheats are soft milling and have a high percentage of bran .
PEKO
1 83
3. Nitrogen content offlour
The crumb structure of the final baked product depends on the protein present,bread flours being in general high protein and biscuit flours low protein . The picture isnot as simple as this as type of protein also influences the quality of the flour but as abroad generalisation the above picture holds true .
4. Water absorption
For reasons mainly of texture, palatability and loaf volume, the flour used for breadbaking must have a high water absorption whilst that for biscuit baking requires a lowabsorption.
RESULTS
The results of the laboratory analysis are presented in the .appendix. The geneticanalysis of one character, maximum resistance, will be discussed in some detail whilstfor the other characters the results of this analysis will merely be presented for discus-sion. The conventional levels of significance of P = 0.05, 0.01 and 0.001 will be used,and symbols will be used in the text and tables to indicate these levels of significance asfollows
•
> 0.05•
= 0.05-0.01•
= 0.01-0.001•
< 0.001
J. B. THOMPSON AND R. N. H. WHITEHOUSE
A summary of the results of all the analyses will be presented at the beginning of thediscussion .
Throughout this article for reason of convenience the term epistasis will be used forwhat has variously been called non allelic interaction, complementary interaction andepistasis .
Maximum resistance
The genetic analysis of a diallel set of crosses (see JINKS I .e ., WHITEHOUSE et al l .c .)involves the calcultaion for each variety of a variance (Vr) of that variety's array anda covariance (Wr) of the array . The regression-relationship of Wr on Vr is then calculatedand plotted in relation to a parabola . The graphs obtained for maximum resistanceare shown in Fig. 2. From these graphs conclusions can be drawn about variousaspects of the genetic control of the character being studied in the environments inwhich the material was grown. The main information is about mean dominance,relative dominance of the parents and epistasis and it is this last aspect which concernsus most for this part of the discussion . A test of significance of the four regression slopesfor agreement with b = 0 and b = 1 gives the following results
1 84
QUALITY IN SPRING WHEATS
0 100V
200
300r
100V r
200
FIG . 2. Maximum Resistance. The Wr, Vr graphs from the four Locations (A = Apu, C = Carpo,F = Fasan, J = Jufy I, P = Peko and S = Svenno) .
1 85
1 8 6
Item
J. B. THOMPSON AND R . N. H. WHITEHOUSE
Location (L)Dominance (D)L x DArrays (A)L x AError
3135
1520
N
MS
10,676.977,843 .51,779 .62,479.05,796.5
94 .4
Clearly in all cases there is a significant regression as indicated by the test of agreementwith b = 0, and only in the case of Headley Hall is there any suggestion that this slopediffers significantly from b = 1 . Deviation from slope b = 1 generally indicates thepresence of epistasis, although other causes cannot be entirely excluded, thus we canconclude there is no epistasis shown by our data except possibly at Headley Hall .
A combined analysis of variance of the four regression slopes gives the following :
VR
113.09824 .5318 .8526.2661 .40
which indicates a significant overall regression and that the four regions agree inshowing the same slope . The slope of the overall regression is b = 0 .91 which showsgood agreement with slope b = 1 (t(16) = 1 .77 P > 0 .05), i .e . overall there is no epistasisshown here in the inheritance of maximum resistance .
An analysis of variance of Wr and Vr (following ALLARD l.c .) gives the followingresults
P
******
The error term of this analysis is a combination of the interaction D X A (which toa large extent represents epistasis) and L x D x A (which is largely the interactionof epistasis with environment) . The two terms in which we are at present most interestedare the term L x D which is the interaction of mean dominance with environment andL x A which is the interaction with environment of order of dominance of the parents,i .e. relative dominance x environment . In this analysis we are thus able to test theinteraction with environment of three components of the genetic make up of thecharacter. The results of these tests for maximum resistance can be summarised asfollows
Item N MS VR P
Overall regression 1 43467 284 .1 ***Heterogeneity of regression 3 171 1 .1 N.S .Error 16 153
b=0 b=1b
t(4) P t(4 ) P
Cambridge . . . . 1.043±0.117 8 .91 *** 0.37 N.S .Headley Hall .
. 0.794±0.042 18 .82 4.88 **Seale Hayne 0.977±0.146 6.69 ** 0.16 N.S .Sprowston .
. 0.840±0.063 13 .31 *** 2.54 N.S .
Extensibility
The individual Wr, Vr analyses again suggest a gene system uncomplicated byepistasis, the individual regression coefficients and the test of agreement with b = 0and b = 1 being as follows
QUALITY IN SPRING WHEATS
The results of the overall regression analysis and the analysis of variance of Wr andVr are
The overall regression slope of b = 0 .880 does not differ from b = 1 (t(16) = 1.596P > 0.05). Again for this character there is no epistasis and thus no epistasy x environ-ment interaction, but there is a highly significant interaction with environment of bothmean dominance and relative dominance of the parents .
Area under curve
The results of the individual analyses are
187
Item N MS VR P
Overall regression 1 305,887 136.86 ***Heterogeneity of regression 3 1,581 N.S .Error 16 2,235
Location (L) 3 1,243,547 109 .25 ***Dominance (D) 1 886,449 77 .87 ***L x D 3 132,160 11 .61 ***Arrays (A) 5 458,477 40.28 ***L x A 15 326,140 28 .65 ***Error 20 11,383
Interaction Source of test
Significance
(a) Mean dominance x environment . . L x D term ***(b) Relative dominance x environment L x A term ***(c) Epistasy x environment Heterogeneity of regression N.S .
b=0 b=1b
t(4) P t(4) P
Cambridge . . . . 0.438±0 .463 0 .95 N.S . 1 .21 N.S.Headley Hall .
. 0.687+0 .164 4.19 * 1 .91 N.S.Seale Hayne 0.842+0.218 3.86 * 0.72 N.S.Sprowston .
. 0.607+0 .169 3 .59 * 2 .33 N.S.
b=0 b=1b
t(4) P t(4 ) P
Cambridge . . . . 0.882+0 .159 5.55 ** 0.74 N.S .Headley Hall .
. 0.978+0 .156 6 .27 ** 0.14 N.S .Seale Hayne 0.944±0 .115 8 .21 ** 0.49 N.S .Sprowston .
. 0.622+0 .165 3.77 * 2.29 N.S .
J. B. THOMPSON AND R. N . H. WHITEHOUSE
and of the overall regression analysis and the analysis of variance of Wr and Vr are :
1 88
In this case the overall regression b = 0 .697 does differ significantly from b = 1(t(16 ) = 2.42 P = 0.05-0 .01). Area under curve is a compound character derived fromthe two preceeding components and it is likely that such a character will show a nonadditive (interaction) effect (see discussion of yield in WHITEHOUSE, et al l .c ., GRAFIUS,1959 and WILLIAMS, 1959). In this case although none of the individual regressionanalyses showed deviation from b = 1 and therefore there is no suggestion of epistasis,when they are joined together in the overall, and probably more sensitive, analysisthere is some suggestion of epistasis . There is, however, no suggestion of epistasy xenvironment interaction nor of mean dominance x environment interaction (L x D) .There is an interaction of relative dominance with environment (L x A).
Maximum stress
Like the previous character maximum stress is also a compound of resistance andextensibility, but unlike area under curve it shows no sign of epistasis as the followingresults show . The results of the test for interaction with environment of both aspects ofdominance are significant .
Individual analyses :
Item N MS VR P
Overall regression 1 8,591,245 30.88Heterogeneity of regression 3 72,020 N.S .Error 16 278,249
Location (L) 3 4,568,762 28 .99 ***Dominance (D) 1 1,146,390 7 .27 *LxD 3 58,598 0.37 N.S .Arrays (A) 5 2,234,468 14.18 ***L x A 15 1,774,987 11 .26 ***Error 20 157,621
b=0 b=1b
t(4) P t(4) P
Cambridge . . . . 0.556+0.302 1 .84 N.S . 1 .47 N.S .Headley Hall .
. 0.970±0.187 5 .19 ** 0.16 N.S .Seale Hayne 1.044+0.175 5 .97 ** 0.25 N.S .Sprowston .
. 0.608±0.209 2 .91 * 1 .88 N.S .
Combined analysis
Item
Cambridge . . .Headley Hall . .Seale HayneSprowston .
.
Combined analysis
Item
b
0.700±0 .5210.668±0.2670.666±0 .1760.315±0 .373
Overall regressionHeterogeneity of regressionError
Locations (L)Dominance (D)L x DArrays (A)L x AError
QUALITY IN SPRING WHEATS
N
N
1316
3135
1520
t(4)
1 .342.503.780.84
b=0
MS
MS
P
119,143430
4,139
123,236470,05212,92128,30618,1582,512
Overall b = 0 .655 . Agreement with b = 1 t(16) = 2.83
N.S .N.S .*N.S .
VR
Overall regression b = 0 .823 . Agreement with b = 1, t( 16) = 1.51 P > 0 .05 .
Percentage bran
Percentage bran is similar to area under curve in the complexities of its genetic makeup. Although the individual Wr, Vr graphs show no epistasis, when combined togetherthere is a suggestion that this interaction may be present, but that it does not interactwith environment. Both mean dominance and relative dominance of the parents dointeract with environment .
Individual analyses
VR
t(4)
0 .581 .241 .901 .84
28 .79
49.06187.12
5 .1410 .017 .23
b=1
P = 0.02-0 .01
P
***********
N.S.N.S.N.S.N.S.
P
1 8 9
Overall regression 1 124,213 49.35 ***Heterogeneity of regression 3 3,261 1 .30 N.S .Error 16 2,517
Locations (L) 3 97,806 70.16 ***Dominance (D) 1 272,255 195 .30 ***L x D 3 5,260 3.77 *Arrays (A) 5 21;964 15 .76 ***L x A 15 14,651 10 .51 ***Error 20 1,394
J . B. THOMPSON AND R. N . H. WHITEHOUSE
Nitrogen content of flour
The results of the individual analyses, as shown below, vary greatly from centre tocentre .
1 90
The overall regression analysis below shows this group to be a highly heterogeneousone, and we can infer that for this character there is an interaction of epistasis withenvironment.
The analysis of variance of Wr and Vr given below shows no items of significance
This lack of significant items is presumably a reflection of the presence of epistasisand of epistasy x environment interaction as shown by the regression analyses . Theerror term of the analysis of variance of Wr and Vr is to a large extent made up ofcomponents related to these interactions and when they are present this error termwill be large relative to the other components of the analysis . These other componentswill thus tend to be non significant. In the presence of epistasis and of epistasy xenvironment interactions the analysis being used in this study thus becomes inefficientat picking out the interactions of dominance components with environment .
Water absorptionThe results of the analyses of water absorption presented below show the genetic
control of this character in the present experiment to be without epistasis but with aninteraction with environment of both of the dominance components .
Item N MS VR P
Overall regression 1 4,229 1 .61 N.S .Heterogeneity of regression 3 10,073 3.84 *Error 16 2,625
Item N I
MS VR P
Locations (L) 3 32,652 1 .72 N.S .Dominance (D) 1 44 N.S .L x D 3 54,490 2.87 N.S .Arrays (A) 5 20,306 1 .07 N.S .L x A 15 19,746 1 .04 N.S.Error 20 19,002
b=0 b = Ib
t(4) P t(4) P
Cambridge . . . . 1 .104+0.168 6 .57 ** 0.62 N.S .Headley Hall .
. -0.034+0 .119 0 .29 N.S . 8 .69 ***Seale Hayne 0.579+0 .124 4 .67 * 3 .40 *Sprowston .
. 1.242-0 .219 5 .67 ** 1 .11 N.S .
Individual analyses :
Cambridge . . . .Headley Hall . .Seale HayneSprowston .
.
Combined analysis :
Item
Overall regressionHeterogeneity of regressionError
Locations (L)Dominance (D)L x DArrays (A)L x AError
QUALITY IN SPRING WHEATS
b
1 .072±0 .0590.877±0.1220.801±0.0731.038±0.062
N
i
MS
13
16
3135
1520
t(4)
18.237.19
11 .0316.87
b=0
P
***********
211,4241,017474
324,747857,60538,77025,85021,826
288
VR
t(4)
1 .221 .012 .740.62
446.042 .15
1127 .592977.80134 .6289 .7675.78
b=I
P
N.S .N.S .N.S .N.S .
P
***N.S .
***************
The overall regression coefficient, b = 0 .938, does not differ significantly fromb = 1 (t(16 ) = 1 .40 P > 0 .05) .
DISCUSSION AND CONCLUSIONS
The results of the analyses presented in the previous section are summarised intable 1 .
The items in the analysis of Variance of Wr and Vr which are summarised in table 1and which have not so far been discussed test for the presence of some of the maineffects whose interaction with environment we are interested in . The locations itemtests the hypothesis that there are no differences between the locations for any of thegenetic components, and with the exception of nitrogen percentage (to be discussedlater) this item is always significant . The Dominance item, again significant in all casesexcept nitrogen percentage tests the hypothesis that Wr = Vr which in F1 wouldindicate complete dominance and in F 2 slight overdominance. In the material studied,with the exception mentioned, there was always some dominance but never sufficientto suggest overdominance .
The Arrays item of the analysis tests the hypothesis that there is no significantspread of points along the Wr, Vr line which would imply that the parents were all ofthe same level of dominance. Again in all cases except Nitrogen percentage this itemis significant indicating that the points are spread out along the line, i .e. that someparents are relatively more dominant than others .
The results of the maximum resistance analysis of the four centres taken individuallyare presented in fig . 2 and the first line of table 1 . The four regression lines are not
1 9 1
J . B. THOMPSON AND R. N. H. WHITEHOUSE
TABLE 1 . A SUMMARY OF THE SIGNIFICANCE LEVELS OF THE ANALYSES FROM THE PREVIOUS SECTION
particularly close to the parabola, suggesting a considerable amount of dominance,and except for Headley Hall all agree with slope b = 1 indicating, as pointed outearlier, absence of epistasis . The analysis of the Headley Hall trial suggests thepresence of epistasis . A further study of fig. 2 shows that the two biscuit wheats Pekoand Jufy I are away from the origin on the Cambridge graph suggesting that their lowresistance to stretching is largely controlled by recessive genes . At Headley Hall thesetwo varieties are near the origin suggesting a dominant control of low resistance whilstat Seale Hayne they occupy an intermediate position on the graph. Carpo, a wheat witha bread flour is away from the origin with the biscuit wheats at Cambridge, amongstthe other bread wheats at Headley Hall, nearer the origin than the biscuit wheats atSeale Hayne and furthest from the origin and from the biscuit wheats at Sprowston .This variation of the relative position of the varieties on the regression line is clearlydemonstrated by the high significance of the L x A item of the analysis of variance ofWr and Vr. As well as the interaction of relative dominance with location the signi-ficance of the item L x D shows an interaction of mean dominance with location, thisbeing a reflection of the different relative positions of line and parabola in the fourgraphs in fig . 2 . Although the Headley Hall trial suggested that this location differedfrom the others in showing epistasis the overall regression analysis discounts thissuggestion of epistasy x environment interaction .
192
Regression of Wr on Vr Analysis of Wr and Vr
Op~U
x
d
x
0Oti3
O
boo~
) O.N
° Do
y
xo
Qoy
a
CC
oA
AXa
.,a d
X
a
Max. Resistance
b=0 *** *** ** *** *** N.S . *** *** *** *** ***b=l N.S . ** N.S . N.S . N.S .
Extensibility
b=0b=l
**N.S .
**N.S .
**N.S.
*N.S .
***N.S .
N.S . *** *** *** *** ***
Area under curve
b=0 N.S . * * * *** N.S . * N.S . *** ***b=1 N.S. N.S . N.S . N.S . *
Max. Stress
b=Ob=l
N.S.N.S.
**N.S .
**N.S .
*N.S .
***N.S .
N.S . *** *** *** ***
Bran
b=0 N.S. N.S . * N.S . *** N.S . *** *** ** *** ***b=l N.S . N.S. N.S . N.S . *
Nitrogen
b=O ** N.S . * ** * N.S . N.S . N.S . N.S. N.S .b=1 N.S . *** * N.S .
Water Abs .
b=0b=l
***N.S .
**N.S .
***N.S .
***N.S .
***N.S .
N.S . *** *** *** *** ***
QUALITY IN SPRING WHEATS
To the breeder the results of any one trial might suggest that in selecting for high orlow resistance selection is increasing the number of dominant or recessive alleles in theselected lines, and this information could serve to give a genetic meaning to the selectionprocess . The use of this information in a programme of breeding for an agriculturalarea such as England however is unfortunately very limited, particularly in the lightof the complex environmental interactions found here .
The results for the other characters studied show a similar set of interactions withenvironment .
Of the seven components into which quality has been divided six show an interactionof relative dominance with environment, five an interaction of mean dominance withenvironment and one an interaction of epistasis with environment . In the one casewhere there is epistasy x environment interaction, i.e. nitrogen percentage, the othertwo interactions are not detected by the analysis, but due to the composition of theerror term the analysis is expected in this case to be inefficient at picking up the twodominance x environment components. Similarly, in the one remaining case (areaunder curve) where there is a non significant L x D component, the efficiency of thedetection of this component is weakened by the inclusion in the error of a significantepistatic effect .
The inheritance of these aspects of quality, as shown by BINGHAM (1961a) for winterwheat and by this analysis for spring wheat, is simple within any one environment, thegene systems being in the main additive with some dominance effects but generallywithout the complications of epistatic interactions . There are however pronouncedfluctuations from environment to environment and these fluctuations do not take theadditive form of general overall alterations but are complicated by marked inter-actions of the two dominance components with environment . The third componentstudied, espistasis, does not play such a large part in the genotype x environmentinteractions, but in this respect it must be pointed out that in only three of the sevencharacters was there any evidence of the presence of epistasis for it to be able to interactwith the environment, and in two of these three characters the epistasis was weak, beingundetected by the individual Wr, Vr analyses and only shown up when they werejoined together in the overall analysis .
The overall picture of the inheritance of quality components we obtain from thisanalysis is thus a complex one suggesting that attempts at an objective integration ofthese components should be made with caution . The approach to an integration ofcharacters can fall between two extremes dependent upon the nature and relationshipsof the characters . In some cases the two attributes of a plant must both be over acertain threshold for the varieties to be acceptable, in which case a progressive selectioncan be made on first one and then the other sub character . On the other hand the inter-relationships of the two sub characters might be such that a certain degree of superiorityfor one of them allows room for a slight loss of desirability in the other, and it is in thecases towards this extreme that the subjective nature of the breeders decision is mostmarked. The relationship of milling to the flour characteristics tends to be of thefirst type, as, to be acceptable under current commercial practice a wheat must reachcertain standards of both milling and flour properties . Water absorption and doughphysicochemical properties bear a similar relationship to one another . Largely due tothe fact that protein type can compensate for protein quantity the relationship between
193
1 94
J . B. THOMPSON AND R. N. H. WHITEHOUSE
APPENDIXThe results of the laboratory quality tests . The varieties Apu, Carpo,
Cambridge Headley Hall
A C F J P S A C F J P S
Maximum ResistanceA
64
74 77 50 52 73 46 64 50 39 32 60C
93 92 77 64 99 64 68 44 43 77F 82 74 63 72 62 37 35 61J 59 40 72 31 24 45P 32 60 26 42S 82 65
ExtensibilityA
19.0
18.5 21 .0 21 .5 25 .5 20.0 21 .0 18 .0 21 .5 24 .0 26 .0 21 .0C
16.0 16.5 16.5 17 .5 17 .5 17 .0 17 .5 21 .5 23 .5 18.5F 16.5 18 .5 19 .0 19 .5 16 .5 23 .5 26 .5 19 .0J 20.0 23 .5 18 .5 28 .0 28 .5 22 .0P 28.5 21 .5 28 .5 28 .0S 19 .0 19 .0
Area Under CurveA
1021
1181 1369 870 1066 1251 783 978 911 764 615 1037C
1191 1242 1046 955 1417 919 1016 815 856 1222F 1127 1163 1006 1199 886 722 697 984J 1030 800 1156 637 398 864P 664 1091 486 995S 1306 1062
Maximum StressA
90
113 129 69 82 118 61 91 77 57 42 101C
131 127 111 90 156 89 96 68 70 121F 113 110 88 118 83 55 48 93J 97 68 112 44 22 74P 45 92 27 77S 128 108
Percentage BranA
15.1
17.2 14.7 16.7 17.1 12 .2 17 .6 16 .3 14 .4 18 .6 17 .6 13 .7C
15.5 13 .6 17.5 17.0 15 .7 18 .6 14 .8 20 .0 16 .0 16 .4F 10.2 14.7 14.6 11 .4 12 .4 16 .3 13 .6 12 .5J 19.1 18 .5 15 .5 20.6 20 .0 15 .5P 18 .6 14 .2 19 .2 17 .5S 12 .2 14 .0
Percentage nitrogenA
2.31
2.22 2.34 2.29 2.27 2.45 2.27 2.04 2 .08 2 .08 2.04 2.22C
2.17 2.37 2.20 2.28 2.37 1 .91 2.00 1 .87 1 .99 2.68F 2 .41 2.27 2.26 2.56 2 .18 1 .99 2.00 2.01J 2 .05 2.09 2 .31 1 .71 1 .85 1 .93P 2.30 2.40 1 .94 2.17S 2.67 2.08
Water AbsorptionA
15.1
15.3 15.8 14.6 14.5 15 .5 15 .0 14.7 14 .8 13 .4 13 .4 15 .2C
15.1 15 .4 14.7 14 .6 15 .6 14 .2 15 .2 13 .1 13 .5 14 .2F 16.3 15 .2 15 .1 16 .2 15 .4 13 .9 14 .2 15 .5J 13 .5 13 .5 14 .9 12 .6 12 .3 13 .4P 13 .6 14 .7 12 .3 13 .8S 16 .1 14 .6
Seale Hayne
I
Sprowston
QUALITY IN SPRING WHEATS
Fasan, Jufy I, Peko and Svenno are indicated by their initial letter .
195
A C F J P S
A
C
F J P S
41 80 66 58 51 84
73
76
68 58 50 7788 85 70 68 90
90
90 70 60 9375 70 53 89
83 64 57 8550 38 65 61 39 68
37 60 39 6094 84
25 .0 16 .5 19 .5 20 .0 24 .5 20 .5
18.0
16.0
17.5 20.5 20.5 18 .516 .5 16 .0 16 .0 19 .5 16 .5
16.0
15.5 16.5 17 .0 16 .017 .0 17 .0 20 .0 17 .0
14.0 17 .0 19 .0 16 .022 .0 25 .0 20.5 17.0 24.0 18 .0
28 .5 23 .5 23 .0 18 .518 .5 17 .0
878 1110 1102 1001 1061 1465
1116
1000
992 1036 873 12271161 1112 942 1116 1250
1130
1118 952 857 11841068 993 916 1268
955 916 929 1107962 830 1154 878 823 1035
845 1207 726 9511468 1161
80 119 101 95 88 140
106
105
91 98 74 122128 115 101 109 132
113
116 99 82 132111 103 83 129
95 90 84 12392 76 117 89 68 106
65 109 54 92157 127
19.3 20 .3 15 .5 20 .8 19 .7 13 .3 16.1
17.3
13.8 16.0 18.8 14 .020 .8 16 .2 22 .2 21 .7 18 .3 19 .0
14.7 19.0 18.3 15 .614 .1 19 .6 17 .1 13 .8 11 .8 16.3 14.8 12 .2
22 .4 23 .8 18 .8 20.6 19.6 16 .721 .7 17 .7 19.5 15 .8
15 .5 13 .1
2 .30 2.19 2.18 2.15 2 .25 2 .49 2.32
2.04
2.06 2,06 2.08 2.292.00 2.05 1 .99 2 .02 2 .16 1 .79
2.03 1 .93 1 .83 2 .022 .25 2.02 2 .19 2.29 2.11 2.04 2.00 2 .15
2.03 2 .15 2.14 1 .83 1 .80 2.102 .22 2.25 1 .82 2.02
2.36 2.19
14.2 14.1 15 .1 13 .8 13 .4 14 .9 15 .5
15.0
15.3 14.2 14.0 15.314.2 14.6 13 .5 13 .7 14 .6 14 .4
15.1 14.1 13 .7 14.615 .3 14.1 14 .4 15 .5 15 .6 14.6 14.3 15.6
13 .5 13 .3 14 .1 13 .5 13 .3 14.413 .2 14 .5 12.8 14.1
14 .8 15.3
1 96
J. B. THOMPSON AND R . N . H. WHITEHOUSE
nitrogen percentage and dough physicochemical properties is probably nearer to theother extreme, a really good extensometer curve to some extent allowing for a ratherinappropriate nitrogen percentage .
Although the assessment of these sub characters of quality is an interesting andnecessary basis to quality breeding, a large part of their co-assessment as quality muststill, as far as we can see, be largely subjective and depend on the interpretative powersof the breeder as well as the techniques of the laboratory technician and statisticalanalyst. Further points that are emphasised by these results are the importance ofconsistency of performance and adequacy of testing facilities . If the character is ascomplex in its genotype environment relationships as this analysis suggests, it isclearly important that selections should be tested over an adequate sample of the totalrange of environments they are likely to meet, and further that consistency of per-formance in this range of environments must rank very high in its importance in thebreeders mind .
ACKNOWLEDGEMENTS
The authors would like to thank DR. G. D. H. BELL for his advice and encourage-ment, MR. J. BINGHAM and DR. J . L. JINKS for helpful discussions and MR. G. E .PORTER and MR. L. R. L. HUDSON for their technical assistance .
REFERENCES
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