INHERITANCE OF PROTEIN CONTENT IN PEA II. HERITABILITY OF PROTEIN CONTENT IN RANGER X STRAL AND PALOMA X STRAL CROSSES

68 RESEARCH REPORTS

ONL Volume 12 1980

INHERITANCE OF PROTEIN CONTENT IN PEA

II. HERITABILITY OF PROTEIN CONTENT IN RANGER X STRAL AND PALOMA X STRAL CROSSES

Swiecicki, W.K., Z. Kaczmarek, Plant Experiment Station, Wiatrowo, Poland

and M. Surma Institute of Plant Genetics, Poznan, Poland

On the basis of breeding data obtained in the past, three varieties were

chosen for studies, viz. 'Ranger¹, 'Stral' and 'Paloma'. The breeding data

showed some strains with a higher protein content (WTD 4011 and WTD 4015),

originating from crosses where one of the parents was the variety Ranger or

Stral. Paloma lias a low protein content, but is among the highest yielding

varieties in Poland. Crosses were made between varieties Ranger x StrSl and

Paloma x Stral. The F1, F2, BC1, BC2, and parents were tested in each cross.

Protein content was analyzed in single seeds by the Kjehldal method.

To assess the degree of genetic control over the protein content in the

seeds, heritability coefficients were estimated in a narrow and a broad sense.

The heritability coefficient estimate in the broad sense was calculated by

a commonly used formula, i.e. by estimating the variance of the F2 and that

of the parents. The value of this coefficient for the cross Ranger x Stral

was 79.8% and that for Paloma x Stral 78.0%.

From the point of view of breeding it is far more interesting to know

the heritability coefficient estimate in the narrow sense, expressed by the

additive to phenotypic variance ratio (Mather and Jinks, 1971). It is possible

to estimate this coefficient when gene action in a given cross is additive-

dominance (Kaczmarek, Surma, and Swiecicki, in press). The adequacy of the

additive-dominance model of gene action was tested using the significance

of differences between the observed and expected means for the analyzed genera-

tions (Chi square statistics). The results are presented in Table 1.

PNL Volume 12 1980

RESEARCH REPORTS 69

Since in both crosses the calculated Chi square values were lower than

the critical values of Chi squareg 05 there is no foundation to reject the

hypothesis of the additive-dominance model of gene action.

Table 2 presents estimates of additive ([d]) and dominant ([fi]) gene

action and of the mean (m), including standard errors as well as the herit-

ability coefficients in the narrow sense (A_ns). The effects of additive

gene action are similar in the two crosses. Marker differences, however, are

noted for the effects of dominance.

Though dominance was well indicated in the lower protein content in both

crosses, the cross Ranger x Stral, i.e. between high and medium protein

varieties, showed a much greater effect of dominance than the cross Paloma

x Stral. This is reflected in the narrow sense heritability coefficients.

The results suggest that in breeding for high protein content the desired

results may be better and easier to obtain when varieties with medium protein

content are crossed.



	68 RESEARCH REPORTS	ONL Volume 12 1980

	INHERITANCE OF PROTEIN CONTENT IN PEA II. HERITABILITY OF PROTEIN CONTENT IN RANGER X STRAL AND PALOMA X STRAL CROSSES Swiecicki, W.K., Z. Kaczmarek, Plant Experiment Station, Wiatrowo, Poland and M. Surma Institute of Plant Genetics, Poznan, Poland On the basis of breeding data obtained in the past, three varieties were chosen for studies, viz. 'Ranger¹, 'Stral' and 'Paloma'. The breeding data showed some strains with a higher protein content (WTD 4011 and WTD 4015), originating from crosses where one of the parents was the variety Ranger or Stral. Paloma lias a low protein content, but is among the highest yielding varieties in Poland. Crosses were made between varieties Ranger x StrSl and Paloma x Stral. The F1, F2, BC1, BC2, and parents were tested in each cross. Protein content was analyzed in single seeds by the Kjehldal method. To assess the degree of genetic control over the protein content in the seeds, heritability coefficients were estimated in a narrow and a broad sense. The heritability coefficient estimate in the broad sense was calculated by a commonly used formula, i.e. by estimating the variance of the F2 and that of the parents. The value of this coefficient for the cross Ranger x Stral was 79.8% and that for Paloma x Stral 78.0%. From the point of view of breeding it is far more interesting to know the heritability coefficient estimate in the narrow sense, expressed by the additive to phenotypic variance ratio (Mather and Jinks, 1971). It is possible to estimate this coefficient when gene action in a given cross is additive- dominance (Kaczmarek, Surma, and Swiecicki, in press). The adequacy of the additive-dominance model of gene action was tested using the significance of differences between the observed and expected means for the analyzed genera- tions (Chi square statistics). The results are presented in Table 1.