12 PNL Volume 19 1987 RESEARCH REPORTS
BREEDING EARLY-MATURING PROTEIN PEAS
Hovinen, S. Hankkija Plant Breeding Institute
SF-04300 Hyryla, Finland
Finland is perhaps the northernmost country where field peas
are cultivated. Our climatic conditions are characterized by
short summers with long days. Daily temperatures drop rapidly in
August-September, accompanied by increasing precipitation.
New well-adapted pea lines, however, grow well under these
conditions. Seed yields can reach 7,000 kg/ha on a plot basis
(Table 1). The mean yield is also high, about 4,500 kg/ha in
trials and 3,000 kg/ha on a farm scale. Depending mainly on seed
yield, protein yields can also rise to a high level. Considerable
year-to-year variability occurs in both characters. The earliest
commercial varieties reach maturity in 93-95 days on average. All
present varieties are low- or semi-high-stemmed (50-80 cm).
The breeding of afila peas was started at the Hankkija Plant
Breeding Institute in 1970. The gene was used to improve lodging
resistance. At first, Usatyj-5 was used as a source of af. Later
many John Innes varieties were included in crosses to transfer af
and st genes into the material. At present, breeding is aimed at
combining afila with early maturity, semi-high stem, small seed
size, and as high a protein content and protein yield as possible.
Under Finnish conditions the crude protein content tends to
remain low. This is a special problem in early afila lines.
Protein content is negatively correlated with seed yield (Table 2)
but protein yield is partly determined by protein content. To
obtain higher protein yields, it is profitable to select in favor
of higher protein content. Comparing normal Leaf type With afila
alone and with afaf_ stst, decreased leaf area was associated with
lower protein content. A highly positive correlation was found
between protein content and flowering period, growing time, and
stem height. However, late and tall varieties are totally unadap-
ted to our climate. They are usually badly lodged when mature,
accounting for the positive correlation between lodging and pro-
tein content.
Protein content is a clear character of variety. Differences
in protein content among varieties persist to some degree from
environment to environment, for example, from one year to another
(Table 3). There are no exceptions to this when observing pure-
lines at different breeding stages. These results are based on
crop, not on single plants. Despite large year-to-year differen-
ces in protein level, the effect of a variety can be easily dis-
tinguished, making selection possible.
Significant differences were observed in protein content be-
tween crosses. To illustrate, some of the best and some of the
most inferior cross combinations are presented in Table A. From
certain crosses it is easy to select lines with a high protein
content, whereas it is virtually hopeless in other crosses. Cer-
tain varieties also tend to give high- or low-protein progeny.
The range of the protein content for single lines (Table 4) was
high, in part reflecting environmental variation.
New afila pea varieties have been released from the program.
PNL Volume 19 1987 RESEARCH REPORTS
13
'Hankkijan Tammi' (Simo/Usatyj-5, 1984) is a relatively late small
blue variety for both protein production and human consumption.
'Pika' (Procco/Hankkijan Tammi, 1986) is an early small blue
variety for the same purposes. 'Helka' and 'Panu' are small blue
protein'peas, released in 1986. Helka (Proco/Hja 51221) is medium
early; Panu (Proco/Hankkijan Tammi) very early.
Table 1. Statistical data of varietal phenotypic characters.
Main trials 1979-85; 388 observations from 8 m2
plots with 2 replications.
Character
Mean
SD
Range
Seed yield (kg/ha)
4506
977
2110-7450
Protein yield (kg/ha)
989
241
410-1841
Flowering period (days)
22.6
9.7
5.0- 51.0
Growing time (days)
100.7
7.1
85.0-122.0
Stem height (cm)
78.6
23.6
31.0-167.0
Lodging (%)
45.8
25.5
0.0-100.0
Crude protein (%)
22.1
3.1
16.0- 29.3
Table 2. Phenotypic correlations between crude protein content
and other varietal characters. Main trials 1979-1985;
388 observations.
Character r
Seed yield -0.19**
Protein yield 0.41***
Leal type -0.39***
Flowering period 0.28**
Growing time 0.28**
Stem height 0.34***
Lodging 0.47***
14 PNL Volume 19 1987 RESEARCH REPORTS
Table 3. Correlations between crude protein content of varieties
in successive years (Anttila exp. farm).
Trial and year
N
r
Main trial 1982 v. main trial 1983
21
0.80***
Main trial 1983 v. main trial 1984
13
0.68*
Main trial 1984 v. main trial 1985
31
0.51**
Main trial 1985 v. main trial 1986
28
0.67***
Preliminary trial 1983 v. prel. trial 1984
56
0.60***
Preliminary trial 1984 v. prel. trial 1985
51
0.65***
Line rows 1984 v. single plots 1985
211
0.41***
Table 4. Crude protein content of different crosses from line
rows in 1984.
Cross
n
Protein
x %
s
t
Frimas x Hankki jan Tammi
11
24.35
1.33
5.83***
L 1837 x Hja 51237
5
23.74
1.03
3.74*
Filby x Vreta
10
23.54
0.89
Filby x Sv IJ 09901
20
22.96
1.23
3.45**
J.I. 758 x Hankkijan Tammi
24
22.92
0.74
5.97***
Omskij x Sv U 09901
15
22.90
1.15
2.96*
J.I. 502 x Hankkijan Tammi
24
22.73
0.99
3.53**
Mean for all 1ines
533
21.96
1.33
Barton x Hankki jan Heikka
11
19.62
0.89
8.91***
Range, single lines
18.0-27.6
*****