Breeding of a protein pea ideotype for Finnish conditions

The characteristics of protein pea (Pisum sativum L.) adapted to cultivation in Finnish conditions were specified. Ideotypes for pure and mixed stands were defined separately. Factors affecting seed yield, protein yield and protein content were determined. Efficiency of biological nitrogen fixation in the varieties was evaluated at two nitrogen application levels, 16 and 80 kg/ha. Selection methods for increasing protein content were discussed. The commercial varieties bred during the programme were presented. The effect of the gene af on different characteristics of the pea was the central object of the studies. The ideotype of peas for cultivation in Finland has to be of the afila-type. This concerns cultivation in both pure and mixed stands. Afila-peas gave seed yields and protein yields as high as the leafed ones. The lodging of afila-peas throughout the generative growth phase was less than that of the conventional leaf types. In mixed cropping the most suitable afila-peas generally formed almost completely unlodged stands together with cereals. The best seed yields were given by the varieties with a stem height of 61 to 94 cm. Due to competition, the corresponding height in mixed stands ranged from 80 to 100 cm. For the same reason, varieties to be used in mixed stands must possess a fairly large seed size and fast growth rate after emergence. The optimum flowering period lasted from 19 to 28 days. The varieties must be early, with a growing time from 91 to 101 days. Late varieties are not adapted to northern conditions, giving low yields and poor quality. The mean yield of the varieties was 4500 kg/ha in pure stands. The high nitrogen application level of 80 kg/ha did not increase pea yield in comparison with the 16 kg/ha level. In contrast, it enhanced the protein content by 1 % and the protein yield slightly. In mixed stands the mean total yield was 4700kg/ha. The hectare yields of crude protein reached levels of 990 and 900 kg respectively. Early varieties tend to have a low protein content. The protein content ranged from 15.4 to 27.6 per cent in the unselected line material. A negative, although weak correlation was found between seed yield and protein content. A variety with the highest protein yield must exceed the average level both in seed yield and protein content. The varieties with the highest protein yields had a content of 23—27 per cent.