Classic Genetics and Breeding - Genetics, Genomics and Breeding of Crop Plants - page 63

determine the genetic gain in breeding sunflowers over 30 years. Results
from 27 locations over two years showed that the five most widely grown
varieties in 2000 (all single cross CMS hybrids) had a mean of 140% of the
yield of the five varieties grown from 1965-1975, which included one open-
pollinated variety (Peredovik), three genic hybrids and one cytoplasmic
hybrid (Vear et al. 2003; Fig. 2-5 ) . This represents 1.3% gain in seed yield per
year, similar to many results for maize, the other main hybrid crop. Yield
improvement was at first due to an increase in seed number /m 2 but, since
1990, to an increase in seed size ( Table 2-1 ).

Table 2-1 Mean characteristics of four groups of the five varieties most widely cultivated
in France from 1970 to 2000, in 2000-2001 trials as % of the first group mean (from Vear
et al. 2003).

1970 1980 1990 2000

Grain yield 1 0 0 112.7 120.3 139.9

Oil yield 1 0 0 119.6 128.4 147.6

Oil content 1 0 0 106.0 106.6 105.8

1,000-seed wt 100 81.2 93.9 106.6

Seed number/m² 100 129.2 128.2 131.0

% moisture 100 94.7 98.8 99.6

Height 1 0 0 98.7 98.8 100.4

% lodging 1 0 0 57.9 35.0 24.7

% Phomopsis 100 95.4 76.0 63.7

% Sclerotinia head rot 1 0 0 94.7 59.3 36.3

Figure 2-5 Yield of the most widely cultivated sunflower varieties in France from 1970 to
2000, measured in 2000-2001 trials, as a percentage of mean of the 1970 varieties (from
Vear et al. 2003).