Correlation coefficients in grain yields in wheat variety tests between locations in Rio Grande do Sul, Brazil for the 3 years, 1966-1968

• Autor(a) principal: Moreira, João Carlos Soares
• Data de Publicação: 2014
• Outros Autores: Medeiros, Milton Costa, Schlehuber, A. M.
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/17616

Data from grain yields grown in the experimental network of wheat variety trials in Rio Grande do Sul, Brazil in 1966, 1967, and 1968, were used to calculate correlation coefficients between the yields of varieties from the different testing sites: Thirty varieties were seeded at each of 7 locations in 1966, 20 varieties at each of 8 locations in 1967 and 25 varieties at each of 8 locations in 1968. Detailed information concerning varieties, testing procedures and general observations for the year 1966 and general observations for the year 1966 and 1967 are presented in the earlier work (Schlehuber et al. 1970) and will not be repeated here. The average grain yield (kg/ha) of each variety at each location was correlated with the average grain yield of the same variety at all other locations. Only the data from the early date of seeding (usually in June) were used, inasmuch in the majority of cases they were superior. Grain yields averaged considerably higher in 1966 and 1968 than in 1987. The highest average yield was produced at Herval in 1968 (2611 kg/ha). The highest positive correlation (0.731) was between São Luiz Gonzaga and Cruz Alta in 1967. Only two highly significant negative correlations were obtained - 0.724 between Piratini and Sananduva in 1967 and - 0.546 between S.L. Gonzaga and Erexim in 1968. São Luiz Gonzaga showed the highest number of significant correlations. At Cruz Alta the varieties generally performed differently than at the other locations. The most consistent relationship was between Pelotas and Piratini. Of the possible 70 correlation coefficients, only 24 were statistically significant and of these only three were negative. Notwithstanding the low number of significant correlations between locations, certain varieties (illustrated by graphical examples in the earlier work of 1966 and 1967 results), performed in a superior manner at many locations regardless of the value of the correlation coefficients between the locations. These 3-year observations are in agreement with those from International Wheat Trials reported by the CIMMYT from Mexico (Krull et al. 1966, 1987).