Vol: 34A Page: 97

Authors:
João Tiago Mexia
Iola Pinto

Title:
 Cultivars and environmental indexes in wheat breeding program in Portugal (1986-2000)

Language: English

Keywords:
joint regression analysis
L2 indexes
multicolinerarity
principal components

Summary:
The environmental index is a synthetic variable that measures the productivity per block in field experiments for cultivars comparison. A linear regression model, having an explicative dummy variables associated with years, locations and cultivars, was adjusted to the estimated environmental indexes. The coefficients for cultivars were corrected taking into account the years and locations in which they were used. The main result obtained was that the set of selected cultivars at the end of the program had significantly higher (p<0.1%) corrected coefficients.