engleski

Resource allocation in a maize breeding program for native resistance to western corn rootworm

Maize breeding programs for native resistance to western corn rootworm (WCR), Diabrotica virgifera virgifera are resource intensive due to labor-consuming digging up the maize root and large scale field-based germplasm screening. Therefore, it is mandatory that the available resources are spent in an optimum way. At the Agricultural institute Osijek, Croatia, 127 maize genotypes were screened in 2007, 2008, 2009 for root damage caused by WCR larvae, root size and superior secondary root growth after the damage. The experiment was conducted in two replications as an alpha design planted at two locations under continuous maize growing conditions in Eastern Croatia, a major maize production area with natural WCR occurrence. In addition to sources of genetic variability, we used estimates of heritability and information on the relative magnitudes of genetic, genetic x environmental, and error variances to optimize allocation of resources in the field-based WCR native resistance breeding programs. Adjusted means from individual experiments were combined in an across-environments analysis to obtain estimates of the year variance, location variance, genotypic variance, corresponding interaction variances and the residual variance. The residual variance included between-plot error variance, within-plot environmental variance and within-plot genetic variance with n=number of plants (roots) sampled per plot. How these parameters impact heritability for three WCR-related traits and the efficiency of breeding program to improve WCR native resistance will be discussed.

maize ; WCR ; vreeding programs

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