Combining ability for rind puncture resistance in maize

Stalk lodging of maize (Zea mays L.) mag cause annual yield losses of more than 5%, Stalk strength can be improved by selecting for rind puncture resistance; however, additional information on the genetic nature of rind puncture resistance is needed. A seven-parent (B73, H111. L266, L329, L605, L668, and L729) diallel was evaluated in 1994 and 1995 with the following objectives: (i) to estimate general (GCA) and specific combining ability (SCA) and reciprocal effects for rind puncture resistance and (ii) to ascertain whether ear-internode data could be used in lieu of Internode 3 data. General combining ability variance was only significant at the ear internode, whereas SCA variance was not significant at either internode. Reciprocal effects were unimportant at either internode. For the ear internode, progeny performance can be adequately predicted from GCA estimates. Inbred lines L329 and L729 exhibited significant positive GCA effects at the ear internode, whereas B73 and L668 showed significant negative GCA effects at this internode, Inbred lines L329 and L729 could be used for developing hybrids or germplasm with stronger stalks. Year x genotype interactions were detected for both internodes, indicating that genotypes should be evaluated in more than one environment. Ear-internode data provided experimental precision similar to that for Internode 3, but genetic differences among crosses were detected only in the ear-internode data. The ear internode provided more convenient and useful information on rind puncture resistance. Rind puncture resistance of the ear internode would be a relatively easy trait to improve by practicing recurrent selection in a population developed from the germplasm evaluated in this study.