Registration of Five Short-Season Stiff Stalk (SS) EarlyGEM Maize Germplasms

In 2000, the North Dakota (ND) maize (Zea mays L.) breeding project initiated the long-term EarlyGEM program to increase the genetic diversity of northern US maize hybrids. The goal was to expand Germplasm Enhancement Maize (GEM) efforts. NDEarlyGEM3 (Reg. No. GP-594, PI 675374), NDEarlyGEM10 (Reg. No. GP-595, PI 675377), NDEarlyGEM21a (Reg. No. GP-596, PI 675378), NDEarlyGEM21b (Reg. No. GP-597, PI 675379), and NDEarlyGEM21c (Reg. No. GP-598, PI 675380) are new maize populations carrying diverse genetics for short-season environments. These populations belong to the Stiff Stalk (SS) heterotic group as per their original GEM pedigree validated by combining ability data. A modified pedigree selection program including elite GEM and ND lines was utilized to move GEM germplasm northward and westward. Early-and late-generation hybrid trials, including EarlyGEM BC1-derived lines were conducted from 2006 to 2010. The bulk-entry method allowed top progenies not only to be recombined to create new populations but also to initiate the development of new elite lines and hybrids. New EarlyGEM populations provide a unique option to expand the gene pool of breeding programs. Four new EarlyGEM lines (ND2014, ND2015, ND2016, and ND2035) derived from released NDEarlyGEM SS populations have recently been released to industry exclusively after being tested across 51 to 64 northern US environments. In this paper, however, only EarlyGEM populations are registered due to the fact that elite EarlyGEM inbred lines have intellectual property exclusive restrictions set up by the North Dakota State University Research Foundation. Adaptation and improvement programs carrying unique and diverse germplasm will be essential in the development of new cultivars tolerant to climate changes.