Registration of 38 Maize (Zea mays L.) Breeding Populations Adapted to Short‐Season Environments

For 21 of the remaining 31 populations, various recurrent selection procedures were employed including selfed progeny (S), half-sib (HS), reciprocal recurrent selection (RRS), or combined S and RRS (COM) (Table 1). Depending on the response of the germplasm to the environmental conditions during a particular growing season, the number of Unes tested per cycle varied from 37 to 100 and the number of selected genotypes to recombine to form the next cycle varied from eight to 30. The remaining 10 of the 38 populations were identified as unadapted germplasm with potential for short-season breeding purposes, and depending on relative maturity, were either subjected directly to mass selection (M) for earliness (PI613093PI613096), or in the case of the least adapted populations, crossed to a very early maturing source [CG-SynA-NL (described below)] and then mass selected for earliness (PI613087PI613092) (Table 1).