We analyzed the variability of a large maize (Zea mays L.) collection of 152 tropical populations for photoperiod sensitivity and grain productivity under long-day conditions to investigate their potential adaptation to temperate conditions. A multilocal experimental design was used: one location with short-day conditions (Guadeloupe), one location with medium-day conditions (late sowing in the south of France) and two locations with long-day conditions (early sowing in both the North and South of France). The photoperiod sensitivity was estimated by the slope of the regression of thermal time from sowing to 50% anthesis on photoperiod. We found highly significant effects of latitude and altitude of the collecting site of the population on photoperiod sensitivity and a significant but small interaction between these two factors. Populations originated from low altitudes and low latitudes are highly sensitive to photoperiod, whereas highland populations never display a high photoperiod sensitivity, whatever the latitude of origin. Grain productivity under long-day conditions was not highly correlated with photoperiod sensitivity. Andean populations were little sensitive to photoperiod and exhibited poor grain production under long-day conditions. In contrast, some populations from the Caribbean such as populations from Cuban Flint and Early Caribbean races exhibited a good grain production although sensitive to photoperiod. The good adaptation of some Caribbean material to temperate conditions is consistent with the hypothesis of the successful introduction of Caribbean germplasm in southern regions of the Old World.
Gouesnard, B; Rebourg, C; Welcker, C; Charcosset, A
Analysis of photoperiod sensitivity within a collection of tropical maize populations
Genetic Resources And Crop Evolution