Genetic analysis of photoperiod sensitivity in a tropical by temperate maize recombinant inbred population using molecular markers.

Photoperiod sensitivity is an important consideration in maize cultivation. Flowering time is affected by photoperiod and sensitivity to it limits the potential for successful exchange of germplasm across different latitudes. For resolving the genetic basis of photoperiod sensitivity in maize, a set of 207 recombinant inbred lines derived from a temperate and tropical inbred line cross was evaluated for 2 years in a long-day and short-day environment. Genetic linkage maps were constructed using 237 SSR markers with a total length 1,974.3 cM, and an average space between two makers of 8.33 cM. Twenty-nine QTL were detected for the five measured photoperiod sensitivity traits using composite interval mapping and multiple interval mapping. QTL for flowering time, plant height and leaf number, under long-day conditions, were found clustered on chromosome 10, while QTL for short-day conditions resided on chromosome 3. The QTL in the bin 10.04 region of chromosome 10 were detected associated with photoperiod sensitivity and related traits during long days. These results indicated that this region might contain an important photoperiod sensitivity element.