Leaf Shape and Pigments for Heat Resistance in a Pea Association Mapping Panel.

Canada is the leading global producer of grain pea, where this dryland crop is mostly grown on the semi-arid western prairies.  Heat stress in pea (Pisum sativum L.) occurs in the field when crops are exposed to daytime air temperatures exceeding 28°C.  To seek leaf traits that can improve heat resistance via canopy cooling in future cultivars, we measured a 94-member pea association mapping panel (PAM) consisting of cultivars selected for north America, western and eastern Europe, and Australia.  Cultivars contained a range of leaf type (normal, tare leaf, semi-leafless), canopy color (bright green, blue-green, red-green, dark green), flower color (red, pink, cream, white), canopy habit (prostrate, vining, upright), determinacy (total and reproductive node number) and lifecycle length.  In 2012 we measured the PAM in Arizona under high temperature, and in 2012 and 2013 in Saskatchewan under normal temperatures with typical short spells of heat stress.  Preliminary results of leaf shape and size, leaf type, stem diameter and canopy habit, and leaf pigments (chlorophyll, carotenoid, anthocyanin) will be presented, as well as their associations with canopy temperature and yield.