Physical and physiological seed characteristics influencing wheat stand establishment

Graduation date: 1987Rate of emergence is an important character for stand\ud establishment. Ability of wheat seeds to germinate and\ud emerge rapidly under different climatic conditions may be\ud regulated by physical and/or physiological characteristics.\ud Seeds of 26 wheat varieties representing five classes\ud were produced in two different environments (Moro and Corvallis,\ud OR). Seed lots were uniformly sized to remove size\ud as a variable. Sized seed lots were compared for emergence\ud rate index (ERI) at three different locations. The germination\ud rate index (GRI) for each seed lot under 15 different\ud combinations of water potential and temperature was\ud determined in the laboratory.\ud Seed characteristics (SC) data collected for all the\ud seed lots were 1000-seed weight, protein quantity per 1000\ud seeds, base temperature, embryo fresh weight, alpha-amylase\ud activity, glutamine synthetase activity, and embryo and\ud endosperm soluble protein.\ud Base temperature (BT) was variety and seed source\ud dependent. BT requirement was reduced with the advancement\ud of the development stage and moisture stress.\ud Wheat varieties showed differential behavior among and\ud in some cases within the classes for ERI.\ud Significant relationships with the ERI for five wheat\ud classes were 1000-seed weight, protein quantity per 1000\ud seeds, base temperature, embryo weight, glutamine synthetase\ud activity, embryo and endosperm soluble protein.\ud Data showed that the ERI can be estimated by GRI\ud determination. The GRI giving the most accurate estimate of\ud ERI is generally location dependent. An exception was at\ud the Moro location where the GRI was seed source dependent\ud for spring varieties.\ud In winter varieties, the GRI and ERI were significantly\ud related to a common SC, BT, at all locations for the\ud Moro source. For the Hyslop source endosperm soluble\ud protein was significantly related to GRI and ERI only at\ud Pendleton. Embryo fresh weight was the SC most closely\ud related to spring varieties only at the Hyslop location for\ud both seed sources.\ud Yield x ERI relationship is positive for fall planted\ud and negative for spring planted wheat under soil moisture\ud stress.\ud Seed characteritics and source may have important\ud implications seed vigor testing, determining the best seed\ud production area, and breeding for specific environments