RELATIONSHIP BETWEEN SEED VIGOR TESTS AND FIELD PERFORMANCE IN WINTER AND SPRING WHEAT (TRITICUM AESTIVUM L.)

Field emergence and plant density may greatly influence grain yield in wheat (Triticum aestivum L.). Seed vigor tests have been developed to assess seed quality in crops. However, the relationship of these vigor tests with field performance in wheat has not been studied extensively. The objectives of these studies were to evaluate several seed vigor tests and to determine their relationship with field performance of wheat. Standard germination, speed of germination, cold test, accelerated aging, respiration rate, and electrical conductivity tests were used to evaluate 10 winter wheat seed lots. Field performance of these lots was evaluated by determining emergence rate index, stand establishment, and grain yield. Emergence rate index was related to accelerated aging, electrical conductivity, and respiration rate values of the seed lots (R = 0.83*). Stand establishment was related to accelerated aging, electrical conductivity, and respiration rate (R = 0.90*); and grain yield was related to the accelerated aging test (R = 0.73*).;In the second year, the sensitivity of certain vigor tests on several seed lots of Newana spring wheat was evaluated. Emergence rate index was related to standard germination and accelerated aging (R = 0.81**); stand establishment to speed of germination index (R = 0.79**); and grain yield to standard germination, glutamic acid decarboxylase activity, and respiration rate (R = 0.86**). Another study was conducted to evaluate the performance of several vigor tests on artificially aged seed lots, when seed quality was variable. Emergence rate index of these seed lots was related to accelerated aging (R = 0.98**); stand establishment to cold test (R = 0.93**); and grain yield to respiration rate and standard germination (R = 0.93**).;In general, field performance in winter wheat was related to accelerated aging, respiration rate and electrical conductivity and in spring wheat to respiration rate, cold test, standard germination, and accelerated aging tests.;Two spring wheat cultivars, 'Lew' and 'Newana', were evaluated using the same laboratory tests as used for winter wheat. In the cultivar Lew, emergence rate index was related to respiration rate (R = 0.72*) and grain yield to respiration rate (R = 0.66**). In Newana, emergence rate index was related to cold test and acclerated aging (R = 0.90**); stand establishment to cold test and respiration rate (R = 0.89**); and grain yield to respiration rate and standard germination (R = 0.84*).