PONDERATION WEIGHT OF PHYSIOLOGICAL QUALITY VARIABLES TO MEASURE VIGOR IN CORN SEED

Abstract

To discriminate among physiological quality variables used in corn (Zea mays L.) seed to measure vigor, in 1997-1998, at Montecillo, México, different materials were evaluated using the standard germination test in laboratory and in microtunnel, using river sand, and porous building stone as substratum with seeding depths of 5 and 10 centimeters; it was determined the relationship among the quality variables measured in both conditions and seed vigor, in function of field seedling establishment. There was a relationship in the vigor expression of corn materials evaluated in laboratory and microtunnel with that showed in the field under favorable and intermediate conditions, when materials were of good or poor quality; however, under unfavorable condition, all treatments showed similar vigor level. In laboratory, multivariate analysis gave the main ponderation weight to aerial dry weight; 49 and 75 % of the variation of stablishment in favorable and intermediate soil conditions was explained for this variable, which was the only significant one to predict field corn establishment. In microtunnel, sand bed and 5 cm seeding depth was the most efficient combination allowing the strongest association of aerial and root dry weight with field establishment aerial dry weight explained 49
and 65 % of the variation in the establishment in favorable and intermediate soil conditions, while root dry weight explained 81 and 77 %. Under microtunnel condition, depending on the substratum and seeding depth, the most important variables to predict field establishment were aerial dry weight, root dry weight and emergence velocity.