Abstract

The wheat Triticum aestivum L. is one of the most important foods in the human diet due to its high nutritional value. The grains can be eaten as bread, noodles, pasta, cookies, among others. The cultivation of wheat in Brazil has high production potential; the southern is region responsible for the largest acreage in the country, due to its soil and climate more favorable for crop development. The objective of this study was to determine the growing degree-days sum and the relationship between the period length from sowing to physiological maturity and sowing dates of thirteen wheat cultivars. The data on wheat crop correspond to the harvests of 2007 to 2011. The treatments consisted of 13 wheat cultivars and 3 sowing dates. The data used for the analysis were: Total elapsed days from sowing to silking, to physiological maturity, and of the silking to physiological maturity, along with the growing degree-days sum for these periods, beyond grains yield and hectoliter weight. The results indicate that the average length of sowing to the silking was 71 days. For the period from silking to physiological maturity the average length was 54 days. The increase in length of time from sowing to the silking in cultivars sown in May 25^th was due to the decrease in air temperature. The average of growing degree-days sum between the period from sowing to physiological maturity was 1487. The cultivars that stood out presenting a shorter period of silking to physiological maturity and high productivity were the cultivars CD 114, CD 120, CD 121, CD 122, CD 124 and Onix.

Key words: Triticum aestivum L., thermal summation, vegetative development.