Growing Degree Day and Seed Yield Relationships in Mustard (Brassica juncea L.) Under Different Sowing Seasons and Locations of Turkey

摘要

Mustard is grown in mild winter regions as late fall and in hard winter regions as late spring crop. Mustard has highdegree of adaptability under wide range of climatic conditions in Turkey. Temperature is an important weather parameteraffecting the growth and development of the mustard. The sum growing degree day (GDD) for a growing season isrelated to plant development which is depends on the accumulation of heat. The aim of this study was to determine theadaptation of mustard, under sowing seasons (spring and fall sowing) and locations in terms of crop growth (emergence,50% flowering, physiological maturity, and sum growing degree days) and seed yield of mustard. Two-year fieldexperiments in a split-plot design with four replications were carried out during 2013-14 and 2014-15 growing seasonsat eight different ecological locations. These locations included Ankara, Ayd?n, Erzurum, Eski?ehir, Isparta, Tekirda?,Tokat and ?anl?urfa provinces of Turkey-as classified by K?ppen-Geiger ecological conditions. The Brassica junceaL. (mustard seeds) were collected from wild conditions in the Konya province of Turkey. The results showed that,sowing seasons and locations significantly affected seed yield and GDD. The maximum seed yield of 3754.9 kg ha-1was obtained from Tokat (warm humid) during fall sowing with total accumulated GDD of 1512.1 °C for mustard. Sumgrowing degree-days accumulated in different sowing seasons and locations occurred between 1132.0 °C and 2285.1 °Cdepending on the related ecological conditions. Fall season crop in Ayd?n location had the maximum growing degreedays. Overall, fall season accumulated more growing degree days due to longer period of sunshine in comparison tospring season with less sunshine days resulting in longer vegetation period.