Changes of Dry Matter, Biomass and Relative Growth Rate with Different Phenological Stages of Corn

Crop growth period and the length of the phenological stages on plant are directly affected by climate condition. Therefore, seasonal climate fluctuations such as maximum and minimum daily temperature changing and precipitation rates are important for quantity of annual corn production in Mediterranean area. This study was carried out to determination of dry matter, biomass, relative growth rate (RGR) values in eleven phenological stages [4 leaf (V4), 8 leaf (V8), 12 leaf (V12), 16 leaf (V16), tasseling (VT), silking (R1), blister (R2), milk (R3), dough (R4), dent (R5) and maturity (R6)] of corn during the period 2005, 2006 and 2007 in Aydın location, which is characteristically Mediterranean weather condition in Turkey. Additionally, calculated growing degree days (GDD), per ear weight, plant and ear height (cm), blank tip of ear (shriveled remnants of kernels because of ineffective pollination) (cm) were measured throughout the phenological stages. The data of the study is average of 31G98 and 32K61 corn hybrids value. It is seeming that a significantly differences amongst the years which the field study establishment. All properties except to per ear weight were significantly affected to years. Maximum dry matter and biomass values on the phenological stages were measured in 2005. Maximum per ear weight, plant and ear height values were also obtained from the first year of the experiment. However maximum blank tip of ear value was obtained from 2007. It is suggested that three parameters should be used for yield estimating and determination of biomass and dry matter values among phenological stages of corn. These parameters are: (i) calculating GDD values, (ii) rainfall amounts and air humidity of the years and (iii) determining the number of days when daily temperature rises above 37.5^oC during growth in stages of corn.