The effects of harvesting time on the yield and yield component of sorghum x sudangrass hybrid (Sorghum bicolor x Sorghum sudanense Stapf) and sudangrass [Sorghum sudanense (Piper) Stapf] cultivars grown as double crop under irrigated conditions of Diyarbakir

This research was conducted to determine the appropriate harvesting time of some cultivars of sorghum x sudangrass hybrid and sudangrass grown as the second crop in Diyarbakır irrigated conditions on the vegetation period of 2015. In this study, it was investigated the effects of yield and yield components of three different harvesting time (completely blooming, milk and dough stages) of some cultivars of Sugar Graz II and Nutri-Honey sorghum x sudangrass hybrid and sudangrass Gözde-80. The field experiment was arranged in respect to the randomized complete block experimental design as split plot with four replications. It was arranged cultivars in main blocks and harvesting times in sub-blocks. In this research, plant height, main stem diameter, number of tillers per plant, number of leaf per plant, leaf ratio per plant, stem ratio per plant, green forage yield, hay yield, crude protein rate, crude protein yield, acid detergent fibre (ADF) ratio and neutral detergent fibre (NDF) ratio characters were investigated. At the result of this study, it was identified statistically differences at the level p≤0.05 and/or p≤0.01 in terms of cultivars of plant height, hay yield, crude protein rate, crude protein yield, ADF and NDF. The effect of harvesting time on all other properties that investigated was statistically significant at p≤0.01 level except the properties of main stem diameter, number of tillers per plant and number of leaf per plant. According to this, it were determined depending on harvested at advanced plant maturity that plant height, main stem diameter, number of tillers per plant, leaf ratio per plant, green forage yield, hay yield and crude protein yield were tended to increased; however, the ratios of number of leaf per plant, leaf ratio per plant, crude protein rate, ADF and NDF were tended to decreased. In the study, Gözde-80 sudangrass came to the fore in the direction of many properties that investigated; the highest average green forage yield (7066.4 kg/da), hay yield (1931.3 kg/da) and crude protein yield (244.17 kg/da) of cultivars were obtained during the period at dough stages.