Water-yield relationships of sorghum-sudangrass hybrid (Sorghum bicolor-Sorghum sudanense) Tekirdag conditions

This research, was carried out in order to determine the water-yield relationships of Sorghum-Sudan grass hybrid (Sorghum Bicolor-Sorghum Sudanence), was carried out in Thrace Region of Turkey (40°59' K - 27°34' D; 20 m) in 2018-2019. In the study, which was planned with three replications according to the trial pattern of random parcels using Sorghum Sudan grass hybrid seed, eight different irrigation treatments were sawed following the form when the plant height reached an average of 95-105 cm. These have been irrigated and rain-fed following some saw and irrigated and rain-fed after all saws. According to the results of the research, the highest yield of green weed, 5.03 and 5.02 t da-1 were obtained from the treatments irrigated (III) following all the saws and irrigated (II0) following the first two saws, respectively. Although the irrigation has an important effect on the increase in yield after the first saw, it has been observed that irrigation will be sufficient following the first two saws, the irrigation is not effective in the yield increase after the second or third saw, and there is no need for irrigation after the third saw. If a single irrigation is required, this should be done following the first saw. The relationship between seasonal evapotranspiration and green weed yield was statistically significant (p < 0.01) and it can be defined by equation of Y= 5,06 ET + 2043,3 (r = 0,82**). Again, for the total growing season, the water yield responce factor (ky) between evapotranspiration and green weed yield was calculated as 0.66. Keywords: Sorghum-Sudan grass hybrid, evapotranspiration, irrigation, water use function, yield response factor, Thrace Region