Field experiment was carried out at Tractors and Farm Machinery Testing &Research Station, Alex. Governorate, Egypt, during the summer season of 2017, to study the impact of planting time, plant density and irrigation intervals on the hibiscus yield in terms of plant height, number of branches, number of flowers, flowers weight, seeds weight and flower hay weight. A split-plot experiment was carried out in the field based on a randomized complete block design with three replications. This work was accomplished by designing 54 experimental units. The main plot was planting time (1 June T1 and 2 July T2) and the sub-plot was three irrigation intervals [ (I1) every week, (4000 m3/fed)according to the Desert Research Center (2010), (I2) every two weeks, (2000 m3/fed) and (I3) every three weeks (1000 m3/fed )] and three plant densities,[D1, 20 cm (16000 plants/fed), D2, 40 cm (10000 plants/fed) and D3 , 60 cm (6670 plants/fed)).
The results showed that the delay in sowing from June 1 to July 2 decreased fruit number and number of branches per plant significantly, the highest values were 74.2 and 13.2 for the treatment T1D2I3, respectively and the lowest values were 34.6 and 4.1 for the treatment T2D1I1 respectively. Also, all the values of the crop characteristics such as the flowers weight and the seeds weight were decreased when the planting time was delayed where the highest values were 337.8 and 850 kg/fed resulted from the treatment T1D2I3, respectively while the lowest values were 254 and 647.5kg/fed resulted from the treatments T2D1I1, respectively. The plant height was significantly affected by the planting time. The earlier it was the higher the value, of plant height. The highest value 206.5 cm for the treatment T1D1I1, and the lowest was 121.3 cm for the treatment T2D3I3.
Generally the early planting time with all irrigation intervals and plant densities showed significant effect on the crop characteristics, where the highest values resulted from the treatment T1D2I3, while the lowest values were obtained form the treatment T2D1I1, in terms of flowers, the number of branches, the weight of flowers and the weight of seeds, while the highest value for plant height was for the treatment T1D1I1 and the lowest value was for the treatment T2D3I3. The treatment T1D2I3 showed the highest value for the water use efficiency 0.34, and the lowest value was 0.06 for the treatment T2D1I1.
The objectives of this work were to study the possibility of the hibiscus (Roselle) cultivation in the lower part of Egypt and the effect of irrigation level, plant density and sowing date on its yield and some morpho-physiological traits.