Effect of Sowing Date and Nitrogen Fertilizer on Vegetative and Reproductive Growth of Okra (Abelmoschus esculentus (L.)Meonch.)

Abstract

Due to the poor performance of okra (Abelmoschus esculentus (L.) Moench.) in Khartoum area during winter, this study was conducted to find out the cause(s). Four sowing dates, namely the last week of, September, October and November, 2011 and the second week of January, 2012 and three levels of nitrogen, using Urea as the source; 70, 140 and 210 kg ha ̄ 1 were arranged in a completely randomized design with six replications. Okra cv. Clemson Spineless seeds were sown in 27 x 27 cm. plastic pots. The mean daily air temperature during the experimental period decreased to be minimum in January. Days to seedling emergence increased with the delay in sowing, in contrast to the number of days to flowering. Dry weight of plants also decreased gradually. The number of flowers per plant was not affected by sowing date. However, the number of fruits per plant was significantly decreased . Likewize was pollen grains diameter, reflecting that the excessive flower abscission with delay in sowing could be attributed , at least partially, to low pollen viability. Thus it seems that the low temperature during the winter season has detrimental effects on both vegetative and reproductive growth.Apparently, nitrogen application had no significant role in alleviating the effect of low temperature.