EFFECT OF IRRIGATION AND PLANT POPULATION DENSITY ON PRODUCTIVITY AND WATER USE EFFICIENCY OF SOME GENOTYPES OF SAFFLOWER (Carthamus tinctorius, L.) UNDER SOUTHERN EGYPT CONDITIONS.

Abstract

This study was conducted on the Experimental Farm of the Shandaweel Research Station at Sohage, Egypt, during 2006/07 and 2007/08 growing seasons. The investigation was aimed to study the effect of irrigation at 45, 60 and 75% of available soil water deficit (ASMD) and two plant population densities (35000 and 70000 plants/ fad.) on productivity and water use efficiency of some genotypes (Lines 1, 2, 3 and Giza1 cv) of safflower. A randomized complete block, split-split plot design with three replicates was used in each season. Irrigation treatments, genotypes and plant population densities were randomly assigned to the main, sub-plots and subsub plots, respectively. Results showed that irrigation at 45% of ASMD significantly increased plant height, number of branches /plant, number of heads /plant, 100-seed weight, weight of seeds /plant, seed yield /fad., seed oil content and oil yield /fad. by 35.0, 45.8, 50.6 13.9, 49.9, 34.0, 7.3 and 43.8%, respectively, compared to irrigation at 75% of ASMD. Increasing plant population densities from 35000 to 70000 plants /fad. significantly increased plant height, seed and oil yield fad-1 , while, decreased number of branches /plant, number of heads /plant, 100-seed weight, weight of seeds /plant. In this case, seed oil content was not affected by plant population density. In general, Line 3 surpassed others genotypes in the most studied characteristics. The interaction between irrigation regime x genotype as well as irrigation regime x plant population density had a significant effect on the 100-seed weight, seed weight /plant, seed yield /fad., seed oil content, oil yield /fad and WUE. Meanwhile, interaction between plant population density x genotype or between three factors, had a significant effect on seed yield /fad. and WUE only. Seasonal water consumptive use was 30.03, 26.05 and 23.95 cm when irrigated safflower plants at 45%, 60% and 75% of ASMD, respectively. Results indicated that irrigation at 60% of ASMD gave the highest value of WUE (31.32 kg seed yield cm-1 of water consumed). Also, plant population densities at 70000 plants /fad. gave the highest value of WUE. Moreover, Line 3 was more efficient in water use than other genotypes. So, from results of seed yield and WUE, a high or medium irrigation rates with high plant population densities and planted safflower genotype Line 3 are adequate under this study condition.