Response of sunflower to irrigation, boron spraying and plant density under new valley conditions

Abstract

Two field experiments were carried out in the Desert Research Center (D.R.C.), Agricultural Experimental station at EL-Kharga, New Valley Governorate, during two late summer growing seasons of 2004 and 2005, to study the effect of irrigation amounts (80, 100 and 120 % at ETa); B spraying rates (0, 226 and 339 ppm) and plant density (28000, 35000 and 46666 plants/fed.) on sunflower (Helianthus annuus, L. hybrid Vidoc). Results showed that adding irrigation water at 120 % ETa was the potent treatment for increasing SPAD value, LAI and dry matter/plant. The highest values of SPAD, LAI and dry matter/plant achieved with spraying B at the rate of 339 ppm. Plant density of 28000 plants/fed. gave the significantly aximal values of SLW and dry matter/plant. While, the highest value of LAI was obtained with high plant density (46666 plants/fed.). Generally, plant height, head diameter, seeds number/head, seed weight/head, 1000-se ed weight as well as oil % and oil, straw and seed yields/fed. significantly enhanced with increasing irrigation levels and showed the highest values with irrigation at 120 % ETa, which were statistically at par with those of 100 % ETa in water use efficiency.. Application of 339 ppm B as foliar spraying recorded the significantly maximal values of yield and its components and oil yield/fed. ecreasing plant density from 46666 to 28000 plant/fed. caused significant increases in yield attributes of sunflower, while plant density of 46666 plants/fed. recorded the maximum straw, seed and oil yields/fed. There were positively and highly significant correlation coefficients between seed yield and dry matter/plant, seeds number and weight/head and 1000-seed weight.