International Water & Irrigation

34 arranged at a distance of 30cms, The soil of the experimental area was classified as 73% sand, 19% silt and 8% clay. Before planting soil chemical analysis was carried out and the results used to determine macro and micronutrients levels both for the fertilization process and applying topdressing. Adrip irrigation systemwas established, with drippers spaced at 0.30 m each providing 2.4 Liters per hour, to ensure a continuous wet strip along the plant rows. Irrigations were carried out each other day, based on the crop evapotranspiration, with reference evapotranspiration (ETo) obtained from a meteorological station conveniently situated adjacent to the test area. The irrigation program was discontinued when the seeds reached the physiological maturation stage. The fertilization process was carried out manually, with the fertilizer applied to a depth of 15 cm. Fertilizers applied were 30 kilograms per hectare of P205, (simple superphosphate). N (40 kg ha’), K (40 kg ha”), S (20 kg ha”) and B (1 kg ha’) were applied as topdressing, using urea, potassium chloride, magnesium sulfate and boric acid, respectively. The evaluated plot area consisted of the four central meters of the two central plant rows. The characteristics evaluated were: • Flowering time ( days from sowing to flowering), • Plant height, • Number of live leaves (at flowering), • Stem diameter, • Capitulum diameter, • Number of lodged and broken plants, • Stem curvature (at the physiological maturation stage), • Relative chlorophyll index (at the leaf physiologically maturity stage), (The relative chlorophyll index was evaluated in the 5th or 6th leaf below the capitulum that was exposed to the sun, in a chlorophyll meter.) The physiological characteristics of the varieties were monitored. • These included • Leaf average temperature, • Leaf transpiration • Photosynthesis of selected physiologically mature leaves (during the flowering stage). Results and discussion The days from sowing to flowering (DSF), plant height, a number of live leaves (NLL), capitulum and stem diameter, lodged and broken plants and stem curvature of the varieties showed significant differences (Table 2) by the F test at 5% of probability. The V2 and V6 varieties displayed early flowering tendencies at 43 and 44 DSF, respectively, while the V3, V7, V9, Vl0, V11, V12, Vl5, Vl 7 and V18 varieties flowered much later (54 to 59 DSF) and did not differ statistically. The differences in flowering periods were largely attributed to the different characteristics between cultivars, with the climatic conditions of the semiarid region (Northeast), where temperatures are higher than the Brazilian South, Southeast and Central-West also playing their part. sunflower Table One: Varieties of sunflower plants that underwent evaluation Identification Variety Identification Variety Identification Variety V1 BRS G26 V8 AGUAR 06 V15 PARAISO 22 V2 BRS 321 V9 OLISUN V16 PARAISO 33 V3 BRS 322 V10 M734 V17 PARAISO 65 V4 BRS 323 V11 NTO 3.0 V18 HELIO 251 V5 BRS 324 V12 NTO 2.0 V19 HELIO 863 V6 EMBRAPA 122 V13 CATISSOL V20 HELIO 253 V7 AGUAR 04 V14 MULTISSOL V21 HELIO 360