THE STUDY OF SUNFLOWER CULTIVARS’ PHENOLOGICAL STAGES BASED ON BBCH STAGE

This plan has been done in farming year 2009 with the purpose of precise recognition life stages and determination of end time of supplementary BBCH stages and plant height in every stage on three sunflower cultivars Hisson 33(V1), Record (V2), and Progress (V3) in research and Educational farm of Damghan. The results indicated that height growth of Record Cultivar was quicker than two other cultivars. At the end of first stage, the height of Record cultivar was more than other cultivars on the same date, that is, increase in the growth rate of cultivar at this stage. The main differences between this cultivar and two other cultivars were started from this stage. Stem elongation starts at third stage and internodes become visible, at this time the difference was observed among cultivars. Record cultivar showed quick elongation growth at this stage and had more height at the same date of taking statistic. Finally this difference of elongation growth speed caused in variation of height average about 8 Cm among Record and Progress and Hisson 33 Cultivars. This matter was observed in the end of growth stages. So that Record cultivar with more height reached its own final growth with shorter time that was an indication of more early ripening of this cultivar in comparison with two other cultivars. According to obtained BBCH results, it is considered that the timing of fertilizing, irrigation and weed control in Record cultivar which is early ripening must perform in different time in comparison with other cultivars

Phenological Stage; Sunflower; BBCH Scale