Effect of some growth regulators on some fruit characteristics and productivity of the Barhee date palm tree cultivar (Phoenix dactylifera L.).Abstract -Introduction. The date palm tree is one of the fruit trees most cultivated in the Arabian Gulf States. Bioregulators were used for the quality and productivity improvement of date palm tree fruits. A study was conducted to assess the relative effectiveness of GA 3 , NAA, ethephon and a mixture of growth regulators on some fruit characteristics and productivity of the Barhee date palm tree cultivar. Materials and methods. Five selected female uniform date palm trees of the cultivar Barhee were pollinated on March 5-15, 1994March 5-15, , 1995March 5-15, and 1996 placing eight fresh male strands on the female spadix center (flower cluster).Ten flower clusters were used on each tree and divided into five groups of two flower clusters. Each of these groups was subjected to one of the following treatments: control (water), 150 mg GA 3 × L -1 , 100 mg NAA × L -1 , 1 000 mg ethephon × L -1 and a mixture of these three growth regulators. Then the fruit setting, fruit flesh and dry matter percentages, the total soluble solids, the fruit ripening, and the fruit weight per bunch and per tree were measured. Results and discussion. The data showed that the application of GA 3 or ethephon on flower clusters of Barhee date palm trees had no constant effect on fruit characteristics and productivity of trees. NAA or growth regulator mixture applications on Barhee flower clusters reduced the fruit dry matter and fruit ripening percentages and increased the fruit weight per bunch and per tree. Conclusion. Treatments of Barhee date palm flower clusters, 20 d after pollination, with NAA or the specific growth regulator mixture decreased the dry matter percentage and the fruit ripening and increased the fruit flesh percentage and the date palm tree yield, therefore, these treatments could be recommended to improve the productivity of date palm trees in the region. Gulf States / Phoenix dactylifera / plant growth substances / spraying / nutrient improvement / crop yield Effet de quelques régulateurs de croissance sur certaines caractéristiques de production du cultivar Barhee de palmier dattier (Phoenix dactylifera L.).Effect of regulators on the Barhee date palm tree 325

Date palm trees are among the most plentiful fruit trees in the Arabian Gulf States. Bioregulators have been used for the improvement of quality and productivity of date plam tree fruits. Application of gibberellic acid (GA3), naphthalene acetic acid (NAA), and ethephon, separately or in a mixture, has significant effects on fruit set, fruit dry matter percentage, fruit soluble percentage, fruit ripening, and yield of date palm trees. A study was conducted to assess relative effectiveness of GA3, NAA, ethephon, and a mixture of growth regulators on some fruit characteristics, and productivity of `Barhee' date plam trees. Five uniform female `Barhee' date palm trees were pollinated on 5–15 Mar. 1994, 1995, and 1996 by placing eight fresh male strands on female spadix centers (flower cluster). Ten flower clusters were used on each tree, and every two flower clusters were subjected to one of the following treatments: control (water), 150 mg·L–1 GA3, 100 mg·L–1 NAA, 1000 mg·L–1 ethephon, and a mixture of growth regulators. The fruit set (%), dry matter (%), total soluble solids (°Brix), fruit ripening (%), and fruit weight (kg per bunch and per tree) were measured. The data showed that the application of GA3 or ethephon on flower clusters of `Barhee' date palm trees had no constant effect on fruit characteristics and productivity of trees. NAA or a mixture of growth regulators reduced fruit dry matter percentage, fruit ripening percentage, and increased fruit weight per bunch and per tree. Spraying `Barhee' date palm flower clusters with NAA or a mixture of growth regulators 20 days after pollination decreased dry matter percentage, fruit ripening, and increased fruit flesh percentage and tree yield.