栽植密度对柑桔树光合生产、生长和结实的影响

栽植密度显著影响柑桔树冠内的光能分布和利用水平,制约树冠叶群的光合生产能力,从而进一步影响树体的生长发育状况,以及营养生长和生殖生长水平,最终表现出果实产量和品质的差异。枳砧温州蜜柑实行合理密植栽培的行距宜控制在3～4m,株距2m左右,当树冠内相对光照水平下降到40%时,必须加强整枝修剪或及时间移。     

Effect of Hydrogen Cyanamide on Vegetative Growth,Yield, and Fruit Quality of Fig cv. Zidi in a Warm Production Area

The fig tree (Ficus carica L.) is widely cultivated in the Mediterranean region under warm climates. Fig yield is governed by the previous crop load and is strongly dependent on shoot length. Special cultural practices are required to stimulate new vegetative growth that will ensure regular and high productivity. The present study focused on the use of the rest breaking agent hydrogen cyanamide (HC) as Dormex to enhance vegetative growth, which influences the yield. A field trial was held in northern Tunisia (36° 49′ N; 9° 48′ E) on mature fig trees cv. Zidi. In reference to untreated trees as control, two hydrogen cyanamide treatments at 1% and 1.5% HC were considered. Bud break rate, vegetative growth, starch content of shoots, yield, and fruit characteristics were assessed. Results indicated that 1.5% HC significantly increased shoot length, fruit number per shoot, and yield. It advanced bud break by 10 days and fruit ripening by 7 days compared to the control. However, leaf number, leaf area, and starch content seem to be unaffected by hydrogen cyanamide treatments. Regarding fruit quality, a 1.5% HC dose significantly increased dry matter content, while fruit diameter and total soluble solids remain unaffected. In conclusion, hydrogen cyanamide could be used under warm conditions to improve vegetative growth of fig trees cv. Zidi and consequently fig productivity. Application of 1.5% HC 40 days before bud break was the most effective in increasing shoot length and yield.